Wooden Involute Gears

[JLT]

Have created a VB program to generate involute gear profiles with the intention of making a wooden geared clock one day. (Searching the forum, it appeared that the technique to date is to scan in an image of a gear from paper and clean it up in a graphics program).

Unfortunately, I have too many other woodworking projects (mostly non-Compucarve) going on at this time, but if someone else is interested, I can easily generate a complete set of gear profiles and post them on the forum. I'd obviously be interested in the end result and associated carving techniques.

Attached are a few samples. These are a matching set of 6, 12, and 60 tooth involute gears, with 1/8" diameter axle holes. When I say matching, specifically I mean that they all consist of the same diametrical pitch (2.5 teeth per diametrical inch) and same pressure angle on the tooth profile (the standard 20 degrees), both of which ensure that they mesh properly. These are intentionally created large (ie, a low diametrical pitch) in order to retain as much resolution as possible when imported into designer and scaled down. For instance, at 128 pixels / inch, the sample 60 tooth gear image is 26" x 26".

Bear in mind that I provide these with no guarantee that the compucarve will be able to carve a smooth working set, but leave it to the interested forum member to experiment with and resolve.

I do not yet have a profile generator for the escapement, but happen to have also created a VB program to extrude a handrail profile as part of an effort to make some bends, and will eventually use some of the techniques from that program to create an escapement wheel profile generator...

Jon

[JLT]

Dan,

Salutations. Better yet, let me send you the VB 6.0 executable, which should work on most Windows operating systems (I know it works on Vista and XP). This will allow you to generate whatever set of gears you require. (I sent you a PM with my email address so that you can seed me an email).

Once you fire up the gear profile generator, the main form identifies the various parameters along with comments to help guide you. Basically, once you decide on the diametrical pitch and pressure angle, you simply change the number of teeth you need and continue generating gears.

I've generated gears with a 6.4 diametrical pitch (ie, 10"+ across for a 64 tooth gear, which put me close to the edge of the 24"x12" board I was cutting from) using a pressure angle of 14.5. Also, I always scale 2x, so the image will come out very large with more detail when importing into Designer. (My 64 tooth gear resulted in a ~36MB BMP file). Keep the "Flood Fill" checked. After you press "Generate", it will open another window containing the graphic image of the gear. The gear window has a "File Save As..." menu option to save the image.

When I import the gear image into the Designer, I uncheck "Floor Edges" of course, and press "Lower" once to remove the white background. Also, very important, if I scaled the image, say 2x, I adjust the size of the image at this time, in my case by half. The resulting gears won't be perfect (due to inaccuracies in Designer and the carving machine itself), but some sanding on the teeth profiles will make them functional. Also, the center axle hole comes out wobbly if you use the image of the hole that is generated, so follow Michael Tyler's advise from this thread: http://forum.carvewright.com/showthread.php?t=9456.

When you go to set up the axles to mesh a set of gears, don't rely simply on calculating the diametrical pitch. Set up a test board, and find the distance between the two axles that provides for the smoothest action. Additionally, you might find a few teeth that require further shaping with sandpaper.

R, Jon

P.S. Don't get the impression I'm that far ahead of you! I've cut a number of gears, have individually confirmed that they mesh, and am partially complete with a prototype wooden geared clock. I am using the 6mm craft ply from Michaels craft store, which is dimensionally stable and cuts cleanly. Minor problem that I'm running into now is that the gears wobble due to inaccurate axle holes (I had already cut the gears by the time Michael T had pointed out a better method), so am having to manually drill press larger axle holes...

[puzzleguy1]

Thanks a bunch! I've made 2 wooden gear clocks with my scroll saw but man is it a labor intensive task! Hoping this will ease things up a bit for me.

[coop2739]

JLT

I am very interested in your work with wooden gears. I am also thinking of building wooden clocks. Could you PM me with some of your information on your designing of gears? I'm sorry I have come into this thread so late but just came onto your discussion and am very interested.

[ggresham1957]

Hi folks,
I'm new to CW but have been building wooden gear clocks with a scroll saw for several years. I have been looking at the CW machines for a while and I finally broke down and bought one. After a few hours of reading posts on cutouts I was able to come up with a a fairly good representation of a gear based on .png export of gears that I used on other clocks. attached image of .mpc file is my first effort. Haven't cut it out yet because I'm waiting for a 1/16" cutting bit to arrive. Here is a link to a video of the last clock I built with scroll saw. Can't wait to build one with this machine.

http://www.youtube.com/watch?v=5TGlYzBNO1A

Many thanks to all your experienced posts for making this much easier than it would have been with just the manual. The clock in the video took almost 6 months of nights and weekends to design and build. Something tells me that the CW will shorten that time considerably.
Gary

[Dan-Woodman]

Gary
Very nice clock, you can be very proud. Welcome to the forum and always post pictures of your projects. We love pictures.
later Daniel

[DocWheeler]

Gary,

Yes, that is a very interesting and good-looking clock. I am looking forward to seeing your future projects.

[CraigBrownDesigns]

Beautiful piece of art! What I thought a wooden clock would look like has been completely changed! Got me very interested.

[James RS]

I was searching around and came across this for making gears if anyone is interested.

http://woodgears.ca/gear_cutting/template.html

[FiddlemakerMills]

Thanks for the link It will be usefull.

