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Old November 7, 2010, 09:13 AM   #1
Doc Hoy
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Made a jig to hold a barrel in a lathe

This is only good for light work like refinishing. I am working on an Leech and Rigdon and am in the part of the project where the pistol is ready for the finish on the surface.

I had to come up with a way to hold the barrel in a lathe but not permit the chuck jaws to touch the finish.

I use the lathe for two things. First of all, since the barrel is round rather than octagonal I can do rough finishing on the round part with the lathe turned on. I am using sand paper of various grits. On the other hand there are parts of the process which require holding the barrel steady for working on the flat sections but still be able to rotate that barrel to get to the next flat section.

So I came up with this jig, made up of a rod, two tapers and a wingnut.



The rod goes into the lathe and the first taper goes onto the rod.




The barrel goes onto the rod followed by the second taper. The purpose of the taper fittings is to hold the barrel centered and to permit the jig to be used with both .36 and .44 caliber barrels.



The wingnut goes onto the end of the jig and the barrel stays nice and tight. The tapered fittings are aluminum so as not to damage the barrel.



You gunsmiths......Is this a prototype or did I reinvent the wheel?
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Old November 7, 2010, 03:59 PM   #2
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You've made something close to a cylinder or tubing arbor. It kinda sorta reinvents the wheel in the sense that there is a different standard setup that may be used instead. That would be a center in the lathe spindle and a live center on the tailstock with the barrel tapped in between. You usually remove the chuck and put a slotted faceplate on the lathe that has a hole through the center big enough to allow the dead center to be placed in the lathe spindle nose taper without interference. The slots in the faceplate are used to drive a lathe dog that turns the workpiece. If no contact is allowed at all (the dog usually bolts to the work), tension from the tailstock against the centers can turn it. The center in the spindle will turn with the spindle by friction, which turns the barrel, while the live center has ball bearings so it will be turned by the barrel. I wouldn't care for the potential to slip and score the centers, so I like your approach better.

You might also want to take a look at the barrel spinner that Brownells sells. It is a piece of square aluminum that holds two ball bearing mounted plastic centers in castings that fit the tubing. The plastic centers face each other and are adjustable as to their distance apart by moving the castings. You trap the barrel between the centers. You then pick it up by the bar and play the barrel against a buffer wheel at an angle so it both spins the barrel and cuts away lathe tool marks. With the correct series of buffing compounds, tool marks are removed with remarkable speed. Brownells sells those, as well, of course. The compounds, that is, not tool marks. Be a little tough to buff around the protrusions on your particular barrel that way, but you could still use it as a holder. I expect you'll be happier with what you've got, though.
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Last edited by Unclenick; November 7, 2010 at 04:24 PM.
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Old November 7, 2010, 06:54 PM   #3
Doc Hoy
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Thanks for the wink back Unclenick

I had the idea to cut a center hole in the end of the rod for a live center if I were going to do any heavy work on the barrel. Lack of experience keeps me clear of much more than just refinishing when it comes to the barrel.
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Old November 7, 2010, 07:33 PM   #4
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Doc,

I am not a gun expert. I am a tool and die maker. I have taught an apprenticeship program for 6 years.

What you have is a great idea and looks like it works fine for what you want it to be. If you like it and comfortable with it, I wouldn't say not to use it. It does have risk. All operations with a lathe have risk. It is the most dangerous of all machines in a shop.

The risk here is even tho' you have solid shaft, high rpms can make that whip, bending at the jaws and becoming a weapon in of itself.

I don't know what rpms it would take or what your machine is capable of.
At that length, I can't say it would or would not happen. I kind of doubt it but be aware.

I have spent 20 years in a machine shop and seen people accidently shift a lever into high speed all too many times. I have seen this exact thing happen and it's not something you forget.

For that reason, I would say that a typical practice is safest. I live tailstock holding the other end in place makes it safe no matter what speed. (one can argue that the tailstock could be left unlocked or pulled back and that is true as well)

There is nothing perfect, even common, safe set ups have risk. Just don't let the rpms run too high-

All that safety stuff said, congrats on your idea. I appreciate a thinking man.

PS, use a #3 or 4 center drill and drill 1/4 inch into your fixture. You can then use a live tailstock with your current set up. You can then run this at any speed.
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Old November 7, 2010, 08:23 PM   #5
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Diitto what l2r said.

That may be reasonably safe at 200 rpm or so,but if you wind it up,its a touch off ballance,it will deflect,then it is more off balance,it will deflect more.
Before you can reach the stop button,that arbor will bend 90 deg and whack you or the lathe.
Myself,I might also lose the wingnut.A hex nut won't try quite so hard to grab some part of you.
Nice project!! Have fun!!
But always try to watch a cartoon in your head of the very worst wreck that can happen ,and where is your body going to be,before you turn on the power.
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Old November 7, 2010, 08:57 PM   #6
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I suppose if you had a really pitted part it might make it easier to polish it down below the level of the pits consistently. I did a ton of refinishing when I 'smithed, and where something like that would come in handy would be with barreled bolt action rifles.

Keep in mind we did refinishing on a pretty large scale ( I had the tanks running nearly every day) and if you walked into out polishing room there was a "skidmark" of Polish-O-Ray" polishing compound 360 degrees around the room, floors, ceiling, etc. I don't think I'd want a bunch of polishing muck on any piece of precision equipment. There was no block polishing in our shop- this was a four wheel station, and a bunch of alternative wheels to install for different work.

"Real" polishing - not bumper shop work- is an art form. I did quite a bit of self-study on it when I was learning it, and both Colt and S&W estimated it took about 10-15 years to really learn it. Polishing a round item like that, especially if it has pitting, is quite the trick. Hold it at 45 degrees to the 240 hard wheel, rotate it and advance one way- now reverse direction and make your polishing marks go 90 degrees to the first set. repeat, etc, etc. Hard stuff.

I'd also be real careful on the lathe too- I've seen some gory pics.
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Old November 7, 2010, 10:46 PM   #7
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Put it between centers and it'll work just fine.
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Old November 8, 2010, 06:26 AM   #8
Doc Hoy
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That did it!

Per your suggestions, I am going to secure the bitter end every time I use it.

For L2R,

I am using a ten inch Grizzly lathe in my home shop and it is set to the lowest speed. I have owned it for about a year and had a different Grizzly before this one. I am getting pretty good at making tools, but I am not good enough with it yet to match speeds to job. But I am getting better.

For Slopemeno,

Your comments on polishing are very interesting. I wish I had the time to just apprentice myself to a local shop but two things work against it. My present position takes up a alot of time and most shops don't think of a 60 year old as an apprentice. Now that I think of it, there is a new gun shop opening up just around the corner from me. They are advertising gunsmith services. I wonder if they would mind me looking over their shoulder.

To all of you.....Thanks greatly for your responses. Very useful and helpful.
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Old November 10, 2010, 07:11 PM   #9
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Carefull- you'll get hooked.

It was fun while it lasted. You rarely do the same thing day-to-day, and the amount you find out that *don't* know is pretty staggering when you start to think about it. A good reference library is a must. Read everything you can.

I used to haunt used book stores looking for Gunsmithing books, and it's surprising what you can turn up if you look. Anything by JB Wood is worth buying. This was before I was online, so places like Powell's Books would be a great resource.
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Old November 10, 2010, 07:39 PM   #10
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Slopemeno

Thanks for the tip.

I have "Hobby Gunsmithing" but I have not found it to be terribly helpful.

Been a long time since I looked inside it and it is worth a review.
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