Gunsmithing Chatter on barrel threads

[Alabama556]

I just got a gun threaded by a local gunsmith and there is some minor chatter on the threads. Is this a cosmetic issue or is this something that needs to be fixed?

Can screws on good and tight and looks good looking down the bore.

 

[skeetlee]

Very common on small job shop type lathes. They will hurt nothing!!!! My little 13" jet left a small amount of chatter on the threads no matter what I tried. When I sold that machine and went up to the 3500 pound 16" grizzly, they went away. rigidity is the key word!! Lee

 

[Alabama556]

This guy is a manufacturer of silencers and Intergral guns. He has been at it for a long time. He has some big lathes and I was expecting better. The crown looks horrible but that is an easy fix.

 

[hermosabeach]

Have you chatted with the builder?

 

[300sniper]

Have you chatted with the builder?

^This

 

[Killswitch Engage]

My 13x40 grizzly doesn't leave any thread chatter on muzzles or tenons. Set up is key and only having what you absolutely need hanging out of the chuck increases that rigidity and improves the finish.

 

[ridgeway]

I use a 12x36 Grizzly and don't have chatter problems with threads. Sharp bit, lots of oil and light cuts should help big time. Keep tool and tenon overhang at a minimum...

 

[jerseymike]

^^^ this

 

[McLarenross]

I have to agree with those above, have you talked to the builder? Setup is key. I started with a 7x10 Harbor Freight lathe and I forced that thing to do stuff it was never meant to do so I have to learn quick about speeds and feeds as well as setup rigidity. You can make a light lathe give you a good finish but its a hell of a lot slower. Im much happier now with my Rockwell and .100" DOC on steel with great finish.

 

[ugsly]

As said above setup is key, I cut at slow rpm and take very small cuts. I run a 12x36 grizzly lathe and the threads come out nice.

Casey

 

[Alabama556]

Have you chatted with the builder?

I decided to just send it to a top notch outfit and have the barrel shortened by 2 inches and have it retreaded. I am only out 50 bucks and I don't want to wait another 4 months with hunting season around the corner.

The rifle is a Remington 700 sbr in 300 whisper. My suppressor is a 12 inch degroat 300 whisper can. I don't want to take any chance with a bad thread job with a 12 inch suppressor you can't get any more.

Thanks for everybody's input.

 

[jonaddis84]

Did they look kind of like these? Somebody sent me this picture of a reasonably well known place was proud enough of them to post them on their Facebook page.

 

[cal50]

Chatter comes from a non-ridged machine / set up or the wrong speeds & feeds.
If the thread form is true & the fit correct then the cosmetics does not matter.

 

[Killswitch Engage]

Did they look kind of like these? Reasonably well known place was proud enough of them to post them on their Facebook page.

Oh snap....you didn't. Lol!

 

[Alabama556]

Did they look kind of like these? Reasonably well known place was proud enough of them to post them on their Facebook page.

Those look better than mine. My crown looks like a beaver got a hold of it. I wish I had a picture. I boxed it up and sent it of this morning.

 

[0311@LAR]

Did they look kind of like these? Somebody sent me this picture of a reasonably well known place was proud enough of them to post them on their Facebook page.

What the fuck is that abortion? Not gonna shoot any world records with those rat-fucked threads.

 

[ridgeway]

As long as the thread fit is pretty close in tolerance, those threads are fine...

 

[jonaddis84]

Sure maybe something will screw on, that doesn't make them ok, unless you're not charging someone for the work.

 

[Straight Shooter]

As bad as those threads look as long as the bore is concentric to them it is a cosmetic issue. I have seen them so bad 50% of the threads were flat torn off and that rifle shot great. That 4 jaw with all that contact area concerns me as much as those threads do.

 

[ugsly]

Did they look kind of like these? Somebody sent me this picture of a reasonably well known place was proud enough of them to post them on their Facebook page.

Jon, those were some of the best threads I have ever cut

Casey

 

[cal50]

In addition to machine setup, rigidity, & speeds and feeds the barrel material and your threading tool play a part on the surface finish off the threads. Stainless steel barrel blanks machine much nicer than 4140 / 4130 barrel blanks IMHO.

 

[chipsfan]

As said above setup is key, I cut at slow rpm and take very small cuts. I run a 12x36 grizzly lathe and the threads come out nice.

Casey

I take heavy cuts at 220 on my 4003g and the threads look great.

 

[cal50]

I don't want to take any chance with a bad thread job with a 12 inch suppressor you can't get any more.

Thanks for everybody's input.

Cosmetics aside if the threads are concentric and perpendicular to the bore CL and gauge correctly I would use them.
I have seen excellent LOOKING threads that were neither concentric and the shoulder not perpendicular to the bore axis. Something like it might work for a flash hider but would be a poor choice for running a suppressor on.


I recently converted an old Enfield #1 MKIII to 45 ACP and adapted one of my SMG cans to use on it.
The 4140 barrel blank machined up pretty nice with a good finish on the threads on both ends ( action and muzzle to attache suppressor ).
Its nice when things fit together correctly WITH a nice finish.

 

[0311@LAR]

^^^ That looks fun as hell to shoot cal50!!!

 

[cal50]

^^^ That looks fun as hell to shoot cal50!!!