Carl

[ChrisAlb]

Hi folks,
I'm new to CW but have been building wooden gear clocks with a scroll saw for several years. I have been looking at the CW machines for a while and I finally broke down and bought one. After a few hours of reading posts on cutouts I was able to come up with a a fairly good representation of a gear based on .png export of gears that I used on other clocks. attached image of .mpc file is my first effort. Haven't cut it out yet because I'm waiting for a 1/16" cutting bit to arrive. Here is a link to a video of the last clock I built with scroll saw. Can't wait to build one with this machine.

http://www.youtube.com/watch?v=5TGlYzBNO1A

Many thanks to all your experienced posts for making this much easier than it would have been with just the manual. The clock in the video took almost 6 months of nights and weekends to design and build. Something tells me that the CW will shorten that time considerably.
Gary

Gary,

That's a phenomenal piece of design work!! If that's your first attempt, You'll be banging gears in no time. Nice work!!

Can't wait to see pictures of it cut out.

[JLT]

Recently, member jlitz pointed me to a superb utility he wrote to convert Adobe Illustrator files to a vector path MPC file. Not satisfied with the raster rendition of gear generation, as it left quite a bit to be desired after applying the "Outline Pattern(s)" feature, I updated the gear generation utility to create an Illustrator file, which in turn is run through jlitz's conversion utility. (See sample gears attached). Was surprised (and duly impressed) at how seamless his utility is in creating vector MPC files.

Won't be able to carve until this weekend, so am anxious to see how the vector path gears turn out. (In an earlier post, Michael Tyler pointed out the use of drill function rather than using a raster image to generate a circle. I was a bit skeptical at first that the resulting hole would be more accurate, but was subsequently proved wrong by the accuracy of the CW when cutting vector paths). So, I'll be scrapping the gears I've created to date, and starting anew with the vector rendered gears.

Still need to clean up the user interface a bit with the gear profile generator before I make it available. Will be seeking a place to host it so that others that expressed an interest in it can download the update freely. Of course, this will also require use of member jlitz's utility...

Jon

[James RS]

Recently, member jlitz pointed me to a superb utility he wrote to convert Adobe Illustrator files to a vector path MPC file. Not satisfied with the raster rendition of gear generation, as it left quite a bit to be desired after applying the "Outline Pattern(s)" feature, I updated the gear generation utility to create an Illustrator file, which in turn is run through jlitz's conversion utility. (See sample gears attached). Was surprised (and duly impressed) at how seamless his utility is in creating vector MPC files.

Won't be able to carve until this weekend, so am anxious to see how the vector path gears turn out. (In an earlier post, Michael Tyler pointed out the use of drill function rather than using a raster image to generate a circle. I was a bit skeptical at first that the resulting hole would be more accurate, but was subsequently proved wrong by the accuracy of the CW when cutting vector paths). So, I'll be scrapping the gears I've created to date, and starting anew with the vector rendered gears.

Still need to clean up the user interface a bit with the gear profile generator before I make it available. Will be seeking a place to host it so that others that expressed an interest in it can download the update freely. Of course, this will also require use of member jlitz's utility...

Jon

Jon,
Do you happen to have a copy of this program you used to get to this point? What I was getting using Corel was a little ridge at the edge, yours doesn't seem to be there so it might just work.

Thanks,
Jim S

[JLT]

Jim,

There are actually two programs at play:

===============

1) I've written a VB program to generate gear profiles, and it produces both raster (ie, BMP file) and vector (ie, a stripped down Adobe Illustrator file) output.

I'm still cleaning up the user interface, and will be seeking a place to post the application, freely available for download.

2) Member jlitz (Jeff) has written a very useful utility dubbed "ai2mpc", which essentially takes the Adobe Illustrator file, and converts it to a MPC file, v1.120. Per Jeff, "there are a lot of restrictions but it works okay for basic shapes. Curves require using bezier paths or tons of line segments". Based upon his experience, complex paths and paths with many segments push Designer to its limits.

See the following links for more information:

http://www.allcw.com/Forum/viewtopic.php?t=301

http://forum.carvewright.com/showthread.php?t=6487

===============

Hope this helps...

Jon

[ggresham1957]

Jon,
I am having trouble getting the ai2mpc to close the path with the -closepath option. when I open the resulting mpc file I get a hugh list of paths instead of just one like your example. Any suggestions? I think I am using option correctly. I have attached a small section of a cycloidal gear in ai format that I am trying to convert. The original file was .dwg format
Thanks,
Gary

[James RS]

I can't get the ai2mpc to open I click on it it shows real quick and disappears

[JLT]

Jim,

It's an old style (but sturdy, and reliable) DOS utility program. You need to open up a command prompt, and manually run it from there, passing the appropriate parameters.

Jon

[ggresham1957]

Jon,
Here is the output from ai2mpc on the file I posted earlier.
Gary

[JLT]

Jon,
I am having trouble getting the ai2mpc to close the path with the -closepath option. when I open the resulting mpc file I get a hugh list of paths instead of just one like your example. Any suggestions? I think I am using option correctly. I have attached a small section of a cycloidal gear in ai format that I am trying to convert. The original file was .dwg format
Thanks,
Gary

Gary,

Take a look at the attached in wordpad. This is the AI file I created for the 8 tooth pinion. You'll notice that I have a long list of contiguous line segments, whereas if you go to the bottom of your file, it's broken up into separate segments. (Every line ending in "m" is the move command). Believe that's why you're ending up with 36 objects, rather than one contiguous object. Not quite sure how Jeff's algorithm works in ai2mpc, but suspect that you have to keep the segments contiguous...

Jon

[JLT]

Gary,

See further two attached files...

I took your AI file into wordpad, and manually 1) simplified the vector segments at the bottom of the file, 2) changed the m's to L's, and the final "S" to a "s".

