Lathe drilling

[TomS]

Will using a collet chuck to hold acrylic blanks prevent blow out while drilling? Or should I continue to drill short and cut off the end of the blank?

Thanks,
Tom

 

[alinc100]

Tom,
I don't think the collet chuck will prevent blow outs.I do enjoy the accuracy that mine brings.
Acrylic is always a gamble,speed,feed rate,sharpness of bit,etc.I would stay with the cut long drill short plan.The benefit in this case is you can insert the blank quite far into the collet chuck and it is supported/stable much better.If you are willing to wait Amazon has the best price on the PSI ,usually 25-30 % of PSI list price.

 

[darthintel]

I use The PSI blank chuck to drill wood and Acrylics on the lathe. Lowest speed and drill slow....have not had any problems with blanks breaking.

 

[jasontg99]

I would continue to drill short and cut off the end. I don't see how a collet would prevent blowouts. The collet will not provide support on the bottom of the blank, only on the sides. The bottom of the blank is the issue with blowouts. If you do not have enough material to drill short, you could always glue on a sacrificial piece of wood/acrylic on the bottom of the blank.

 

[IPD_Mr]

I have yet to have a blowout since using a collet chuck, with the exception of after a visit to one of our fine Mexican eateries. :biggrin:

 

[leehljp]

An old fellow well known for his new ideas used to wrap his very delicate blanks with thread and CA it before turning. I have done the same a few times. On a delicate blank that I did not want to re-construct, I would spend the time necessary to protect its integrity while drilling out on the lathe. On special blanks, time is not the issue.

I feel from your post that you are just trying to get consistent. Consistency comes with experience and observation. Old dogs can learn new tricks! :biggrin:

 

[ren-lathe]

The collet chuck will not prevent blow out. What will is taking your time when you get close to the end of the blank. Mark your drill and when you are close to the end slow down on how fast you are feeding the drill.

 

[butchf18a]

backer blocks

if you are concerned with blow out try gluing a backer block to your blank first. the blank will not blow out and when you get to the backer material you'll know when you are all the way through. then just cut the backer block off. this is especially useful on expensive blanks. the pictures show some Cebloex. Has expensive as this stuff is, don't want to waste any by making blank long and cutting off excess after partial drilling. works everytime

jmoicbw-bidi

 

[ctubbs]

I have yet to have a blowout since using a collet chuck, with the exception of after a visit to one of our fine Mexican eateries. :biggrin:

When afflicted with that problem again, capture it, compress it and use it as CNG for your truck:biggrin:
Charles

 

[mikespenturningz]

I purchased a Nova G3 and should have it tomorrow for just this same thing. I hope it works for me. I have a lot of corian blanks that are just big enough for a comfort pen but I have a very hard time with my shopsmith and a V-block on the boring machine getting right down the middle. I hope this will fix that problem.

 

[Rich L]

I'm a relative newcomer to the forum so let me humbly ask what drill point included angle are you folks using that causes the blowouts exiting the material. I don't know if it's been discussed before. I use a large included angle (more blunt than sharp) for acrylics and plastics and it prevents the shattering problem on exit.

Cheers,
Rich

 

[leehljp]

I'm a relative newcomer to the forum so let me humbly ask what drill point included angle are you folks using that causes the blowouts exiting the material. I don't know if it's been discussed before. I use a large included angle (more blunt than sharp) for acrylics and plastics and it prevents the shattering problem on exit.

Cheers,
Rich

You are right about that aspect but the other problem with the more blunt angle is that it leads to less than perfect entrance points, particularly on some hard grained woods. Precision entrance points ( .01 or better) are a necessity in many cases. For me, I will start a pilot hole and then move to a better bit as you mentioned, but most people will not.

You make a great point! I rarely see people matching the bit type to the material's need, and the right speed for the bit used for that specific material.