Blank preparation problems

[bluesguitar]

I have two problems with preparing my blanks, and hoping you all can help me figure them out:

1. I'm using a HF variable speed mini-lathe with the PSI dedication pen chuck and drilling my blanks with that setup. The lathe does have some play in the tailstock so I can lock it down in different ways and suspect it could be off by a couple degrees sometimes. The drill bit moves forward as the live center is advanced and things seem to working OK but when I take the blank out of the chuck, the exit hole is off center, sometimes 4-5mm. I haven't wrecked a blank yet, but I could. Do you figure it's the lathe or am I doing something wrong?

2. I'm using the PSI barrel trimmer to line up the ends of my blanks but after trimming down to the end of the brass tube, the wood is still "wavy" as opposed to totally flat. I'm not noticing it until I go to assemble the pen and I end up having to sand it flat. Maybe I'm just not going far enough down on the end of the blank?

Any help appreciated,

Mitch

 

[Dave Turner]

If your tailstock is not locking down in precise alignment with the headstock each time you lock it, then that's probably your problem. With no pen blank in place, advance the drill bit all the way into the center hole on the dedicated pen blank drilling chuck (at the bottom of the jaws). Is it perfectly centered within the hole? Is it perfectly centered each time you bring up your tailstock?

I use a disc sander for squaring my blanks, so can't help you with problem #2.

 

[bluesguitar]

Thanks that's helpful.

 

[johnnycnc]

Mitch,
Are you backing the drill out every so often, to clear the chips?
I'd say every 1/4-3/8" you normally want to pull the drill out and clear the hole and flutes. A packed drill will do all sorts of bad stuff, including drift as it goes deeper.

Sounds like your trimmer head is dull. sometimes they don't last too well. Try trimming the blanks to no more than 1/16" extra after you drill your hole,before you
glue the tube in. Too high of rpm will speed the dulling and chatter up, also. i do not like to use mine with any more than a nudge of power in the cordless drill.

 

[bluesguitar]

Not pulling the drill bit out could be it but it's a slow process so I'm always tempted to push along. Thanks for the advice -- I'll keep on trying!
Mitch