These adjustments close the path, and result in a single path. But...

The paths are crisscrossing, so there will have to be a bit more logic involved in cleaning up the file before you can run it through Jeff's ai2mpc utility to get the results you want...

Jon

[bjbethke]

I always wanted to build a wooden clock. Sure looks like fun. Lots of parts, it will take me till summer to get all the MPC gear files made. This pattern uses the same arraignment of the gears for all the clock frames. I only have three of then on this CD. This gear is one of the larger gears. may need a little more work.

[ggresham1957]

Jon,
Thanks for the help. I went back into the .ai file and removed the additional S entries that occurred after all the m's that you removed and that cleaned it right up. Sometimes I let the obvious go right by. I'm kind of ashamed that I've been in the IT field for over thirty years and didn't even think to look at the ai files to see if they were plain text. I just assumed they were binary files. Oh well.....live and learn. By the way have you had the opportunity to cut out one of the gears that you created with ai2mpc? I'm out of town on business and won't be able to try the one I did tonight until I get home Friday night. I was really disappointed with the results of the one I imported as a raster file, outlined and then created a cutpath. The gear teeth were not very consistent and had some rough edges. I have high hopes for the pure vector path.

Thanks Again, I really appreciate the response.
Gary

[JLT]

Gary,

No problem with the ai file assistance. Glad to hear you were able to make the necessary adjustments. Have been dabbling with the ai files for the last week or so, and knew right where to look, and generally how to adjust them.

And as for me, I've been in IT for about 25 years, although I don't plan on making a career out of it. ; - )

I also happen to be out of town, so haven't had the opportunity to try the vector version yet. Will be doing so this weekend. I fully expect the results to be better than the raster version, but am not sure how much better. I have a "fudge factor" on my gear generation to increase the width of the teeth in the event that I find in the end that I'll have to sand down to the profile. Will post this weekend's results.

Obviously interested in your results, as maybe the cycloidal profile comes out better than the involute...

Jon

P.S. Also interested in other techniques you've obviously hurdled (such as reducing wobble on gears, how you generally float your axles in the frame, etc), but these questions can wait for another day...

[ggresham1957]

Jon,
I know what you mean about not planning to make a career out of it. I'm working on my second retirement and I still haven't decided what I want to do for a living. When I get back home, I'll be glad to share whatever I can about arbors, bearings, pivots and the like. I learned most of what I know about building clocks from hard knocks, plenty of failures and much more wood in the scrap bin than in the clocks, so I am happy to relieve new folks of as much of that pain as I can. the final gear with the continuous cut path is attached. I hope this does the trick. I bought my cw last week specifically for cutting gears. Fingers get tired cutting them on a scroll saw. Thanks again,
Gary

[Digitalwoodshop]

Gary,

I am a old Navy Analog Computer Tech and the gears fascinate me....

I had a thought that rather than making the gear from one solid piece why not make it in .125 thick wafers and gluing them together or making a laminated gear. You could make a cut path with the areas that are cut out in the center and design each layer with the cut outs that you could remove after the outer layer is glued using the center as a alignment pin.

I also did this as a 1/16 inch bit cut path. I think the resolution would be better. You could apply the .125 skins to a carrier board with double sticky tape or use a product I have yet to try called "Fat Mats" that are sticky, reusable and cleanable to restore the stickiness. Engraving Shops use them.

Just my 2 Cents as I finish at 2 AM and needed to wait to reset the timer on my Epoxy Oven.

AL

[BBrooks]

Fellas,

I downloaded sketchup this past weekend and in a search for info came across an involute gear generator plugin for it. While I've not had time to carve any yet, it looks promising.
The MPC is a quick file i threw together to check the carveability and the png is of a 9tooth gear, 14.5 pressure angle and .833 pitch radius. The pngs it makes are pretty smooth and look clean in designer. The teeth look a little deep so there may be some tweaking to do when I get time away from work and back in the workshop where I belong :)

cheers

[pkunk]

For a good place to post large files, I use 4shared.com. It's free up to 5 gb & 100 mb per file.

[James RS]

Fellas,

I downloaded sketchup this past weekend and in a search for info came across an involute gear generator plugin for it. While I've not had time to carve any yet, it looks promising.
The MPC is a quick file i threw together to check the carveability and the png is of a 9tooth gear, 14.5 pressure angle and .833 pitch radius. The pngs it makes are pretty smooth and look clean in designer. The teeth look a little deep so there may be some tweaking to do when I get time away from work and back in the workshop where I belong :)

cheers

Where did you find the plugin for sketchup also how did you export the file if you don't mind me asking.

James RS

[DocWheeler]

I just wanted to say that I appreciate you guys contributing your time and sharing as you have done here. I certainly hope that you are using a program to generate the path for the gear cut-outs as I would go both blind and crazy trying to produce one of those.

Curious about the bearings; is there a rule about what can be used (written or unwritten)?

[brdad]

I was chatting online about a totally different subject when I was asked about a yarn swift. Oddly enough, I ended up at this site - some cool wooden gear clocks!

http://lisaboyer.com/Claytonsite/Claytonsite1.htm

[James RS]

JLT I finally got the ai2mpc to work, problem now is all the path files when I open the mpc in Carverwright. It's not like yours with one path, how did you do that. Here's the file

Thanks,
James RS

I added the 8toothgear AI file zipped up

[JLT]

Jim,

Edit your post, and include the associated ".ai" file also.

