Repair question

[Kragax]

I was making a 7mm pen with a stylus and found a crack that needed to be reworked. both the tip and the transmission were installed. I pulled the transmission out, and trashed it in the process. Does anyone have a way to pull one and still be able to reuse it?

 

[oneleggimp]

This article from the IAP Library is the best technique I have found.

http://content.penturners.org/library/tools_and_jigs/A_SIMPLE_7MM_DISASSEMBLY_TOOL.pdf

Having said that I stll trash some 7mm/slimline tranmissions and ended up buying a few extra from Woodturningz in case that happens. Woodnwhimsies has them also. Pretty cheap insurance against not being able to re-use a pen kit.

 

[monophoto]

Craig

I saw an approach somewhere several years ago that I used once or twice. It does work most of the time, but since the idea is to save a transmission that otherwise would have to be scrapped, the fact that it sometimes fails is probably OK.

It requires that you make a jig (of course). Drill a 1/4" hole in a scrap hardwood blank about 2" long, and then carefully cut a saw kerf longitudinally about 2/3 of the way through the blank, making sure that the kerf aligns with the axis of the hole. The jig then becomes a soft collet to grip the transmission without crushing it.

Find two flat washers that fits over the transmission, and slip them down to the end where the transmission enters the pen body. Then, put the transmission into the collet, and grip it in a bench vise so that the split portion of the collet is squeezed by the vise. Slide the transmission down into the collet and the end of the blank where the transmission has been inserted, leaving 1/8" or less free space, and clamp down on the vise to firmly grip the transmission.

Then, slip a flat-blade screwdriver between the two washers and gently twist. Twisting the screwdrive forces the washers to separate. Since the transmission is gripped by the grooved block held in the vise, the only way the washers can move apart is for the upper washer push the pen body off the end of the transmission.

 

[Sabaharr]

There are many ways to do this that are tedious and mildly successful. One method that is 100% successful is buy a 5 pack of extra transmissions for a few dollars and don't sweat it. I usually trash enough pens to have spare parts around anyway, but that's me. Extracting a transmission stresses the mechanism a little also and can do damage you can't see that might manifest itself after you send the pen to its forever home. Then either you get it back to repair or get a bad name. Best insurance is a new transmission for the negligible price.

 

[WriteON]

PSI has a decent 7MM disassembling kit.

 

[Kragax]

Thanks all.

 

[Skie_M]

Craig

I saw an approach somewhere several years ago that I used once or twice. It does work most of the time, but since the idea is to save a transmission that otherwise would have to be scrapped, the fact that it sometimes fails is probably OK.

It requires that you make a jig (of course). Drill a 1/4" hole in a scrap hardwood blank about 2" long, and then carefully cut a saw kerf longitudinally about 2/3 of the way through the blank, making sure that the kerf aligns with the axis of the hole. The jig then becomes a soft collet to grip the transmission without crushing it.

Find two flat washers that fits over the transmission, and slip them down to the end where the transmission enters the pen body. Then, put the transmission into the collet, and grip it in a bench vise so that the split portion of the collet is squeezed by the vise. Slide the transmission down into the collet and the end of the blank where the transmission has been inserted, leaving 1/8" or less free space, and clamp down on the vise to firmly grip the transmission.

Then, slip a flat-blade screwdriver between the two washers and gently twist. Twisting the screwdrive forces the washers to separate. Since the transmission is gripped by the grooved block held in the vise, the only way the washers can move apart is for the upper washer push the pen body off the end of the transmission.

One piece of advice I'ld like to offer ....

To avoid any damage to the pen barrel and give you extra leverage, use TWO flat bladed screwdrivers from opposite sides. This will help keep the top washer flat against the pen barrel and give you extra pushing power.

 

[Chasper]

You don't pull them out, you push them out. I've removed dozens, maybe hundreds and can't remember damaging one. Use a thin transfer punch and push it through the transmission down to the nib, hold it in your hand and bang on it a couple times with a hammer. Turn it around and use a bigger transfer punch, the largest that will go in the tube and knock out the transmission.

I've had people come to me while I'm selling at a show, pick out a slim pen with chrome parts and ask if I have it in gold. I grab a gold pen of the same type, knock out the components, do the same with the one the buyer wants, swap and re-assemble and have it ready in 5 minutes.