Designer twists and a 3d printed transmission jig

[jschoolcraft]

A bunch of Designer Twist (no tenon variety) pens from PSI wrapped in a bunch of different wood, no idea on most of it. Some really nice chatoyancy on some.

Finishing:

• Sanded 120-600
• Quick wipe with alcohol
• Mylands Cellulose Sanding Sealer
• Doctor's Woodshop Pen's Plus (just one application)
• Renaissance Wax

I have a friend going to a craft fair tomorrow and she offered to put out some of my pens. I prepped and turned all of them over the last few days.

Now, onto the 3d printed transmission jig that made assembly a treat. I used it on every one of those pens and they all came out perfect extension.



This was heavily inspired by others:

• A Quick Tip for Seating Transmissions by Bob Swartzendruber seems to be the source for most of these.
• Mark Dyer demonstrates this in 10 Minutes to Better Pen Making - Assembly.
• Dave (@egnald) made very cool jig described in this thread: https://www.penturners.org/threads/press-perfect-jig.178095/#post-2189931

Mine, and I'll add a reply once I get this uploaded to thingiverse or something, is two sided. One side has a shallow recess to fit over one side of the milescraft pen press and the other side is an 8mm by 13/16 hole to accept the transmission. The instructions for the pen say to leave 13/16" of the transmission exposed.

So, you press the transmission in with the jig, then I flipped the whole assembly around to press in the tip while the transmission was still protected in the jig. Worked great.

Things I might do differently (or suggest someone else to do differently):

• Make the entire diameter bigger so the shallow recess fits both press fittings
• Remove the shallow recess altogether and just let the surfaces meet on the press fittings
• Print it with an embedded magnet and then you might be able to accommodate both a 13/16" depth and swap in a drill rod like Dave has to set the 1 3/4" depth for the other style pens (or make that's 6 of one, 1/2 dozen of the other)

 

[BHuij]

I wanted to like those designer twist kits a lot, but I just didn't care for the way they handled the center bands. They just rotate and sit loose unless you glue them to the wood of the top half, which rather defeats the purpose of the "tenonless" design IMO.

That said, these look great! I've always just used the "guess and check, err on the side of pushing it in not enough" approach to seating the transmissions. If I was going to make a big pile of kits, I'd definitely print a jig like this. Smart.