Are anyone’s stainless steel motor screws (w/threadlocker pre-applied) stripping? We bought a pack and are using a brand new allen wrench to put them in our motors, but some are going in and some are not.
Is anyone else having this problem?
Yes, our teams have had lots of problems with these. I have found them almost unusable and we have reverted to using locktite thread locker on standard screws.
You can make them into flat-head screws before using them by cutting a slot in the head then using a flat-head screwdriver. We have had lots of issues with motor screws stripping without the threadlocker, so it’s not really surprising they don’t like the extra torque.
I have some 6-32 screws with nylon patch (probably from Mcmaster), and they are unusable for motor screws as delivered.
The screw head strips trying to get the nylon threaded the first time.
Maybe running a torch on it or running them in and out of a thin nut to strip off most of the nylon would work.
I think I was even using a new ‘hex-plus’ high torque allen wrench.
Idea for Worlds - competition show off robot:
A line of screws in a visible location using every different material/finish/type of head available through McMaster, etc. Pan head, oval head, square head, flanged, hex head, slotted, square drive, robertson, phillips, allen, torx, anti-tamper types 1 through N, Nylon, aluminum, copper, steel-black-oxidized, stainless, …
If your screws get stripped into the motors you can also use a torx head screwdriver to get them out. They are only a couple bucks at any hardware store and they work magic.
A T-8 Torx to be exact: McMaster-Carr. They are The Best at removing motor screws with rounded heads.
So for getting them in, it seems like cutting a slit on the head and using a flat-head screw driver is the best thing we can do. Anyone else have an opinion? If they strip so easily in the motors, why does Vex sell them? Doesn’t that defeat the purpose of having a stainless steel screw with locktite pre-applied?
I’ve used them with no problems… We didn’t realize anyone was having issues.
-John
I wouldn’t do this, I think jgraber’s suggestion of removing most of the thread locker is the best approach, that what I tried to do before just deciding to use alternative screws with locktite. As any 6-32 screw is also now competition legal, where there’s room we use socket head parts as these rarely strip.
They fit in 269 motors, but I’m having problems using them on 393 motors.
I went back to the bin in the warehouse and grabbed some random bags. I found some that are “pretty tight” but nothing that seems unreasonable…
I’m having my QC folks take a closer look. We can discuss with our supplier using less locking compound.
-John
My team hasn’t experienced any problems except that one time when we had an entirely different and slightly more interesting result surface;):
On a three wire motor we started screwing in the screw when, completely randomly, half-way through the screwing in I noticed that the screw was spinning inside the housing and wasn’t driving in. What happened was that the threadlocking glue adhered to the metal screw housing in the motor so hard that when I spinned the allen wrench (a T-Handle by the way) I ripped the bonding between the metal housing of the screw and the plastic housing of the actual motor.
Has anyone had this happened to them, and if so, how were you able to solve it? It would be depressing to have to get rid of the motor.
Is the locktite supposed to be extremely hard? We wanted to see if we could remove some threadlocker so we soaked a screw in acetone. After a solid 30 minutes, we saw that the threadlocker didn’t come off so we tried “clawing” it off with a razor blade which was unsuccessful.
Nylon is not dissolved by acetone.
Best thing is to run the screw through a 6-32 nut (or other threaded hole) a few times. You could scrape some off but be careful not to damage the threads.
I was not aware that the threadlocker was nylon. Thanks for clearing that up.
Actually I don’t know that it is, it was just a guess. The nuts probably are as they are called “Nylock” nuts but the screws may be different.
They look similar to mcmaster “nylon patch” screws.