Jump to content

Screw cutting a rimfire barrel


Jimiles
 Share

Recommended Posts

On 15/01/2019 at 08:20, Jimiles said:

I am going to take my Remington 597 to a local machine shop and ask them to shorten the barrel to about 14"and then re-cut the thread. They've not done this before but they're quite happy to simply replicate the original pattern. Before they do this can anybody explain why there is such a wide & deep groove as arrowed between the thread and the machined face? Why can't the thread simply continue up to the face?  I am concerned that this groove looks to be quite deep but surely removing so much metal here is creating an unnecessarily weak point in the barrel. 

My other concern is the crown of which I've got no understanding at all. Looking at my rifle it appears to be a simple rounding of the muzzle area with a slight chamfer cut inside the bore. Is that all that is required or should I use this opportunity to get a more elaborate crown machined?

 

P1090134.JPG

It's simply there to allow the threading tool to be stopped before it hits the face of the barrel. 

Link to comment
Share on other sites

11 hours ago, Big Mat said:

 

And to allowed whatever to screw up to the shoulder. You can stop the threader before it hits the barrel whether you put an undercut in or not

Yep but you need an undercut to stop a threading tool in if not using a die, I was thinking of much larger diameters cut on a lathe in a previous life.

Link to comment
Share on other sites

3 hours ago, Salopian said:

I highly recommend Mike Norris Unit G2  Sandford Industrial Park , Whitchurch SY13 2AN 

Thanks Salopian, Brock & Norris were actually the first recommendation given to me...and I may still end up going there. It is their price that made me think twice, Brock & Norris charge £125 plus VAT to do this work. When I factored in the fuel costs to take the rifle up to Whitchurch and then go back and collect it on completion its going to total up to about £140. It was at that point I thought I'd try a machine shop!

Link to comment
Share on other sites

1 hour ago, Jimiles said:

Thanks Salopian, Brock & Norris were actually the first recommendation given to me...and I may still end up going there. It is their price that made me think twice, Brock & Norris charge £125 plus VAT to do this work. When I factored in the fuel costs to take the rifle up to Whitchurch and then go back and collect it on completion its going to total up to about £140. It was at that point I thought I'd try a machine shop!

If you ask, there’s a decent chance he’ll do it while you wait by arrangement.

T

Link to comment
Share on other sites

23 hours ago, wildrover77 said:

Gunsmith are not wizards with special powers.

Any good machinist can do the job.

 

Yes and when you need you rifle rebarreling or bedding or trigger tuned or stock chequered the machinist won’t help as he doesn’t have the experience or tools but the gunsmith will be shut as he went out of business.  Don’t be afraid to support your local trades men of any type.  

Link to comment
Share on other sites

make sure the machine shot do not hammer a mandrel into the bore to use for centring. seen it done, had to recut.

the one reason to put a relief or back cut in is to the mod shoulder has good meat to butt up to and square up. a good screw cut, dont to your mod and a good shoulder is paramount.

you can cut the thread the other way, basically spin it all the other way, still cutting the thread right handed but having the cutter start as the shoulder end. then you can run the lathe faster and not worry about cutter crash. you only need enough relief cut to start the cut, cutter dependent. if its cnc then no need to worry, they can rattle it out, longest part is setting up.

20 minute job, just remember to clean the bore after. and make sure they crown it properly so no burr in the bore. 

all ready said, none pressure part. no need for proofing. 

Link to comment
Share on other sites

4 minutes ago, activeviii said:

you can cut the thread the other way, basically spin it all the other way, still cutting the thread right handed but having the cutter start as the shoulder end. then you can run the lathe faster and not worry about cutter crash. you only need enough relief cut to start the cut, cutter dependent. if its cnc then no need to worry, they can rattle it out, longest part is setting up.

but would you have to cut with the bottom of your threading tool? I don't think you could get it high enough to center on mine (Colchester Bantam).

Link to comment
Share on other sites

7 minutes ago, Dibble said:

but would you have to cut with the bottom of your threading tool? I don't think you could get it high enough to center on mine (Colchester Bantam).

 

 

lift off the tool post and put two cutters on the slide and then the post on top and bolt down. cutters just shim it up. use slips if you have them

Edited by activeviii
Link to comment
Share on other sites

36 minutes ago, PPP said:

Agree with Welshie BUT shape gun smiths will sub this out to machinists anyway and pocket the 100 quid, sometimes don’t help themselves

You’d have to add them to the RFD insure them and then transport to and fro doubt it get sub out often, he’ll have a lathe for numerous other jobs so it’s just time and consumables  

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...