Jon

[JLT]

Attached are the results of the vector generated gear profiles. Much more consistent result than the raster generated gears, as one might expect. They arn't perfect, but presentable. Still a bit of tearout on the top side of the gears, though.

Both boards (24" x 12" x 6mm craft board, 5 ply, from Michaels craft store) took about an hour each to cut. It would have been faster, except I actually cut the pinions twice, as I realized that drilling a smaller arbor hole would lead to a tighter fit on the arbors (duh!). (I bought 1/2" poplar dowel rod from Lowes, and cutting an arbor hole of 0.49" offered a tight fit, thereby virtually eliminating gear wobble).

This is still a prototype, to work out the kinks and the techniques, and at this point the wheels and pinions are mounted on a temporary frame, and includes the power train (the two big gears leading up to the escapement) and the hour hand chain (the gears on the lower front side). Still requires the escapement pallets (grasshopper style), the pendulum, and the weight.

Surprisingly, the total time to generate the gears, add some design embellishments to them, and clean them up was under 4 hrs. I spent a subsequent 6 hrs (!) laying the gears out into the frame, and am still not satisified, as the upper large wheel's pinion meshes too tight with the large wheel below it, causing some loss of power transference.

A couple of findings:

1) The vector drawings push Designer (v1.132) to the limit, which did not surprise me as I was forewarned in an earlier side bar by Jeff (aka, member "jlitz"), author of the ai2mpc utility. The more complex board had on order of 2K+ vectors, causing Designer to "think" for some time occasionally while moving the large vector objects and rendering screens. (I'm using an HP Pavilion dv7, dual core AMD, with 4GB of RAM, although the task manager was reporting that Designer was consuming ~135MB RAM). Although Designer was sluggish, it was functional, and never crashed. Just requires patience, liberal use of the zoom command to work around all the adjustable number handles on the objects, and the ability to resist temptation to continue clicking the mouse while Designer is pondering.

2) I made frequent use of the drill function followed by the "Center Both" function, but ran into a quirk when copying the result to another open project. The copied version of the gear and drill hole could not be moved, until I realized that I had to "uncenter" the drill hole. Ie, select "Center Both" again on the drill hole, which toggles the center function off, and then I was able to move the combination of the gear and drill hole. This had me confused for a while, as the copied object was not centered on the project that I pasted it to, although the "Center Both" function was still inforce.

So, I now 1) apply the drill function, 2) Center Both, and 3) Center Both again, to toggle off the centering function, before copying the gear and drill hole to the destination project.

3) The sled board is simply 3/4" plywood, and I simply screwed down the 3.5" buffer boards and the project piece. Ran into issues when the machine went to measure the length, as it could not find the front edge. I used blue painter's tape to no avail, but found that black electrical tape did the trick. (I would remove the tape during the bit load operation, as the vinyl black electrical tape would come undone in a few minutes due to its elasticity). I'm now going to paint my sled board black to permanently solve the problem.


Not sure if I'll have any more time this weekend to dabble with this, but might find some time while watching the playoff games. Need to get some more advice from Gary on the finer points of arbors, too...

Jon

[James RS]

Nice looking, I think I might have got onto something. I took the dxf file into Corel combined it changed it to a shape then exported it as a bmp. I then opened it up in Designer, I attached (this time) the dxf file and the mpc file.

Thanks,
Jim

[JLT]

JLT I finally got the ai2mpc to work, problem now is all the path files when I open the mpc in Carverwright. It's not like yours with one path, how did you do that. Here's the file

Thanks,
James RS

I added the 8toothgear AI file zipped up


Jim,

Open up your ".ai" file in Wordpad, and take a look towards the bottom half. Any line containing an "S" or "s" is essentially terminating the segment, and any line ending in "m" moves the active vector point to a new position. Compare that with the ".ai" file I had posted earlier for Gary's consideration.

If you're planning to head down the dxf and Corel path (no pun intended), you might have to doctor the ".ai" file by removing the "S" lines (while retaining the very last "s"), and removing the "m" move commands.

Jon

[JLT]

Nice looking, I think I might have got onto something. I took the dxf file into Corel combined it changed it to a shape then exported it as a bmp. I then opened it up in Designer, I attached (this time) the dxf file and the mpc file.

Thanks,
Jim

Jim,

Looks good, although you're back to importing a raster rather than vector image.

I need another day or so to clean up the user interface on my gear generation utility that now generates vector gears. I can forward you the update when it's complete.

Jon

[James RS]

Thanks Jon, i went into notepad and looked at the ai file there were no S" or s" just c" and C"
I attached the notepad file

[jlitz]

Thanks Jon, i went into notepad and looked at the ai file there were no S" or s" just c" and C"
I attached the notepad file

There are tons of stroke ("S" and "s") commands in your file. These commands end the path.

The overall problem is either the source dxf contains a ton of unconnected paths or whatever was used to convert the dxf to ai did a horrible job. Cleaning up that ai would take a lot of manual work. There tons of silly things like this:
78.4471 97.8729 m
77.5454 92.7683 L
78.4471 97.8729 L
78.4471 97.8729 L
s
Basically a line that says start at A, go to B, go back to A, go to A again for the fun of it. Oh, and make it a closed path.

[BBrooks]

Where did you find the plugin for sketchup also how did you export the file if you don't mind me asking.

