Double Eagle M916A Stock Shimming

[Chincey]

Hi All,

 

Shot in the dark here. But I don't suppose anyone knows the stock shimming setup for a Double Eagle M916A? Very new to teching any gun and took apart my gearbox to check compression, during the process I knocked a shim or two and didn't know exactly which gear they was sat on. Any help would be greatly appreciated!

 

Cheers!

[Nick G]

Probably easier to start from scratch and reshim the whole box tbh since the shimming of any 2 gearboxes is never quite the same .

 

There are quite a few decent tutorials on youtube .

 

Have a stab at it, there are folk on here who can advise if you run into serious issues.

 

 

[Speedbird_666]

Yeh - there's no such thing as a 'stock shimming' other than what's bespoke to your particular gun at the point of manufacturing. 

 

You could buy five identical guns from the same manufacturer and not one will be the same when it comes to the number of shims in the gearbox.

 

It's not a dark art, it just requires a little patience and you don't need to be absolutely perfect for UK power levels and relatively 'standard' out of the box performance (High power and high speed performance setups obviously need more care).

 

Gawd knows how many Chinasoft guns have arrived in the UK with barely any semblance of shimming that have spent years being abused by punters as site rentals and are still going strong. Too tight= bad, too loose=bad, but the band in the middle allows for some wiggle room. 

 

There are people that take genuine pleasure in getting the gear meshing absolutely perfect - fair play - but I'm not one of them and I have yet to strip a gear. But I also don't any desire for a 400fps DMR or have any interest in 35+RPS burrrrrrrrrp guns. 

 

 

[Chincey]

4 hours ago, Nick G said:

Probably easier to start from scratch and reshim the whole box tbh since the shimming of any 2 gearboxes is never quite the same .

 

There are quite a few decent tutorials on youtube .

 

Have a stab at it, there are folk on here who can advise if you run into serious issues.

 

 

Yeah this was something I debated. But maybe wasn't mentally prepared for haha.

 

1 hour ago, Speedbird_666 said:

Yeh - there's no such thing as a 'stock shimming' other than what's bespoke to your particular gun at the point of manufacturing. 

 

You could buy five identical guns from the same manufacturer and not one will be the same when it comes to the number of shims in the gearbox.

 

It's not a dark art, it just requires a little patience and you don't need to be absolutely perfect for UK power levels and relatively 'standard' out of the box performance (High power and high speed performance setups obviously need more care).

 

Gawd knows how many Chinasoft guns have arrived in the UK with barely any semblance of shimming that have spent years being abused by punters as site rentals and are still going strong. Too tight= bad, too loose=bad, but the band in the middle allows for some wiggle room. 

 

There are people that take genuine pleasure in getting the gear meshing absolutely perfect - fair play - but I'm not one of them and I have yet to strip a gear. But I also don't any desire for a 400fps DMR or have any interest in 35+RPS burrrrrrrrrp guns. 

 

 

Thanks for the info. I assumed maybe as the boxes are mass produced that there might be a sort of out the factory shim configuration. But that makes more sense. Looks like I'm going to have to dive deep into some YouTube videos. Definitely on the same boat though, perfecting shimming won't be an interested as long as it operates fine that will suffice for me. Any tips for a clear indication of bad Shimming? Is there a sound or feel that I can look out for?

[Fatboy40]

36 minutes ago, Chincey said:

I assumed maybe as the boxes are mass produced that there might be a sort of out the factory shim configuration.

 

Of the three DE M900's I have I've opened the gearboxes of two of them with the work that I've done on them, and both had a single shim either side of each of the three gears (I've no idea how thick the shims are though). DE manufacture masses of various toys in China (some of their "Lego" like construction vehicles look amazing), and like you I doubt that they shim each and every gearbox uniquely.

[RostokMcSpoons]

I'm no expert, having shimmed :checks notes: one gearbox (a few times though).   And I'm not sure how good a job I made of it.
However, I'm share my tiny amount of experience gleaned from watching several different 'how to' videos.

 

1. It can be a very time consuming thing to try to do when you're a duffer like me, but an expert can do it in about five minutes (see Luke's video - Negative Airsoft on YT)
2. My experience in trying to manipulate gears, looking inside the gearbox (a v3 in my case) etc, to check how teeth were engaging with each other, never seemed to tally much with how easy videos made it look
   
   ... so avoid shimming if you can ... but if you have to (and you do) ...
    
3. Better to shim too loose than too tight
4. Make sure all the gears can spin as freely as possible ('duh')
5. You should be able to press on the ends of the gear axles through the bushings from each side of the gearbox (closed and screwed up tight), and see that axle move each way a tiny, but noticeable amount
6. No whiny noises
7. No grindy noises
8. ... errr that's it from me

Edit: Here's that video... skip to 4'10" for the 'how to shim the Luke way"
 

 

 

Good luck!

Edited March 2, 2023 by RostokMcSpoons

[Chincey]

3 hours ago, Fatboy40 said:

 

Of the three DE M900's I have I've opened the gearboxes of two of them with the work that I've done on them, and both had a single shim either side of each of the three gears (I've no idea how thick the shims are though). DE manufacture masses of various toys in China (some of their "Lego" like construction vehicles look amazing), and like you I doubt that they shim each and every gearbox uniquely.

Cheers for this! I'm pretty sure I only knocked 1 or two shims off, that where definitely from the top side of the gears. Looking under one, seems there's atleast two shims. Which has thrown my theory of copying another 9x series shimming setup out the window! Bugger!

 

3 hours ago, RostokMcSpoons said:

I'm no expert, having shimmed :checks notes: one gearbox (a few times though).   And I'm not sure how good a job I made of it.
However, I'm share my tiny amount of experience gleaned from watching several different 'how to' videos.

 

1. It can be a very time consuming thing to try to do when you're a duffer like me, but an expert can do it in about five minutes (see Luke's video - Negative Airsoft on YT)
2. My experience in trying to manipulate gears, looking inside the gearbox (a v3 in my case) etc, to check how teeth were engaging with each other, never seemed to tally much with how easy videos made it look
   
   ... so avoid shimming if you can ... but if you have to (and you do) ...
    
3. Better to shim too loose than too tight
4. Make sure all the gears can spin as freely as possible ('duh')
5. You should be able to press on the ends of the gear axles through the bushings from each side of the gearbox (closed and screwed up tight), and see that axle move each way a tiny, but noticeable amount
6. No whiny noises
7. No grindy noises
8. ... errr that's it from me

Edit: Here's that video... skip to 4'10" for the 'how to shim the Luke way"
 

 

 

Good luck!

Wow, thanks for the in-depth info, I really appreciate it!

 

I've done the typical thing of tinkering a day before a game day, which I'm now heavily regretting, but lesson learnt I spose. 

 

I'll see what I can achieve keeping this information in mind.