Lathe experts ?

[Donny]

I have a 15/16" .45 cal. GM bbl at 36".
I would like to reduce wt. and turn it Oct. to rd.
My question is it difficult for any machinist to do this correctly? My go to Harley guy has quite a machine shop but hasn't done gun stuff. What should we look for to not screw up something?
( Working on my bike, he is a good teacher and usually sits and smokes and drinks a beer watching & giving me instruction as I fix it.)
Not many shops offer you beer after a job.

 

[MSW]

no 'cut' at your HD guy - by all means, if you're confident with him, go for it ... but ... having said that, you may want to contact Bobby Hoyt
1 717 642-6696

 

[Donny]

I am not confident. :shocked2:
I just don't know.
.
That is why the question, how difficult is it to screw it up. :hmm:

 

[Boomerang]

It's a simple job as long as he uses a 3 jaw chuck(That will clamp on the flats with some sort of thin padding to protect from scratches)and uses a live center in the end. :thumbsup:

 

[Obi-Wan Cannoli]

for the barrel work:

Bob Hoyt
717-642-6696

 

[SDSmlf]

Your machinist will know how to do the setup. A 3-jaw chuck is NOT the way to go. Holding octagon stock like a ML barrel requires a 4-jaw chuck or a special collet.

 

[ZUG]

It is true that a 4 jaw chuck or octagon collet is for this kind of turning you also need a bit more - like a follow rest. If you don't support the work as the cutter is traveling along the cut the barrel WILL flex and the tool bit will not cut true also the tool will chatter leaving a lot of wavy tool marks. Find someone that has experience with turning barrels or you WILL be crying at the results :wink: .

 

[tiswell]

Probably going to have to offset the tailstock or use a taper attachment to get an appropriate taper on the barrel. I too would suggest Hoyt or someone familiar with turning barrels. The wrong tooling and experience can leave you with a barrel that has a finish that looks like rope or worse. And not pretty rope.

 

[Tinker2]

My question is it difficult for any machinist to do this correctly? usually sits and smokes and drinks a beer

Yes, pass on him :slap:

 

[jerrywh]

I have turned a few barrels and it is not like turning any old bar. There is stuff you need to know that most average lathe operators don't know.
A follower rest will not work because the proper way to do a octagon to round has a tapered round or swamped.Most taper attachments are not long enough. If the guy is real smart he can figure it out. From my experience beer drinking and turning swamped barrels doesn't mix well at all. Nobody is better than Bobby Hoyt.

 

[ohio ramrod]

Octagon to straight round with a "wedding band" isn't that difficult for a GOOD lathe operator . Octagon to round tapered is more difficult if you don't have a long enough taper attachment. It can be done with two or more "set ups" blended together, but it isn't simple. :idunno:

 

[M. De Land]

I've done it in my lathe. Just have him remove the breech plug and make two brass center spuds snug slip fit into the barrel and turn it between centers.
Remove just enough to make the flats disappear because if you try to step it down two much it looks really funky, wedding band or not.
If it's tapered you will have to either set the tail stock over the correct taper amount or use a sine bar.
Take light cuts and you shouldn't have any trouble with barrel warp.
A steady rest is a good idea but can only be used on an octagon with a spider which take a lot of time to dial indicate center.
I had now trouble with chatter doing the barrel on my Rolling Block at 28 inches. The key is a sharp tool bit and very light cuts and slow feed.
Another trick is to cut a band mid barrel, larger than the round you want to finish at, for the steady rest.

 

[BJC]

Just be sure to indicate it in really good and get the speeds and feed correct.

High Carbon Steel barrel that is almost 1 inch in diameter being cut with a High Speed Steel cutter should be turning about 240 sfm (surface feet a minute)which is 1048 for your spindle speed.

You will have to figure out your own feed rate but slow is not always best.

All these numbers change with different steels and tool material.

 

[zimmerstutzen]

Years back, I hand filed an octagon barrel to go from octagon to round, complete with wedding band. Sounds like a weeks full time work but it only took a few hours. Start 1/3of the way down the barrel and draw file on the corner. And file toward the muzzle so it appears to have a 1/16th flat. Do the same all the way round keeping the filed flats even as you go. Once you have 16 equal flats at the Muzzle end, start again half way down the barrel to make 32 flats. By that time the muzzle looks round and can be polished that way.

 

[jerrywh]

MD. had a good idea about leaving a portion in the middle that is not turned down as a place to use a steady rest. Most of the barrels I have turned are shotgun barrels with very thin walls and are 32" long. That is much more difficult than turning down a rifle barrel. The walls on the last one I turned at the muzzle were only .032 thick for the last 12 inches. I did a pair of those for a double gun. What you have in mind will not look conventional or like an original if that matters.
Conventional octagon to round barrels were tapered octagon for about 40% of the length and then swamped or tapered round for the remainder to the muzzle with or without a wedding band or more than one wedding bands.
Straight octagon to straight round will look very amateurish if that matters to you.
Then there is the problem of making it look right in the barrel channel. I would rethink if I were you. But I'm not.

 

[Donny]

thanks all for the replies.

This will be an offhand target rifle. Oct. to Rd with a wedding band.
The purpose is just to reduce wt. on the front end, & I have inlet Oct. to rd before.
I plan to reproduce a rifle on the ALR site,
& don't care if it is not precise/ HC as the one there.

 

[M. De Land]

I think you will be amazed at how little weight you will remove if just clearing the flats and not swamping.
The real weight comes off in shortening the barrel.
I cut off a two inch section of .45 caliber barrel scrap the other day , one inch across the flats and it weighed 5.5 ounces on my postal scale.

 

[Zonie]

If you just turned off the flats and corners of the barrel, your 15/16" barrel would lose .038 cubic inches of material for every inch of length the cut was made.

Steel weighs about .283 pounds per cubic inch so the barrel would become .0107 pounds (or 0.17 ounces) lighter for every inch it was machined.

If 24 inches of the barrel length was machined the weight reduction would be 4.1098 ounces or 0.2569 pounds.

This assumes only the points and flats were removed and obviously, if the diameter was machined smaller, more weight would be removed.

What if you really got carried away and had the lathe operator machine the round area down to 3/4" diameter?

That would remove 0.2863 cubic inches of material per inch which would reduce the weight of the barrel 0.081 pounds per inch.

If the 3/4" diameter size was machined for a distance of 24 inches that would reduce the weight 1.9447 pounds.

OK. I'll go back to sitting in the corner again.

 

[F.G. Ford]

Hi,
I have a ( my style ) Pennsylvania percussion .45 long rifle.
Barrel is 42", 15/16" at the breech, and 5/8" at the muzzle.
I hand filed a taper of 25/32 14" from the breech, then turned a wedding band, from there I tapered the from the wedding band to the muzzle.
It was relatively easy.
The hard part was draw filing the taper on the flats. ( not really hard but time consuming )
You must use a four jaw chuck, and you MUST center the barrel in the chuck ( if you don't...you will have a mess)
Now the rifle feels like a fly rod.
Two deer taken, way too many ground hogs and squirrels have surrendered to it.
It is "The" rifle to take for a walk about and long distance travel.
Any experienced machinist can do it.
Good luck on your venture.
Fred

 

[Boomerang]

Your machinist will know how to do the setup. A 3-jaw chuck is NOT the way to go. Holding octagon stock like a ML barrel requires a 4-jaw chuck or a special collet.

Yes, I mean a 4 jaw not a 3 jaw. I was thinking hexagon not octagon. I wouldn't turn more than a foot at a time if it isn't supported in the middle or you will get chatter and it would be hard to use a steady rest on the octagon part. It would need to be indicated in to be on center.