Threading help/advice.

[farmer7]

Just wondered if anyone could steer me in the right direction, I bought a new rifle and had it threaded by a reputable riflesmith down south before having it sent up here. I requested 18x1 to fit my ATEC Maxim which I also use on another rifle.

 

Unfortunately my mod will only go on one turn and stop. I'm not going to try and force it for obvious reasons. But rather than go to the expense and hassle of sending it back down the road I wondered if its acceptable to try and get hold of an 18x1 split die and make it fit that way.

 

It was suggested to me to try fine valve grinding paste mixed with a little oil and thread it on half a turn a time and back it off but am reluctant to go there as my ATEC fits my other rifle fine.

 

And to clarify it is 18x1 my threaded cap from the other rifle fits on ok, albeit a hair tighter.

 

Advice or opinions would be great. Thank you.

[Ronin]

Not all M18 x 1 threads are equal it seems.

 

I often have this problem, you cut a thread to standard using a thread go gauge, then find the moderator thread doesnt conform..

 

 

Wither run a tap into the mod as it will have carbon build up in there (which will clean it out) or do as you say, run a die down the barrel thread (d try the former first)

[bradders]

Chase it with the die.

As long as there's a good shoulder you shouldn't have any issues

[farmer7]

Chase it with the die.

As long as there's a good shoulder you shouldn't have any issues

Not all M18 x 1 threads are equal it seems.

 

Wither run a tap into the mod as it will have carbon build up in there (which will clean it out) or do as you say, run a die down the barrel thread (d try the former first)

Thanks for the advice chaps, just wanted to check if it was acceptable practice first and not likely to cause any issues!

 

Regarding the tap to clean the threads Ronin, I have neither a tap or die in 18x1 so will have to buy one but without buying both I'm assuming the die would be my best bet?

 

Mark, by shoulder does that refer to the start of the thread or what the mod bottoms out on?

[SWShooter]

Thanks for the advice chaps, just wanted to check if it was acceptable practice first and not likely to cause any issues!

 

Regarding the tap to clean the threads Ronin, I have neither a tap or die in 18x1 so will have to buy one but without buying both I'm assuming the die would be my best bet?

 

Mark, by shoulder does that refer to the start of the thread or what the mod bottoms out on?

 

 

 

An 18x1 tap or die will cost similar money to shipping the gun plus you will need a wrench to hold it

 

With the benefit of hindsight I guess it would be better to ship your mod with your gat.

[bradders]

 

Mark, by shoulder does that refer to the start of the thread or what the mod bottoms out on?

 

Correct

[baldie]

Its high time people who are undertaking this kind of work invested in the correct equipment to do the job.

 

Cutting a thread without a certified ring gauge is simply guessing. Threading a barrel to fit a mod is simply guessing. What happens when the gun is sold and the new owner tries a different mod.

 

A thread cut to a class 2A or 6G standard, will always be just that. A correct, standard thread.

 

I had a guy walk in with a Remington on friday, and one of the new wildcat reflex mods. I screwed the mod onto the gun and there was so much free play on the rear of the mod, i smelt a rat.

 

The thread should have measured 0.625" across [it was a 5/8" x 18 ] It actually measured 0.0612" . It was 13 thou undersized and as loose as a second hand assh ole.

 

I refused to ream the rear bush and fit it, as it would have come undone at the first shot and tipped up.

[Shuggy]

I would agree that the standard of a lot of thread cutting in the UK is shocking. A walk along the display rack in any gun shop will show you that. But I also wonder how well the threads are cut in most moderators? Are some brands considered better than others?

[SWShooter]

Its high time people who are undertaking this kind of work invested in the correct equipment to do the job.

 

Cutting a thread without a certified ring gauge is simply guessing. Threading a barrel to fit a mod is simply guessing. What happens when the gun is sold and the new owner tries a different mod.

 

A thread cut to a class 2A or 6G standard, will always be just that. A correct, standard thread.

 

I had a guy walk in with a Remington on friday, and one of the new wildcat reflex mods. I screwed the mod onto the gun and there was so much free play on the rear of the mod, i smelt a rat.

 

The thread should have measured 0.625" across [it was a 5/8" x 18 ] It actually measured 0.0612" . It was 13 thou undersized and as loose as a second hand assh ole.

 

I refused to ream the rear bush and fit it, as it would have come undone at the first shot and tipped up.

 

As a layman what should I be asking my gunsmith before I hand over my pride and joy for threading ? I appreciate you are a professional but you are a long way from where I live so I would have a lot of shipping and RFD costs added to a thread job so a local gunsmith is the only option.

[Ronin]

Ask if they have a set of thread gauges...

 

Ask if they cut the thread using a lathe ……or a die (if the latter,,,,decline their service)

 

Ask how the barrel is set up in the lathe before threading - how do they check the bore is running true.

 

 

If you don't get answers that satisfy those questions, choose someone else.

[farmer7]

Just a quick update. Peter Jackson of Jackson Rifles kindly sent up an M18x1 split die and die stock along with instructions so I had a go yesterday and the mod now fits perfectly.

 

Previously I was over at Callum Fergusons collecting powder and took the rifle with me, he had a look and measured the threads and he concluded that it was just an intolerance between the mod and barrel thread, as the thread had been cut on the larger side. He had a new Maxim which screwed on exactly the same as mine. He then got a new SL5 which did screw on all the way ok, seemed very snug though.

 

Finally I was able to shoot it and put 40 rounds through it yesterday and no issues with coming loose or blowing chunks of my mod! (Also shot my smallest group ever with it so I'm very,very happy!!!)

 

Thanks for the guidance all.