Probs a dumb question on counting teeth

[Pollynator_bravo2]

Evening

so I need to replace a piston as it’s moved to the afterlife. I read I need to count the teeth to make sure the sector gear and piston have the same number of teeth. I’m counting 16 teeth but I can’t find a 16 tooth piston. Am I counting right ? Or have I missed something ?‍?
 

 

[Ussli]

晚上

所以我需要更换一个活塞，因为它已经转移到来世。我读到我需要计算齿数以确保扇形齿轮和活塞具有相同的齿数。我数的是 16 齿，但我找不到 16 齿活塞。我数对了吗？还是我错过了什么?‍?
 

Why do you need 16 teeth? Usually it is necessary to cut the teeth and reduce it. Are you not a standard gearbox?

View attachment 89420

 

[Adolf Hamster]

Evening

so I need to replace a piston as it’s moved to the afterlife. I read I need to count the teeth to make sure the sector gear and piston have the same number of teeth. I’m counting 16 teeth but I can’t find a 16 tooth piston. Am I counting right ? Or have I missed something ?‍?
 

the majority of standard guns the tooth count is the same and doesn't count the initial pickup tooth.

when you see for example "15t" "14.5t" and "14t" pistons that's generally referring to wether or not the first regular tooth (ie not the pickup one) has been filed down a bit (aka a half tooth in a 14.5) or removed completely (14tooth as in the above image).

this is to allow clearance for the initial pickup stage so the sector gear doesn't hit that tooth on its way round to start pulling the piston back.

 

[Pollynator_bravo2]

Why do you need 16 teeth? Usually it is necessary to cut the teeth and reduce it. Are you not a standard gearbox?

View attachment 89420

These are what was in there but the piston was bending down and locking up. Brought the gun second hand. King Arms Dinosaur but the gb didn’t look like the diagram ?

View attachment 89475

View attachment 89476

 

[Adolf Hamster]

These are what was in there but the piston was bending down and locking up. Brought the gun second hand. King Arms Dinosaur but the gb didn’t look like the diagram ?

how do you mean bending down and locking up?

 

[Lozart]

These are what was in there but the piston was bending down and locking up. Brought the gun second hand. King Arms Dinosaur but the gb didn’t look like the diagram ?

View attachment 89475

View attachment 89476

Looks drier than a nun's fanny in there! Make sure you give it some lube before you put it back together! 

 

[Pollynator_bravo2]

how do you mean bending down and locking up?

I was hoping I had some videos or pictures to show what I mean but sadly not. Three of the teeth are a bit chewed up. The whole gear box wasn’t lubed up great inside in all fairness but I’ve seen worse

Looks drier than a nun's fanny in there! Make sure you give it some lube before you put it back together! 

For sure. It wasn’t in great condition

 

[Adolf Hamster]

I was hoping I had some videos or pictures to show what I mean but sadly not. Three of the teeth are a bit chewed up. The whole gear box wasn’t lubed up great inside in all fairness but I’ve seen worse

could be it's bedding itself in, the sector gear carving it's own idea of aoe, hard to tell from the pics with the way the lighting is.

but mostly that doesn't look too bad (apart from being dry, idk if you cleaned it before taking those pics)

 

[Pollynator_bravo2]

could be it's bedding itself in, the sector gear carving it's own idea of aoe, hard to tell from the pics with the way the lighting is.

but mostly that doesn't look too bad (apart from being dry, idk if you cleaned it before taking those pics)

Do you use silicon oil or grease on the piston ? Also the O ring should it be loose ? 

 

[Adolf Hamster]

Do you use silicon oil or grease on the piston ? Also the O ring should it be loose ? 

grease on the piston, and the o ring should be loose on the piston, it seals against the back face of the groove when firing then moves forward allowing air through when being drawn back.

 

[Pollynator_bravo2]

grease on the piston, and the o ring should be loose on the piston, it seals against the back face of the groove when firing then moves forward allowing air through when being drawn back.

There is space around the piston and cylinder body but that looks normal I guess ? Do you put any grease on the cylinder head ?

what’s best to use to get rid of the old grease?

 

[Skara]

That piston says PME all over the place. There could be too much friction inside the cylinder or the piston guides due to no lubrication, or the spring is so soft it can't push the piston forward fast enough.

Or, the easiest option, someone got a jam and kept firing.

Cylinder head requires a tiny amount of lube around the sealing o-ring(s), I use silicone grease (just a dab) for that.

To remove old grease/oil just wipe the thing with a cloth/paper towel.

 

[Adolf Hamster]

That piston says PME all over the place.

does it? teeth look ok to me, although can't see them too well with the lighting?

 

[Skara]

does it? teeth look ok to me, although can't see them too well with the lighting?

1st(pick up), 4th and 5th teeth are chewed up, with the 2nd and 3rd being spotless.

 

[Adolf Hamster]

1st(pick up), 4th and 5th teeth are chewed up, with the 2nd and 3rd being spotless.

Hmm, must have a better monitor than i do lol, they all look the same to me.....

 

[Skara]

Hmm, must have a better monitor than i do lol, they all look the same to me.....

Sry for being nitpicky  original picture is also low quality so it makes it harder to detect, but:

yellow: what the tooth should look like

blue: what the tooth is actually like

 

[Adolf Hamster]

Sry for being nitpicky  original picture is also low quality so it makes it harder to detect, but:

yellow: what the tooth should look like

blue: what the tooth is actually like

yeah it's just washing out on all my screens, maybe got me vibrancy set too high

 

[Pollynator_bravo2]

That piston says PME all over the place. There could be too much friction inside the cylinder or the piston guides due to no lubrication, or the spring is so soft it can't push the piston forward fast enough.

Or, the easiest option, someone got a jam and kept firing.

Cylinder head requires a tiny amount of lube around the sealing o-ring(s), I use silicone grease (just a dab) for that.

To remove old grease/oil just wipe the thing with a cloth/paper towel.

PME ?

Sry for being nitpicky  original picture is also low quality so it makes it harder to detect, but:

yellow: what the tooth should look like

blue: what the tooth is actually like

Good info thanks 

 

[Adolf Hamster]

PME ?

Premature engagement

Basically the piston isn't fully forwards when the sector gear tries to pick it up, teeth are badly aligned and something ends up breaking.

Most common cause is when folk are building a gun thats running too fast for its power, but as @Skara says can also occurr when something like a bb jam is restricting forward motion of the piston.

its one of the arguments for plastic tooth pistons, the teeth are an intentional point of failure where a metal rack might push the failure onto the gears.

 

[Pollynator_bravo2]

Premature engagement

Basically the piston isn't fully forwards when the sector gear tries to pick it up, teeth are badly aligned and something ends up breaking.

Most common cause is when folk are building a gun thats running too fast for its power, but as @Skara says can also occurr when something like a bb jam is restricting forward motion of the piston.

its one of the arguments for plastic tooth pistons, the teeth are an intentional point of failure where a metal rack might push the failure onto the gears.

I noticed the AOE was not right based on some videos I’ve seen tbf