James RS

I got the plugin here:

http://www.ohyeahcad.com/download/

In the Sketchup file menu there is an option to export and png is an option.

cheers

[ggresham1957]

Jon,
From the pictures, your results look pretty good. I have cut several gears out of oak and baltic birch ply with the pure vector paths. Even though the vector paths of each tooth are exactly the same I am getting some teeth that have some slightly irregular edges. The biggest issue though is tear out on the top edge of the teeth. I don't know if I will be able to get them to look as good as they do with a scroll saw. I guess some of this wooden gear clock making is more art that technology. I'm leaning toward using the CW for the carving aspect of wood working and leaving the gears to the scroll saw. For some reason, I seem to be hitting the point of diminishing returns on getting accurate gears from the CW. Especially since I'm really moving away from what draws me to clock making which is working with the wood. And also because I work in the computer field its sometimes like bringing work home.

At any rate, about your questions on the arbors, pivots and bushings. Like I said in an earlier post, I have put much more wood in the scrap bin than in the clocks. You learn a lot from trial and error. As to pivots and bushings (clock speak for bearings), I have used wood on wood, wood on teflon, metal on teflon, wood on metal, metal on metal, metal on lignum Vitae (a self lubricating wood) and probably others that I don't remember. As for the arbors, I have used both wood and metal. I guess the bottom line is just how much of a purest you end up being after you have built a few clocks. As for me, I have migrated away from the purest philosophy to a much more pragmatic solution. My clocks are still for the most part all wood, but for accuracy, ease of maintenance and long running time, I have settled on the following configuration. For the Great Wheel arbor (Drive gear), I typically use a 3/8 stainless steel arbor. On all subsequent wheels and the escapement arbors, I use 1/4 inch brass. for the bushings I use RC car wheel bearings which I get from VXB bearings on the internet. The big brown truck will bring you almost anything. I use sealed roller bearings with an inside diameter slightly smaller than the arbor diameter (3/16 inch for a 1/4 inch arbor). You get very slight increase in friction from the sealed bearings over other types of pivots and bushings but the worry free operation is worth it. I then place the arbor in my drill press chuck and file a 1/16 inch hub on each end for the bearing to ride on. The clocks that I have used this method on have been completely trouble free and have been running continuously for years. The only application where the roller bearings will cause problems is on any arbor that moves in a back and forth motion such as the escape anchor arbor. This will eventually cause irregular ware on most roller bearings and significantly increase friction. On those applications I usually use brass in a teflon bushing. Thats my experience in a nut shell. If you are really a mood for late night reading, the link below is a forum I belong to that has the war and peace version of every aspect of wooden gear clock building.

http://www.bealltool.com/clockforum/index.php

Have fun.
Gary

[JLT]

Gary,

Thanks for saving me from contributing to my scrap bin, by sharing your lessons learned concerning arbors, pivots, and bushings! I'm guessing, too, that the "purity" of the art lay in the materials used, and not necessarily the tools used, as it appears that typically a shop full of tools are required! After mulling over your suggestions, rather than the wood dowels and #6 nails that I'm currently using, I'm leaning towards the path of using brass rod (3/16") and nylon spacers (all from Lowes).

I've been to the Beall Tool website before (as a "lurker"). Coincidently, I'm fashioning the grasshopper escapement from resources found on the Beall Tool website. (Specifically, Guy D Aydlett's excellent 1971 paper entitled "The Anatomy of The Grasshopper"). I revisited the site upon your recommendation, and stumbled into a relevant discussion concerning CNC and gear tooth tearout. Seems that 5 - 7 layers of epoxyed veneer is the recommendation rather than plywood, but that's less than a 3/16" thick gear, which implies a delicate mechanism!

I'm generating gears with a 6.4 diametrical pitch (ie, the 64 tooth wheel is 10"+ across, and the 8 tooth pinion is 1.25"+ across) specifically for the reason that I'm using a 1/8" cutting bit. Like you say, the tooth profile doesn't come out perfect (eg, my 8 tooth involute profile is not quite involute!), but I guess I'm willing to sacrifice some accuracy, as long as they still function with little loss of power, to be able to focus on the design aspects of the clock itself. Ie, refocusing the time and energy associated with the tedium of manually cutting teeth, and redirecting it to the more creative aspects of design and asthetics, which the CarveWright can bring to the art...

Jon


(On another note, does anyone know the policy for posting ZIP files with executables (virus checked via McAfee of course)? The vector gear generating program I developed compresses to only 40KB, and have no problem making it freely available for others to experiment with. It, of course, requires the "ai2mpc" utility authored by member "jlitz").

[ggresham1957]

Jon,
I am assuming that you are intending on making a bushing out of the nylon spacer for the brass to ride in. I have used the brass and nylon combination before. It will work quite well with very little friction if you polish the brass where it rides in the bushing. One word of caution, though, nylon like teflon can turn almost liquid and "flow" under high pressure, low rpm situations. For that reason I wouldn't use it on the drive gear arbor unless you are making a short run time clock that doesn't require much weight. You will enjoy working with the grasshopper escapement. I too have a well worn copy of Guy's Anatomy of the Grasshopper paper. I used it to make two escapements. The nice thing about learning how to draw them yourself is that you can change the angles to increase or decrease the pendulum arc. The grasshopper is probably the most forgiving escapement I have used to date. No matter how many clocks I make though, there is always someone doing it just a little bit better. Take a look at the link below. Its a humbling experience. Happy clockin!
Gary

http://flashpages.prodigy.net/rpirtle/_ufiles/detail_watch.html

[JLT]

Gary,

Thanks for the heads up. You're a wealth of information! I would have never suspected the liquification of the nylon under heavy weight...

And am glad to hear that you find the grasshopper escapement forgiving! It's a little daunting at first site!

