[k-9 krippler]

A friend of mine recently purchased a lathe from a man we work with. He is interested in chambering barrels and trueing actions. I understand that most people run the barrel through the headstock and support the rear side of the barrel with a spider. This seems like a pretty good way to do this operation to me, but it seems to me that you are at the mercy of how tight the bearrings are in youre lathe. (( How can you tell how much play is in spindle, when pressure is applied?))

The lathe that he bought is an old Hendley probably a WW2 leftover it's big. The head on this thing is probably 30" through. This tell"s me that any barrel work will have to be done from a steadyrest. (( How do you accurately turn a barrel through a steady without maring it up?)) ((Do you take a light contour cut on the barrel after all other operations?)) If you did take a light cleanup pass on the contour would'nt a lathe dog or center in the bore present a problem? I have never chambered a barrel before, have been a machinist for more than 10 years. Thank's in advance k-9

 

[Mortis]

A friend of mine recently purchased a lathe from a man we work with. He is interested in chambering barrels and trueing actions. I understand that most people run the barrel through the headstock and support the rear side of the barrel with a spider. This seems like a pretty good way to do this operation to me, but it seems to me that you are at the mercy of how tight the bearrings are in youre lathe. (( How can you tell how much play is in spindle, when pressure is applied?))

The lathe that he bought is an old Hendley probably a WW2 leftover it's big. The head on this thing is probably 30" through. This tell"s me that any barrel work will have to be done from a steadyrest. (( How do you accurately turn a barrel through a steady without maring it up?)) ((Do you take a light contour cut on the barrel after all other operations?)) If you did take a light cleanup pass on the contour would'nt a lathe dog or center in the bore present a problem? I have never chambered a barrel before, have been a machinist for more than 10 years. Thank's in advance k-9

I certainly hope it has a 4-jaw chuck so any barrels can be indicated in.

 

[k-9 krippler]

Yes!

 

[Scott James]

The barrels I have done have been away from the chuck in a steady rest. Bead blasting has always cleaned them up and being barrels are just things that end up in a lathe that is the finish they always end up with.

******* gunsmith note...I have a .5 MOA 1000 yard barrel with a steady rest ring on it! FWIW you can still read the Kreiger magic marker name on the side too! Barrels don't care how they look just how they are finished!

 

[k-9 krippler]

I will keep that in mind, thanks.

 

[kaferhaus]

There's no reason to leave a "steady rest ring" on a barrel.... the rest has brass or bronze contact points and they don't need to be iron man tight on the barrel, they only need to be making light contact.

When properly oiled (this has to be done many times during the process) they'll only leave a very light rub mark on the barrel. This can be removed with any copper remover.

In any event final polishing of the barrel to what ever finish you want is the last operation performed and it's always done between centers.....

Granted a nice finish won't make the barrel shoot a bit better, it does say something about pride in workmanship and I'd hate to explain any "ring" to a paying customer..

On another note, if there is play in the headstock bearings, it won't matter which way you perform the work, there's gonna be runout. Slight wear at low speeds will negate it a bit but anything done over 100rpm or so is going to get progressively worse with speed increases as it loads the bearings more.

I've seen excellent work turned out on crap machines if the operator knew how to massage the machine and did things very slowly.

A machine that old and that big was more than likely a production machine at one time in its life and I'd be very surprised if it didn't exhibit wear not only in the headstock but also on the ways.

If your friend is a skilled machinist he can likely still turn out good work, but it'll be much more difficult than using a decent machine to begin with.

I bought new equipment 3 years ago and wish I'd done it way before that.... life is much easier now and work gets done in less than half the time with even better results.

Also, I hope he got lots of tooling with it..... otherwise the cost of the lathe will be a pittance to what he's getting ready to spend!

 

[Carl Porter]

lathe

Grizzily has come out with a couple of lathe that address some of your questions. The steady/follow rest comes with roller tips, the head has a built in spider on the outboard side, bearings are high precision, the tail stock is factory aligned to be no more than .001" off of the chuck centerline and can be torqued true.
See here for more details:
http://www.grizzly.com/products/g0509g

I imagine they have similar products that can be used on bigger lathes. If you can believe some of the documentaries then some of those old WW2 machines and machinists were putting out work that has finer tolerances than most shops can put out today even with CNC.

 

[Alan in GA]

some thoughts,,,aided by the application of caffein,

a steady rest is "gonna leave a mark" no matter what, so you do procedures in certain 'order'. Just like suturing up a patient,,,gotta finish up on the insides before worrying about what the staples/stitches look like. Even the large high quality lathes that have ROLLER tipped steady rest fingers will BURNISH a mark on the surface of any barrel. When working on take offs [sign of someone too cheap to buy new] barrels,,,"I" use steel steady fingers with TEFLON tips and Lithium or Teflon grease. Fine marks left in the blueing, if any, can be touch blued. Soft finger tips will wear even when 'lubed' so frequent attention to them is needed to be sure slop has not come in. Take offs are worth working on usually when you or a buddy own the machinery and the money clock is NOT running! Take offs are for fun, experimental, and sometimes non logical projects.
IF the headstock spindle bearings are worn,,working out on the ways in a steady might be best. If headstock is that long,,,working out on the ways will be easier anyway. Perfection in my mind [?] is about a large spindle hole 12 x 36" lathe for "inside the spindle" barrel mounting.

Working on the ways:
mount barrel chamber end in dialed in chuck [4 or 6 jaw,,or TRUE AJUST chuck]. Mount muzzle end in tailstock center [bore]. Yes, it will possibly 'marr' what is now the crown lips,,it's ok.
Turn a true shank about 1.5" long on muzzle OD. Just enough to be able to mount in the chuck and get a cut all the way around what may not be a centered bore barrel.
Reverse barrel, mount newly trued muzzle end in chuck,,dial in recheck can be done [on surface of new shank next to chuck jaws.
Mount chamber end onto tailstock center. True cut OD at chamber cylinder just enough for full contact cut all perimeter [also may not have bore in center]. Cut shank and threads leaving tailstock center in bore. Then mount steady rest on the trued surface cylinder area of the chamber, back from the thread shank as far as possible [2"?]. Remove tailstock center and cut barrel face and counterbore if needed, and do chambering.
Remount tailstock in new chamber with center rest. Remove steadyrest. File finish/abrasive cloth finish steady marks[protect lathe ways with cover that won't snag in anything moving].
Turn barrel around and mount finished chamber end into chuck on largest OD [chamber]. Protect the chamber surface with paper or thin card [business card] stock. Mount muzzle on tailstock center AND steady rest. Then remove center and cut muzzle off 1/4" or so,,turn crown lips, finish muzzle cuts using only the steady rest for support.
Remove steady rest,,and SLOW turn barrel held only by chuck at chamber end [Remember, FULL contact of chuck jaws on cylindrical chamber area], and lightly finish last steady rest contact spot. CAREFUL~!-- the barrel is UNsupported at muzzle and SLOW speed is only speed used. Light contact of barrel only,,,you don't want to stress it from one side if possible - it is supported only be the full contact of the chuck jaws on large chamber end OD. You are ONLY doing final surface finish with hand held [careful!] emory paper or what ever you use to finish surface.
Barrel is finished if I, under the influence of caffein, have not missed something.
Lathes is fun.
{I'm not a real machinist,,I just play one on the internet}.