Sigh....
Realistically - the motor height gets set first or one of the first things...
Rough check in top half of box....
Yeah - if you wanted to picky drill holes etc....
but if take a good look from a few angles you get it nigh on sitting exactly right....
Then you shim bevel gear on top to mesh to pinion's height
This figure can be ANYTHING from 0.1mm to say 0.6mm
You have gauge this yourself - dial guage/feeler guage or a very accurate guess/gut feeling to how it "looks"
normally It falls between 0.2mm to say 0.4mm - on bushings very unlikely over 0.25
bearings sit a bit lower so likely 0.30~0.40mm
SHS chunky bushings can be next to nothing in some boxes
(people have sanded the bushing above the bevel just get a worn SHS hex shim 0.9~0.11mm on there)
DON'T WORRY ABOUT UNDERNEATH BEVEL GEAR - it going nowhere with the motor/pinion gear inserted
(I mean you could take up a bit/half of slack later if ya wish but it ain't going nowhere with pinion installed)
The motor height should NOT really move/tweak more than 1/2 turn absolute max from your setting
if you have to turn the motor height screw any more than your initial height you under/over shimmed bevel
if you have to drop motor say one turn - you over shimmed the bevel - say 0.3mm go to 0.20mm maybe
if you have to raise motor beyond half a turn you under shimmed bevel say 0.1 - go to 0.2mm maybe
The other gears roughly
Spur/step gear 0.15 aprox under gear & what ever needed on top
Sector - usually half & half will suffice as a rough initial guess say 0.3 & 0.3 on top
Then look to see how they all stack up & spin....
switch stuff around if needed
hold box on side, selector plate side up, push up sector from underneath
WATCH spur gear - it should NOT rise as you push sector upwards
if so take up excess slack, reshim/stack the gears etc....
check sector's operation in top side of box with tappet plate blah blah blah
if you have a nightmare - focus mainly on sector/step gear (remove bevel for moment)
get them spinning with a low-ish spur gear and a center spaced sector
spin the gears (COL raised of course) - spin gears with box fully upright, then on its side(s)
listen for rubbing, maybe sector cam rubs on gearbox case & other stuff
yeah gears won't spin quite so much on sides as upright but you listening for bad rubbing etc...
get them gears really spinning sweet - tiny drop of light grease/oil on axles/ wiped of
(if using bushings as performing fast spins - it can squeak)
Get the gears spinning nicely with about 0.25~0.30mm side to side play clamping box together by hand
Now tighten box up with screws - tighten by thumb & forefinger nipping up M3 bolts
DON'T over tighten with clenched fist to strip the little M3 threads
you should be able to nip the threads just enough using thumb+forefinger & not strip threads
That side to side play should now halve to say 0.125~0.15mm on axles - mainly the spur/sector
(bevel might have more play as you didn't go nuts shimming out all play underneath (no real need to)
In general the spur sits low(ish) with about a 0.15 shim undeneath
could be 0.1 if using chunky shs bushings - could be 0.20+ if using bearings but around that
sector usually sits half n half aprox - could be 45/55 or 55/45 space but roughly about that
BUT this a ultra rough ball park guide only - every set of gears in all different boxes
plus different bushings/bearing throws all sorts of crap into the mix
I've had boxes say with low 6mm bushings where I have to pile on shims both sides to take up loads of slack
Other boxes where I had to sand bushings or on Cyma drop the bushing above spur for a 8mm bearing
coz it was tight using higher speed chunkier gears etc.....
So the above is massive rough as old boots guide only - you gotta do ya own checks n stuff
I mean if ya want you watch Rogers - shut up gears on youtube if you wanna go ultra nutz
way way ott ultra nutz but worth a watch & aim for something nearish that with what you got
obviously him drilling holes and loads of dial guages may be beyond most people
but if you aim for something like near that with a bit of attention to detail
well you should see the rewards or fruits of your work improve
Shimming is the airsoft version of riding a bike....
You can watch all the videos, read all the guides, run it all through ya head
but in the end no matter what, you gotta just figure most of it out yourself and yup you will mess up
but after a while you wibble & wobble ya way along and eventually figure out your own technique/method
You won't win the Tour De France but you should finally grasp it enough to remove your stabilisers
Shimming is same thing - the more you do it, the better you become
Most people end up shimming way too tightly, way too tightly - bollox to it
it's why you test it all tightened up the screws etc.... same tension thumb forefinger etc...
Some say 0.1mm side to side play - hmm bit bollox imho (no really)
0.10mm is a f*cking tiny amount of play on bushings, often bushings are not set 101% 90° to axle/box
& often these cheapo China gears never rotate 101% balanced and true
I mean there have been sectors which ran like a buckled f*cked bicycle wheel....
With stuff like that what friggin' chance ya got ???
(if they are that f*cked then yeah bin that gear/gearset but you got the point nowt is 101% NASA precise)
On bushings even if you got a 0.20 or 0.25 play and it spins ok the sector doesn't lift the spur
no rubbing sounds on its side, good bit of teeth meshing then yeah go with it
than have the thing so tight 0.05~0.10 and spins very little
I mean if you just back off a screw near bevel or spur and she spins by hand much better
well yeah it's obvious your shimming is too tight in some place(s)
In the end you will likely take a bit of this, a bit of that plus trial & error and wotnot
then kinda figure it out yourself like learning to ride a bike
In the end it is all down your attention to detail & checking
you can slap stuff together but that won't work too well - you need to pay close attention
try to get it all stacked & shimmed as best as humanly possible within your abilities
shimming is the foundation of how well & efficiently your box runs
if you ain't checking then you ain't really teching
reckon 75% of bad shimming is down to bad motor height ramming the bevel against gearbox
(terrible way to make everything run hot straining to cycle etc...)
16% too tightly shimmed trying get next to zero side to side play - rarely works well
9% $hit motor angle and/or badly stacked shims or box tightened too much on final assembly
PITA to get everything really running sweet, coz to do stuff well really simply takes more time
no matter how experienced you are - extra checks simply take longer but worth it in the end
