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So I have been struggling with my drum sander (Performax 16/32). After 11 years the threads on the cast aluminum housing that elevates the drum wore away to nothing. I then used a Helicoil in it and that worked for a few months but the strong steel in the coil ultimately wore all the threads off of the shaft that elevates the drum. So then I took it to a machine shop to have them "do it right" and they made a bit thicker shaft out of harder steel and put in a larger helicoil... But now the coil works free of the plate.

I have used Red LocTite and put the coil back in, but is there something stronger I can use to cement the coil in place? My next step us is a wide belt, but I am just not prepared to drop that kind of money on one yet. I need to get this to limp along until then.

Thanks for your help.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Have you tried Metal-Set? It's an epoxy with an aluminum (IIRC) filler. Really tough stuff.
Most auto supply places used to carry it, but I haven't seen it in a while.
Frustrating problem! Good luck, getting it fixed Brock.

Thanks guys.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Assuming the helicoil is chrome moly or something harder, clean everything WELL with acetone or mek then.....JB Weld, which is essentially the same thing as Metal-Set, a metal filled epoxy.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Good to know. Thanks!

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

There's threaded inserts that are alot stronger than heli-coils. What size do you need? GM dealerships use "Time-serts", and most dealerships have most any size. http://www.timesert.com/ PM or e-mail me if you can't find any and I'll see what I can come up with.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

I would try GREEN LocTite. It is designed to re-set bearings in a cup when the cup has become oversized. I bet my life on all the colors of Loctite for 15 years. Green really locks stuff in place. So, I would try the sterile cleaning already recommended and give the green a try. Note that it is designed for applications where frictional heat will develope(64 yoa spelling) so you had better want the piece where you put it! I reset a pinion shaft in a $2500 magnesium cased quick change sprint car rear end using green and it never moved-the upper shaft(this allows the quick change) bearing wore out before the fixed one-did the same repair and lived happily ever after. You may have to purchase through a fastener supply specialty house.

Totally different idea. Jet has locations arround the country where repair work is done. They tend to look like old auto repair garages. I've been in one in Nashville. Piles of old machine parts laying arround. Bet you could buy that part really cheap with a little searching.

I have done a little searching for the part, and it appears that the new ones are not the same design as the old models and nobody can guantee they will work, and I have not been able to locate a NOS part that will work on a performax as old as mine.

But that is a good idea worth looking into if I can't find a way to lock that coil down tight. I hope that I don't have to get more than another year out of this thing before I get Grizzly to send me one of those snazzy wide belts.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Brock-had you already been through the green stage? If not, really, it is stronger than red. I can't say it would beat out JB because JB to set a Heli-Coil would "add metal" in the female of the threaded piece that captures the insert.

In the year 1964-5 I worked for a progressive fastener company in Downer's Grove , Ill. They were an early center for Heli-Coil and Loctite products. I was 18-19 then and learned quite a bit that helped me when I started racing-building, maintaining and driving.

Sounds like the heart of it has something to do with not enough threads into the base coupled with a harder shaft threading into a soft metal... That was a classic Steel threads into Aluminum base problem that plagued cars for a long time... They ended up with 2-3x more threads or using thick steel inserts in the Aluminum..

The 2nd part is that usually -- helicoils and these type inserts aren't made for adjustable sections.. they are made to screw in and tighten and stay put

You may need to have a solid steel insert made up and then fitted into place -- they can thread the hole a bit tight and red-loctite a larger solid steel insert into place.. or they can make an insert that press-fits into place with green loctite....

It may be worth checking out the cost on all this... You may decide it's time to retire the old mule and get something new.... You earned it.

Thanks

John

Get key-locking inserts (sometimes called keyserts). I'd say they're the 'right way' to fix something like this; I've thought of helicoils as a patch at best since I've used those.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

No doubt, Bob G is onto the best solution. Bet you could do that without machine shop help. Check mcmaster carr

Ooooooops

That is exactly the situation. I am hoping to just limp another year out then go for the wide belt.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

If your sander is anything like my 16-32 Plus there is a lug with the female thread on an aluminum plate. If I were looking for a longer term solution on mine I would cut off the lug and weld on a new one and then retap it. I would avoid anything that involves a glue.

I'm with Bob on the use of helicoils. Never have liked them on something that has constant use. If the keyserts are the ones with the stakes that punch down to hold the insert in place those work well for assembly/disassembly and prevent the insert from turning in either direction. Been a long time since I've used those, and mostly under 1/4", so not sure of the name without doing some research. It would involve buying an oversized tap and an installation tool or looking around for someone who may happen to have them.

Tim

Those are the ones. There are options so far as the size of the outside VS the inside thread (so you can use a big exterior thread to get more strength). You can install them with a hammer and screwdriver or anything else that'll knock the pins down. Not the best idea in production, but there's no need to buy an installation tool if you're only using a few of them.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Apparently, depending on the situation it can be made to work. We've got an aluminum part with a helicoil type insert (at least it looks like a helicoil, haven't truly inspected it that closely) that get's sterilized (autoclaved) each time it's used and I've never heard of one failing. It is however, a very coarse thread.

I'd get it fixed one way or another so it's worth more when you sell it.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Go with the keylock insert and rethread, just makes the most sense