Carving Bits finer than 1/16"

[cycollins]

This will probably be an incredibly naive question, but I'm interested in getting super-fine detail. Is there such a thing as 1/32" carving bit? And if there were such a thing, would the CW machine/software know what to do with it (no rude comments, please)? Obviously CW doesn't advertise such a bit, but I've been following the talk about 3rd-party bits. Or does the size of the tip make that much difference? I've noticed that the 1/16" carving bit is able to generate details that are much finer than 1/16" by attacking the feature from either side. Still, it seems like the size of the bit puts an absolute limit on certain kinds of relief. Try scaling a reasonable pattern down to a very small size and you'll see what I mean. Any thoughts?

DCC

[Julie Coffey]

Hello DCC and no rude comments from me. I'm not sure how one would adapt a bit such as that so it would work. If anyone *has* I've not heard of it yet.

Superfine detail would be really nice- I just don't think it OR us are there 'yet'.

J

[SpiffyDog]

I like the idea of having finer detail. I don't think it would work well unless the machine knows it has a smaller bit. Machine speed is the factor. Maybe CW should come out with a smaller version for crafting. Something that would use bits from a Dremel tool. Now that is something my wife and kids would be very interested in.

[JOHNB]

Since Breaking My Carving Bit And Knowing It 'll Be A Long Time For A Replacment - I Use A Dremel Bit With .25 Adapter. Works Fine For Little Carving I've Done. (waiting For New Machine Now) As Far As I'm Concern, It Will Use Any Bit You Put In It. As Long As You Are Smarter Than The Bit!

[Kenm810]

JOHNB

Quote (As Long As You Are Smarter Than The Bit!) hummm
could that be interpreted as, "As Long As You Are Sharper Than The Bit!"

aaah - Ma! - now their calling us pin heads! :p

[rgant05]

CY,

I think the answer to your question is that you wouldn't be able to use a smaller bit because the software (Designer program) is designed to expect the actions and abilities of a particular set of bit sizes and shapes (as designated in the library of bits in Designer) That is not to say that you couldn't successfully use a smaller bit, but the machine is going to expect the size of the 1/16" bit along with its strength and cutting ability. When making details it is also going to expect the shape and size of the 1/16" bit, and act accordingling. Consequently you will get a different shape but not "more" or "finer" details. My guess is that you will break a smaller bit quite often because it is not going to remove wood as quickly as a 1/16" bit would and the machine is going to be moving at a speed expecting the removal rate of the 1/16" bit. Now at some point they might change there software to add the shape, bit strength and bit cutting rate to allow the use of a smaller bit, but that is up to them and what ever expansion and future plans they have. As for my feelings, I would rather they work on getting a machine that is working for everyone before they expand its capabilities LOL Once they get the machine successfully into productions THEN look at future capabilities. I was instructe yesterday to remove a cable to a sensor that is no longer used but in doing this to correct a problem (close door error) it disables the use of the Scanning Probe feature which I just ordered earlier this week. It will be a month or two before they have a solution to be able to use the Probe by connecting it another way. My fealing is that if they look too much to the future, they will loose everything because without a good foundation of a stable working machine from overseas production, they aren't going to have a client base to sell any future development to. But thats just my opinion.

Roger

[Dan-Woodman]

I believe the feed rate in best quality is .005 , so with a smaller bit it would skip part of the wood. In other words, if your moving .005 with a 1/16" bit and you carving with a 1/32" bit it would probably leave .0025 between passes.

[rgant05]

No, thats the confusing part about it. If the X feed rate is .005 per pass, it is always going to be .005 per pass regardless of what size bit you have in it unless they change it in the programming. That is the X feed rate. The Y feed rate, I don't think they specify and that is where my main concern is. It also will remain at what ever rate they come up with (which I don't know how they do it) It would be nice to be able to slow it down for a smaller bit in the Y direction as well as the X direction. There actually two feed rates that are involved (X & Y). Both of which will add to the pressure that is put on the bit. Z axis will also factor into it the deeper the relief is on your pattern. The whole issue is that when it is making the decisions of how and when to make the Z axis plunges, it is basing it on making the cut of the 1/16" carving bit. You can't get any more detail until the machine beleives that it is making a smaller cut and calculates the z-axis moves accordingly.... and that has to be done in the software.

[RC Woodworks]

cy, go to pricecutter.com and order item # p13-2100. It is a 22 degree bit. It might show it on the site. I took a few picture and I will try to post them. This bit has a very sharp point. I think it is what you are looking for.

