Pentel Pencil Conversion Mandrel

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Chuck Key

Chuck Key

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May 3, 2005
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Pentel Pencil Conversion Mandrel FAQ

I had a mandrel made about seven years ago to aid in turning Pentel pencil conversions. I have made countless pencils with it to date and will continue. Here is a photo of the mandrel.



20085944232_PPCM3.jpg



It uses two 1/4 x 28 nuts and a slimline size bushing on one end and two 8-32 nuts with a shop made bushing on the other end. Here are additional photos of the mandrel with a blank mounted and another picture of the setup mounted on a lathe.



20085944612_pblank.jpg





20085944643_ppcm2.jpg



This setup makes it easy to turn the Pentel pencil conversion.

Chuckie
 
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FAQ #1

My only other question is I've got a step bit per the specs that Don Ward published and as it turns out it is 17/64 instead of 1/4. Do you think a 64th would make any difference?

Answer #1

Look at the first picture above. You will see some blue painters tape wrapped around the mandrel. That is what I use to take up that 1/64th. The tape does make a difference. I usually use two wraps around the mandrel which is about right for my drill.
 
FAQ #2

What do you mean by SHOP MADE BUSHING?????

Answer #2

I find it helpful to make and use a small step bushing on the business end of the pencil as shown in this picture.



200851221510_PPCM4.jpg



The yellow piece is the shop made step bushing. The RED step is a guide to make a tenon for the pencil nib. Is is cut with a 1/8 inch parting tool (YELLOW X)

The second step BLUE provides a guide line for the start of the outside diameter of the pencil body.
 
FAQ #3

My question is how the mandrel will be connected on the lathe, especially with the small threaded end.

I'm assuming maybe a sleeve and nut(s) go on the small end; Will the small end go to the headstock with a chuck on the nut?

Answer #3

I hold the mandrel on the threads in either a drill chuck, collet chuck, or usually in the three jaw chuck on my metal lathe. I have been doing this on the same mandrel for over seven years. The threads are worn slightly but they get to where they tolerate the pressure.
 
FAQ #4

If I have it right so far, the 1/4 end has an indent in the end to accomodate the tailstock?


Answer #4

You are correct. The other end will accept a 60 degree center to hold it in place.
 
FAQ #5

Always time for questions!

Q. The main body of your mandrel was made from an old "regular" mandrel?

A. Yes, I purchased several new mandrels and are modifying those for the conversion mandrel.


Q. The smaller end, the nib end, is the same as the inside diameter of the pentel mechanism, right?

A. Yes, again. You are correct.

Q. How did you get the 60 degree indent, did you drill it yourself?

A. The 60 degree indent is original to the mandrels I purchased. I do not modify that part at all.

I am planning to attend the NOVA Picnic this weekend. Maybe we can share a few of our secrets in this area :)
 
FAQ #6

Nuts? Are you nuts?

Answer #6

You will need to pick up a couple of 1 x 28 tpi nuts if you do not have them. They are available at Lowes in the Special fastener drawers in Drawer section C.
 
Originally posted by Chuck Key

FAQ #6

Nuts? Are you nuts?

Answer #6

You will need to pick up a couple of 1 x 28 tpi nuts if you do not have them. They are available at Lowes in the Special fastener drawers in Drawer section C.
Click to expand...

Make that 1/4 x 28 not 1 x 28, duh!
 
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