To Carve the Dust Cap

[bergerud]

I am starting this thread as a venue for solving the problem of carving the Dust Cap system on the Carvewright machine. This is an effort which I believe will succeed with help from forum members. I hope that members will "beta" carve some of the prototypes and test them and offer feedback. I also welcome the contribution of all the good ideas I know you guys will have. Ideas on how to find or make parts, how to simplify procedures, and so on.

I should say up front what I plan (hope) to do with the project in the end. When all is said and done, I will put the project on the Carvewright website for as cheap as they will let me sell it. I think this will maximize the benefit for both the other users and for LHR. I will assume that, if you contribute to this project, you are in agreement with this plan.

To start, here is my first attempt at the Dust Cap in Designer. Have a look. It is already old news as the ideas are flowing. (See the Dust Cap thread.)

[eelamb]

While waiting for a customer to call me, I decided to create the model for the dust cap with the information I have. Maybe I am getting close now.

[bergerud]

I split my carving as you suggested. I think this is good. After I clean these up a little, I think I'll try a carve.

The model looks good. I am curious though. Since the cap can be modeled easily in Designer, what advantage do you think modeling outside Designer has?

[eelamb]

Now for the slicing of the model. carving is 2 sided, with inside being the deepest carve of .375" and set to the top of the board. Outside is carved to .125 and on the back of the board.
Do not carve this without using double sided tape to hold loose pieces in place while carving.
board size is 7X5X.5 corian or cast acrylic, so a sled is needed, or change the board to include the extra 4 inches on each end.
size of the carving is 1.75" OD large circle, 1.5" ID large circle, 1" OD suction side, .5" ID through hole, and .75"x 5/32" bearing hole.
The slot is 1.25 long by .25 height (gave a little here for strength).
Through pin hole can be drilled or placed on the MPC file where needed.

I will be looking at the bit plate from images of bergerud, and see what I can come up with for carving. Should be no problem to carve this too.

So we need a bit plate, and base bracket yet. Well unless there are changes, and bergerud will have to let me know from what I have so far.

Edited: added bit optimization to the patterns.

[eelamb]

Your MPC files look great, and in this case I do not see an advantage with how you designed the MPC's.

[jaroot]

I've been watching this thread with some interest. It is really cool what you've come up with here. I hope that you are able to get it put together for future CW owners. I personally bought the CW unit, built a base for it and then bought a 4" line DC for it so I probably won't do this myself but it is appears to be a real nice addition to the options available for the unit.

[bergerud]

You are fast! The sides look thin. Is that from the carving bit. I was going to use the cutting bit to drill the holes so the sides would be vertical. We seem to be moving in different directions. You want to carve as much of it as you can and I want to mill as much of it as I can.

The bottom of the cap and the base plate have to be figured out. I am not sure whether 1/4 acrylic will strong enough for the base plate, especially with a gap in the front for the scanning probe wire. The cap has to be easily removable and not be able to rotate. I am not happy with the notches you see on the cap bottom. Also there has to be a brush down there somehow. Actually, I am satisfied that the cap can be carved (details!) and will turn attention to the base plate.

The bit plate is a simple planer shape. There is, however, the interesting problem of a simple spring system.

[eelamb]

From looking at the shoe you had made, I would suggest the cap has a section to fit the opening in the base (not just the hole but split section). This would keep it from rotating. I am sure you will work out the brush part.

The taper does harm the carve on side profiles, yet these are not deep carves. I believe the cutting bit could be chosen, have not tried it.
The side walls will be .125 using the dimensions you posted of 1.75 OD and 1.5 ID.
I think you are right about the base. Experimentation is necessary, but metal is a better choice.

[eelamb]

Forgot to mention, as to the wall thickness, it needs to be set to best bit optimization, then it will look more like your wall thickness.

One advantage of doing it your way is the MPC is made in parts, thus a bit selection can be made for each part. A 3d model pattern is one piece thus only one choice of bits for the entire pattern.

[bergerud]

First try at the Dust Cap top. Bearing hole over carved - no surprise. Back to front not quite lined up. Too much carving bit taper on the outside. Looking good! Enough for today.

(I do think these could be made of fine grain hardwood though. This was arbutus.)

[eelamb]

Looking good. Nice work on the MPC.

[bergerud]

I probably should not post anything yet but I have now carved all of the parts for the Dust Cap (some only out of wood). I am now "fine tuning". Here is the first part, the base, which I hope is the final piece. It is carved from a 3 by 3 by 1/4 square of cast acrylic as are many of the parts. If you are interested in following the project and carving the parts, you need to first carve a carrier board for these squares. My board simply has a square hole 1/4 deep in the center which I press fit the squares into. (I also made a smaller hole right through so I can push out the squares from behind.)

