Quick Question on Tread Size.

Comeraghshooter · 07-09-2011 09:57AM #1

I know my barrel is threaded to fit a moderator of size 5/8 but can someone tell me how do i find out if its 5/8 X 18 or 5/8 X 24

Thanks
CS

Tackleberrywho · 07-09-2011 11:05AM

Comeraghshooter wrote: »

I know my barrel is threaded to fit a moderator of size 5/8 but can someone tell me how do i find out if its 5/8 X 18 or 5/8 X 24

Thanks
CS

AFAIK
5/8 x18 is 5/8th of an inch by 18mm or 5/8th x 24mm

A mongrel of a measurement with Imperial and metric.
You can often buy cheap Verniers that covert Metric to Imperial for small money in Aldi/Lidl

ormondprop · 07-09-2011 11:14AM

I think your wrong tack i think 5/8x18 is a thread 5/8 of an inch wide with 18 threads along an inch in length where the 5/8x24 will have 24 threads per inch length ways, so they are not interchangeable,

Vegeta · 07-09-2011 11:15AM

Tack is it tpi or mm?

EDIT: ormondprop got there before me

Comeraghshooter · 07-09-2011 12:00PM

Thanks lads, do ye know what is the most commonly used in 5/8 ??

Vegeta · 07-09-2011 12:03PM

Do you have any sort of steel ruler/engineering ruler or calipers?

http://www.roton.com/identify_threads.aspx

Could measure it and work it out.

I've no clue which is more popular unfortunately

ormondprop · 07-09-2011 12:17PM

I think 5/8 x 18 is more popular, i've never seen a 5/8x24 before

Cass · 07-09-2011 12:21PM

ormondprop has it on the money on both accounts.

clivej · 07-09-2011 01:25PM

5/8 x 18 is the same as 5/8 UNF and would be the standard for a 5/8 thread the other one is a barstard size with a finer thread used in the states

Rovi · 07-09-2011 01:47PM

5/8 - 18 is 5/8 inch in diameter with 18 TPI (Threads Per Inch), this is the standardised 5/8" UNF (Unified Fine) thread.

5/8 - 24 is 5/8 inch in diameter with 24 TPI, this is the standardised 5/8" UNEF (Unified Extra Fine) thread.

More here: http://en.wikipedia.org/wiki/Unified_Thread_Standard

Comeraghshooter · 07-09-2011 02:03PM

Thanks for all the info lads!

Half-cocked · 07-09-2011 02:34PM

Be careful it's not a metric fine 16mm thread. 5/8 = 15.875mm. There are some metric fine threaded moderators out there - I've threaded a few barrels for them. You really need some one with a thread gauge to make 100% sure what you have.

Its most likely a 5/8 UNF, but get that verified.

Tackleberrywho · 07-09-2011 03:03PM

Apologies for my mish-stake earlier.
Yes my Mods are 5/8 UNF

I have a problem of a different nature at the moment that I can't get a thread of the same pitch for my 105CTi. All the Remington chokes have the same thread, but the probore chokes I have, have a slower thread and wider.

So I feel your pain OP with thread sizes.

Over the years in Industry I have seen many threads mangled with the wrong nut put on.
Cheapest way of testing the thread is getting a 5/8UNF nut and seeing if it screw on easily.
Or get the loan of a thread gauge if you do not have one.

5/8 UNF also normally is a Varmint profile type thread. skinny barrels need a different thread to tighten the mod properly.

deeksofdoom · 07-09-2011 03:20PM

Comeraghshooter wrote: »

Thanks for all the info lads!

It might go on easier with the help of a ball peen hammer and some Vaseline.

Cass · 07-09-2011 03:20PM

Tackleberrywho wrote: »

skinny barrels need a different thread to tighten the mod properly.

Skinny barrels need a different thread size (usually 1/2") because a 5/8" thread simply cannot be done on the barrel. Usually because the barrel is not even 5/8 in diameter.

Much in the same way you wouldn't normally put a 1/2" thread on a varmint barrel. No need to remove so much of the barrel, however i say "normally" because i have seen varmint barrel with 1/2" thread jobs and it looks crap.

I think the better option when getting a barrel threaded, just speaking generally, is to buy the mod/brake and then bring it to a gunsmith and have them thread the barrel to suit the thread of the mod. I know most are a common size, but you get a much better fit it the gunsmith can check the mod as he is threading. The threading on the Father's 30-06 was "generic". As in done for any 1/2" mod. His mod fitted fine. However when the lad that bought the mod off the Father went to get his rifle threaded and came back the mod was a much better fit on his rifle than on my Fathers. Better thread job and it was "tailored" to the mo rather than a generic job to suit all 1/2".

Comeraghshooter · 07-09-2011 03:36PM

deeksofdoom wrote: »

It might go on easier with the help of a ball peen hammer and some Vaseline.

Thanks for the input Deeks, very helpful as usual :rolleyes:

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Quick Question on Tread Size.

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