after sevastopol i was a little dissatisfied with the noise from my mp40 gearbox so i though i'd put some helical gears in it to quiet it down,after fitting the gears and re-assembling the box i went to adjust the motor pinion engagement,a job usually done with a grub screw at the end of the motor houseing whitch pushes the motor in to the gearbox to get the proper mesh between the pinion on the motor and the bevel gear.you need to remove the trigger assembly but thats just two screws and it comes of the end of the motor houseing and then i thought i just need to use an allen key to adjust it,thats when i found that despite a threaded hole there was no grub screw in it,it even has the disk that the grub screw pushes on ?
so i thought i'll pop one in (m5 5mm long alen grub screw) and adjust,whitch all went well and i got it to the sweet spot and locktighted it.
haveing another mp40 in for a little work i thought i'd have a look and "lo and behold" no grub screw either,now im wondering has anybody else found this on their mp40?i can post some pictures if needed but didnt think to take any at the time.just seems a really small thing to economise on 
armoury
m1a1 Thompson,sten mk2,mp40,stg44,sterling,mk2 bren gun,lee Enfield no4 mk1,Mauser Kar98, Walther ppk,smith and Weston m10 and Mauser m712
Give me a big enough hammer and a place to stand and I could fix the world.
i'll kill a man in a fair fight or if i think he's going to start a fair fight or over a woman or.......
a problem shared is a problem halved ,but an advantage shared is no advantage at all
if a job's not worth doing then its certainly not worth doing well
Yes had the same thing on a second hand mp40 I bought. Sold as not working properly knew I was taking risk but it was very cheap. Anyway I made a grup screw ,as i thought that was causing the problem, and reshimed the gear box only used for a couple of games but had no problems since.
Armoury: AGM MP40, AGM Sten MkII, K98K/vsr and Maruzen P38.
Chinese M14s are the same, but the hole isn't even threaded. Similarly I had to shim the bevel gear first to make sure it meshed with the pinion gear.