[pkunk]

No, thats the confusing part about it. If the X feed rate is .005 per pass, it is always going to be .005 per pass regardless of what size bit you have in it unless they change it in the programming. That is the X feed rate. The Y feed rate, I don't think they specify and that is where my main concern is. It also will remain at what ever rate they come up with (which I don't know how they do it) It would be nice to be able to slow it down for a smaller bit in the Y direction as well as the X direction. There actually two feed rates that are involved (X & Y). Both of which will add to the pressure that is put on the bit. Z axis will also factor into it the deeper the relief is on your pattern. The whole issue is that when it is making the decisions of how and when to make the Z axis plunges, it is basing it on making the cut of the 1/16" carving bit. You can't get any more detail until the machine beleives that it is making a smaller cut and calculates the z-axis moves accordingly.... and that has to be done in the software.
The software does control the feedrate as well as depth of cut per pass. You can see a major difference when it does centerline text with a much larger bit, deeper carve & much larger chips. Rpm's also drop & rise as the work load varies. The software is instructed by you when you select a bit or in the case of 'raster', it chooses the 1/16" BN bit.

[rgant05]

Thats exactly my point pkunk,
You can't choose a 1/32" ballnose carving bit (because the software is not designed for it), so it is not going to be able to adjust all of the factors accordingly to use that bit. It is going to think it has a 1/16" carving bit, which will (in my guess) break a 1/32" bit in short order because it doesn't have the strength of the 1/16" bit nor the ability to do the work at the same speed a 1/16" bit would do it. When forced to do it.... it will break.

[pkunk]

Thats exactly my point pkunk,
You can't choose a 1/32" ballnose carving bit (because the software is not designed for it), so it is not going to be able to adjust all of the factors accordingly to use that bit. It is going to think it has a 1/16" carving bit, which will (in my guess) break a 1/32" bit in short order because it doesn't have the strength of the 1/16" bit nor the ability to do the work at the same speed a 1/16" bit would do it. When forced to do it.... it will break.
At this point in the MC evolution, you are exactly right!:D

[JOHNB]

Here Is The Bit I Have Been Using. No Problem With The Bit Cutting. I Believe 3/32 Tip, Dremel, Maybe #9740, Diamond Particles, 1/8 Shank With 1/4 Adapter.

[Navigator]

You said your are adapting the Dremel 1/8 shank bits. Similar
diamond bit shapes but with 1/4 shanks are available from Harbor Freight, a full set for about $20. The larger shank provides more heat transfer to the chuck and prolongs the bit life.

As a new guy on the forum I am not sure how to correct another posters error so don't jump to hard. Earlier in this thread it was "agreed" that the bit moves .005 in the best quality mode and that that by using a 1/16 bit there would be gaps in the cut.

First - I question the distance of .005 (5 thousandths of an inch), the specs claim an accuracy of only .010 (10 thousandths or 1 hundredth of an inch). That's a difference of .0095!

Second - Referring to the above math a 1/16 bit is .0635 in diameter. That works out to almost 13 passes for a bit to travel 1/16 of an inch at .005 per pass, or about 6 passes to travel at .010 per pass. In either case there will be no gaps in the cuts. These dimensions are at the metal cutting level of accuracy, wood moves (swells and shrinks) more than this just sitting in the machine.

Third - I did not see any discussion regarding the depth of cut expected when using these small diameter bits. The 60 degree bevel point bit is the absolute smallest diameter you can find. Depending on depth it has almost 0 (zero) diameter and could function much like an engraving tool. Following this, almost any bit that comes to a point can be substitued for the 60 degree bit and used as long as it is not asked to make deep cuts.

The problem as I see it is that we have no way to define new tool bits. The CW software forces us to "fool" the program when we substitute bits with often unexpected results.

Finally - Heat is the number 1 problem for bit life. The woodworking trade magazines are constantly evaluating router bits from different companies and putting them thru really tough conditions. The routers they use are usually the 1 1/2 to 3 hp range. These are ceratinly more powerful than our 1 hp cable router in the CW. The problem is the ability of the bit to get rid of the heat generated so the bit doesn't lose its temper. Conclusions - 1/2 shank bits last the longest - 1/4 shank bits are not recommended for any extensive cutting and 1/8 shank hobby bits are dangerous because they come apart.

