Slim Line disassembly

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Woodchipper

Woodchipper

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Got the clip and the nib out with no trouble- a few quick, light taps like described in another thread. However, the twist mechanism is a different story. I have worked on it for several minutes but it hasn't budged. Would a shade tree setup on the DP give any more pressure than the plastic mallet and the punch? Again, your help is most appreciated.
FWIW, got the calipers on the top part and don't need to take too much off.
 
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There is a trick that I saw described somewhere - - -

You are going to need a scrap of wood (the end of a pen blank is fine), a drill bit with a diameter that is very slightly larger than the diameter of the transmission (your standard 7mm pen bit is fine), two washers with a hole diameter the same as the drill bit, two flat blade screwdrivers, and a bench vise.

Drill a hole in a scrap of wood that is very slightly larger than the diameter of the transmission. This technique works best if the hole is into the end-grain of the wood. Then, make a saw cut into the block that leaves a kerf that is parallel to the wood grain and that ends in the tubular hole.

Then, lightly clamp the block of wood in a bench vise with the saw kerf parallel to the jaws of the vise - when you clamp down with the vise, you want to squeeze that kerf closed. Insert the transmission through the two washers and into the hole. Adjust the position of the pen so that you can separate the two washers by about 1/16", and then tighten the vise so that it clamps down on the barrel of the transmission. Because the hole is round, the force on the transmission barrel will the uniform around the circumference and should not damage the transmission. Essentially, the block of wood is now a 'soft touch' collet to hold the transmission.

Finally, insert the blades of two flat-blade screwdrivers between the washers - with the two screwdrivers on opposite sides of the washers. Gently twist the screwdrivers to force the washers further apart. Because the transmission barrel is tightly gripped in the hole n the scrap of wood, separating the washers will create a force in the direction to remove the turned barrel of the pen from the transmission, and that force will be applied to the end of the turned barrel without causing any damage.
 
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I simply use an extra 7mm tube, slide it over the tranny all the way up to the tube in the blank. Stand the assy upright with the spare tube resting on some solid metal like the lathe ways, anvil, etc. Just a tap or two (and they usually don't have to be very hard) on the punch will drive the tranny out of the blank & into the spare tube.

If you're careful & don't tap too hard, you might be able to pull the tranny out of the spare tube & reuse it. But slim tubes & granny's are cheap, so I keep a number of both on hand & don't worry about losing the tranny when I drive it out.

Edgar
 
Thanks, guys.
Edgar, I'm cheap- don't like to ruin parts but will take your method under consideration.
Louie, thanks. Will print and read in detail.
 
Did you pop the nib out? I find it easier to push the transmission out, rather than any method of prying it out.

A 1/8" transfer punch (or old, long drill) fits in the center hold of a 7mm transmission. Use it to tap out the nib.

A 15/64 transfer punch can be used to tap out the transmission from the nib end. A better option is to use a pen blank offcut slightly longer (1/2" maybe) than a transmission, and drill a hole just slightly larger than the diameter of the transmission. Place it over the transmission, put the 15/64 transfer punch in the opposite end, and use a clamp, or vise, or lathe, or drill press, or pen press to expell the transmission.
 
The nib came out with no problem. I went in from the nib end and couldn't get the tranny to budge. I could see progress on the clip and the nib while tapping the punch.
 
Two things: -

- I assume you got the nib out by sliding a small diameter punch or drill bit through the center of the transmission

- I don't understand what you mean by "a shade tree setup on the DP", although I do know that DP = drill press
 
I just drilled a hole in a block of wood the size of the transmission and used the proper HF transfer punch but instead of hitting it with a hammer I use my drill press as an arbor press by putting the transfer punch into it.

Was it maybe glued in?
 
Cliff and Burlman, thanks.
The tranny isn't glued in. Will check the link.
Edit- Just looked at the link and it is really simple. So easy a nine year old could do it. Just need to find a nine year old. Thanks. It's surprising what you can find in the library.
 
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