Barrel profiling

[Will Henry]

Gosh, I don't know where to start. When I started out, back in the late '70's, we cut almost every barrel from 1 1/4 blanks. I have contoured barrels down to .475" at the muzzle and even today, I frequently alter contours somewhat to achieve the balance I want. I have used taper attachments, copiers, and I have offset the tailstock. I have used various techniques to overcome chatter which does happen.
Probably the most important things are the profile of the tool, the tool height and the rate of feed. The tool is a similar to a chip breaker but with a "u" groove behind the cutting edge. The cutting edge is very sharp so chip pressure is minimal. Cobalt steel is the best material as carbide is a bit fragile though it will last longer without sharpening. I have seen some inserts which come close. If I'm honest, it sometimes seems like the perfect tool is ground by accident and when one cuts particularly well I wish I knew why! The tool should be set about .015" above center and must be ground with just enough clearance to enable this.
A following steady which will dampen the vibration is effective. Running the barrel straight with the taper being established with a copier will produce less chatter than will an offset tailstock.
One barrelmaker told me it worked better to hold the muzzle end withe the dog at the headstock end and run the chamber end on the tailstock center. I've not tried this yet but I have a couple of blanks to contour so maybe I will. WH

 

[Rdlningcltchdmpr]

Need help here as I'm doing this first time.
I have a SS barrel that is 1.25" straight and need to cut it to 1.055" for savage action then part of it to .90" and down to .75" at muzzle.
About 10" or so from .90" to .75". It is on manual lathe by adjusting tail stock.
I see two option 1. between centers 2. keeping chamber end in 4 jaw chuck.
With option 1 I'm afraid chatter and it may walk from chuck in option 2.
Any suggestions? Thanks.

I bought a barrel that was too big so i called the manufacturer and they recontoured it to the right shape for $50. Very good deal.

 

[strobes]

Gosh, I don't know where to start. When I started out, back in the late '70's, we cut almost every barrel from 1 1/4 blanks. I have contoured barrels down to .475" at the muzzle and even today, I frequently alter contours somewhat to achieve the balance I want. I have used taper attachments, copiers, and I have offset the tailstock. I have used various techniques to overcome chatter which does happen.
Probably the most important things are the profile of the tool, the tool height and the rate of feed. The tool is a similar to a chip breaker but with a "u" groove behind the cutting edge. The cutting edge is very sharp so chip pressure is minimal. Cobalt steel is the best material as carbide is a bit fragile though it will last longer without sharpening. I have seen some inserts which come close. If I'm honest, it sometimes seems like the perfect tool is ground by accident and when one cuts particularly well I wish I knew why! The tool should be set about .015" above center and must be ground with just enough clearance to enable this.
A following steady which will dampen the vibration is effective. Running the barrel straight with the taper being established with a copier will produce less chatter than will an offset tailstock.
One barrelmaker told me it worked better to hold the muzzle end withe the dog at the headstock end and run the chamber end on the tailstock center. I've not tried this yet but I have a couple of blanks to contour so maybe I will. WH

I'll try this. Thank you.

 

[Phil Peterson]

Put barrel between centers, run
lathe backwards with tool upside down. You can take the top totally off the steady rest. I always try to run this way with a steady.Learned this 55 years ago.

 

[Phil Peterson]

If a manufacturer can turn one down, then why can't you guys?

 

[butchlambert]

Phil, they have different tooling than you or I. I have plans for air actuated cylinders to bear on the barrel in a following rest. I saw one like it at Harold Broughton's barrel shop many years ago. What very few I had were re contoured by the barrel company.

 

[GenePoole]

I think @DaveTooley posted a picture a while back of a dual hydraulic rest of some sort for profiling.

 

[DaveTooley]

If a manufacturer can turn one down, then why can't you guys?

Not in the business uh? Probably haven't heard of a programmable following rest either.

 

[Phil Peterson]

I have never used a follower rest. I can put my steady rest near the middle of the barrel, cut up to it, then move it to the right side of the carriage and cut to where the shank contour starts. I take about .010 inch cuts. For the shank I trace the contour of any barrel I choose with a dial indicator.

