set screw removal

jim_uny · Nov 11, 2013

have elevator w/ drive shaft gears with rusted on set screws. broke t-handle hex when trying to move them. heated, pbs blasted no luck. can you drill w/ titanium ? what are some tricks that work ?

dr sportster · Nov 11, 2013

Left hand drill bit. Snap-on tool that you hammer in a splined shaft then place a nut with internal splines on top,turn with wrench. Drill with tap drill for those threads pic out leftovers with pic. Lots of ways.

John730D · Nov 11, 2013

You said you heated. Was it red hot or just heated. If red hot the screw should come out squeaking. If it stops squeaking, reheat. Lots of heat and patience.

Bill M. From Illinois · Nov 11, 2013

I have found an impact drive will remove allen screws that are super tight and risk being stripped out. I recently removed allen head screws on baler knife that would not budge but came right out with impact driver. I think I had to use adapter from 1/2 to 3/8 drive. On smaller set screws you have to be careful of stripping it out if and always best to use fresh allen wrench. A 1/4 impact works good on these if it wont loosen by hand. Just ran into that on my sink handles.

Jason the Red · Nov 11, 2013

You don't specify what size of set screw, but you could use an 3/8 to 1/2 adapter and a long handle ratchet (be careful of breakage if the set screw is small).

Are you sure the set screw has not got Loctite? This is common practice, but ample heat should have loosened this up.

Also, there could be a jam screw on top. If the hex in the jam screw lines up perfectly with the hex in the set screw, the hex key could slip through the jam and cause you to be trying to loosen both the jam and the set screw at the same time.

Butch(OH) · Nov 11, 2013

If they will still hold a wrench heat red and try again. If they wont hold a wrench everyone has their favored tricks. I prefer methods that don't make the problem worse if they don't work. Welding, easy outs, heating and then quenching all have that distinct possibility. A Cobalt drill that is to tap size for the screw thread is what I would use. Do not step drill. You need good bits with the correct percentage of Cobalt not cheapo junk that claims to be Cobalt so go to McMaster -Carr or Grainger web site, or a machine tool supply if you have one near and get a couple extras, Cobalt bits are brittle. The set screws are hard but not super hard and the trick to drilling with Cobalt bits is to run the drill slow, use plenty of any kind of oil but cutting oil is best and take it easy pushing until you have the bit past the broaching for the wrench and then push hard enough so the bit is pulling a good chip, this is what cools the bit and keeps it cutting, zing the drill wide open just once with no pressure and you will know why I said get extra bits. It is easy to tell when you break through the screw.

JMS/.MN · Nov 12, 2013

Heat red hot, cool with candle wax. Repeat if necessary. Even with drilling, take advantage of the heat generated and melt the wax into the threads.

Dick L · Nov 12, 2013

I would choose to drill them out. I have a stuck bolt in a mold insert and will be drilling it out and cleaning the threads with a tap this morning when I get to work. I'll have the inset fixed, the mold back together and in a press, cycled in and ready to run in the morning at start up. Customer needs parts not excuses.

Dick L · Nov 12, 2013

I got my stuck, broken off 3/8" allen bolt drilled out, threads cleaned out and in the mold base. I did twist a hard drill bit at the chuck when it broke thru. Took the end of the bolt out with a standard high speed drill bit. The end was like a big shaving. Also changed out two inserts in the mold and polished out some spots. Changing inserts also causes the need to change to matching ejector pins. The mold is hanging on the hoist ready to snag with the forklift and slide in the press. The mold is a 12 inch ditch tile guard and bracket.

Hope your stuck setscrew is going as good.

showcrop · Nov 12, 2013

As Dr Sportster said, left handed drill bit, extractor, not EZ out.

Anonymous-0 · Nov 12, 2013

Use a pin punch down inside of the existing hex in the top of the set screw. Give it a couple of good whacks with a bug hammer. It releases the tip compression and knocks the rust loose.

bog · Nov 12, 2013

The toolmakers life. Broken bolts, bad prints, no downtime to repair tool and managers and engineers that think that your job is easy.

Brian G. NY · Nov 12, 2013

Vern,
Your idea makes a lot of sense.
It is certainly worth a try.
I am placing that one in my "memory bank" along with a lot of tips my old man gave me years ago.
'course at '72 my memory bank is getting pretty full and stuff doesn't seem to stay there like it used to. LOL

Anonymous-0 · Nov 12, 2013

Dick, seems those molds always have broken or stuck screws. Especially the ones that run real hot. I have finally started putting a dab of anti-sieze on most of the screws when I reassemble the molds..

Dick L · Nov 12, 2013

This one was caused by someone putting in a allen bolt that was longer than the threads were deep in the P20 insert. Don't know if they twisted it off going in or trying to take it out. When that happens alla the magic potions and candle wax in the world won't loosen it up. If you could get a grip and turn it out the mushroomed end would take alla the threads out on the way out.
Tool makers know what its all about.

Dick L · Nov 12, 2013

Ya but I love it. Only job you can work 34 hours straight thru getting a new mold running good parts to make a new customer happy. I did that when we had the chance to get the first pantyhose legs egg molds in production for Hanes hosiery. Hot tip mold manifold would grow. I can't remember how many times I altered the tip distance before all cavities would run even and continuous. Hanes was selling and sales was growing fast and they were packing from a pair prototype molds that went down. We had a new mold built by a Dayton Ohio mold maker that wouldn't run and we were in Michigan. Boss said get it running and fast.

jim_uny · Nov 13, 2013

saw this on youtube. gonna get irwin set and try left handed drill w/ extractor. my drill doctor 750 has acc option for sharpening left handed drills. called company for instructions.
http://www.youtube.com/watch?v=dbZZFWaIzyU

Butch(OH) · Nov 13, 2013

Rotsa Ruck,
Let us know how they work out.

Anonymous-0 · Nov 13, 2013

I had a 4" flat pully on a Wis engine with the setscrew broken. I took it out with a small holesaw that just fit over the screw. I first made a hole with the saw in a piece of scrap I could clamp over the pully. I then took the center drill out, using the hole in the scrap for a guide. I didn't want the pully but I could have tapped it for a bigger screw. Worked slick.

bison · Nov 14, 2013

(quoted from post at 13:49:03 11/12/13) Use a pin punch down inside of the existing hex in the top of the set screw. Give it a couple of good whacks with a bug hammer. It releases the tip compression and knocks the rust loose.

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set screw removal

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