SP-15 Worm & Crescent


I have a Vandercook SP-15 and the crescent just broke for the second time. The first time this happened was over 2 years ago. This time though, I can see that points on the worm are knocked off too. Why is this happening? What can I do to prevent this wear?

Last time I purchased a replacement crescent thru NA Graphics — who I’ll probably contact again. Also, I’ve emailed Don Black Linecasting — but where else can I procure replacement parts?

I know I need a replacement crescent and am hopeful I can replace the worm too.

Lily / Lilco
Dallas, TX

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Here are some pics:

image: crescent_01.jpg


image: worm_02.jpg


image: worm_01.jpg


Have you been lubricating it with vaseline?
This time you should replace the crescent holder as well, because wear to the holder or the crescent post could change the alignment and lead to broken points. The crescent post and holder should be lubricated with graphite grease when reassembled.

Hello Lily,
When I have seen crescents completely broken like this it is typically from someone dropping the oscillating roller from its cleaning position rather than letting it down gently. Was someone else using the press when this happened?

When you put the new one in make sure you don’t tighten the main bolt too much. It should be loose enough to move freely when you turn the oscillator by hand- the Allen head bolt should keep that main bolt from backing out or working loose.

If possible, you should try to get all three parts- crescent, crescent holder and worm gear. Put a little bit of oil in the holder before installing it.

Daniel Morris
The Arm Letterpress
Brooklyn, NY

Thanks for all your comments.

@ Parallel_Imp: Yes, I have been using vaseline. I try and check it every it other job just to be sure it doesn’t dry out.

@ Daniel: This is the second time the crescent has broken and I cannot figure it out. I’m very gentle when printing never ever drop the oscillating roller. No, I never loan my press or let anyone else use it. This time, the break happened at the end of the press bed — as the paper was releasing from the buttons. So weird!

I was talking with Casey McGarr (Inky Lips Press) and he thought perhaps I was left the main bolt too loose and that the crescent was wobbling too much therefore wearing the channel and points of the worm. However, your comment to not over tighten makes sense too. How do I know what is correct?

Update! I have new crescents from Fritz and hopefully have located a replacement worm from Don Black. But, I don’t know what the crescent holder is — I guess I need to look at the diagram again.


Oh, so the crescent holder is the hollow bolt that screws into the vibrator assembly that the shaft of the crescent inserts inside. Why would this part need replacing? Isn’t it just a tube — what can wrong with it? Sorry, is that a dumb question?

The post of the crescent pivots in the crescent holder. If the crescent post wears and wobbles, it can also wear the holder. Then the replacement crescent may not ride true, and wear prematurely.
What is the correct position for the holder? If too high it will ride above the surface of the roller. If too low it could bind and impede the movement of the crescent. Don’t forget the setscrew on the end of the oscillating roller that keeps the holder in place.