Is making a delrin transfer port a bad idea?

[rovercoupe]

I have a rifle with a transfer port thats too big and making it inconsistent so need to knock up another so would one in delrin work or would it just implode with the pressure? Its only a small port about 8mm width by 10mm high with a 2mm hole

Or should i just order some brass bar!

[Hsing-ee]

How would you make sure that such a slippery material would stay in place? The elaborate process for gluing-in delrin buttons on a piston would make me think brass would be a much simpler and more reliable answer, and one which tuners have been using for years.

The dimensions you quote are strange! Surely a transfer port only has a diameter and a length? Unless it is some weird kind of Cardew-inspired venturi...

[robs5230]

How would you make sure that such a slippery material would stay in place? The elaborate process for gluing-in delrin buttons on a piston would make me think brass would be a much simpler and more reliable answer, and one which tuners have been using for years.

The dimensions you quote are strange! Surely a transfer port only has a diameter and a length? Unless it is some weird kind of Cardew-inspired venturi...

The transfer port on BSA Ultra , r10 etc is roughly as the op decribes though not those dimensions. Its in effect a brass tube set between the cylinder and breech and sealed by O rings. Though I do get what you mean in that the transfer port is just the "hole" that the air passes through. A TP on a springer is basically a hole of a length and a diameter drilled in the end of the cylinder

[Hsing-ee]

The transfer port on BSA Ultra , r10 etc is roughly as the op decribes though not those dimensions. Its in effect a brass tube set between the cylinder and breech and sealed by O rings. Though I do get what you mean in that the transfer port is just the "hole" that the air passes through. A TP on a springer is basically a hole of a length and a diameter drilled in the end of the cylinder

fort you ment a SPRINGER........ apologies...

[Barryg]

In a springer I have heard that the temperature generated in the TP is very high, if this is true then a delrin TP would not be suitable.

[robs5230]

Given the dimensions Barry, the OP seems to be referring to a tp on a pcp, co2 rifle

[Barryg]

Given the dimensions Barry, the OP seems to be referring to a tp on a pcp, co2 rifle

Thanks for clarifying

[TonyL]

I can't see there being a problem. Our own Jim, AirGun World fame, has done so ... see this month's edition. I have also made delrin transfer ports for a pcp when experimenting a bit.

Cheers, Phil

In a springer I have heard that the temperature generated in the TP is very high, if this is true then a delrin TP would not be suitable.

Okay, slightly off at a tangent, as it's not a springer that the OP is referring to, but, Barry, as Phil says above, Jim's been playing with acetal transfer ports on TXs. All good. And that silly high temperature is only generated for a miniscule amount of time meaning no ill effects with the synthetic TP.

[rovercoupe]

Hopefully here is a pic of the port in question,

[NickG]

Okay, slightly off at a tangent, as it's not a springer that the OP is referring to, but, Barry, as Phil says above, Jim's been playing with acetal transfer ports on TXs. All good. And that silly high temperature is only generated for a miniscule amount of time meaning no ill effects with the synthetic TP.

Don't wish to be anti Jim as he does some fantastic work, i spotted a problem with his trans port as part of the stroke shortening plug he is testing. once cocked the breech lock up will be non existent as the barrel would push the plug rearwards when the cocking lever is returned , leaving just the o rings to take the pressure , on the TX the trans port creates the cavity for the o rings to work once it contacts the barrel. Jim is only using this set up to test with so not a problem .
I tried delrin for o ring piston heads and after time it broke up, cant say if this was due to temperature or the impact.

[Phil Russell]

I can't see there being a problem. Our own Jim, AirGun World fame, has done so ... see this month's edition. I have also made delrin transfer ports for a pcp when experimenting a bit.
What rifle? Just curious as 2mm is quite small. It sounds as if your current port is removeable.. or is 8mm the width of a recess?
Cheers, Phil

[robs5230]

I'd suggest you'd need to clarify how the TP seals. If o rings are present around the TP then delrin should be fine as said above.
I've worked on some rifle where O rings have in effect been the TP. When crushed via breech and cylinder mating together, they can distort and reduce air flow. In these situations a harder less compressible (but still sealable) material is needed.

[greenwayjames]

I have a rifle with a transfer port thats too big and making it inconsistent so need to knock up another so would one in delrin work or would it just implode with the pressure? Its only a small port about 8mm width by 10mm high with a 2mm hole

Or should i just order some brass bar!

Stalker used BSA and Daystate rifles as a base for many of his products but Bowket also produced handmade actions for some of the range. Leopard, Lynx, Bobcat, big bore Pumas etc. The 50 ft/lbs version of the Leopard was popular in Japan apparently Most were FAC versions he told me so it might be wise to contact him as he would know the best dimensions for a transfer port suitable for your Stalker. Have a look on the Facebook JB Fanpage for piccies of some.