Wicked! Love it
Wicked! Love it
So after making some new motor mounts I was finally able to try and drive Pressure Point for the first time yesterday, and it went well.... for about 5 seconds I just moved the bot forwards, backwards, and was turning left and right on the spot when the left hand threaded screw that holds the wheel onto the drill motor sheared.
The motors are the standard 12V Argos value drill motor/gearboxes running on 5s and as far as I am aware, lots of people use this motor this way. Likewise the wheels are 100mm diameter Nylon with mountain bike tires screwed on.
Have I just got unlucky here with the screw shearing or am I doing something wrong and is there anything I can check for? I have scrounged another left hand thread screw and would like to check before I risk breaking another one.
Last edited by Al_; 2nd May 2017 at 08:45.
Sounds like you just got extremely unlucky. There's no reason you should have sheared one of those screws... It's never happened to me.
It still a little weight which you could use else where.
Bad luck with the Gearbox, any chance when you where hacking it you did up the bolt too much?
Can you put some pics on of what you have done? And how much thread is off.
How iv done mine in my prototype seems perfect. Can Rally it around full pelt even carrying adults back and forward and there is no hint of that happening, and I'm talking 10 mins at at time so it's no light work.
I don't think I have done anything out of the ordinary, just a 3/8 UNF insert melted into the wheel centre which screws up to the shoulder on the gearbox output shaft. This is then retained by the left hand threaded screw and a flat washer. I'll get a few pics up when I have chance. Hopefully I was just unlucky but the break in the screw was almost level with the end of the gearbox shaft hole, so could be tricky to remove.
Was the screw taking sideways pressure rather than just squeezing the nut to the wheel?
If it helps I found some hand screws on Amazon that are a bit longer than the standard Argos one - up to 30mm length, which might make it a bit stronger?
Last edited by lowndsy; 3rd May 2017 at 14:36.
I don't think there should have been any sideways pressure on the screw, its all taken by the gearbox output shaft, so the screw should have been just squeezing the nut in the wheel on to the shaft. I'll double check its all square and true when I get to have a look at it it at the weekend. Is there any chance you could drop me a link for the longer LH screws please? I got this spare out of an old dead battery drill, but if I break this one too then I'm out of them.
Sounds like it must be a bad one. I used drill drives for years (still do occasionally) and I've never had a LH screw shear from normal use. Even after several matches, they're usually fine.
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