I wrote another program (can you say code junkie?!) based on Guy Aydlett's paper to generate a vector version of the grasshopper escape wheel, in addition to a wire frame of the layout of the three pallets. I use the wire frame of the critical shape and pivots (ie, the entry and exit pallets, along with the connecting pallet arm) to guide my design. Unfortunately, Designer doesn't have a center of gravity (CG) function, pinpointing the CG of an object, which would be very useful in determining the balancing point of the pallets, so I'm guessing at the CG, and including extra material in the pallets that I can waste away to find just the right balancing point. I've cut the pallets, and my goal, albeit ambitious, is to have it "hopping" this weekend.

And yes, "humbling" is an understatement concerning the link provided! That's an impressive amalgamation of mechanics and art!

Jon

[Also, for those interested, as I saw no objections to my earlier post, attached is the VB program I wrote to generate involute gear profiles. Please take the time to peruse the included "readme.txt" file.]

[James RS]

Thank you Jon,

Jim S

[James RS]

Jon,
Thanks for the program, I played around with it. It does look promising, a real novice at this gear making this will help.

Thanks,
Jim

[James RS]

Attached are the results of the vector generated gear profiles. Much more consistent result than the raster generated gears, as one might expect. They arn't perfect, but presentable. Still a bit of tearout on the top side of the gears, though.

Both boards (24" x 12" x 6mm craft board, 5 ply, from Michaels craft store) took about an hour each to cut. It would have been faster, except I actually cut the pinions twice, as I realized that drilling a smaller arbor hole would lead to a tighter fit on the arbors (duh!). (I bought 1/2" poplar dowel rod from Lowes, and cutting an arbor hole of 0.49" offered a tight fit, thereby virtually eliminating gear wobble).

This is still a prototype, to work out the kinks and the techniques, and at this point the wheels and pinions are mounted on a temporary frame, and includes the power train (the two big gears leading up to the escapement) and the hour hand chain (the gears on the lower front side). Still requires the escapement pallets (grasshopper style), the pendulum, and the weight.

Surprisingly, the total time to generate the gears, add some design embellishments to them, and clean them up was under 4 hrs. I spent a subsequent 6 hrs (!) laying the gears out into the frame, and am still not satisified, as the upper large wheel's pinion meshes too tight with the large wheel below it, causing some loss of power transference.

A couple of findings:

1) The vector drawings push Designer (v1.132) to the limit, which did not surprise me as I was forewarned in an earlier side bar by Jeff (aka, member "jlitz"), author of the ai2mpc utility. The more complex board had on order of 2K+ vectors, causing Designer to "think" for some time occasionally while moving the large vector objects and rendering screens. (I'm using an HP Pavilion dv7, dual core AMD, with 4GB of RAM, although the task manager was reporting that Designer was consuming ~135MB RAM). Although Designer was sluggish, it was functional, and never crashed. Just requires patience, liberal use of the zoom command to work around all the adjustable number handles on the objects, and the ability to resist temptation to continue clicking the mouse while Designer is pondering.

2) I made frequent use of the drill function followed by the "Center Both" function, but ran into a quirk when copying the result to another open project. The copied version of the gear and drill hole could not be moved, until I realized that I had to "uncenter" the drill hole. Ie, select "Center Both" again on the drill hole, which toggles the center function off, and then I was able to move the combination of the gear and drill hole. This had me confused for a while, as the copied object was not centered on the project that I pasted it to, although the "Center Both" function was still inforce.

So, I now 1) apply the drill function, 2) Center Both, and 3) Center Both again, to toggle off the centering function, before copying the gear and drill hole to the destination project.

3) The sled board is simply 3/4" plywood, and I simply screwed down the 3.5" buffer boards and the project piece. Ran into issues when the machine went to measure the length, as it could not find the front edge. I used blue painter's tape to no avail, but found that black electrical tape did the trick. (I would remove the tape during the bit load operation, as the vinyl black electrical tape would come undone in a few minutes due to its elasticity). I'm now going to paint my sled board black to permanently solve the problem.


Not sure if I'll have any more time this weekend to dabble with this, but might find some time while watching the playoff games. Need to get some more advice from Gary on the finer points of arbors, too...

Jon

Jon,
How did you do the gear in the center picture upper left with the angled teeth?

Thanks,
Jim

[JLT]

Jim,

The gear with the angled teeth is actually the escape wheel based on what's known as a "Grasshopper Escapement". Escape mechanisms also require "pallets" to assist in regulating the escape wheel, in addition to giving the pendulum a slight push to keep it alive. (Do a bit of "googling around" and you'll find plenty of resources. Plus, the link provided by Gary earlier is a great resource).

I'm still in the midst of dabbling with it. Once I confirm that it's functional, I can also provide that utility. But, it's not as automatic as the generation of the gears. More specifically, the utility will automatically generate the escape wheel profile, but the pallets have to be hand designed from a wire frame that provides the critical points of the three pallets. (See attached. Once you study up on the grasshopper, the picture will make more sense to you)...

Jon

[JLT]

Finished the prototype wooden geared clock. Still some minor issues (such as fine tuning the grasshopper escapement) and as you can tell from the pictures, the weight is improvised!

The bulk of the cuts and drilling was performed by the CW: the wheels and pinions, escape wheel, hands, the entry and exit pallets, the main pallet, and the front and back frame (drilling the arbor holes). Had to manually trim the main and exit pallets, though, from their original size for better balance. Used table saw and chop saw to cut the frame to size.

Total time for all the cuts: ~3 hrs. Total time to piece it together: ~20+ hrs.

