segmented blank not quite square

[jdmyers4]

I've made a segmented blank, but it's not quite square. The problem is, what's the easiest way to drill a hole through the exact center using the lathe? Do I get myself a spur and turn the blank round first, then put the rounded blank in the chuck (jawed or collet) and bore the hole?

What kind of spur center do you recommend? I have a Oneway Talon chuck on my lathe, but I also have a Beall Collet chuck. Do I just use my live center at the tailstock end?

 

[leehljp]

Concerning the spur center, that should do it to get it round with relation to the center, then drill it. I don't have a spur center myself.

I have a jig on my TS and one on my BS that I trim an un-square segmented blank. From there I use my chuck. If it is out of center in the chuck, it won't do any good to drill it.

On my jigs, I use calipers for measuring and use paper or other very thin material to shim the segmented blank to bring it into square with relation to keeping it precisely centered.

Then I use the chuck and lathe. I need to get me a spur center!

 

[VisExp]

I mark the centers on both sides of the blank. By centers I mean the center of the design, not necessarily the center of the blank. Then I mount it on the lathe with a PSI 5/8" Super drive center at the headstock and a 60 degree live center at the tailstock.

http://www.pennstateind.com/store/LCENTSS21.html

Get a 5/8" drive center, that way you can turn the blank down to 3/4" without worrying about hitting the center with your skew/gouge. Use a 3/4" wrench as a gauge. When the wrench drops over the round blank it is 3/4".

Cut the blank in two, mount each half in your beall collet chuck and drill away.

 

[jdmyers4]

Ah! That sounds like a solution. Thank you both for the comments. I was getting very frustrated trying to drill a straight hole down the center with my DP on the segmented blanks.

 

[911redneck]

Drilling pen blanks with lathe

I use my chuck with pin jaws to drill my pen blanks. Because the pin jaws are much longer than regular jaws, it holds the blank perfectly to drill it perfectly centered.

 

[akbar24601]

It looks like Hank and Keith got you going in the right direction. Very good input from both.