finding size of screw cut.....

conorkelly

Member
I know to some of you this may sound silly but i bought a second hand rifle which was already screw cut and had mod with it. But i want to change the mod but do not know the size i need. what is the best way to find out what thread i have.
 
You need a thread gauge...you can find them at Axminster Tools and all good retailers!
 
lol my local RFD would p*ss himself if I asked him what thread my rifle was. RFD's don't always have knowledge, e.g ask a mercedes sales man how to change an air filter and he won't have a clue!

Get yourself to a rifle "smith" not that there are many in the uk. Where in the highlands are you? I know a very good chap in cumbria.
 
Some, but not all mods have the thread size engraved / stamped on the body or rear of the can.

If its a Reflex (BR Toute) there is a code, which a phone call to Jackson Rifles will resolve.


If you home load and have access to a dial caliper (thats zero'd)

Measure the thread outside diameter and post here.


Should get you in ball park, unless your thread is a variant of UNF (UNEF)
 
lol my local RFD would p*ss himself if I asked him what thread my rifle was. RFD's don't always have knowledge, e.g ask a mercedes sales man how to change an air filter and he won't have a clue!

Get yourself to a rifle "smith" not that there are many in the uk. Where in the highlands are you? I know a very good chap in cumbria.

Your local Rfd must be in the wrong Business then, our local is on the ball, as was his father before him ;)

Most car salesmen only know how to DRINK their profits, it's the bosses who coin it in.

Maybe your guy should take up Mechanics, he'd know how to change that air filter then :doh:

Kind Rgds. Buck.

PS. +1 Redmist. (Peter) JACKSON RIFLES :thumb:
 
If you can get yourself into an engineers merchants, you can purchase (cheap enough) a set of pitch gauges, this will give you the exact id of what you have thread wise, (teeth per inch/ mm, also the pitch)
 
measure it, go to the neares metric size and the nearest imperial size then very gently offer them up and see what fits; under no cicumstances force it!

Dave
 
Hi all

thanks for the response. Just out of interest I tried may sound mod that is on my ruger 22lr semi auto which is factory cut. It is a perfect fit for my .223. the Mod is an aluminium SAK does this shed any light on the situation. can anyone tell of the top of there heads which tread it is now.

Cheers

conor
 
Sak mods are produced in 1/2 x 20 and a few in 1/2 x 28, count the pitches over half an inch and that will tell you what it is.

Neil. :)
 
hi neil

you may dumb that down a little for me, what are the pitches

cheers for the help

He means TPI Threads per inch if measuring over a 1/2". Pitch is used for metric (yes all threads have a pitch, I know) It is simply a measurement of tip to tip of thread (pitch) so for example M6x1 6mm thread x 1mm 'pitch' note counting a metric pitch over a 1/2" is a waste of time and counting over a 1/2" is not the way to do it..can you accurately gauge the start and finish of your 1/2" to be certain?

FYI 'gunsmithing' is a game where you will find unusual threads! (see my thread regarding a moderator, my rifle has a muzzle thread of 0.6"x24UN form)

You really need a thread gauge to be certain of a thread small deviations or a mix-up of imperial and metric will cause major problems, so advise is see a local engineering shop if you do not have a gunsmith that will check it for you.
 
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Any good nut and bolt supplier will have the gauges that you can use to sort out what fits. They use them all the time to be able to sell nuts and bolts they need to know whats what.
 
Pitch is relevant both to Metric and non-Metric.

Yes read the post instead of filling your boots...

"He means TPI Threads per inch if measuring over a 1/2". Pitch is used for metric (yes all threads have a pitch, I know)"

Just so that you can understand ... It is easier to differentiate between IMPERIAL TPI and METRIC PITCH
Try to understand that there is a difference.

You do know that the screws / bolts are not interchangeable between imp & metric? or you just like to confuse the poor lad?
 
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Yes read the post instead of filling your boots...

"He means TPI Threads per inch if measuring over a 1/2". Pitch is used for metric (yes all threads have a pitch, I know)"

Just so that you can understand ... It is easier to differentiate between IMPERIAL TPI and METRIC PITCH
Try to understand that there is a difference.

You do know that the screws / bolts are not interchangeable between imp & metric? or you just like to confuse the poor lad?

Filling my boots? :lol:

Steady on, I think your post was the more confusing.
 
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