Hey guys, Ive got a question. I'm thinking about adding a 7.62 muzzle device to my CZ858 but cant find the info I'm looking for anywhere. The muzzle uses a standard 5/8x24 thread, while the CZ is M14x1. I am wondering if an M14x1.0R helicoil would have a large enough outer diameter to require drilling out the 5/8" threads and tapping something larger in. 11/16" should be enough I figure but I just dont want to buy a helicoil kit that *might* work. Can anyone shed some light on this?
M14x1.0R Helicoil tap size
- Thread starter supernova
- Start date
What are you looking at for a Helicoil kit, cost-wise?
I think that hunting down a brake that fits is gonna be cheaper in the long run. Heck, getting what you want MADE, would be cheaper, in all likelihood.
Here. http://www.helicoil.in/pdf/HeliCoil Catalogue.pdf Probably more than you ever wanted to know about helicoils.
Cheers
Trev
I think that hunting down a brake that fits is gonna be cheaper in the long run. Heck, getting what you want MADE, would be cheaper, in all likelihood.
Here. http://www.helicoil.in/pdf/HeliCoil Catalogue.pdf Probably more than you ever wanted to know about helicoils.
Cheers
Trev
Trevj
the cost of the heli-coil kit is not an issue if it works, its wasting money and paying a restocking fee if it doesnt. The muzzle I'm looking into is the new troy claymore, I want a forward blow compensator rather than a louder device. ATRS advised me that the Levang is too small to bore out to .30 cal and making one to work with the 7.62x39 round would cost several hundred dollars. I'l check that site out and see if theyve got something that will work. Thanks
the cost of the heli-coil kit is not an issue if it works, its wasting money and paying a restocking fee if it doesnt. The muzzle I'm looking into is the new troy claymore, I want a forward blow compensator rather than a louder device. ATRS advised me that the Levang is too small to bore out to .30 cal and making one to work with the 7.62x39 round would cost several hundred dollars. I'l check that site out and see if theyve got something that will work. Thanks
I recently installed a Medieval on a shortened Norc M14. There are two different sized threads inside the Medieval. The outer threads are larger than the inner and 40 tpi, not 11/16" BTW, and the inner set smaller and 32 tpi, sorry can't remember the sizes. I made a sleeve for the brake that would engage the outer set of threads of 40 tpi and slip inside the inner threads as well as slide into the unthreaded portion to support the front. I shortened the barrel up for the guy and threaded it to a minor of .500" so his barrel would be strong. This sleeve is a one off custom thread size because the OD threads are already odd sized and the barrel really should be at least .500" thick.
I don't think adding a helicoil to your existing barrel threads will do it. Since this plan would already require the services of a smith because he would need to redo the brake's internal threads, he can also make an adaptor for your existing barrel threads that fits the brakes new threads.
I don't think adding a helicoil to your existing barrel threads will do it. Since this plan would already require the services of a smith because he would need to redo the brake's internal threads, he can also make an adaptor for your existing barrel threads that fits the brakes new threads.
PEIRob, I think we may have gotten lost in translation? Is that the M-14 Medieval? That would be standard US M14 threads right? I'm looking at the 7.62 Claymore which is 5/8x24 according to the site. After some measuring it doesnt look like a heli-coil will have enough meat to get past the 5/8" threads, I had thought about your idea of having a thread adaptor made, I just dont know if it would be thick enough going from M14x1.0 to 5/8x24. I do as much of my own work as possible, drilling and tapping the brake is no problem if need be. I think I'll just phone up some machine shops and see what can be done. Thanks to all for the help
Ok guys, one more question. Troy replied to an email and said the O.D. of the threaded area on the Claymore is 7/8" which is 22.225mm. The helicoil spreadsheet that Trevj posted didnt show M14x1.0 but does show an M14x1.5 helicoil has a 17.25mm O.D. which would leave 2.48mm of wall thickness between the helicoil threads and O.D. of the brakes threaded area. This seems acceptable to me, what do you guys think? The rifle isnt used hard so it wont be taking any serious hits or abuse.
The Claymore may be 7/8" but I would bet the wrench slot is 3/4".
You would still need to machine the Claymore because the pitch would need to be 1mm for the helicoil and they don't make a kit in M14x1mm and certainly nobody makes a tap that size. Besides, it should be made straight by a machine.
I would enlarge the threads of the Claymore, keeping them 24tpi, and make a sleeve. Not all gunsmiths have metric capable lathes.
You would still need to machine the Claymore because the pitch would need to be 1mm for the helicoil and they don't make a kit in M14x1mm and certainly nobody makes a tap that size. Besides, it should be made straight by a machine.
I would enlarge the threads of the Claymore, keeping them 24tpi, and make a sleeve. Not all gunsmiths have metric capable lathes.
PEI Rob
7/8" came straight from troy industries. I'm not using a helicoil brand kit, Ive found an M14x1.0 kit from the UK that comes with tap drill, tap, inserts and installation tool. The 17.25mm is a spec from a helicoil brand insert from the spreadsheet trevj posted. I have emailed the mfr. to make sure his kit is in the same size range. Then I will know for sure what tolerances are being dealt with. a 5/8" drill bit I have mic'd out at just under 16mm so if the insert is between 17 and 18mm then I should be removing all of the original threads when boring with the tap drill bit in the kit. The whole point here is avoiding paying someone, I'm not the kind of guy who runs to a pro and forks over cash to get things done.
7/8" came straight from troy industries. I'm not using a helicoil brand kit, Ive found an M14x1.0 kit from the UK that comes with tap drill, tap, inserts and installation tool. The 17.25mm is a spec from a helicoil brand insert from the spreadsheet trevj posted. I have emailed the mfr. to make sure his kit is in the same size range. Then I will know for sure what tolerances are being dealt with. a 5/8" drill bit I have mic'd out at just under 16mm so if the insert is between 17 and 18mm then I should be removing all of the original threads when boring with the tap drill bit in the kit. The whole point here is avoiding paying someone, I'm not the kind of guy who runs to a pro and forks over cash to get things done.
