Oval plunge holes

[DickB]

I tried making a cribbage board and the holes came out oval not round. These are straight plunge holes, .125". There should be no x-movement, but the holes are slightly elongated in the x-direction.

39905

I searched and found others with similar problems, and checked my machine and technique accordingly. The original piece was oak, could have slipped I suppose, but I ran tests in pine with the same results. The belts are in good shape, the brass roller is tracking well (you can even see slight impressions in the pine), guide bar is not too tight, roller pressure is 79.5. The truck feels tight, the z-axis wheels are tight and tracking with no slippage. I put my finger on the edge of the board and support outside of the machine and I could detect no x movement while the holes were being drilled.

I tried the same test with my carving bit and got similar results, so I don't think it is the bit.

39906

I'm not sure where to go from here. Any suggestions?

[AskBud]

I tried making a cribbage board and the holes came out oval not round. These are straight plunge holes, .125". There should be no x-movement, but the holes are slightly elongated in the x-direction.

39905

I searched and found others with similar problems, and checked my machine and technique accordingly. The original piece was oak, could have slipped I suppose, but I ran tests in pine with the same results. The belts are in good shape, the brass roller is tracking well (you can even see slight impressions in the pine), guide bar is not too tight, roller pressure is 79.5. The truck feels tight, the z-axis wheels are tight and tracking with no slippage. I put my finger on the edge of the board and support outside of the machine and I could detect no x movement while the holes were being drilled.

I tried the same test with my carving bit and got similar results, so I don't think it is the bit.

39906

I'm not sure where to go from here. Any suggestions?
What chuck are you using?
AskBud

[Fletcher]

I find the 1/8' cutter that comes with the CW flexes a lot due to the extra long flutes - that's why it screams so much when doing cutouts. I have used other 1/8 bits with better success. Your holes could be getting ovalized due to vibration alone...

[Digitalwoodshop]

I think a calibration is needed...

I would be sure to place tape along the brass roller track to make a rack and pinion.

How many cut hours? Over 500 then bad Y bearing in the gear box.

AL

[DickB]

Thanks guys. I'm using the CarveTight chuck. I don't think tape and roller is an issue, because the board is not moving in the x direction as these are plunge holes only. I also don't see how this would be a calibration issue since there is no x and y movement. Cut time is 170 hours. The vibrating bit makes sense. Can you give a source for a 1/8 drill bit and collet for the CarveTight?

Anyone use a standard drill bit to drill holes?

[Digitalwoodshop]

Sorry to lead you astray....

AL

[JLT]

Am wondering if by chance the machine happened to offer to scale the project due to the actual board size not matching the project? This might possibly be a cause...

[AskBud]

Thanks guys. I'm using the CarveTight chuck. I don't think tape and roller is an issue, because the board is not moving in the x direction as these are plunge holes only. I also don't see how this would be a calibration issue since there is no x and y movement. Cut time is 170 hours. The vibrating bit makes sense. Can you give a source for a 1/8 drill bit and collet for the CarveTight?

Anyone use a standard drill bit to drill holes?
You need to buy your Carving and 1/8 Cutting bits from LHR. They come with the needed "Pressed ON" sleeves. Any other sleeve/collet combination of these two bits may be asking for trouble. They are Carbide and need the specified combination from LHR.
AskBud

[DickB]

Am wondering if by chance the machine happened to offer to scale the project due to the actual board size not matching the project? This might possibly be a cause...
Good thought, but no.

[DickB]

You need to buy your Carving and 1/8 Cutting bits from LHR. They come with the needed "Pressed ON" sleeves. Any other sleeve/collet combination of these two bits may be asking for trouble. They are Carbide and need the specified combination from LHR.
AskBud

I understand regarding bits with carbide shafts. But LHR sold me a slip-on collet to use with the router bit collection that I also got from them. These extra bits have steel shafts as I understand it. So I should be able to use a drill bit in a collet, just like the router bits. If I could get one.

[AskBud]

I understand regarding bits with carbide shafts. But LHR sold me a slip-on collet to use with the router bit collection that I also got from them. These extra bits have steel shafts as I understand it. So I should be able to use a drill bit in a collet, just like the router bits. If I could get one.
No promise that it will do the job, in the CT chuck, but here is a link to Ron Justice's site. You will find a 1/8 to 1/2 split collet there.
AskBud
http://www.cw-parts.com/page2.html

[lovejoys]

Dick B I sent you a Private Message about this

[DickB]

I got some off-line advice on this issue, but didn't get to apply it until now.

I believe that the majority of the problem is the cutting bit. I picked up a set of Dremel high-speed drill bits and a Roto-zip 1/8" to 1/4" adapter. I really only needed the 1/8" bit, but now I have a set of four all with a 1/8" shaft, possibly for future use. The bit and adapter go into the CarveTight 1/4" adapter and then into the CarveTight. I'm sure that Ron's adapter would be superior, but I was able to get this one at the local home center for $6.

40864

The holes were drilled with the same project file, just different bits. Can you tell which is which?

40865

Not all of the drilled holes are perfect, but much better than the cutting bit ones and I think will be fine for future projects.

[Digitalwoodshop]

Can you explain that again please.... you lost me...

Drill bit and Roto Zip Bit?

Roto Zip bits I have can be bent so they can wobble so they should never be used in the CW.... I have the bit holder too.

AL

[DickB]

I'm using a Roto-Zip adapter only, not a Roto-Zip bit. It adapts a tool - in this case, a drill bit - with a 1/8" shaft to a 1/4" collet. The bit is a Dremel brad-point drill bit, made for high-speed operation.