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]

5 hours ago, Pollynator_bravo2 said:

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?

[Adolf Hamster]

11 hours ago, Pollynator_bravo2 said:

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]

On 29/04/2022 at 03:36, Ussli said:

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

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 🤔

[Adolf Hamster]

1 hour ago, Pollynator_bravo2 said:

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]

6 hours ago, Pollynator_bravo2 said:

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 🤔

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

[Pollynator_bravo2]

7 hours ago, Adolf Hamster said:

 

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

2 hours ago, Lozart said:

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]

3 hours ago, Pollynator_bravo2 said:

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]

11 hours ago, Adolf Hamster said:

 

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]

4 minutes ago, Pollynator_bravo2 said:

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]

3 hours ago, Adolf Hamster said:

 

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]

18 minutes ago, Skara said:

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]

2 minutes ago, Adolf Hamster said:

 

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]

12 minutes ago, Skara said:

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]

13 minutes ago, Adolf Hamster said:

 

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]

10 minutes ago, Skara said:

 

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]

On 02/05/2022 at 13:32, Skara said:

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 ?

On 02/05/2022 at 14:24, Skara said:

 

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]

5 minutes ago, Pollynator_bravo2 said:

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]

On 05/05/2022 at 21:26, Adolf Hamster said:

 

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

[Adolf Hamster]

9 hours ago, Pollynator_bravo2 said:

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

 

aoe wouldn't really do that, it'd be more on the rearmost pickup tooth.

 

i'd be wary of videos on the topic, aoe is one of those subjects that you see a lot of people blanket suggesting large adjustments when the reality is the vast majority of pews don't need anything so drastic.

[Skara]

Fucking YouTube videos.