Shiming

[Callum861]

HI all im wondering if anyone can help me iv decided to learn to do my own tech work so I brought myself boneyard jg mp5 ras to work on to see if I could get it working and doing so iv tried shimming the gearbox myself I followed a video by the airsoft tech which iv seen a few people mention however he uses the pistol grip and half she box method which seems really easy. u

Unfortunately the gun i have i cant do that as the pistol grip and lower receiver is all one peice and so iv tried to do it and its not worked as got a awful sound. I wasnt expecting it to be right as its my first time but my question is has anyone els had the same problem with the pistol grip and lower receiver being one peice and how did you get round it when shimming it is there a different way to shim the gears when I cant use this current method? 

 

Thank you in advance 

[Mtemprell]

The way I shim up is remove everything out the gearbox and get just the 3 gears. The bevel gear have no shim on the Bottom and fit the other half of the box and test to see what play you have, then start at smallest shim and keep testing till have minimal play, you don't want it tight up otherwise it won't spin freely. For the spur fit it in with the Bevel and using a feelers gauge find the gap at the base of the gear to the bearing and use the shim that is same as that gap. Repeat again with fitting top of gear box and shimming till the play is minimal. Repeat again for the sector gear. Once done screw the gear box together with all gears and shims inside and test for correct meshing and try manually turning the gears to ensure free movement. 

 

Once your happy grease up gears and bearings and rebuild the box. It is a slow process but at the end there's big pride in what you've achieved. 

[The_Lord_Poncho]

13 hours ago, Callum861 said:

Unfortunately the gun i have i cant do that as the pistol grip and lower receiver is all one peice and so iv tried to do it and its not worked as got a awful sound.

 

I presume that you have tried adjusting the motor height? Sorry if that's rather basic advice, but it caught me out at the start!

[Adolf Hamster]

It might be that you have to just install/check/remove/adjust multiple times to get it perfect.

 

Thats the thing, its not the difficulty, its the labriousness of having to try adjust try until you get it dialled in.

[johnnyj]

It's great that your doing this , so many people never try ! 

Another thing that is sometimes missed if a gear is twisted or the axle off plum , had this on some new gear sets in the past never mind old sets.

[Callum861]

6 hours ago, The_Lord_Poncho said:

 

I presume that you have tried adjusting the motor height? Sorry if that's rather basic advice, but it caught me out at the start!

I thought that two I adjusted it but couldnt seem to get it to stop making the noise 

18 hours ago, Mtemprell said:

The way I shim up is remove everything out the gearbox and get just the 3 gears. The bevel gear have no shim on the Bottom and fit the other half of the box and test to see what play you have, then start at smallest shim and keep testing till have minimal play, you don't want it tight up otherwise it won't spin freely. For the spur fit it in with the Bevel and using a feelers gauge find the gap at the base of the gear to the bearing and use the shim that is same as that gap. Repeat again with fitting top of gear box and shimming till the play is minimal. Repeat again for the sector gear. Once done screw the gear box together with all gears and shims inside and test for correct meshing and try manually turning the gears to ensure free movement. 

 

Once your happy grease up gears and bearings and rebuild the box. It is a slow process but at the end there's big pride in what you've achieved. 

Thank you ill give it a go 

4 hours ago, johnnyj said:

It's great that your doing this , so many people never try ! 

Another thing that is sometimes missed if a gear is twisted or the axle off plum , had this on some new gear sets in the past never mind old sets.

Thank you i always wanted to but didn't have the time to really give it a try till now ok ill bear that in mind I am useing the old gears still as theres nothing wrong with them but ill bear that in mind thank you 

5 hours ago, Adolf Hamster said:

It might be that you have to just install/check/remove/adjust multiple times to get it perfect.

 

Thats the thing, its not the difficulty, its the labriousness of having to try adjust try until you get it dialled in.

Thats what im hoping it is as the gearbox did function fine before had it was bonyard for a different reason.

[Mtemprell]

27 minutes ago, Callum861 said:

Thank you ill give it a go

Good luck and enjoy bud. It is definitely worth the effort for the end product. To know you made a gun run so much better by yourself. 

[Adolf Hamster]

1 hour ago, Callum861 said:

Thats what im hoping it is as the gearbox did function fine before had it was bonyard for a different reason.

 

The bad news is there will be many many mistakes left to go on the road to learning good teching.

 

The good news is a boneyard gun is absolutely a great way to start, unlike some of us that made the mistake of doing so on their first and only pew........

[Callum861]

So thank you for all your replies and advice iv managed to get it working sounds a little squeechy still if thats the right word but what do you guys thinks 

[Mtemprell]

1 hour ago, Callum861 said:

So thank you for all your replies and advice iv managed to get it working sounds a little squeechy still if thats the right word but what do you guys thinks 

That doesn't sound too bad at all. Done a good job there. Motor hight might be a tad high that's all I'd say, but through my phone speakers I'd says it's a good job. 

[Colin Allen]

3 hours ago, Callum861 said:

So thank you for all your replies and advice iv managed to get it working sounds a little squeechy still if thats the right word but what do you guys thinks 

That sounds pretty decent, although there is still a small amount of noise coming from somewhere; you could try adjusting the motor height to see if that gets rid of it.  If it doesn't, then it is really your decision as to whether you can live with that bit of noise.

It sounds better than most guns I hear on the field.

Edited August 7 by Colin Allen

[Adolf Hamster]

Not horrible, as mentioned check the motor height.

 

Best practice for motor height is start wound in all the way, if you start all the way out it might strip gears but if its too tight the motor will just stall (dont hold a stalled motor for any length of time mind you as the current will be trying to cook it)

 

If that's the best sounding it can get maybe drop the bevel a tad and try again.

[Callum861]

22 hours ago, Adolf Hamster said:

Not horrible, as mentioned check the motor height.

 

Best practice for motor height is start wound in all the way, if you start all the way out it might strip gears but if its too tight the motor will just stall (dont hold a stalled motor for any length of time mind you as the current will be trying to cook it)

 

If that's the best sounding it can get maybe drop the bevel a tad and try again.

Ill give that a try thank you by dropping the bevel gear do you mean bring it closer to the gearbox or motor gear? 

[Adolf Hamster]

21 minutes ago, Callum861 said:

Ill give that a try thank you by dropping the bevel gear do you mean bring it closer to the gearbox or motor gear? 

 

closer to the gearbox, although if that's worse then could try the opposite.

 

if it's a non-factory motor it's also possible that the pinion isn't a good mesh with the bevel (ie things like the profile of the teeth) and that'll limit how smooth sounding it can get, which then gets to swapping out gearsets.