[JLT]

Jon,
How did you do the gear in the center picture upper left with the angled teeth?

Thanks,
Jim


Jim,

Attached is the utility to generate the grasshopper escapement. (This is what I used for my prototype clock). Take a look at the readme.txt file, and I highly recommend that you peruse the Beall Tool web site (at http://www.bealltool.com/clockforum/), as they have some excellent resources concerning the grasshopper.

Jon

[leroy]

Great to hear someone else has looked at cutting wooden clock gears. I have built 4 clocks but had to cut the gears with a saw. I would love to look at your program and learn more.

chiefsplace@msn.com
Leroy Barker

[leroy]

Great to hear someone else has looked at cutting wooden clock gears. I have built 4 clocks but had to cut the gears with a saw. I would love to look at your program and learn more. I have the comp. and it's running fine.

chiefsplace@msn.com
Leroy Barker

[JLT]

Great to hear someone else has looked at cutting wooden clock gears. I have built 4 clocks but had to cut the gears with a saw. I would love to look at your program and learn more. I have the comp. and it's running fine.

chiefsplace@msn.com
Leroy Barker

Leroy,

Take a look at the attachments to posts #43 and #49 in this thread.

I haven't cut any gears with a diametrical pitch greater than 6.4 teeth/in, and have only used the 1/8" cutting bit to date. As you can imagine, there is a bit of tear out on the teeth, and the tooth profiles arn't perfect. That being said, they are functional.

I'm actually falling back from my prototype now, and am putting together a design to create a finished, displayable piece. Also, rather than using the craft ply from Michael's Craft store, will be using veneer (or thin stock), epoxy, and a press to fabricate the wheels and pinions, per the wisdom of more experienced wooden clock builders. (This will hopefully reduce tear out). And likely making use of the 1/16" cutting bit. My goal is to cut as much of the clock as possible using the CW.

Jon

[leroy]

:roll:Thanks for the Tips, Keep me posted on how it's going. I am using baltic birch for all parts on my clock and it works pretty well. I get it from (www.woodnshop.com) they ship fast and you can get it in all sizes. Here is a photo of my last clock. It even keeps good time!!! I am thinking of putting a finish on the wood before cutting it in the CR. I know you can't have a finish on the mating gear teeth but I think finishing it before cutting the teeth might help with any tearout, what do you think.

[JLT]

Leroy,

Nice clock!

Thanks for the 411 on your source of baltic birch. Looks similar to the 5 ply, 6mm craft wood I acquired from Michael's.

Attached is a closeup of some of the tearout I'm talking about, with the larger tearout being the worst that I experienced. Notice, of course, that it has to do with the direction of the grain. (No surprise there). I actually counted the total teeth that I had cut, and with 500+ teeth (counting front and back individually), there was about 10% tearout. This was a critical count, as I included even the smallest amount of tearout. Surprisingly, the underside experienced about half as much tearout as the top, but then again, it had some more protection against the sled. (I say "surprisingly", because looking top down, the CW was "racing the cut", whereas looking from the sled board up, it was routing in the direction you normally would).

Let me know how the baltic birch turns out. And finishing might help, particularly if you poly. Let me know how that turns out too if you proceed down that path. If I continue to run into tearout issues with epoxied veneer, I'm going to attempt to "clamp" (using screws) a thin (ie, 1/8" or less) piece of wood to the top of the gear blank...

Jon

[karossii]

Wow.

Those clocks are just amazing.

I would love to get started into something like this; just no time to pick up yet another hobby at the moment. But then again...

For someone who has never made a clock before, and as of yet has no idea how he would get started making one, how much time would need to be invested from starting to read up on the subject all the way through making his first crappy clock?

[leroy]

I am going to try the 1/16" bit if I can ever get the teeth in the system good enough.

[leroy]

Not that much, You can get plans on the net for very little. I would start with that and expand from there. If took about 50 hours on the last clock but a lot of time putting the parts into CW. If I can figure out how to cut the gear teeth on the CW that will help a lot. Would like some help with that!

[leroy]

Not that much, You can get plans on the net for very little. I would start with that and expand from there. If took about 50 hours on the last clock but a lot of time putting the parts into CW. If I can figure out how to cut the gear teeth on the CW that will help a lot. Would like some help with that

[leroy]

Thanks

If I might ask, How are putting your gears into CW. Im not having much luck with the teeth.

[JLT]

Take a look at post #33, and you'll see the sled setup I used. (Also, check out "ISSUE 7 April 2008 – Carving Jigs – Carrier Boards, Sleds and Rails" under Tips & Tricks). Specifically what bad luck are you having?

[leroy]

I would like to try your gear program. I need the following
8 tooth
10 tooth
30 tooth
32 tooth
60 tooth

All are at .25 TPI at 20

Can you help?

[JLT]

Download the attached gear profile generator program in post #43 of this thread. (It works on the "Wintel" platform).

Also, what do you mean by ".25 TPI at 20"? The program that you'll be downloading generates the gear profiles based on Teeth per Diametrical Pitch. For example, a value of 10 T/DP will generate a 60 tooth gear that is 6" across at the Pitch Diameter (essentially the point where the teeth should mesh)...

[JLT]

To eliminate tooth tear out, I experimented with a combination of sled set up, veneers, and glues.

======

Substrate: Despite my earlier comment about moving away from the craft board, I opted to make use of the three (3) millimeter craft board from Michael's Craft store (believe this is similar to Baltic Birch) as a veneer substrate, rather than glue up 5 - 7 layers of veneer.

