My Engineering teacher challenged me to take stripped shaft collars off several drive shafts(for a reward of 1% extra credit, but that’s not important). I’ve got seven of these and though the easiest thing would be to cut the axle itself and get rid of the part with the shaft collar on it, some of the axles have the shaft collar smack dab in the of the drive shafts. (And I don’t have a power saw at home anyway)
I haven’t really found any solutions. I’ve tried the rather standard approach of angling the 5/64" screwdriver but the setscrews are so stripped they’ve practically formed a round hole. I’ve also tried drilling through the setscrew, but I’ve got tools designed to drill holes through wood, not metal, so they have a very minimal effect (I could probably get through them all, but it would take around > 3 hours to get through one). I also almost drilled a hole in my finger because i was careless.
Are there any other ways besides the ones I’ve tried?
Some strategies that people use for that include putting a rubber band between the Allan key and the screw, and also using a slightly larger Allen key size
Get a Dremel (or equivalent rotary tool) and some thin cutoff wheels and cut the collars. The other idea I have is drilling the screw and threads right out, but that requires a good drill bit and a lot more precision.
Get yourself one of these:
As the description says, hammer it into a stripped screw, then, using a manual bit driver, twist the extractor and screw out together. Make sure you hammer the extractor into the screw hard enough for the extractor to bite the screw.
Put on some safety glasses. Then maybe try cutting the head off a nail, dulling its tip a little, then putting it into a drill. Set the drill to run in reverse, press the somewhat dull nail tip into the socket of the stripped set screw, then run the drill (in reverse). If you’re lucky, you will generate enough friction and vibration to back out the set screw. Don’t try to run the drill too fast: you’ll get the best frictional/vibrational effects at a slower speed. Worth a try maybe, but it’s not 100% guaranteed.
Wow - that’s awesome! Does that actually work? Those set screws seem to get stripped and stuck with depressingly bad timing, usually in an area that the best we can hope for is to carefully dremel the collar off (time consuming and costly).
Well, caveat emptor. I haven’t ever seen a stripped-screw removal system that works 100%.
C-4?
That’s actually really cool.
Not sure if it’ll ship in time for what I’m going to do, but that’s definitely something I’m looking into.
Something I’m yet to try is to mix salt and vinegar onto a cotton swab and then hook it up to a 9-volt battery in a particular way (one end on the cotton swab and the other onto the shaft collar).
It burns through the metal, but I’m yet to see HOW effective. It’s a cheap way to engrave tools at home.
@FullMetalMentor I’ll give that a try. It’s an interesting thing to try (in the end i’m going to teach my teacher a more DIY way of dealing with this problem)
Really the bigger problem is to teach students to not shove ball-tipped screwdrivers into shaft collars. It can be quite brutal to watch at times.
I confess, I’ve never tried that stuff.
On screws.
It generally works unless the screw has been stripped to the point where it just has a circular hole. If it doesn’t work the first time, just hammer in the extractor harder and try again; you’ll get used to knowing when the extractor has bitten the screw after a few tries. Also, when twisting out the screw, also apply force through the driver toward the screw to minimize the chance of the extractor losing its bite on the screw.
I use an appropriately sized torx bit. A T-9 works well. I gently tap the end of either the bit or the screw driver with a small mallet, the side of a pair of pliers, or even a length of c channel. The edges of the torx driver bite into the set screw and it comes out fine. I usually have to use a vice or vice grips to get the set screw off the driver.
Here’s the bit I use:
And here’s the Home Depot set it came from:
Also small left hand drill bits may engage the screw. Sometimes WD-40. We have replaced most collar set screws with #8-32 x 3/23 stainless steel set screws. The stainless is stronger than VEX originals and have a deeper socket for the wrench. The screw does extend from the collar but in most cases this is not an issue.
Clamp the shaft collar so the axel is vertical, make sure it’s clamped securley and then hit the axel really hard with a hammer, not every solution is elegent
Thermite, anyone?
+1 just grind some rust of the iron axel and grind some of the aluminum off of a c-channel or something, Boom, thermite.
I have plenty of pyro grade iron oxide, so sure. That’s a good idea.
LOL have fun waiting for it to cool off. I wanna see a video, if anyone does it xD