What sort of lathe is needed?

[andym79]

Hi guys, what size lathe and what spindle size and RPM are needed to be able to thread and chamber barrels?

I am guessing at least 1" and ideally 75rpm or less? How long distance between centres (as you don't need a lot of the barrel to thread and chamber)?

I only have a $1000 to spare right now, but looking through new lathes I figure this would be nearer to what is needed a 12" X 36"
http://www.machineryhouse.com.au/L183#


$3000
am I right? Could you do with a smaller one or would this a minimum?

 

[rcmodel]

IMO:
10" x 48" with at least a 1"+ spindle bore is the minimum you can get by with.

I fitted a lot of barrels with an old Atlas 9"x36" lathe.

But you quickly run out of bed & into problems when tapering a 26" barrel and need room for a steady rest, etc.
It is real hard to taper half a barrel from one end.
Then turn it around in the lathe and finish tapering the other end to match!!!

Best go big, or go home when it comes to barrel work.

If you are close to a big city with industrial tool dealers?
I'd look at the used equipment trade-in lathes they get rather then buying a New Chinese one.

You might stumble across a pretty good old South Bend or something for less money.

Rc

 

[andym79]

Thanks for the quick reply, at this stage I am not too bothered about tapering, just threading and chambering. What size lathe would you need just for that?

Though I guess you never know what the future might bring and what project your mind mind might dream up!

I think you are completely right on avoid anything made in china is possible!

 

[rcmodel]

Well, at a minimum, I would look for a 1" plus spindle hole as bull barrels come in 1" plus.

On the other hand, buying a lathe is a lifetime investment.
A good one will outlast you and whatever your interest or skill is 10-20, or 50 years from now.

So don't start out too small.

Big ones do 'Smaller' or 'shorter'.

But little ones don't do 'bigger' or 'longer' when the time comes you might need them too.

rc

 

[OldmanFCSA]

All depends on what caliber options you want. I needed a 60" bed length to handle 36" long barrel blanks that required using a steady rest to hold far end of barrel with carriage beyond that with tailstock still on bed. I use 2" barrel blanks for a v50BMG target rifle. My LeBlond tool room lathe is just about perfect for the job, but a larger spindle bore with a 4-jaw chuck on each end would be a great idea.

 

[BBBBill]

All good advice. I have an old South Bend 9x36 (between centers). Sweet little lathe with little being the operative term. It takes a lot of creative thinking to get a barrel in to do threading, etc. The hole through the spindle is only 7/8". Three jaw chucks are seldom accurate enough for any precision work. A four or six jaw with individually adjustable jaws is needed for that.

 

[Jim Watson]

My FLG has a 9x36 Sears/South Bend and it is adequate since he does mostly pistol work.
I got him to cut, crown, and turn down an AR barrel and it was about the maximum for the machine.

 

[dprice3844444]

look for a 10 inch delta rockwell or check grizzley.com for gunsmith lathes

 

[brickeyee]

A double chuck setup is complete overkill.

All you need on the outboard end is a 'spider.'
A 4 screw ring.

If the outboard end of the headstock is not threaded a slip tight ring with a set screw and four screws will be fine.

 

[4v50 Gary]

What brickeyee said. You can always mount the barrel through the headstock so long as you use a spider to ensure there's no wobble on the other end. The only real disadvantage of the shorter bed lathe is that you can taper a very long barrel at one shot.

 

[andym79]

Am I right in assuming that spindle size is going to me a lot more of an issue that distance between centres for threading and chambering a barrel, forget contouring.

I am merely talking about just threading a chambering! For example is it doable on a smaller lathe if it had a large spindle?

 

[brickeyee]

Threading and chambering are best done with most of the barrel in the headstock and as short a length hanging out on the bed side as possible.

Larger swing lathes are also heavier and producer cleaner cuts.

For fine work even having 3-phase power is better.

 

[Howard Roark]

I prefer chambering and threading through the headstock. My lathe is a 11x36 Rockwell.

I also wouldn't taper cut a barrel that has been rifled unless just for the heck of it. Barrels should be profiled, then bored and rifled.

 

[rcmodel]

I would normally agree.

But at one time, I had an unlimited supply of Bliss Titus & Douglas .30 cal bull barrels coming off AMU match rifles.
Like a 55 gal barrel full of them!
Free for the taking.

So I cut, re-threaded, and tapered a lot of them and made Mauser .308 & 30-06 sporter barrels out of them.

Never had one that wouldn't still hold 1" 5-shot groups or less at 100 yards.
And that's plenty good enough for a light weight hunting rifle.

Rc

 

[OldmanFCSA]

Spider is just a cheap version of a chuck.
Either way, a "chuck" is required on spindle left or right to properly center the barrel.
How you achieve that is up to you. (I've seen wooden wedges used also.)

 

[krs]

You've probably already had someone recommend a South Bend "Heavy 10" and the reason is its 1 3/8" spindle bore. It's also a very accurate lathe if in good shape.