LOTS of fun.....

http://www.snipershide.com/shooting/sniper-hide-gunsmithing/267732-enfiled-1-mkiii-conversion-45acp-suppressor~-cheap-fun-gun.html#post3288318

 

[kyle528]

Just look at thunder valley precision's Facebook page. Tom posts a lot of pics of threads that have marks just like that, and he is a seriously good builder. And in case you don't know him, he does hold world records at 1000 yards with rifles he built

 

[Alabama556]

Here is a picture of the crown before I had it fixed. It looks like someone did it with hands tools. The picture does not do it justice.

i sent the gun to predator custom shop and they fixed what my local smith messed up and it only took 5 days door to door.

 

[cal50]

Here is a picture of the crown before I had it fixed. It looks like someone did it with hands tools. The picture does not do it justice.

i sent the gun to predator custom shop and they fixed what my local smith messed up and it only took 5 days door to door.

That's not a crown, its a chamfer with chatter.
A crown should be burr and chatter free.

 

[Geno C.]

Here is a picture of the crown before I had it fixed. It looks like someone did it with hands tools. The picture does not do it justice.

i sent the gun to predator custom shop and they fixed what my local smith messed up and it only took 5 days door to door.

WOW.... I'm gonna say my 7 year old could have done that by hand with a dull 1/2" drill bit

 

[flounderv2]

Just look at thunder valley precision's Facebook page. Tom posts a lot of pics of threads that have marks just like that, and he is a seriously good builder. And in case you don't know him, he does hold world records at 1000 yards with rifles he built

Just to help clarify, Tom was not building his own rifles at the time when he was competing in BR. Tom just started his rifle building business in the last 2-3 years.

 

[Ledzep]

Did they look kind of like these? Somebody sent me this picture of a reasonably well known place was proud enough of them to post them on their Facebook page.

Seeing stuff like this really makes me wonder. Here's the first barrel I ever cut threads on. I recently went back and checked them over. They pass GO/NOGO gauges, are about .002" over nominal, and the tenon length is about .003" short. I did them on a Grizzly 7x12" mini lathe. They are concentric to the bore and I've run a couple different cans on them with no problem. So what the hell are "professionals" doing to produce crap like that on big machines and charging people? I'm no machinist, I was just a bored Corporal who bought a mini lathe and fucked around in his barracks room... After I got done with them I made a promise to myself never to sell that barrel because they weren't clean enough...

 

[jonaddis84]

That is a really good question, especially considering the amount of contact he's got with those aluminum pads that are likely stressing the hell out of the barrel (if it's getting dialed in by an outboard spider).

I don't know if I could purposely put that much chatter on my threads.

 

[Rthur]

Usually that happens when you have to much hanging out of the chuck and get it humming/harmonics. It appears to be up tight in the chuck/headstock. I'm going to say an balance issue on the headstock/drive system could also cause this. Assuming the tools are sharp.

R

 

[cal50]

You can have the best machine and tooling available but if you do not have the knowledge or experience to use it, its a moot point.
I agree that some people have balls charging others for hack jobs.

 

[moore_man]

probably a dull tool or bad speed and feed combo.

 

[Threadcutter308]

Usually that happens when you have to much hanging out of the chuck and get it humming/harmonics. It appears to be up tight in the chuck/headstock. I'm going to say an balance issue on the headstock/drive system could also cause this. Assuming the tools are sharp.

R

And, do you have (and use) a "spider" support for the muzzle end of the barrel on the backend of the headstock ? Dial indicate both ends in to +/- .0002" or .0003" (target = .0001") and you're GTG. Otherwise, the barrel tenon will hum like a mofo when trying to cut threads. In addition to that, I'm +1 with everyone else that has already mentioned machine rigidity and SHARP tools. Tight is nice, sharp is good, slow feed speeds too.....

 

[Gene Poole]

I got threads like this once when I forgot to lock down the tool-holder on the post. It was basically just hanging by gravity on the dovetail. I was surprised it cut at all.

 

[Threadcutter308]

Yeouch!!!! (Been there, done that....). The ceramic threading insert just disintegrated into a pile of dust when it happened to me......The best you can hope for is that it happens at the beginning of the threading exercise and not your final, cleanup pass....

 

[cav has been]

I thought maybe that was the latest in weight saving innovations, sorta like diamond fluting............

 

[hero's machine]

Wow....

 

[Murica]

Ouch !!! All I can say.

 

[300sniper]

All chattered up.

 

[Boxcar]

Did they look kind of like these? Somebody sent me this picture of a reasonably well known place was proud enough of them to post them on their Facebook page. [IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/tapatalk.imageshack.com\/v2\/14\/08\/29\/24a88095c880d037e0038e866d14f59b.jpg"}[/IMG2]

Thinking I recognize the lathe here. Would I be wrong in saying this is another Ohio gunsmith, and definitely not SAC?


Edit; Nevermind I guessed right, I found the picture on their FB.

 

[BillyGoatMachine]

I just got a gun threaded by a local gunsmith and there is some minor chatter on the threads. Is this a cosmetic issue or is this something that needs to be fixed?

Can screws on good and tight and looks good looking down the bore.

Most likely everything will be fine. Minor chatter will not cause issues as long as the barrel was dialed in and the bore is inline with the threads. No baffle strikes, no problem. Now if your muzzle device has a ton of slop when screwing on, it was a crappy job regardless of chatter. I recently had lathe #1 in my shop suffer this fate after moving it. I changed out the spindle bearings and re-adjusted the gibs to get it back in operation. It's still not perfect and I won't do any jobs on it until the issue is resolved. Lathe #2 has picked up the slack.