Decided to have a crack, pulling the UMP 45 apart.
While working , its fps had dropped quite a bit ( from 290-160) and it was a bit noisy.
Followed the low guido teardown vid.
The blaster comes apart quite easily. More should be designed like this.
The external mosfet had me a little concerned, but treading gently around it should work.
Guido doesn’t use rubber gloves / touches it with his bare hands, so maybe i was a bit overly worried about frying it with static electricity.
yeah, its the same material as the piston head.
An additional outer layer.
It does clip into the detent…but comes out very easily.
I suspect a layer of glue might not have it clip in intimately…and not last long.
High reciprocating loads.
Probably better off, with a solid one piece head.
I thought about greasing the dry gears…but seem to remember being told…Dont.
With the external mosfet, grease could get flung out, build up, and ruin it.
Interestingly, the AR latch doesn’t seem to engage…return spring is weak and flimsy…
Yeah, no glue’s ever going to be permanent… unless you put a shock pad in the cylinder, but it should already have one on the back of the cylinder head.
Might want to check AOE if you fit a new thinner one, it’ll change. maybe for the better, knowing China.
AOE is “angle of engagement” between the first tooth (pickup tooth) on the sector gear and the first tooth on the piston rack.
Correct AOE should see the sector pickup tooth engaging with full contact on the rack tooth. If the piston is too far forward the pickup tooth will contact at the tip of the tooth before full engagement.
Generally people correct AOE with rubber discs or similar to put the piston in the right spot under full spring tension to guarantee proper engagement.
Incorrect AOE will cause premature wear of your sector gear.
Here ya go. A picture’s worth a thousand words, a video is worth a million.
I got a new piston head from xforce, a new v3 spring kit with a stiffer AR spring. I have the xforce bearing lube/grease kit so i did the following…
AR latch was quite stiff in the post, so a lot of dry movement to wear it in a bit, then lube on the post with the new stiffer spring. Moving much better now.
Painted on a VERY thin layer of gear grease with an art paintbrush, a very light coating.
The V3 gearboxes are a dream to put back together, the gears sit properly in position with very little movement. Sector and crown gear went straight into their upper slots. Only the bevel gear needed a bit of lateral movement to go back in.
Clunk…and its back together … that easy…
Whats that i left out .? Oh, only the piston…!!! Open it up, and do it all again.
Clunk… Back together again… Easy.
All the wires on the outside makes it a lot easier too…
Fitted motor cage, make test firing easy, before re-assembly.
Mosfet still runs fine, circuit board anxiety for nothing…
Original mag on the left.
The one on the right doesnt get power and feed…mag springs must not be making contact.
What would be the best way to add some conducting girth to the contacts to widen them…just add some solder…?
“Its wouldn’t be gel, if you didn’t have to screw with it…!!”
If the new mag’s terminals are closer together there should still be contact… looks like there’s plenty of metal there. Maybe the terminal plates on the newie are set deeper and your springs can’t reach?
Good idea too to check the new mag out with a 9v battery to rule out a faulty motor or bad wiring.
It’s actually a shame ldt went with such a proprietary gearbox and mosfet setup on these, Airsoft is basically a standard V3 box… but such low volume build definitely keeps working examples value high. True collectors items!