Thread size help please...

[Nickoli]

I'm the first to admit that I'm a simple muppet when it comes to engineering, so I have no problem asking this: is a 1/2x20 thread size the same as 1/2x20UNF?
Feel free to poke fun, but only if you give me a straight answer....

[Kiwi Greg]

I'm the first to admit that I'm a simple muppet when it comes to engineering, so I have no problem asking this: is a 1/2x20 thread size the same as 1/2x20UNF?
Feel free to poke fun, but only if you give me a straight answer....

Yep

[P38]

Yep

UNF = Unified National Fine.

Cheers
Pete

[Nickoli]

Thanks guys - means my rifle has had the wrong thread applied.....next challenge is to determine what thread it is...

[DPT]

Thanks guys - means my rifle has had the wrong thread applied.....next challenge is to determine what thread it is...

Messure the diameter of the thread and post a photo of it on here, should be able to figger it out pretty easy.

[Nickoli]

Poor quality photos attached - rifle is a 75 Finnlight.

[DPT]

It looks like 1/2-20. Why do you say its not?

[Nickoli]

Tried my 1/2x20 suppressor on it, and there is a bit of resistance - not sure it's a good idea to force it (I requested 1/2x20 thread for the rifle - to fit one of your suppressors that I use on another rifle quite happily). Might be I should try again....

[DPT]

The thread may be slightly oversize, it always pays to supply the suppressor when having the rifle threaded so you get a perfect fit.

[rambo-6mmrem]

how much resistance is there a little tight is a good thing as its less likely to come lose while shooting if it goes on smooth but is just a bit tight that's ok In my mind but I know nothing @DPT is the man to listen to he dose suppressors for a living... 95% of .22lr's are 1/2-20unf so if you have a 22 that's supressed you could try your 22 suppressor on it to see if that fits (I know your not dumb but don't fire it lol)

[rambo-6mmrem]

just another thing I thought of is it an over barrel can? if so have you checked the barrel dia on your sako to make sure the barrel will fit in the rear bushing at the point where it would be fully tight? it may be that binding and not the thread at all ?

[Nickoli]

just another thing I thought of is it an over barrel can? if so have you checked the barrel dia on your sako to make sure the barrel will fit in the rear bushing at the point where it would be fully tight? it may be that binding and not the thread at all ?

All good - is an over barrel type and there is good clearance on bush, the suppressor engages the thread fine but encounters a bit of resistance after several turns - have not pushed it. Seems to hold on OK with the few turns, but am loathe to fire it just yet.

[DPT]

All good - is an over barrel type and there is good clearance on bush, the suppressor engages the thread fine but encounters a bit of resistance after several turns - have not pushed it. Seems to hold on OK with the few turns, but am loathe to fire it just yet.

Dont fire it with only a few turns on, it could blow off. Where are you located?

[Nickoli]

Napier - will take it into Rivers To Ranges (it was threaded there) to be safe.
Thanks for the advice.

[gadgetman]

Looking at those callipers the thread seems to be cut oversize.