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Drills and countersinks

Posted: Fri Nov 22, 2013 12:57 am
by BobR
A couple of noob questions.

1) Do you guys use different length tapered drill bits for different length stems (i.e. billiard Vs.Lovat).

1A) Does anyone make custom tapered bits where the diameter Vs. distance can be specified or am I over thinking it?

2) What countersink angle is recommended or typical. I see there is 60,82, and 90 degrees for the zero-flute countersinks at McMaster-Carr. I'm assuming 60 degrees is about right?

4) If a delrin tenon is used, does the mortise still need to be contersinked since the tenon/stem interface should be at a clean 90 degrees unlike a turned tenon.

Thanks!

Re: Drills and countersinks

Posted: Fri Nov 22, 2013 1:14 am
by Ocelot55
BobR wrote:A couple of noob questions.

1) Do you guys use different length tapered drill bits for different length stems (i.e. billiard Vs.Lovat).

1A) Does anyone make custom tapered bits where the diameter Vs. distance can be specified or am I over thinking it?

2) What countersink angle is recommended or typical. I see there is 60,82, and 90 degrees for the zero-flute countersinks at McMaster-Carr. I'm assuming 60 degrees is about right?

4) If a delrin tenon is used, does the mortise still need to be contersinked since the tenon/stem interface should be at a clean 90 degrees unlike a turned tenon.

Thanks!
I don't know much about bits, but I always countersink the mortise. It takes two seconds and you never know if someone will need the pipe restemmed and the repairman uses an integral tenon.

Re: Drills and countersinks

Posted: Fri Nov 22, 2013 9:30 am
by KurtHuhn
BobR wrote:1) Do you guys use different length tapered drill bits for different length stems (i.e. billiard Vs.Lovat).
Only if the stem is particularly long. For 80% of my stems I use a jobber-length drill bit (the typical length you can find in the hardware store). Other than that, it's important to keep the length of the stem appropriate to the hole you want to drill, since a long drill bit will flex more, be more unstable, and want to wander and go off track. You won't gain anything by using an 8" drill bit to make a hole 3" long.
BobR wrote:1A) Does anyone make custom tapered bits where the diameter Vs. distance can be specified or am I over thinking it?
Overthinking. :) Just use the ones found here:
http://www.mcmaster.com/#wood-screw-drill-bits/

BobR wrote:2) What countersink angle is recommended or typical. I see there is 60,82, and 90 degrees for the zero-flute countersinks at McMaster-Carr. I'm assuming 60 degrees is about right?
I use 60 degrees for everything. It's a fairly standard countersink angle, and I can use it with a host of other stuff as well.

BobR wrote:4) If a delrin tenon is used, does the mortise still need to be contersinked since the tenon/stem interface should be at a clean 90 degrees unlike a turned tenon.
Yes. You will still get a much better fitment if you countersink. Plus it looks better.

-K

Re: Drills and countersinks

Posted: Fri Nov 22, 2013 11:46 am
by BobR
Thanks guys.