Veneers: Walnut, Honduran Mahogany, Maple, Elm Burl, ?Madrone Burl, and Cherry.

Adhesive #1, Epoxy: Used two part epoxy as part of one experiment, having a 60 - 90 minute open time. Laid down a thick layer of epoxy, and placed in a vacuum veneer press for 3 hrs. Upon removing from the press, the epoxy was not totally set, particularly for the Elm and ?Madrone burls, which almost immediately began curling and pealing from the substrate. The other four (4) veneers held, although there was much bleed through with the Maple. I set it aside for 24 hrs to cure. Then used an orbital sander with 100 grit to smooth and clean the surface, although the epoxy bleed through could not be totally removed.

Adhesive #2, Titebond III: Laid down a generous layer (without puddling of course) of Titebond III, with the intent of forcing the glue through the veneer to increase the bond. Left in the press for 90 minutes, and then pulled to rinse the excess glue. (I use freezer paper between the veneer and the caul, which slows the curing process for the glue that bleeds through. After pulling from the press, I remove the freezer paper, then mist and wipe with an absorbent cotton rag a few rounds to remove the bleed through). Unfortunately, I laid on the glue too thick, and the veneers showed signs of minor glue puddles underneath, particularly on the veneers with less bleed through (ie, Mahogany). After wiping the excess glue, I placed it back in the press for another hour. Then, after pulling it from the press, I set it aside for 24 hrs to cure. I then used the old trick of an iron and spray bottle to smooth out any minor puddled spots where I could. Then used an orbital sander with 100 grit to smooth and clean the surface, with no bleed through showing whatsoever.


Sled setup: Base was 3/4" plywood, then used a layer of luan, and on the top of course was the double sided veneered 3mm craft board. I used numerous 1" trim screws to hold down the 3mm craft board to the luan and plywood. The purpose behind the luan is to provide a disposable flat surface for the bottom side of the 3mm craft board. The luan is a twice use board, once for each of its sides.


Gear Profiles: Purposely used tight teeth profiles of 10 teeth per diametrical inch, but unfortunately, did not have access to a 1/16" cutting bit (LHR is currently out of stock). So, I used the 1/8" cutting bit. From each sample, I cut a 48, 30, and 8 tooth set of gears.

======

Preliminary Results: I cut 24 gears, for a total of 688 teeth, or counting both sides, 1376 teeth. Both the Epoxy and Titebond III prevented tear out completely, as not one tooth revealed the nearly 10% tear out count experienced using the plain craft board. (I was actually surprised at the result, particularly with the burls as they are always seem fragile due to their squirrelly grain pattern). Before cutting the gears from the tabs, I used an orbital sander with 100 grit to smooth the fuzzies at the cut line. I then cut the elm burl gear from the tabs, and spent some time lightly sanding (with 220 grit) the tooth profiles.

I have yet to sand down the tooth profiles of an epoxied gear, as given the success of the Titebond III experiment, I'm now leaning towards buying water based glue that's specifically designed for veneering. Epoxy, although likely providing a stronger bond, is a mess to deal with and clean, and bleed through is problematic...

As an aside, for those without a veneer press, the method of using a hot iron and thermoplastic glues might do the trick...

[leroy]

Thanks for the program!
I had used a program that used teeth per inch rather than TDI. I do like yours better.
I see you can save the files as Vector, but I don't understand just how to do it. Can you educate a dummy?

[cnsranch]

Can you educate a dummy?

If you're a "dummy", I'm in real trouble.

I've been watching this thread since the beginning, and have absolutely no idea what you geniuses are talking about :p

[JLT]

Thanks for the program!
I had used a program that used teeth per inch rather than TDI. I do like yours better.
I see you can save the files as Vector, but I don't understand just how to do it. Can you educate a dummy?

Follow this link http://allcw.com/Forum/viewtopic.php?p=896#896, and at the bottom you can download "ai2mpc_v0.30.zip".

This is a great utility that fellow member "jlitz" put together that takes the AI files and generates MPC files. You need to co-locate the ai2mpc.exe with the gear generator program. Then, when you do a "Save As Vector...", it will use jlitz's utility to generate your MPC file.

[JLT]

If you're a "dummy", I'm in real trouble.

I've been watching this thread since the beginning, and have absolutely no idea what you geniuses are talking about :p

I think you give too much credit, at least in my case (I can't speak for the others)! If I was a genuis, I'd have a fully functioning clock built by now! Given the current state of affairs, "mule-headed and persistent" is a better category to throw me in. ;-)

[Eagle Hollow]

If you're a "dummy", I'm in real trouble.

I've been watching this thread since the beginning, and have absolutely no idea what you geniuses are talking about :p

You too.Huh? Could it be our name?

[leroy]

Now your talken, That works great. Now it I can master the escape gear I'll be good to go!

Thanks so much

[Xblack]

The ai2mpc files that are made up of a million unconnected paths need to be "joined" in Illustrator before being saved as an .ai file.

Open DXF in Illustrator, pick ONLY the pieces you want contiguous then hit (mac) apple (or command) "J" -Viola! Nice clean simple contiguous arcs and lines. If you get random lines joining different parts of your drawing, it's because you must pick ONLY those pieces you want contiguous.

When using more recent versions of Illustrator than supported by ai2mpc: go ahead and save as .ai -you will be given the option in the next screen to save as an older version. I found V3 to be the cleanest.

When you "cut path" an ai2mpc file in Designer, Flip Cut is reversed from when used on a Trace (for me at least).