lathing question

[kruzer1]

OK follow up question.

Thanks everyone for letting me know some sources for smoothbore blanks.

I am going to get a straight octagon and lathe this 16th century spanish barrel:

My friend owns the lathe and guide's me in using it. My question is for this profile I will have to take a lot of metal out in the center. I am thinking of getting a 1" tube in either .54, .58, or .62.

Generally the bigger the caliber the better for my project, but I want to make sure I have enough to make it look decent and keep it safe

 

[kruzer1]

Ok on a private message I got I did a scale up model. ..

Assuming the end of barrel can be lathed left at 1, the narrowest part of the profile would be turned down to about .71 .... This would leave wall thickness toward the muzzle thickness of about .71... which would leave about
.62- .09 (.045/side)
.58- .13 (.065/side)
.54 .17 (0.085/side)

My math may be off this :idunno:

Just not sure what is a safe thickness. Just checked a 16 guage barrel and it was .067 toward the muzzle.

 

[Greebe]

OK follow up question.

Thanks everyone for letting me know some sources for smoothbore blanks.

I am going to get a straight octagon and lathe this 16th century spanish barrel:

My friend owns the lathe and guide's me in using it. My question is for this profile I will have to take a lot of metal out in the center. I am thinking of getting a 1" tube in either .54, .58, or .62.

Generally the bigger the caliber the better for my project, but I want to make sure I have enough to make it look decent and keep it safe

First of all what exactly are you wanting to do? You mention getting an octagon barrel and using it and then talk about get a 1" tube. 1" tube as in DOM?

Your question is not a complete sentence either so I am having a hard time knowing what your questions is. Your question is that you will have to take off a lot of metal? Yes presumably you will take off a lot of metal to profile a barrel.

Ok on a private message I got I did a scale up model. ..

Assuming the end of barrel can be lathed left at 1, the narrowest part of the profile would be turned down to about .71 .... This would leave wall thickness toward the muzzle thickness of about .71... which would leave about
.62- .09 (.045/side)
.58- .13 (.065/side)
.54 .17 (0.085/side)

My math may be off this :idunno:

Just not sure what is a safe thickness. Just checked a 16 guage barrel and it was .067 toward the muzzle.

I guess you are talking about turning the barrel with one taper from the muzzle to the breach. Is this correct?

If you go look at Track of The Wolf's drawing of their smoothbore octagon to round barrels more of them are in the .800"-.900" range at the muzzle. Your proposed muzzle diamer of .710" Seems on the small side.

 

[kruzer1]

Sorry trying not to be cryptic..., just some of the jargon is new.

Rough calculations is to turn down a straight octagon barrel (which comes in 1" for the caliburs I want) to match this profile down to .71.... But I can make adjustments to keep the profile similiar.

I just need to know what is the safe thickness for a muzzleloader barrel... It's looking like .62 would be pushing it to much and .58 or .54 would be safer.

 

[Greebe]

Also you are killing me with your incorrect terminology for machine work.

It is not lathing. It is turning, or maybe as in your subject it would be plural as in "Lathe Question".

It is not lathed. It is turned.

A lathe is a machine tool. It cannot lathe anything, but instead it can turn or machine a workpiece.

Just trying to help you out because you come off sounding like a real FNG to a machinist. No offense meant by that, just the way it is.

Be safe and if you friend is not experienced find someone else to help you so you don't hurt yourself.

Best of luck.

 

[Greebe]

Sorry trying not to be cryptic..., just some of the jargon is new.

Rough calculations is to turn down a straight octagon barrel (which comes in 1" for the caliburs I want) to match this profile down to .71.... But I can make adjustments to keep the profile similiar.

I just need to know what is the safe thickness for a muzzleloader barrel... It's looking like .62 would be pushing it to much and .58 or .54 would be safer.

OK so it looks like you are wanting to make a swamped barrel. Look at this image to help you understand a common profile for a .62cal / 20 g smoothebore. It is profile "C".

If it is swamped it will be the thinnest about a third of the distance from the muzzle and flare back out.

So if you were trying to get a swamped barrel with a muzzle around .710", your are going to be very thin at that point.

 

[kruzer1]

He has 40 year's experience working with a lathe. Obviously I have none, besides working with him on the last two barrels we turned. :surrender:

Sorry I don't know the terms you machinests use- ever profession has a set of jargon and terminology and it takes a bit to get used to thema all.

Sorry for offending you- :redface:

 

[Greebe]

No worries man. Sometimes I come off strong, but I get that from having working in the construction industry and being a machinist. There can be some rough people in these industries and sometimes it rubs off on the best of us, not that that is me or anything. :blah:

That is cool if you friend has a lot of experience. You can learn more from him in a short time then on your own.

Machine work is very rewarding, and a great skill to have. There are not many "real" machinists these days as most of the people who think they are machinists really are just button pushers on a CNC machine. I bought a CNC center for my company a few years back and still get more use out of the manual lathes and milling machines. I am in the process of selling the cnc machine if that tells you anything.

Good luck and have fun.

 

[kruzer1]

No problem, no offense taken. I'd rather be corrected than continue using imprecise words :v

Thanks for the diagram. I forgot to look at those Track the wolf diagram's.

So expanding on that I might get by with the following diamaters on the smallest diamater of the barrel:

.62- .780
.58- .776
.54- .772

I can modify the profile to get close to the same look- I noticed in my research they were not all done exactly the same. Also my .71 estimate was rough.

Just trying to plan my minimum safe tolerances before I start

Oh noticed that they do the "C" profile in 16guage, so might have another .04 to size down but I hate to run my clearances too tight.

 

[Zonie]

First off allow me to say that using a modern smokeless barrel as a reference for a suitable barrel wall is dangerous.
Modern barrels made for smokeless powder are made of stronger steel than muzzleloading barrels are made from.

As you know, the pressures inside a barrel are highest at the breech. They decrease in pressure as one moves from the breech to the muzzle which allows tapering the barrel safely.

The "C" weight barrel shown in Greebe's post above comes in bore sizes up to a 16 guage.

The .62 caliber you mention is the equivalent of a 20 guage so if you use the sizes shown for the "C" weight barrel as a guide, your barrel should be fine.

I'm not saying you should try to duplicate the exact taper the C barrel has. Just use the sizes as a reference for a minimum size. If your barrels outer size is larger somewhere it will be fine.