In case you are wondering, all of the parts are designed to be made with only the 1/16 carving bit and the 1/8 cutting bit.

An important part of the Dust Cap is the 1/2 X 3/4 X 5/32 bearing for the out pipe. You can find them on the web or on eBay (or maybe in an RC hobby shop). They are cheap so get some. (All of the other parts should be easy to find locally.)

I also included the most complicated part, the Dust Cap bottom, so you see what is coming. I have yet to carve it out of acrylic. I am going to try and glue three 1/4 layers together to make the 3/4 needed. It would be nice if the whole project required only 1/4 sheet cast acrylic. (Note that if you buy 1/4 cast acrylic sheet, take your calipers along. I think the thickness of these sheets can vary so make sure it is 0.25.)

Anyway, carve the base out of something, test for accuracy and see how it fits. You will eventually need to find longer screws than the screws holding the board sensor. (They are metric M3 X 0.5 )

[Digitalwoodshop]

That is pretty impressive.....

AL

[DurhamDev]

This is pure awesome. Thanks so much for sharing your idea, and your plans with us. I am watching intently, as this will undoubtedly be a huge boon to everybody!

[Sallen1215]

dont know if you know this or not but to bond the acrylic sheets you will need a liquid welder like Weld-on 3, its a very thin liquid which softens the acrylic and allows then to weld together with no separation, do a search on TAP plastics both on thier site and on you tube to see how plastic welding is accomplished. I use it on my Lithos and im curently working on a litho lamp shade which requires welding of several acrylic panes.


Stephen

[bergerud]

I am using methylene chloride. Seems to work ok. I wonder if that Weld 0n 3 is the same or better?

[Sallen1215]

"Contains Methylene
Chloride (75-09-2), Trichloroethylene (79-01-6) and Methyl Methacrylate Monomer (80-62-6). Methylene Chloride
and Trichloroethylene are listed as cancer causing materials. OSHA has established special requirements for work
place monitoring and protection. Extent of health risk depends on level and duration of exposure, as well as
individual sensitivity. Do not use this product for other than intended use."

http://www.tapplastics.com/uploads/pdf/PB-IPS3.pdf (http://www.tapplastics.com/uploads/pdf/PB-IPS3.pdf)

[b.sumner47]

Thanks for all of the updates. Capt Barry

[ktjwilliams]

First try at the Dust Cap top. Bearing hole over carved - no surprise. Back to front not quite lined up. Too much carving bit taper on the outside. Looking good! Enough for today.

(I do think these could be made of fine grain hardwood though. This was arbutus.) Don't have to be pretty,,, Just has to work ....

[bergerud]

Here is the Dust Cap carved by the Carvewright. The files to carve and instructions to follow.

[bergerud]

INTRODUCTION

The following instructions are not meant to be complete instructions for everyone but only highlights and tips for the experienced carver - tinker who is interested in contributing to the prototype stage of this project.

All of the acrylic parts for the Dust Cap are made from single or layered 3 by 3 squares of 1/4 inch thick cast acrylic. You will need at least 14 of these squares. This is not the most efficient method to cut out the parts, but it is the most convenient method at this prototype stage.


THE CARRIER BOARDS

Before any of the parts can be carved, one must cut the 10 inch carrier boards.

The 3 X 3 X 0.25 board is used to hold a single square of acrylic. With the exception of the base it is used for simple single sided cuts.

The 3 X 3 X 0.5 board is used to carve the Dust Cap top and the two pipe pieces.

The 3 X 3 X 0.75 board is used to carve the Dust Cap bottom.

I used press fit to hold the acrylic in the carrier boards. One could use screws instead.

This is an exercise in accuracy and I suggest you change the default touch to jog to touch on the machine. In many cases, you will want to touch down on the acrylic and not the board. (This is especially important if the acrylic is not exactly 0.25. I will assume in the following instructions that your acrylic may be a little less than 0.25.)

On all carving, I suggest removing the paper just before the carving or cutting starts. On single sided parts, remove the back paper before placing in the carrier board.

I have a Dust Cap which works well to remove the acrylic cuttings. If you do not have a dust collecting system, you must take extra care to keep your machine clean. The acrylic cuttings are sticky and fowl up the carriage rollers. They also act like ball bearings between the board and sandpaper belts.

[bergerud]

THE BASE

The base is carved out of single 3 by 3 piece. Open the file base.mpc and upload to the card. Choose optimal. For the back carve, touch on the acrylic. After the back carve, flip the acrylic in the carrier board. This time touch on the board.


