Sector gear shimming issues

Hopefully someone can help me get my head around this issue! I got a singularity gearbox and some Fighting Bro 16:1 gears. When I go to shim the gears they seem to be perfect until I do the screws up. Once screws are tightened the sector gear becomes really tight to spin with my finger. No shims have been put on the sector gear and also it seems to be rubbing on the spur gear making a f$&kin shit noise! How do I fix this? I been trying to shim this box for HOURS (all day lol) and it’s doing my f&@kin head in!! Please help!!??

Idk what to tell you about the sector gear but the spur gear has that sleeve over the axle which you can shorten to free it up more (I had to shorten mine)

Hopefully the veterans here will have an easy solution for you shortly :wink:

There is no easy solution.
If the gears you bought don’t have the brass sleeves that you can shorten then you need to get them machined down.
Normally the sector gear is ok but not allways.
This is what GBA call fixing the issue !

Would it be worth doing a dodgy and shaving down the bushings for the sector gear? (Then he could shim it into position)

Edit: dunno why autocorrect put “love” in there… Dumb phone… I know we love blasters but please…

That is possible but not if using bearings.
You also can cause more issues with the gears hitting each other or rubbing on the housing

Yeah I’m using the fighting bro bearings.

So is it the girth of the mounting post on the gear causing my dilemma or the length of it??
The 9:1 gears shim up good but they way too mental for the gel balls to shoot properly and I only got 11.1v batteries.

Man what an expensive nightmare haha

I’d say it’s the length since the bearings only allow the axle through anyway…
The only problems with shortening the length of the sleeves is that, like Rattler said, you might end up with gears rubbing against the gearbox casing (but then your shims should come into play to fix that)
Edit: Also, if you shorten the sleeve from the top where the tappet pin/plate interact with it, the pin and plate might give you grief…

Something that might be worth looking into is taking out one or both sector side bearings and removing a bit of the gearbox casing so they can sit further in like the rest of your bearings (notice the sector gear bearings sit proud compared to the others)

But then you might run into the issues Rattler mentioned yet again where the gear rubs against the casing itself (it’ll be a long task of testing then removing a little more and testing again)

Other than that, maybe there’s a way to put a shim or something in between the case halves with a screw ending up through it to stop the case from squashing real close together near the sector gear? (Sounds like a bad idea though)

So if it’s the length you talking about the fatter part not the skinny part of the axle yeh??

Yeah, these parts (the sleeves on the axle)

Thanks bro. Looks like a job for deemed maybe???

@XTOPC is correct, they need the shoulders machined back a bit.
If you can remove it from the correct sides you should be ok.
If you can measure the height of the original gears and make the new one match, then shim it you should be good.
It needs to be done properly.
I had to do it with my vectors and they are now perfect.

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Yeah, totally recommend getting it done right by a professional with the right tools (especially if the sleeves aren’t brass)

I did my spur gear sleeve myself with a small pipe cutter then broke off the small part that was cut (since brass is soft enough for that) but I wouldn’t recommend it without a similar tool or it might not be cut straight and you’ll run into weird wobbling sounding issues even with shims…
Doesn’t help that the sector gear doesn’t give much room to play with…

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@Rattler & @XTOPC … thanks so much guys, honestly after the cost of my m4 (now two), vector and then upgrading everything I started thinking I had gone too far or got ripped by lies and incorrect product!

I may know someone with a lathe so will start the hunt!

Thanks again :sunglasses:


Good luck, bro (I’ve felt like that at one stage too)


I’ve got the same gearbox and so I opted for shs 12:1 as the FB I had their sleeve was too big. the shs dropped in without a breeze. Are your bushings seated in deep enough as I found I had to very lightly Dremel the inner ring of the sector hole :stuck_out_tongue_winking_eye: so my bearings could be glued in properly. Hope that helps

Yeah i have been taking the bearing/bushing holes down lightly/carefully too! Don’t wanna take too much out though, A) I might wanna change gears and will end up needing a shit load of shims to pack it back out. B) don’t want my bearings to end up on the piss (not level), maybe I’m over thinking it???

Glue the bearings? If I’m using bearings should I glue them in?? What glue is used and what method? Obviously we don’t glue the bearings back into bushings lol

I use a couple drop of Loctite superglue from Bunnings. It’s just enough to keep the bearings in place but with a punch I can easily remove them if they needed replacing. And I used a Dremel and the pedestal drill stand you can Buy to mount the Dremel in so i can get a perfect level recess

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Ah yes the old pedestal drill stand! Legend, I get one I think. Thanks for your tips brother, much appreciated.

Hey by any chance have you used the BIGRRR Gears that TacticleEdge sell? Might get a set?

Nah I haven’t was keen to try myself IV only got lonex and shs