Help! I can’t get this screw out of my SP-15!

Here’s the end on view. Doesn’t the set screw hole appear to be in the wrong spot?

Hi All!
This screw in the vibrator assembly of my SP-15, a screw which my manual tells me is properly know as the Crescent Holder, is stuck. It has been three days now soaking in alternating baths of WD-40 and PB Blaster, and it still won’t budge.

It’s purpose is to insert the Crescent into the Worm, so that we get the oscillation (or vibration) we need to spread ink. The worm itself will turn about one-half turn with relative ease. I’m a bit afraid to force it after that.

I am open to suggestions about how to persuade this screw to exit — preferably leaving it intact. I have not, as yet, involved any process that includes the use of a propane torch, but wonder if that would be a viable option.

Thanks for any help.

Greg

Subscribe
Notify of
23 Comments
Newest
Oldest Most Voted
Inline Feedbacks
View all comments
Lauren Faulkenberry
11 years ago

I’m late to the party, but I found a cleaner called Krud Kutter at my local hardware store (non-toxic, not abrasive) that works shockingly well for cleaning parts. It took about 20 years worth of grime off our #3 and freed quite a few parts that were lodged in place with dirt and ink.

Enrique
11 years ago

It’s awesome you found the worm collar.
And that’s a wise advice from your machinist.
Better exhaust your possibilities before trying anything on the lathe.
In the end, cosmetically it might not look so great, but functionally it should work perfectly fine, unless there are deep scratches beneath the rust.
Keep us posted. At least I’m very interested in seeing your progress.
Good luck!

Widmark
11 years ago

I take it back, it’s off axis on my 219 as well!

Before I take it out and measure it, Fritz (or anyone), any idea what the specs for the set screw should be? My crescent holder keeps working itself tight. When Dave Seat was here he took it out and cleaned it out and we assumed some old ink was keeping the set screw from holding the crescent holder tight and it worked well for a while but then it started doing it again, where I’ll hear the oscillator jump and can see that it’s suddenly tight and I have to back off on the holder again. I’m wondering if my set screw isn’t just worn down?

Eric Holub
Editor
11 years ago

The setscrew in this configuration will contact the threads of the holder almost at a tangent, but with enough contact to do the job. And maybe with less chance of thread damage, compared to a setscrew that locks right on the axis.

Fritz Klinke
Admin
11 years ago

Now that it’s daylight, I think there is no crescent present or some sort of substitute and we are seeing the threads for the crescent holder. When that hole is drilled through the tube and into the end casting, it is then threaded all the way. And the retaining set screw is absolutely in the correct position for the SP-15.

Widmark
11 years ago

Regarding the question in the photo caption…is it normal for the set screw to be so far from the crescent holder? On my 219 it’s directly in line. In this photo it’s hard to see how the set screw would secure the crescent holder.

Eric Holub
Editor
11 years ago

OK, I misremebered the position of the setscrew (it seems Alzheimer’s may be contagious). Fritz is right about the visible threds, it suggests that the crescent isn’t there, or maybe it broke off and only its post is left.
Another thing, if the setscrew has been over-tightened to the point it damages the threads of the holder, it may also interfere with removal, as will dried ink or thread-lock compound.

Fritz Klinke
Admin
11 years ago

What’s wrong with the end view of the ink drum?? It sure looks like someone replaced the crescent with a threaded screw–there are no threads on a crescent and I see a lot of threads staring back at me, and that’s why the thing doesn’t work in the first place. This thing is literally screwed up.

Fritz

Fritz Klinke
Admin
11 years ago

An impact screw driver may work, but I’d try the propane torch approach first, heating the head of the screw and the area around it to cause expansion of the drum and crescent holder–that often breaks things loose. It may be a combination of rust and ink that is holding the holder in place and heat will cause the ink to loosen up.

The set screw is indeed in the right place and has to be backed off as the very first thing. We have replacement crescent holders and crescents, so it’s not a loss if the head of the holder breaks or has to be drilled out, but the crescent stem goes up inside the holder and the crescent is hardened cast steel.

The cresent stem needs periodic lubrication with graphite grease as a point of reference. And has been pointed out, get rid of all that rust on the ink drum.

Fritz

Ray Nichols
11 years ago

You might try buying a can of spray air and just blasting it for a bit to radically cool the metal. Might get the seal between them to break enough to get the screw moving. I’ve done this a couple of times on other kinds of things like this.

Paul Moxon, Moderator
Admin
11 years ago

The set screw is the the normal postion. Once it is backed out, lock a pair of Vise Grippers onto the shaft of your screw driver and turn it counterclockwise.

Enrique
11 years ago

My recommendation would be to remove all the rust first with evapo-Rust. A nice and generous bath for a day or so.. and then try to get it out.. you definitely have rust in your screw.

Eric Holub
Editor
11 years ago

Yes, the allen set screw would be the problem, especially when you don’t know it is there.
The strange thing is it is not visible in the picture. I can see the notch that the crescent slides though, and the set screw should be in line between the notch and the holder screw in question. I don’t see a thing. Can it be buried under a perfect layer of silver ink?

Lad Boyle
11 years ago

Think about letting a machine shop get the screw out for you. If you mess it up, it will cost a lot more to deal with the new problem

Widmark
11 years ago

Have you applied the PB Blaster to the set screw on the side as well? Though I imagine it should soak through from the top. I have a similar issue in which my crescent holder works itself tight during use, despite the set screw being tight, so I routinely (not too often), have to pull back on the holder. I probably need a new set screw.

Copyright © 2024 vandercookpress.infoTheme by SiteOrigin
Scroll to top
23
0
Would love your thoughts, please comment.x
()
x