V2 gearbox

[uniweekendwarrior]

Hi all,

 

I know there are tutorials locked to the top of this section of the forum but every link gives me 404 not found. 

 

So I am new to teching and I have a totally disassembled v2 gear to work on with motor. Every time I put it back together the gears won't turn. I have double bushings installed and I did shim the gearbox. I thought I might have shimmed it too tight so I removed them but before reassembling I noticed the gears are just sliding around up and down etc. So what do I do? How freely should the gears move when the guns been shimmed? 

 

Thanks 

[Guest]

Have you put the reversal latch in back to front? 

 

Are you trying to turn the gears by hand against the spring?

[uniweekendwarrior]

Nope the reversal latch is in the correct way and no haha. I tested the gearbox when shimmed and piston etc installed with the motor and no movement at all. I then placed the gears in the shell without the piston spring etc, tightened up the gear box and then span the gears by hand and they spin fine without any shims but they wobble side to side. 

[Nick G]

Have you tried spinning the gears by hand with the same shimming you had when it locked up ? It could be that you had it shimmed too tight. Does it work on the motor without the shims ? 

[uniweekendwarrior]

I havnt managed to test the gearbox with the motor yet without shims, ran out of time before having to go out. But yes I did try spinning the gears by hand when it was shimmed and they did spin but obviously not as well without shimming. 

[Prisce]

By any chance have you connected the motor wires the wrong way around? So it’s spinning the wrong way? A guy on site did this recently, I didn’t know it was possible...

 

 

If not, send a pic in of the gearbox, let us see if we can see anything obvious.

[Nick G]

21 minutes ago, Prisce said:

By any chance have you connected the motor wires the wrong way around? So it’s spinning the wrong way? A guy on site did this recently, I didn’t know it was possible...

By any chance have you connected the motor wires the wrong way around? So it’s spinning the wrong way? A guy on site did this recently, I didn’t know it was possible...

 

 

If not, send a pic in of the gearbox, let us see if we can see anything obvious.

Easy enough to do, its only 2 wires after all , could be a good call

[uniweekendwarrior]

The wires were already in place in the box when I got it, so they could be the wrong way around I wouldn't know haha. Ignore the blue heat wrap the wires were frayed so I covered them to prevent a short on the box.

[Nick G]

How about the connections on the motor though ? have you checked those, there will be a very small + symbol next to one which should have the red wire connected to it.

[uniweekendwarrior]

It doesn't have a plus that I could see but the connection was coloured red one side so I assumed red to red. 

[Nick G]

Yep that should do it. Does the motor spin if you connect it up and pull the trigger with the motor out of the gearbox ? Have you defiantly got power flowing ? could be a broken wire or trigger issue.

[uniweekendwarrior]

Yea the motor spins fine with the battery connected so no trigger or shorting problems 

[Nick G]

sounds like something is binding up. If it were me I would put the box back together with the shims in but without the piston and see if it spins. If it does then its a sign that something is jamming  when the piston is in. You did have the piston on its guides ?

This is useful for checking alignment etc. It's in German but self explanitory

Thinking about it I've had the tappet plate jam up in the past because it wasn't seated correctly

[uniweekendwarrior]

I did try it with just the gears no piston and spring and they did spin, not sure if they had some friction or not as they didn't seem to spin that quickly which would suggest to tight a shim. I did check the piston was on the guides when I started to close the box but I did have an issue when the sector gear was shimmed it didn't sit flat so I couldn't get the gear to fit into the bushing very easily so it's possible I pushed it out of alignment. Not sure if it's a slightly warped shim or because it's pushing on something else. I'll give that video a watch tomorrow and give it another go.

[Sitting Duck]

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

[uniweekendwarrior]

Sitting duck, thank you for that. 

 

I've been watching shimming guides etc so I did start with the motor height and half shell  method etc. I've obviously just not got the hang of it yet haha. 

 

I'll use this information and give it another bash tomorrow.