Spur gear bearing hole grind down question

the drill bit set finally came in today, so was practicing on the broken box,
(sorry for the photo quality = .=, old sony doesn’t work well under low light…)

on the back it seems flush with the back of the gearbox,
but from inside it looks a bit uneven, or could be just lighting issue, i am no sure,
i free-handed it, not it’s def not gonna be perfectly flat :sweat_smile:

how crucial is it to have it perfectly flat?
and if it has to be perfect, what could i use as reference?
coz nothing seems flat on the inside of the gearbox

being a perfectionist i’m going with absolutely critical…

for the rest of you hack jobs :rofl: :rofl: :rofl: its a matter of function.

the gear need to spin freely and true
and the pushing needs not to move laterally or rotate in plate

so…if you ensure both of the above aren’t issues for you its likely that you will be fine.

in terms of running out the solution on your running box, i recommend the use of a press stand and leveling aids


What do u mean by that o.o?
Also being share house with small room I have no space to to setyp even the small jaycar stand :disappointed_relieved:

you don’t want your bush to be wobbling about like an old woman.

it’ll create wear, heat, melty woe and ultimately a headache for you.

as i tap that out…where are you based? do you have a stand press of some sort?

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I am in vic where toys are actually illegal…
So don’t tell the cops :disappointed:

i don’t recognise your blue bullies as legitimate authority.


Come to think if it, I could maybe use my mechanic’s press drill… And just be really really careful with it…

Also the bearing bushing will get glued in so it should be fine in that regard

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Just my two cents worth, but you should be able to press the bushes in with a reasonable amount of force without a press. If they’re the right size bushes and you’re careful about lining everything up and keeping things square… you should be able to do it by hand no problem. :+1:

I wouldn’t be drilling out any of the bush holes in the gearbox cases under any circumstsnces… reducing the height of the nylon bosses to acheive correct end float and clearance maybe, but I wouldn’t be touching the bores of the bush locating holes. Better to use the right hardware for the job. :+1:


Yah, when I say press drill I mean to use a step drill bit to lower the sitting area, coz press drill has flat platform and a straight drilling line(?), not the drill out the bore of it, ir press the bearing/bushing in

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With the set of drill bit it has 3 different size steper, one 3-4-5-6-7-8-9-10, thats what I used for the clear box in the pics, sits inside the bore relatively straight

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