 

[Walt Krafft]

I have never used a follower rest. I can put my steady rest near the middle of the barrel, cut up to it, then move it to the right side of the carriage and cut to where the shank contour starts. I take about .010 inch cuts. For the shank I trace the contour of any barrel I choose with a dial indicator.

And if you start with a 1.250 straight blank, at .010 you will take way more time to do one than anybody is ever going to pay.

 

[tobnpr]

Ya got more time than money, or more money than time?

Of course it can be done (am I the only one here with a taper attachment, no one's even mentioned it yet...).
But it's a day-long project if there's multiple tapered angles, cutting, blending, filing...then multiple grits of emery paper....

When a completely custom, contour costs $25 I'd sooner spend an hour in the chair at the dentist than do that kind of mind-numbing turning for hours on end.

 

[MClark]

If a manufacturer can turn one down, then why can't you guys?

We have a hydraulic tracer lathe from the '50’s for tapering barrels. It is huge and pretty much useless for anything else. Most smiths do not have the space or money to tie up with a single function machine.
That said once I learned to use it it does a good job.

 

[Phil Peterson]

I did not say I contour barrels for a living OR stand in front of a lathe all day. Just saying that if I need to recontour a barrel I know how to do it myself and not send it to anyone!

 

[Dusty Stevens]

I did not say I contour barrels for a living OR stand in front of a lathe all day. Just saying that if I need to recontour a barrel I know how to do it myself and not send it to anyone!

What tool do you use?

 

[Tommy Leroy Johnson]

If a manufacturer can turn one down, then why can't you guys?

Hi Phil
Back in the last century when I went to Gunsmith school tapering a barrel was machine shop 101, if you couldn't get it done in a reasonable amount of time without chatter and using a steady or follower rest you could not pass the class, we also had to grind our own tools with HSS blanks.
I prefer pre contoured barrels today but I can contour a barrel in about 4 hours without having to stand in front of the lathe constantly, once it's setup with the right tool geometry just turn it on and let it run.
If anyone wants to know my barreling lathe is a Clausing 5914, I use a 1/2 " HSS blank with a chip breaker ground into it starting with a .050" cut and gradually going to smaller cuts as I get to the contour I'm looking for.
I'll see you at the range.
Oh yeah if anyone cares I am a qualified gunsmith and I am in the business.

 

[Stan Taylor]

You know Dusty Stevens made a good point send it to me 10 minutes it's done another 15 or so to touch up the crown an another 10 minute to polish an reship.LOL

 

[Will Henry]

A follower which will work well consists of a cast bar which pivots just above center. On this bar is mounted a pot which contains a handful of lead shot. The lead shot absorbs vibration and the follower will follow the taper of the barrel.
I once had a barrel which would not stop chattering (I was using no steady). I filled the barrel with #7 1/2 shot and it settled right down. This was a .375 cal barrel. The same trick might not work as well on a .22
As I said before, running the barrel straight and tapering with a taper attachment or copier is preferable to offsetting the tailstock. The heavier the machine, the better but I tapered a bunch of barrels on a 12x36 bench lathe.
A good friend of mine once contoured a barrel on his six inch Atlas by mounting the tailstock on a block on the bench and contouring half the barrel then turning it around and doing the other half. He turned the 1 1/4 inch blank to match his 1886 Winchester barrel and did it well enough that the stock and barrel bands fit perfectly. By the way, years later, this same guy retired from his mechanic job and became a very good barrel maker. WH

 

[Phil Peterson]

These days I am using kennemetal inserts TPG222 running them upside down with lathe turning backwards.

 

[shortgrass]

If a manufacturer can turn one down, then why can't you guys?

Time Phil,,,, time. Not everyone who has replied to this thread is a hobbyist. Machine time cost. The barrel makers are using CNC lathes and special built pneumatic follow rests. The is NO possible way for a manual lathe to keep up with a CNC specially set-up to contour barrels.

 

[Tommy Leroy Johnson]

Time Phil,,,, time. Not everyone who has replied to this thread is a hobbyist. Machine time cost. The barrel makers are using CNC lathes and special built pneumatic follow rests. The is NO possible way for a manual lathe to keep up with a CNC specially set-up to contour barrels.