I dont know if anyone has done this before... but the idea came to me last night so I had to try it and you know what, I think it may be my favorite mod ever!
Here is my write up:
what you need:
*4/40 blind nuts (pick them up at your favorite hobby establishment, I used DuBro ones)
*a 9/64 drill bit with a drill to spin it
*clod gearbox halves
*some JB weld or epoxy
*dremmel with a grinding wheel
First off,
I take the blind nuts and grind down the little "teeth" they have around their flange. Dont completly grind them off just take them down to little nubs, you will want the nubs there to bite into the gearbox but if you leave the full length they will just bend.
Once thats done take the 9/64 drill bit and open on the 4 holes around where the axle tube mates to the gearbox. You may need to open the hole up a bit more with a body reamer inside the gearbox to help fit the blind nut in.. Be careful, you want it to be a tight fit though.
NEXT
Take your blind nuts and apply a TINY but of your selected adhesive onto the surface that will be applied to the gearbox.
NOTE: Be extremely careful not to get and in the inner threaded portion of the blind nut or you will never be able to get the screw in.
And now for the kind of tricky, but not that tricky part. Take a 4/40 bolt and slide a large sturdy washer over it. Then take the blind nut with the adhesive on it and push it into one of the holes you enlarged in the gearbox from the inside. You may need to grind back some internal bracing to make room for the blind nuts in the deeper half of the gearbox push it in as far as you can with your finger then take the bolt you placed the washer on, and thread it in from the opposite (oustside) side of the gearbox and start tightening it till the washer is pressed up against the oustide of the gearbox then keep tightening. This will pull the blind nut into the hole in the gearbox and secure it there. Tighten this till the blind nut is fully pressed in and then take the screw out and repeat 15 times on the rest of the axle tubes!
All you have left to do is install the axle tubes with some 4/40 hardware of your choice and you are set.
This makes axle tube swaps/installs super easy as you dont need to open the gearbox to get to the screws or nuts and you can use threadlock since its now basically a metal insert. I like this method more than using the 6/32 bolt tapped into the gearbox because it is much more forgiving to being miss threaded and just feels more secure.
Hope this mod takes off! I sure know its awsome!
Added notes,
The ammount of matterial drilled out is tiny, less so than tapping threads in and the surface area of the back of the blind nut should provide good pressure distribution. this is going on my new Berzeker so well see how it holds up on a serious racer.
As for the spikes, you need to grind them down to the point they are next to nothing.. almost to little burs. you dont want them completly gone IMO, just enough of a bur to dig into the surface of the plastic to keep them from spinning while you tighten them before the glue drys.
Thanks, Tier
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