Moderator thread change 1/2x20UNF to 1/2x28?

[Muskett]

How can you get a 1/2 x20UNF to fit a 1/2x28? I just have a moderator with the former and as a moderator goes love it. Annoyingly the new combo I'm putting together is threaded 1/2x28.

All suggestions welcome, thank you in advance.

[Bellycrawler]

No adaptors available as far as I know. 28 tpi is more common in the USA. I have a SAK in 28tpi but no idea if those are still available. Might be easier to Google for an answer.

[Neil54]

Found an adaptor.
Ant supplies - type A1.
https://www.ant-supplies.uk/rifle-ac...-adapters.html

[angrybear]

I'm pretty sure Wildcat do an adaptor, they also do a complete baffle in 28tpi for the Panther.

[Shed tuner]

the adapter will surely just extend everthing by around an inch, and might give rise to alignment issues ?

[u.k.neil]

the adapter will surely just extend everthing by around an inch, and might give rise to alignment issues ?

Way back in my machining days. I made just such a barrel adaptor for the Birmingham Proof House so that they could proof a batch of screw on moderators that I had made with the 1/2"- 28 UNEF thread.



Neil

[Shed tuner]

Way back in my machining days.

before you re-retired

[u.k.neil]

before you re-retired

Spot on mate........



Neil

[angrybear]

the adapter will surely just extend everthing by around an inch, and might give rise to alignment issues ?

More like 1/2" but there is no other option.

[BC312]

If i was in your situation i would, if i have a lathe bore out the 28 tpi thread and press fit a tight insert treaded for 20 tpi, but i would have to look at the silencer to see if its feasible, most probably not. Don't understand why anyone doesn't stick to the standard than make these odd sizes, someone trying to be clever.

[Shed tuner]

28tpi actually makes some sense, as it's less likely to come loose, but I agree with you in as much as having a standard, it'd be a lot easier of everyone followed it.

[Muskett]

Found an adaptor.
Ant supplies - type A1.
https://www.ant-supplies.uk/rifle-ac...-adapters.html

That may well work well enough. Thank you.

It is a Pope Swift moderator which comes over the barrel too by a tad over an inch. With adapters its how wel they fit and what effect to the harmonics.

This exercise is after all just a machining task, as most moderators are turned on a lathe at some point. But these kinds of things of messing about don't warrant the cost, as buying a whole unit is less than some people's/machinist's time. Sadly, my good friend hobby machinist passed away a few years back. He would have loved the challenge; frankly any excuse to fire up his lathe.

[yellowvanman]

I've got an ant supplies adapter on the way as we speak, his are made of alloy, go to that well known auction site, look for seller sanokmk he makes both directions of adapter in steel too.

[angrybear]

If i was in your situation i would, if i have a lathe bore out the 28 tpi thread and press fit a tight insert treaded for 20 tpi, but i would have to look at the silencer to see if its feasible, most probably not. Don't understand why anyone doesn't stick to the standard than make these odd sizes, someone trying to be clever.

The OP clearly states the mod is 20tpi, it's the barrel that is 28tpi so he'd have to chop off & re-machine the barrel.

Sorry but when did anyone make 1/2" 20tpi 'the standard' ?

It might be the most common on UK air rifles & rimfire, but there are plenty of manufacturers & countries that prefer other threads, 28tpi is more common in the USA.
And more threads equals more surface area, equals more holding power, equals a stronger join.

[u.k.neil]

It might be the most common on UK air rifles & rimfire, but there are plenty of manufacturers & countries that prefer other threads, 28tpi is more common in the USA.
And more threads equals more surface area, equals more holding power, equals a stronger join.

Spot. on, it is the most common 1/2" moderator thread in the U.S.A.


Neil.