[kerfster]

You said your are adapting the Dremel 1/8 shank bits. Similar
diamond bit shapes but with 1/4 shanks are available from Harbor Freight, a full set for about $20. The larger shank provides more heat transfer to the chuck and prolongs the bit life.

As a new guy on the forum I am not sure how to correct another posters error so don't jump to hard. Earlier in this thread it was "agreed" that the bit moves .005 in the best quality mode and that that by using a 1/16 bit there would be gaps in the cut.

First - I question the distance of .005 (5 thousandths of an inch), the specs claim an accuracy of only .010 (10 thousandths or 1 hundredth of an inch). That's a difference of .0095!

>>>The difference is 0.005". A bigger problem is that a "feedrate" is exressed in units of distance/time (like inches/minute). The 0.005" quoted in the specs is the "step-over" or the overlap between successive raster cuts.

Second - Referring to the above math a 1/16 bit is .0635 in diameter. That works out to almost 13 passes for a bit to travel 1/16 of an inch at .005 per pass, or about 6 passes to travel at .010 per pass. In either case there will be no gaps in the cuts. These dimensions are at the metal cutting level of accuracy, wood moves (swells and shrinks) more than this just sitting in the machine.

>>> very true. When 3D carving with a true ball-nose cutter a typical step-over is 10% to 15% of the diameter of the ball. At 10% there are virtually no detectable topo artifacts between successive passes. I suspect the CW uses 0.005" because the runout at the tip of the bit (wobble) is so large (0.002" to 0.010") that a certain amount of pattern smearing occurs. For treatment of measuring runout, go to:

http://www.precisebits.com/tutorials/spindle_runout.htm

Third - I did not see any discussion regarding the depth of cut expected when using these small diameter bits. The 60 degree bevel point bit is the absolute smallest diameter you can find. Depending on depth it has almost 0 (zero) diameter and could function much like an engraving tool. Following this, almost any bit that comes to a point can be substitued for the 60 degree bit and used as long as it is not asked to make deep cuts.

The problem as I see it is that we have no way to define new tool bits. The CW software forces us to "fool" the program when we substitute bits with often unexpected results.

>>> Amen to that

Finally - Heat is the number 1 problem for bit life. The woodworking trade magazines are constantly evaluating router bits from different companies and putting them thru really tough conditions. The routers they use are usually the 1 1/2 to 3 hp range. These are ceratinly more powerful than our 1 hp cable router in the CW. The problem is the ability of the bit to get rid of the heat generated so the bit doesn't lose its temper. Conclusions - 1/2 shank bits last the longest - 1/4 shank bits are not recommended for any extensive cutting and 1/8 shank hobby bits are dangerous because they come apart.

>>> In woodworking, the primary cause of heat is a imbalance between the speed (RPM) and feedrate (inches/revolution). Every tool has a sweetspot that is different for every material being cut. An easy method to determine this is found at:

http://www.precisebits.com/tutorials/calibrating_feeds_n_speeds.htm

At the temperature encountered in woodworking, tungsten carbide does not lose its "temper" (actually the material is not tempered). High heat can cause cobalt leaching and resulting embrittlement but not in this type of woodworking. At the current state of the art, the submicrograin carbides available for micro-tooling are the toughest in the industry and are almost always used in 1/8" shank tooling. They do NOT come apart during operation. The biggest problem is convincing folks to run them as fast as they need to run. I am talking about 0.0313" (1/32") dia end-mills that cut hard-rock maple at 100 inches per minute (40 KRPM) with a single pass plunge of 0.125".

[kerfster]

You said your are adapting the Dremel 1/8 shank bits. Similar
diamond bit shapes but with 1/4 shanks are available from Harbor Freight, a full set for about $20. The larger shank provides more heat transfer to the chuck and prolongs the bit life.

As a new guy on the forum I am not sure how to correct another posters error so don't jump to hard. Earlier in this thread it was "agreed" that the bit moves .005 in the best quality mode and that that by using a 1/16 bit there would be gaps in the cut.

First - I question the distance of .005 (5 thousandths of an inch), the specs claim an accuracy of only .010 (10 thousandths or 1 hundredth of an inch). That's a difference of .0095!

>>>The difference is 0.005". A bigger problem is that a "feedrate" is exressed in units of distance/time (like inches/minute). The 0.005" quoted in the specs is the "step-over" or the overlap between successive raster cuts.

