drill size vs. blank size

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avbill

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I have avoided using 3/4 blanks for kit with 33/64 drill bits. b/c there little or no room for drilling error. I just did the math and there is .127 inch room on all 4 sides of the blank Is that enough room?

Reason i have 20 kits of the big pens and no 7/8 blanks. Any comments


Thanks
 
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That assumes the blank is:
1) At least 3/4" square
2) Perfectly square
3) Zero warp

If you can guarantee all of the above (and can drill accurately), then all you have to do is check two things:
1) Are any kit items (centerband, finial, etc.) larger than that
2) Are any desired design elements (beads, etc.) larger than that
 
How are you trying to drill? Drill press, on lathe? Have you checked your setup for runout? Are your bits sharp? What kind of bits? Difficult to fully answer your question as it is so general.
 
Hmmmm....why not pick up some 7/8th or 1 inch blanks and not worry about it? Are you sure you can even get it round with what's left. You only have about 17/64th total which translates to about 17/128th to work with on each flat side if you drill dead center with no wobble. with 7/8th you get to 25/64th or about 50% more blank to work with.
 
Smitty37 said:
Hmmmm....why not pick up some 7/8th or 1 inch blanks and not worry about it? Are you sure you can even get it round with what's left. You only have about 17/64th total which translates to about 17/128th to work with on each flat side if you drill dead center with no wobble. with 7/8th you get to 25/64th or about 50% more blank to work with.
Click to expand...
I agree, I'll hardly ever buy any 3/4 X3/4 blanks anymore. Plus I want them at least 5 1/4" long. And I've never even made one of those larger pens. I just want the wiggle room so I can drill off center if I like a side better than another. And longer so I can make it closed ended or with a custom finial.
 
I'd suggest trying your setup on a 3/4" blank that you are not fond of.
Pick one that is as good or bad as the one you want to use.
I'd also suggest that you turn it round first, get the entire length the same diameter and use a method that holds it absolutely centered on the lathe and drill away.
It's doable...just a bit scary!
 
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