8 replies to this topic

[Samurai kidd]

Attempt at contribootin':

While working on a 17/32 brass breech for my longshot, I was having problems with the internal o-ring to PT face seal. I figured out that the problem was the o-ring; it was torn. I had no way of getting to ACE and didn't have the right replacement on hand, so I decided to replace the sealing method altogether. I did this by using the same design concept as the breech itself; brass-to-brass coupling.

Essentially, I put a ring of brass inside the small endpiece on the PT face. The size I used was 5/8 brass. This ring of 5/8 sealed with another ring of 19/32 on the base of the bolt near the black plastic circle. The 19/32 encases the 9/16 that I used for the bolt. This concept should also work for breeches with a 5/8 bolt; just use a 21/32 base for the bolt base and an 11/16 piece on the PT face.
Here are some in progress pictures:

PT face with ring of 5/8:


Bolt with piece of 19/32 over the 9/16 bolt:



Some MS paint photos to better illustrate the concept:

Open:


Closed:


Feedback?

[quertyman]

I have had this idea for a while now. (seriously not trying to steal credit or anything) But great job and now it should have a perfect seal. Does it?

[andtheherois]

I would suggest using an alternate method to size up the brass to fit in the PT opening. The Etape will most likely come undone with the breech opening and closing. You also have to make sure you get it completely straight or you'll be in for a world of friction. This sealing method is good, but doesn't look like it'll have much tolerance for the breech being even slightly crooked.

[Samurai kidd]

I have had this idea for a while now. (seriously not trying to steal credit or anything) But great job and now it should have a perfect seal. Does it?

Yes. At first it didn't, but the brass was slightly warped. I replaced it and it gets a perfect (or at least close to it) with a superlative.

I would suggest using an alternate method to size up the brass to fit in the PT opening. The Etape will most likely come undone with the breech opening and closing. You also have to make sure you get it completely straight or you'll be in for a world of friction. This sealing method is good, but doesn't look like it'll have much tolerance for the breech being even slightly crooked.

Yeah, I expect that will happen eventually. Since 5/8 OD is the same as cpvc I could possibly ream something or use a partial coupler. I'll have to see what fits. So far, I've had a surprisingly low amount of friction. I let the superglue set with the breech installed, so that probably helped alignment.

Edited by Samurai_kidd, 30 January 2013 - 08:49 PM.

[Buffdaddy]

Can't we just stick a thin rubber washer in there and seal the entire face?

[thedom21]

Can't we just stick a thin rubber washer in there and seal the entire face?

I use a rubber washer and an o-ring and have had absolutely not problems with it.

[quertyman]

I use a rubber washer and an o-ring and have had absolutely not problems with it.

This is why it is called "alternative"

[thedom21]

This is why it is called "alternative"

Alternative but its also more expensive and more complicated than slipping a rubber washer and an o-ring on.

[Samurai kidd]

Alternative but its also more expensive and more complicated than slipping a rubber washer and an o-ring on.

It's also more reliable and gives you an extra ~1 mm of travel, which can be crucial for brass breeches.
If you don't like it, you don't have to use it.

Sidenote, I just realized that this can be used to replace the o-ring method even if the plunger-pusher (The circular piece that you normally fill with hotglue) is broken. The dimensions don't need to be as exact and you don't need the small lip at the front, so this could theoretically be used for repairs.