Second - Referring to the above math a 1/16 bit is .0635 in diameter. That works out to almost 13 passes for a bit to travel 1/16 of an inch at .005 per pass, or about 6 passes to travel at .010 per pass. In either case there will be no gaps in the cuts. These dimensions are at the metal cutting level of accuracy, wood moves (swells and shrinks) more than this just sitting in the machine.

>>> very true. When 3D carving with a true ball-nose cutter a typical step-over is 10% to 15% of the diameter of the ball. At 10% there are virtually no detectable topo artifacts between successive passes. I suspect the CW uses 0.005" because the runout at the tip of the bit (wobble) is so large (0.002" to 0.010") that a certain amount of pattern smearing occurs. For treatment of measuring runout, go to:

http://www.precisebits.com/tutorials/spindle_runout.htm

Third - I did not see any discussion regarding the depth of cut expected when using these small diameter bits. The 60 degree bevel point bit is the absolute smallest diameter you can find. Depending on depth it has almost 0 (zero) diameter and could function much like an engraving tool. Following this, almost any bit that comes to a point can be substitued for the 60 degree bit and used as long as it is not asked to make deep cuts.

The problem as I see it is that we have no way to define new tool bits. The CW software forces us to "fool" the program when we substitute bits with often unexpected results.

>>> Amen to that

Finally - Heat is the number 1 problem for bit life. The woodworking trade magazines are constantly evaluating router bits from different companies and putting them thru really tough conditions. The routers they use are usually the 1 1/2 to 3 hp range. These are ceratinly more powerful than our 1 hp cable router in the CW. The problem is the ability of the bit to get rid of the heat generated so the bit doesn't lose its temper. Conclusions - 1/2 shank bits last the longest - 1/4 shank bits are not recommended for any extensive cutting and 1/8 shank hobby bits are dangerous because they come apart.

>>> In woodworking, the primary cause of heat is an imbalance between the speed (RPM) and feedrate (inches/revolution). Every tool has a sweetspot that is different for every material being cut. An easy method to determine this is found at:

http://www.precisebits.com/tutorials/calibrating_feeds_n_speeds.htm

At the temperatures encountered in woodworking, tungsten carbide does not lose its "temper" (actually the material is not tempered). Excessive heat CAN cause cobalt leaching and resulting embrittlement but not in this type of woodworking. At the current state of the art, the submicrograin carbides available for micro-tooling are the toughest in the industry and are almost always used in 1/8" shank tooling. They do NOT come apart during operation. The biggest problem is convincing folks to run them as fast as they need to run. I am talking about 0.0313" (1/32") dia end-mills that cut hard-rock maple at 100 inches per minute (40 KRPM) with a single pass plunge of 0.125". The folks at LHR are VERY aware of this and, I am sure, future software upgrades will allow the creation of accurate material tables that will exploit the qualities of the premium tools available on the market today.

[cjacobus1]

CY:
Would you think it would be possible to use a "grinding/sanding" bit that is the same size as the cutting bit, and would be used after the cut is made to smooth out the cutting bit "burrs".

Chuck


CY,

I think the answer to your question is that you wouldn't be able to use a smaller bit because the software (Designer program) is designed to expect the actions and abilities of a particular set of bit sizes and shapes (as designated in the library of bits in Designer) That is not to say that you couldn't successfully use a smaller bit, but the machine is going to expect the size of the 1/16" bit along with its strength and cutting ability. When making details it is also going to expect the shape and size of the 1/16" bit, and act accordingling. Consequently you will get a different shape but not "more" or "finer" details. My guess is that you will break a smaller bit quite often because it is not going to remove wood as quickly as a 1/16" bit would and the machine is going to be moving at a speed expecting the removal rate of the 1/16" bit. Now at some point they might change there software to add the shape, bit strength and bit cutting rate to allow the use of a smaller bit, but that is up to them and what ever expansion and future plans they have. As for my feelings, I would rather they work on getting a machine that is working for everyone before they expand its capabilities LOL Once they get the machine successfully into productions THEN look at future capabilities. I was instructe yesterday to remove a cable to a sensor that is no longer used but in doing this to correct a problem (close door error) it disables the use of the Scanning Probe feature which I just ordered earlier this week. It will be a month or two before they have a solution to be able to use the Probe by connecting it another way. My fealing is that if they look too much to the future, they will loose everything because without a good foundation of a stable working machine from overseas production, they aren't going to have a client base to sell any future development to. But thats just my opinion.

Roger