THE DUST CAP TOP

The top is made of two squares glued together. It may take a try or two to get the procedure right, but, once you get it, it is easy. Remove the paper from one side of the two squares and place them face up. Double check to see that the surfaces are dust free. Pour about 1 cc of methylene chloride (or weld-on 3) onto one of the squares. Place the other square on top and pivoting from one edge, slowly lower the top square onto the bottom square. Some liquid should seep out of the joint. Press and hold for 30 seconds.

Open the file dustcap top.mpc and upload to the card. Choose optimal. For the back carve, touch on the acrylic. After the back carve, flip the carrier board and touch on the board. Do not cut out the top from the block. The thin layer of acrylic left is needed for a “seamless” glue to the bottom.


THE DUST CAP BOTTOM

The bottom is made from three squares glued together. Use the same procedure as for the top but glue on one more square.

Open the file dustcap bottom.mpc and upload to the card. Choose optimal. For the back carve, touch on the acrylic. After the back carve, flip the carrier board and touch on the board. Do not cut out the bottom from the block.

Now the top and the bottom blocks have to be glued together. Using two 1/8 inch pins, test how the top and the bottom line up. Lay the bottom top up and carefully pour the methylene chloride around the area to be joined. (A syringe or small squirt bottle is useful.) Press them together and hold for 30 seconds.

Wait for a few hours then, using a small saw or Dremel, cut the cap out of the block. The cap requires quite a bit of clean up. The front of the cap beside the bearing hole needs to be made into a window by sanding and polishing inside and out.


THE BASE RING

The base ring glues on to the bottom of the cap to help hold the cap onto the base. It is a single side cut.

Open the file base ring.mpc and upload to the card. Touch on the acrylic.

To glue the base ring onto the bottom of the cap requires a thicker glue. I used Weld-on #16 in a tube. Note the hole in the base ring to line up with the bit plate shaft in the cap.


THE CAP TOP

The cap top is needed so the centrifugal force does not throw dust out of the cap top. The hole in the cap, however, has to be big enough for what ever chuck you are using (Forget about the ½ roundover bit!). I am using an ER16M and need only a 1” hole. The CT may need a 1.3” hole (Grind down the allen bolt?). The Rock is smaller I think. The QC cannot even work unless its plastic cover is removed. You have to decide on the size hole you need. (I expect a report on this issue.)

Open the file base cap top.mpc and upload to the card. Touch on the board.

[bergerud]

THE BIT PLATE

The bit plate is a simple cut out.

Open the file base bitplate.mpc and upload to the card. Touch on the board.

The bit plate pivots on a 1/8 inch shaft about a inch long. The spring can be fashioned from a (right handed) pen spring. A small slot can be cut in the dust cap top to hold the top of the spring.


THE STOP PLATE

The stop plate will replace the standard bit plate on the machine. The stop plate has two functions: to stop the carriage from hitting the machine casing and to activate the new bit plate in the cap.

Open the file base stop plate.mpc and upload to the card. Touch on the board.

The small wheel is glued onto the stub using the Weld-on #16. (One can modify this to use a bearing but for now keep it simple.) The stop plate then fits on the pin which held the original bit plate. (Some effort is required to remove the original bit plate.)

THE BRUSH RING

The brush ring is a simple ring which glues under the cap to provide a slot for a brush. Like the top cap, it also stops spinning dust from flying out.

Open the file base brush ring.mpc and upload to the card. Touch on the board.

A brush can be fashioned from window or door seal brushes. One might also try a felt ring with many slices. These have to be glued in with contact cement.

THE PIPE

The pipe is a double sided carve of two squares glued together. Use the same carrier board as the Dust Cap top. It is thin and accuracy is important. It is important that the block be 0.5 thick.

Open the file base pipe.mpc and upload to the card. Touch on the board on both sides.

Leave the tabs on the pipe to help in the gluing. Weld-on #16 again. Leave small nubs from the tabs on the bearing end to help in a click fit into the bearing.

THE VACUUM CONNECTOR

I have included a file to cut a vacuum connector in case you cannot find something around the shop. It is an inch thick. Cut it out of whatever you like.

PARTS TO BUY

You will need a few feet of flexible, ½ inside diameter hose. I found Laguna pool hose at the local hardware to be fine. You may find something better.

You will need a 1/2 X 3/4 X 5/32 sealed bearing. These are available on eBay. They are RC bearings and so I suppose a local hobby store could supply them.

Also, a 1/2 OD thin wall brass tube is useful for the vacuum connector. (You have to drill a 1/2 hole in the Carvewright unless you can find a better way out.) The hobby store should have these as well.

[ktjwilliams]

Thx Dan,,,, Gonna go get some plastic and give it a whirl !!! By the way that looks like some really good work... Appreciate the time and effort U put into these projects and UR willingness to share.. Wouldn't be surprised to see some DOUCHE putting it for sale on EBAY...

Kevin...