profiling barrel blanks

tarawa · May 27, 2008

What is the best way to profile a straight barrel blank? I want to make two identical barrels for a side by side double 12 gauge bore gun. I am starting out with two 29" rifled Hastings paradox barrels.

Kurt Westfall · May 27, 2008

Between centers. Off set the tail stock to the taper you want and do both barrels at the same setting.

MDH · May 27, 2008

The problem that I've found with profiling barrels between centers is the chatter, start getting 6-8 inches down the barrel and there is too much flex. Can't use a follow rest because the stock is tapered.

Best way that I've foud is cutting inch by inch sticking out of the headstock, then filing down the little ridges & polishing between centers.

Mike Hunter

huntinguy · May 28, 2008

my guess

small radius tool, really really sharp (not the place for carbide unless it is a honed edge), low feed rate, low rpm, I dampen the part by letting my finger ride along with the tool. Thats how I do long tubes anyway, haven't tried a barrel, yet.

I have always wondered about filling the barrel with sand or lead shot and plugging the ends, It works for boring bars. Just an idea.

MDH · May 28, 2008

I’ve tried all sorts of “remedies” to solve the chatter problem, carbide, high speed slow feed, slow speed high feed, HSS different profiles, heavy cuts..light cuts, shot bag on the barrel etc.. nothing seemed to work for me, I even considered building a hydraulic follow rest. I make a few barrels in the shop, some with 3 different tapers to them, and I’ve considered getting a tracer attachment for my lathe, but the biggest thing keeping me from do it is controlling the chatter.

What I do now is cut inch by inch coming out of the headstock, then mount the barrel in an old Sheldon lathe with a belt sander mounted on the carriage, a few passes to remove the ridges and barrel looks pretty good.

I suspect that most commercial barrels are ground with something akin to a tool post grinder…just on a much larger scale.

Mike Hunter
www.Hunterrestorations.com

RWO · May 28, 2008

No doubt the commercial barrel makers use CNC lathes to profile barrel blanks. I'm guessing the follow rest and the tool slide are both under computer control and move in sync to keep the barrel straight, bore centered, and follow the desired taper.

Weatherby once ground barrels full length for finishing after they were rough turned. I don't know if they still do.

RWO

GGaskill · May 28, 2008

The barrel maker I knew used a hydraulic follow rest.

huntinguy · May 29, 2008

MDH said:
I’ve tried all sorts of “remedies” to solve the chatter problem, carbide, high speed slow feed, slow speed high feed, HSS different profiles, heavy cuts..light cuts, shot bag on the barrel etc.. nothing seemed to work for me, I even considered building a hydraulic follow rest. I make a few barrels in the shop, some with 3 different tapers to them, and I’ve considered getting a tracer attachment for my lathe, but the biggest thing keeping me from do it is controlling the chatter.

What I do now is cut inch by inch coming out of the headstock, then mount the barrel in an old Sheldon lathe with a belt sander mounted on the carriage, a few passes to remove the ridges and barrel looks pretty good.

I suspect that most commercial barrels are ground with something akin to a tool post grinder…just on a much larger scale.

Mike Hunter
www.Hunterrestorations.com

I never had much luck with shot bags, or shot shells but that is a diffrent story

. Once the chatter starts it is almost impossible to stop.

It is possible to use a follower rest infront of the cutter and taper the barrel with a tracer attachemt. I have done lots of shafts that way. If you want to explore the tracer idea, look up a MIMIC (sp) they replace the compound and are one of the neatest tracers I have ever seen.

http://www.mimiktracer.com/

AW · May 29, 2008

For what it's worth-
I turn between centers. Clean up to run true every 7 to 8" for the steady. Live center.
I turn the taper in 1/2" steps, watching the readout. back out the tool the proper amount and engage the feed again. A few thou error on the feed stop does not mean sh--. I can hit it within .005 easy.
Cover up and belt sand the profile. Usually a couple of grits, then finer with emory. Finished up in 40 minutes if I need to take two passes.
800 rpm, 5 to 7 thou feed. water sol coolant.

HTH
Alan

tony wilson · Jun 23, 2008

Sometimes the lathe is the problem! Make sure all bearings are good and bushings are running tight.
The cutter shape is also important. I use a special cutting tool I grind with a knife edge. It is similar to a cutter one of the old time barrel makers designed for his own use. I don't remember which one but I will try to look and see if I can find out who if anyone wants the name.

quasi · Jun 23, 2008

after switching to a spring loaded live center made by Cocentric Tool, my chatter problems have disapeared. Thank you George Fullmer!

willbird · Jun 29, 2008

AW said:
For what it's worth-
I turn between centers. Clean up to run true every 7 to 8" for the steady. Live center.
I turn the taper in 1/2" steps, watching the readout. back out the tool the proper amount and engage the feed again. A few thou error on the feed stop does not mean sh--. I can hit it within .005 easy.
Cover up and belt sand the profile. Usually a couple of grits, then finer with emory. Finished up in 40 minutes if I need to take two passes.
800 rpm, 5 to 7 thou feed. water sol coolant.

HTH
Alan

I agree that using the steady helps a great deal.....I have only did one myself, but I found that a very coarse feed helped with the chatter as well, and reversing directions of cut each pass also helps from building a harmonic pattern into the turned dia, then a lot of work afterwards with alternate methods such as a 5" disk sander :-).

Bill

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profiling barrel blanks

tarawa

Aluminum

Kurt Westfall

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MDH

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huntinguy

Cast Iron

MDH

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RWO

Cast Iron

GGaskill

Titanium

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AW

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tony wilson

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quasi

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