Spiders are the way to go although if I ever found a spindle for my SB Heavy 10 that was long enough to thread for a back end 4 jaw I'd jump on making my lathe be able to mount it just for the time it could save.

Lots of barrels have been chambered on the bed using a center support and some guys believe it's the best way to get the chamber, bore, and thread mount true with each other but everything, especially the adjuster mechanisms for the support, has to be in good shape to be able to get both ends running true on he same axis. I tried it once and went running back to my chuck with spider through the headstock because I went nuts working at getting the barrel trued up.

All you really have to do is make the threads and chamber without changing the setup in between.

 

[Howard Roark]

I tried it once and went running back to my chuck with spider through the headstock because I went nuts working at getting the barrel trued up.

Me too. I've used steady rests with and without rollers and don't care for any of them. No steady rest I've seen is as steady as a 30 pound chuck.

 

[andym79]

Hi guys, maybe I am still not getting it, being a novice to all of this, but if you don't want to contour barrels and just chamber and thread them, then couldn't you do that with a 1" spindle?

A lot of barrel contours would allow 3/4 or more of a barrel to pass through the headstock, providing they are tapered and not straight!

Again why do you really need 40" or 36" of between centre if you can get 3/4 or more of the barrel through the headstock?

Having said that, I like the look of this lathe

Coolant System
Tool Height To Suit
12mm
Distance Between Centres
910mm
Swing Over Bed
300mm
Swing Over Cross-slide
178mm
Swing In Gap
450mm
Centre Height
150mm
Spindle Bore
38mm
Spindle Nose Size or Type
D1-4 Camlock
Bed Width
180mm
Headstock Spindle Taper
5MT
Tailstock Taper
3MT
Cross Slide Travel
170mm
Compound Slide Travel
76mm
Leadscrew
Imperial
Cross Feed Range (X-Axis)
0.014 - 0.344mm/rev
Longitudinal Feed Range (Z-Axis)
0.05 - 1.29mm/rev
Metric Thread Steps & Pitch Range
36 (0.4 - 7mm)
Imperial Thread Steps & TPI Range
36 (4 - 60tpi)
3 Jaw Chuck Diameter
160mm
4 Jaw Chuck Diameter
200mm
Spindle Steps / Speed Range
9 (75 - 1400rpm)
Motor Power
1.5kW / 2hp
Voltage
240V
Weight (nett)
460kg



Perhaps I should just leave it a few months till I have the 3K to get something like this. Second hand lathe in anything but bad condition are hard to come by here in Aus.

 

[OldmanFCSA]

The longer bed length is required for barrels that won't fit thru the spindle, thus requiring the use of a steady rest. The carriage and tailstock must extend beyond the longest barrel you wish to machine, with clearance for tooling blocks and tailstock travel with live center to support barrel while turning a true diameter for steady rest.

YMMV. and they usually do.

 

[krs]

Sure. Some have successfully threaded and chambered a barrel using the little 7"x12" Chinese hobby lathes because where there's a will there's a way. You can turn nice fountain pens with those too when your barrel is done.

I've had my lathe since a while before the first of the Asian imports arrived and it's been a useful tool for more things than I can remember, including cutting a few barrels.

I keep a little one in the kitchen too, in case it's cold in the shop.

 

[tgonza]

Lathe

I bought a used Jet lathe several years ago and have threaded and crowned a few barrels. It's a 10x24. It would be nice to have a longer one, but the good thing about this lathe is it's got a fairly big spindle, 1 1/16. I think that's really important and can make up for a shorter bed. I made a spider for the back end that really helps in trueing up the barrel.

 

[jmorris]

The advise on buying a "good" used lathe is sound. As is the advice on buying a larger lathe than you think you might want or need.

A barrel can be chambered and threaded without a lathe at all but would be much more difficult/time consuming.

 

[earlthegoat2]

I only ever do barrel and chamber modifications and I have never needed one bigger than 12x36. I did just say modifications, not barrel work. I would need something bigger if I were to start with a barrel blank and go from there.

For what I do, the 12x36 is fine. I have wanted bigger but never needed bigger and I probably will not ever need one.

So figure out what your needs are now and 20 years into the future and the best and biggest used lathe you can find.

 

[brickeyee]

A barrel can be chambered and threaded without a lathe at all but would be much more difficult/time consuming.

And very unlikely to be as precise as a lathe job.

While chamber reamers (like all reamers) tend to center themselves, a rigid setup means the holes are more likely to be closer to perfect for their entire length.

A floating reamer holder and a solid lathe setup will cut a very round precise chamber.
I use a 1/10,000 indicator to measure reamer travel.

But what do all those bench rest guys know?

 

[krs]

And very unlikely to be as precise as a lathe job.

But what do all those bench rest guys know?

Yeah. Bunch of old codgers who can't hit anything without flat stocks, two bags, overpowered scopes, and a bunch of flags to warn them if the wind blows.