Anyone have any suggestions how to remove one of these aluminum shaft couplers when the bolts are rusted and the socket heads are stripped? I want to replace the M8 threaded rod I’m using as a leadscrew, but the nuts on this coupler won’t budge. I considered Dremeling it off but I don’t want the heat to affect the surrounding plastic.
It’s headaches like this that keep my printer out of commission for a good part of the year… Just want to get back in, and a headache like this kicks me back out for a few more months until I try again.
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Craftsman makes a pretty nice stripped head bolt removal set. I’ll try to find a link. If you have a Dremel with a cutoff wheel you can cut the top bolt as well. Go slow on the cut and take a few breaks to keep the heat down (if you can fit a Dremel in there).
Also, what’s on the other end? Can you remove it all attached, then address the stripped bolts on the bench?
When all else fails, drill the heads of the screws.
There should also be another pair if set screws as well. If you can get those out, you may be able to get the rod out.
Google socket out. I’ve used them at my job and they work great. I’ve seen guys make them from a allen key one size bigger then the scew…
I agree with @Eric_Edwards , either drill the heads off or use a left hand drill bit to try to back it out. Shouldn’t damage anything, once you’ve got it on the bench you can try to replace them, but it they are bound in you may need a new coupler.
Easy outs worked like a charm when my belt gear screws were stripped. Can buy them local (Home Depot, Lowes, ect) too.
use a small pointed diamond abrasive bit and cut two notches on opposite sides on the rim of the screw head. Then use a flat-head screw-driver.
If you have applied Loctite some tips from this thread http://www.practicalmachinist.com/vb/general/solvent-loctite-186460/ suggest acetone or super glue dissolver, or applying a soldering iron to the cap screws to loosen them, at a guess I would say the screws are grade 5 or 8 so they will be hard to cut through, it may be easier to cut a section from the top and bottom parts of the coupling so it no longer clamps the shafts.
Spray bolts and nuts with crc (buy at local hardware store) leave a couple of minutes, presto come apart easily.
take pins holding your stepper out. Manually turn the threaded rod out of your machine. operate on the parts on the bench.
You only really need to remove the socket head closest to the stepper.
choose your weapon;
. epoxy the socket head with hex wrench inside it.
. liquid wrench and patience
. score the head with cutting tool and use a flathead…
. decide the price of a stepper motor is acceptable to not have to do any of this.
@Mike_Dobrick there’s nothing on the other end - no nut. The hole on the other side is tapped, if I remember correctly.
Thanks for the advice everyone. Haven’t tried anything yet. There is no loctite in there - it’s just screwed tight into the tapped threads on the other side. I would like to be able to keep the couplers but if I have to destroy them, that’s fine. I’ll try the suggestions above and post my results. Thanks!
Coka Cola works magic on rusted parts.
@Rob_Martin This is a good way to go - if the heads are big enough you use a thing called an extractor. They are a reverse direction screw (sort of). Usually comes as a set (with appropriate drill bits) See here:
Beware, these may not work well on small bolts.
