ASR 33 Print Hammer Repair

The rubber pad on my new ASR 33 Teletype's print hammer was worn down to the metal, and what was left of it was hardened. I've attempted a repair by cleaning it and then sticking a Bumpon (stick-on rubber/vinyl equipment foot) on the end, but I'm concerned that the Bumpon will fly off at some point during printing, especially after oil has managed to migrate up the hammer and weaken the adhesive. If I don't catch that in time, then the print drum could be wrecked.



Do any of y'all have better ideas for repairing the print hammer?

I gather the accepted method is to put a bit of thickish vinyl tube of the head. There has been some discussion on 3d printing replacements as you can get soft materials to print in 3d...

I repaired the print hammer on my Teletype ASR Model 33 using a rubber like compound as can be seen on my blog at http://www.foxdata.com/blog/?p=777

I got the idea of using a Bumpon from a web page I found while searching for ASR 33 info. The rubber tube and rubber-like compound (i.e. Shoe Goo) both sound like better ideas. I may have some tough fuel line hose of a suitable size that I can try out later today. The 3D printing idea also sounds interesting. I didn't know that they had rubbery materials for those.

Thanks!

or remove the gunky hammer pad and put a pvc tube over the bare metal hammer

http://www.vintagecomputer.net/teletype/ARS33_sn659854/Printer-hammer-re-padded.JPG

I have more info herehttp://www.vintagecomputer.net/browse_thread.cfm?id=461

Tygon is a bit softer and doesn't harden up with time/oil. I use Tygon for tape capstan repairs.

Is Tygon tough enough to withstand hammering against the type drum, though? I thought it's pretty soft, and I'd think that it might wear quickly.

I was thinking of the very stretchy yellow tubing used for things like lab burner hoses, wrist rockets and water weenines when I saw Tygon. However, searching for Tygon tubing at McMaster-Carr turns up all sorts of stuff under the Tygon brand name, so maybe you meant something different?

When I was at the LCM they had also taken a piece of tube and used that to replace the hammers on their teletype machines.

I found some 5/16" ID SAE 30R3 fuel hose out in the workshop. It fits snugly over the end of the hammer.

I think that you're thinking of latex tubing:



Tygon looks a lot like vinyl tubing, but is slightly yellowish (still transparent). It's used a lot for fuel lines and in the medical racket. Great stuff--oil won't bother it.

pvc tubing is considered the "accepted" replacement solution on the greenkeys teletype mailing list community. It works quite well. I use extensively. I replace the tube each time I replace the ribbon.

Latex tubing is what I was thinking of when I read "Tygon". I dimly remember it being called "Tygon tubing" back in college, but my memory and/or what we called it could certainly be wrong.

The hammer is back in place now, and it seems to be working. I had to replace the tubing with a shorter piece to avoid interference with the ribbon advance mechanism. Print is light; I put in an unused ribbon, but I think it's still a bit too dry. I also notice that the first two characters of the line are jammed together, so some more adjustment is needed.



I also removed the print drum and thoroughly cleaned it. The linkage which resets the print hammer was a bit tricky to deal with. It probably would have been easier to adjust if I had a 1/4" combination wrench handy. I just had a socket driver handy, so I couldn't tighten the lock nut while holding the eccentric stationary with an Allen wrench.

I need to load up some better paper. I might have some out in the workshop already. The paper that came with it is brown and brittle.

Edited to add: Another tool that would have made things easier would be a spanner to hold the print drum in place while tightening its nut.