Semi Auto is Full Auto

[Trojan]

Can you tell if this is a worn or a good sector cut off lever?

I replaced my trigger trolly and my gears so its either of those at fault here...

I have only got a few shims on the bottom of the sector gear, I can move one or two from the top but what is the best way to check the gear actually makes contact with the lever


Thanks please advise how you check semi auto functionality while the GB is open.. eg if the cut off lever works with trigger trolley, or the gear.

 

[Samurai]

Looks fine, however if it's worn, you can't see that either.

If by trigger trolly you mean the moving part of the switch, then it is not unusual for it to be simply incompatible with the cutoff you have. Try replacing the cutoff too, or the moving part of the switch with an other brand. Or if you can get the original brand, that would be the best.

 

[CaptainSwoop]

Wear on the Cutoff lever is usualy at the end that contacts the switch, not cam end. They are cheap, why not replace it?

 

[Mr Monkey Nuts]

More likely than not something got caught or was pushing on the plate when you put it back together, strip it down and carefully re build it and see if it still happens. It worked for me.

 

[Trojan]

OK well I have fixed the issue

the Lonex upper trolley does not have as much material as the SHS ones, replaced for that and works. However the semi auto does not work if the trigger trolley is mid way (a light pull) and only works on full pulls (when the trigger trolley is all the way in)... this is an issue because if I pull slowly on semi it bursts and then goes into semi.

Help?

 

[CaptainSwoop]

Make sure you use good strong pulls.

 

[Samurai]

...Or if you can get the original brand, that would be the best.

Click to shrink...

 

[Ian_Gere]

Yeah, you don't necessarily need to stick to the original manufacturer, but when you mix parts from various manufacturers, as you've discovered, you can run into this kind of problem - if you replace the trigger mech with company X's product, you probably should replace the cutoff lever with company X's version also. The problem is that it can be difficult to find all the parts you want from 1 supplier, which may not be much of an issue, but it will end up costing you more for shipping. However the supply of parts seems to ebb and flow - if it's OOS somewhere it will often disappear from everywhere for a few months.

TBH I find sourcing upgrade parts, discovering their quirks, and finding bodges to make them work to be part and parcel of the hobby/sport and while i do swear vociferously and whinge when something which ostensibly should work doesn't, in truth I have more fun using guns which I have sweated blood over than off the shelf guns.

Just a heads up: you may find that some gears do not gel well with some anti-reversal latches.

To the original question about how can you tell when it's working - during your shimming process you'll have time when you close the gb without the spring to spin the gears and see whether your estimate is good or needs more/less shims - well you can tell if the cutoff lever is engaged because it puts drag on the sector gear and makes it stop spinning at a point where the cam is off. If you do get a problem where you have had to shim the sector gear high (for eg if you have had to shim the spur gear high to stop it rubbing against a moulding on the gb shell), then it can make very little contact with the cutoff lever, which is a recipe for a fragment of metal to shear off. You can use one of the tiny diameter shims which often come as stock on factory gear sets to lift the cutoff lever up a little.

 

[Trojan]

Thank you very much Ian very well explained, will try adding shims

How will I know i have shimmed the cut off too high, want to shim it so there is a fair bit of work in talk so it can work properly... if the sector is .5up will shim the cut off .3 up

could you clarify what you meant by drag on the sector.. have a hard time following text unfortunately

and also was not going to stick with original parts, i too prefer my own guns.. over time my gb has been completely rebuilt from scratch in the inside. i have a few quirks with it though that i will address in another topic

 

[Samurai]

Shim the gears, not the cutoff.

 

[Ian_Gere]

Thank you very much Ian very well explained

Click to shrink...

have a hard time following text unfortunately

Click to shrink...

I'll just leave that there.

How will I know i have shimmed the cut off too high, want to shim it so there is a fair bit of work in talk so it can work properly... if the sector is .5up will shim the cut off .3 up

Click to shrink...

If the selector plate doesn't push the opposite end from the part of the cut off lever which presses against the sector gear cam, it is too high... and as Samurai said, you should shim the gears, but also, depending on the shape of the cam*, the width and shape of the cut off lever, and the height of the shims needed for the sector gear to clear the spur gear, you can end up with poor contact between lever and cam, only part of the width of each, and the less contact the more pressure the metal is under. That's fine if you have a steel cut off lever, but a pot metal one can break. Putting one factory shim under it must lessen that pressure, but I wouldn't go higher than that, because there is very little extra width on the selector plate end (without getting the micrometer out, the ones i have lurking in my bits box look to be mostly 0.2mm but some are thicker, probably 0.3mm).

*I have seen at least one sector gear which has an extra bit on the cam, like a pre-moulded shim.

could you clarify what you meant by drag on the sector

Click to shrink...

When the cam presses against the cut off lever, the spring pushes back, so it acts as a brake on the spinning sector gear. Obviously if the lever is not engaging with the cam, the gear would spin completely freely.