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The threads in the motor mount slide of my 16-32 Performax drum sander stripped off first thing this morning. Argh. That's the part that moves the drum sander head and motor up and down. I have a replacement part on order that's the corresponding part for a Jet 16-32. Based on the parts diagrams and photos of the part, it appears to be the same thing. Looks like I'm going to get to know my drum sander a lot better next week.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

That is not a very good start. The last thing I would have expected.

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http://www.Harvestmoonguitars.com

It's strange because the vertical adjustment screw has been turning fine. That part does carry a lot of weight though and I guess the metal in the motor mount part wasn't up to the task over the long term.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I would probably drill it out and replace it with a press screw:
https://www.mcmaster.com/press-screws/h ... ew-clamps/
or
https://www.amazon.com/Tools-6709-Heavy ... JQ5Y1P5F05
But I am a bit of a tool bodger, and "cheap" to boot.

Sorry to hear that. Not the best way to start the day

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

That would be an option for someone with the know how and tools for that, but that's not me. As it is, the disassembly and reassembly is going to take some time since I haven't done it before and who knows what problems will crop in the process. For now, I'd rather have a drop in replacement part to minimize the time and complexity.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I looked at mine and it occurred to me that it is a place that could use some lubricant every now and then. I have a jet 22/44 that has the same screw and plate. When you get is disassembled you might one to know how to get your hands on the correct tap for the plate. I would have thought the screw was the harder metal. I am wondering if something was pulled in and started the stripping. In any case the plate maybe a bit stripped as well.

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http://www.Harvestmoonguitars.com

That sucks...

Actually, it's the threads in the plate that are stripped. The screw threads are fine. The metal rings in the screw threads in the photo are what's left of some of the threads from the plate.

Since the threads in the plate are shot, tapping it would mean enlarging the threaded hole in the plate, wouldn't it? Then I would need to find a replacement screw with a larger diameter and I don't know it that would fit through the top of the frame for the crank handle to attach to.

I agree that lubricating this part every now and then is a good thing.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Dang! So have you noticed it behaving oddly up to that point? Did it seem to get stuck before it stripped?

Standard procedure is to drill/tap to a larger size and install a steel threaded insert or stainless steel helicoil. The problem would be finding that particular thread size, which is super fine (and metric, no doubt).
This is very common in aluminum.
I think I will put some oil on mine before I use it again.
My sandet is the Ryobi WDS 1600 knockoff, and the slides were too tight when I first got it, making the adjustment wheel unnecessarily hard to turn. If I hadn't rectified the issue, I may have experienced the same problem.

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John

No. When it failed, I was cranking the drum upwards to get clearance for a piece. It was cranking fine with little resistance. All of a sudden what little resistance there was went to zero and the drum head and motor dropped down to the table. I had actually oiled the threads about a week ago because the resistance had increased a little bit recently, but it wasn't much of an increase. It still cranked easily and smoothly and the oil brought it back to where it had been.

I don't know how old the machine is. I bought it used about 9 years ago from another builder who was upgrading to a bigger drum sander. I don't know how long he had it, but it was very clean at the time I bought it.

Is it even possible that sanding dust getting into the threads could lead to a failure like this?

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I like to use "white grease" (lithium grease, lubriplate) rather than oil. It seems to stay in place better than most lubricants. The problem with aluminium, titanium, and stainless alloys is that unless well lubricated they tend to gall from the friction generated by turning the screw. Plain carbon steel doesn't do that.

You can probably find helical thread inserts, and the proper tap for them in a set. We used them in the shop. Aluminum does have the strength for much load in bolt holes. They easily cross thread, like spark plug holes.

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Why be normal?

I have the 10-20 model and it did the same thing. This is a known issue with the smaller version and the repair is somewhat more challenging, as the threaded plate is part of the actual housing and not a separate piece that can be replaced independently. I knew this was a weak link and had kept it lubricated with the white lithium grease Clay mentioned. Thought I was smarter than the average bear and it worked great until it didn't. Then—boom—game over. All fixed now and hopefully for good. Time will tell. I really, Really, REALLY like having a drum sander.

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George :-)

Thanks for everyone's advice on ways to fix the existing motor mount plate. If the Jet replacement part that I have coming turns out to be incompatible with my Performax, I'll go down that path. I hope it doesn't come to that though.

However it gets fixed, I'm going to be more religious about keeping the mechanism lubricated in the future in case that contributed to the failure.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Yes it really is a design fault. There's a fair bit of stress on that thread and the Aluminium is not up to the job. Jet (and the others) should have put in a steel insert.

I am almost neurotic about squirting with lithium grease but would not be surprised if it goes one day. As George says I absolutely would not be without the machine!

Dave

Thanks for the lubrication reminder!

Sorry your machine is down - Last month I lost the motor in my combo sander. It was down for almost 2 weeks before the fresh motor arrived.

Performax/Supermax have switched to iron for the frame components. The change is reflected in the weight of the thing for sure. I was able to load my old performax 16/32 into my pickup by myself. Not so much with my Supermax 19/38. I think it weighs in at about 300#. I can still get 300# off the ground - after that...?

Best, M

I have the Ryobi version of the 16/32. The plate is painted black and appears to be cast iron, but I could be wrong. I tried to carve a little metal off a sharp corner with my pocket knife, but it wouldn't cut into it. Usually aluminium carves pretty easily.
Greasing the slides John mentioned is something I hadn't thought about, but is something I will do next time I use the sander.

Michael, this old fat guy can still get 300 lbs. off the ground too, as long as I have my cane to help pull myself up.

That part of the Ryobi is definitely iron or steel, as confirmed with a magnet. I would not have guessed, since much of it is made from cast aluminum. The slides are adjustable, though it is not easy to get it adjusted just right. Free moving with no discernible play is the goal.

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John

Gotta say, Jay’s pic looks like iron. I remember most of mine being aluminum - my memory makes stuff up often.

Because of the lack of rust on the unpainted (my assumption) part I thought it was aluminium or some other softer alloy. Maybe he could do the magnet test.

Magnet test says the plate is aluminum.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Since the replacement plate was scheduled to arrive today, I pulled the drum head and motor out of the sander yesterday. It turned out to be pretty easy. Four bolts (called Gib screws) and a set screw.




The threads in the plate that engage with the adjuster rod were stripped clean. You can see where they were, but the inside surface is completely smooth.





I took advantage of having the drum head off to replace the feed belt with a new one I've had sitting around for several months. It's easier with the drum head out of the way to get to two bolts under the motor end of the head that have to be removed to pull the table to swap the belt.




The new plate arrived late this morning so I disassembled the drum head/plate/motor. Again, pretty easy. Four bolts and another set screw. The new plate is on the right below:



The new Jet plate is not identical to the old Performax plate, but it is identical where it matters. All the bolt holes line up and the threads match the threads on adjuster rod. The new plate has some features I like. The biggest improvement is that the block at the top of the plate that the threaded adjuster rod goes through is much taller (red arrow). That should spread the load out over more threads and hopfully make it less prone to failure. Another change is that the surfaces around the slots that the Gib screws slide on are wider. Also, two braces were added at the top.




Drum head/plate/motor reassembled:




Back in action. This was actually an easy repair and didn't take much time to do. Amazingly, no problems reared their ugly heads.
For anyone who might be interested at some point, I got the new motor mount slide plate from eReplacementParts.com.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Good job! The redesign is much superior.

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John