Adjustable pen mill

[kenbu]

Just started turning pens -- and it's fun! Started with Slimlines and got a 7mm pen mill for trimming blanks, which worked fine. But, on kits with larger tubes, the mill was a sloppy fit inside the tube. I see mill kits with multiple shafts available, but they are a bit pricey, and aren't sized for every tube diameter. I tried sanding them, but the blanks aren't always (OK, almost never) square and true with the center hole.

It occurred to me that I already own a very large collection of shafts with precisely graduated diameters: my drill bit index! I could find one to slip snugly inside any tube I'm likely to encounter and chuck it in my M2 tailstock chuck. All I had to do is reverse the direction of the pen mill cutter and mount it in my headstock chuck. I just slide the blank into the spinning cutter until I see the shiny brass ring. Cheap, simple, accurate and easy.

Here is my 7mm pen mill ready to trim a Push Click blank sliding on a 21/64 bit.



Ken

[JPG]

Just started turning pens -- and it's fun! Started with Slimlines and got a 7mm pen mill for trimming blanks, which worked fine. But, on kits with larger tubes, the mill was a sloppy fit inside the tube. I see mill kits with multiple shafts available, but they are a bit pricey, and aren't sized for every tube diameter. I tried sanding them, but the blanks aren't always (OK, almost never) square and true with the center hole.

It occurred to me that I already own a very large collection of shafts with precisely graduated diameters: my drill bit index! I could find one to slip snugly inside any tube I'm likely to encounter and chuck it in my M2 tailstock chuck. All I had to do is reverse the direction of the pen mill cutter and mount it in my headstock chuck. I just slide the blank into the spinning cutter until I see the shiny brass ring. Cheap, simple, accurate and easy.

Here is my 7mm pen mill ready to trim a Push Click blank sliding on a 21/64 bit.

. . .

Ken

There be transfer punches that would work better(think drill bit with no flutes - i.e. different sized straight 'rods').

http://www.harborfreight.com/28-piece-transfer-punch-set-3577.html

[RobertTaylor]

if you turn your drill bit around you will have good results. myself I just "turn" different sized wood blanks to fit inside the larger tubes as I use the disk sander to square up the ends. as your pen mill gets dull you will destroy a few blanks and ask yourself/others if there is a better way.

[kenbu]

There be transfer punches that would work better(think drill bit with no flutes - i.e. different sized straight 'rods').

http://www.harborfreight.com/28-piece-transfer-punch-set-3577.html

Hmmm. Would these also be useful in pen disassembly?

[JPG]

Hmmm. Would these also be useful in pen disassembly?

Not having ever 'disassembled' one, I ain't gotta clue!:o

[Culprit]

Hmmm. Would these also be useful in pen disassembly?

Yes. Transfer punches are one of the preferred disassembly tools.

[terrydowning]

+1 on the punches.
+1 on Bob's approach with the disc sander. I find raising the tailstock slightly provides additional surface area for on the sanding and keeps the paper from wearing out i one spot.