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Thread: Can I thread JB Weld
12-26-2009, 07:59 PM #1
Can I thread JB Weld
I have an Al pulley with a setscrew hole that the threads are almost all stripped out. I was wondering if JBweld could be used to fill the hole then rethread.
I think a Helicoil leaves a tang blocking the hole so a set screw would not work? No room to rethread next to existing hole. It is keyed onto the shaft so I think the set screw is not that highly loaded. This is a custom pulley with a geartooth pattern on one side for indexing or I would just make/buy a new one.
12-26-2009, 08:06 PM #2
You could clean the hole well and butter some jbweld on the sides of the hole. Then spray a proper sized bolt with pam cooking spray and give a couple of minutes to dry. Just thread the coated bolt into the hole and allow to set up. This will salvage what is left of your existing threads.
The pam cooking spray will prevent many glues and rosins from adhering.
12-26-2009, 08:10 PM #3
12-26-2009, 08:23 PM #4
any "heli-coil" I have ever used had a score on the tang allowing it to be broken off with a puch once wound to depth. perhaps there are different kinds with non-detachable tangs that I am unaware of. I would highly recommend a heli-coil (or equivalent) kit, they are a terrific means of internal thread repair.
I've only used JB weld to scab a very non-critical motorcycle case crack. I would never trust it on such an application.
12-26-2009, 08:51 PM #5
Helicoil it. Use the shortest Helicoil, or cut a longer one shorter and thread one from each end of the pulley to leave the set screw hole clear.
12-26-2009, 09:49 PM #6
A helicoil would work, but there are many other thread repair options out there. Keenserts, for example, are much more durable, and do not require a special tap - they use standard threads. It's worth looking into if you only have one to do, so you can buy one $2 insert instead of a $35 kit. Check McMaster-Carr or your local (good) hardware store, if you have one.
12-27-2009, 08:15 AM #7
Locktite makes a product to repair damaged threads, used in the same way for the most part as their thread locking stuff. I have not used it, and don't know what limits regarding strength that it may have.
12-27-2009, 08:49 AM #8
My .02 cents on JB weld and others is: totally worthless goo. If you only have a small area to oversize, then helicoil is best. Keenserts work good, but are bigger in diameter, therefore needing more space.
12-27-2009, 08:58 AM #9
My limited experience with JB Weld and thread repair has taught me the stuff is too "crunchy" to really accept a tap. Reminds me of trying to thread one of my ex-wife's brownies.
I did have some luck with a greased pipe plug, slowly turning it while it set up. As I look back, it became a challenge rather than an accepted method of repair.
12-27-2009, 08:59 AM #10
Would it be possible to weld the hole closed, dress up the weld, re-drill and re-tap?
12-27-2009, 10:15 AM #11
Why not tap the next size larger? Perhaps with a fine thread...
12-27-2009, 11:53 AM #12
I think this idea would work for you without using JB Weld. I am not against the
JB Weld idea and I use it hear and there. I know the directions say it can hold
threads but I wouldn't do it.
Try this. Drill and tap the existing hole a few sizes larger in diameter. Get a bolt
and cut it down and drill and tap the center with your set screw hole. Screw in
the larger bolt into the larger hole with JB Weld on the threads. It will make a
good repair and the threads that mate with the allen screw will not get stripped
12-27-2009, 05:18 PM #13
Like WHHJR said above - Is there a Happy metric size you can squeze in there?
12-27-2009, 06:02 PM #14
12-27-2009, 06:36 PM #15
Try timeserts. Available at Pendergrasstools.com