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Discussion Starter · #1 ·
I went to an auction two weeks ago and bought this Hurco CNC lathe with 8 station tool holder. Since it won't fit in my old motorcycle shop and we don't have 3 phase current it went to our friend's fabrication shop and sits beside the CNC mill that I bought two years ago. My son has been working there getting it wired in, adding tooling so my friend can run parts that he has been farming out, and basically checking it out. I asked him if he would write a program for the end of the barrel that goes into a stub. Yesterday he made the first one in aluminum. I can now have any barrel machined precisely for a stub in a matter of minutes. The machine has a 12 inch center to center limit so I can't profile the muzzle end of a rifle barrel but it will hold .0001 so I think I might be able to turn one down by doing 4 inches at a time and then polishing out any minor irregularities in a regular lathe. That's a later project.

On the stubs themselves, we have decided to try to machine them out in one piece. Welding the two pieces together has not produced an acceptable product on a consistent basis. We have access to our friend's Okuma machining center and now with the CNC lathe we should be able to turn them out. Time will tell.
 

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My hat goes off to you. I think machining with an intgral lug is the way to go. Next big problem is finding a suitable steel that is sold in a form that doesn't create a lot of waste. Looking to see your progress, I wish you the best, Regards Piney Creek
 

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Discussion Starter · #5 ·
Thanks guys.

Piney, what would you consider a suitable steel? If it is available I don't think we would have a problem getting it. A part of my friend's business is custom sawing. He frequently saws steel for one of the local steel distributors. Thanks for the kind words.

Orders. I wish I could think that far ahead. Once this idea moved past the stage of welding up parts and manual machining its pretty much on my son. He's a shooter (better than me, he was 2006 Indiana Junior 3P state champion), an Engineer and likes the Handi's so he will get it done.
 

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WLB, I have used 1018, 1144 stressproof, 4140 and 4142 annealed. The only one I can get in small amounts from online steel suppliers that is anywhere close dimentialy is 1018. All the rest are alloy steels and only available to me in rounds. Correction, 1144 stressproof is not alloy but also only available to me in rounds. 1018 is OK if you use it just for low powered rifle and pistol cartridges. Regards, Piney Creek
 

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Discussion Starter · #9 ·
wookie, Looks like a good video. Yes, on the barrel, we will need to have some way of getting the OD true to the bore. I will likely continue to chamber by hand.





Thanks Piney, 1018 and 4140 are probably what we would use. Both are readily available. First ones will be paperweights out of aluminum or plastic to set up machine.

ulav8r, OUCH, $68.00 per foot plus shipping for 4140. Their 1018 prices seemed over the top also. Sure hope Jeff gets a better deal than that.

I may go down to the shop with my son today and see the lathe in operation. They will be turning dual wheel adapters for an ag machine today.
 

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I did not search for best price but wanted to show availability in other than rounds. Check with local machine shops for drops or see if they would be willing to add a bar for you to an order with their supplier. Some would be willing to order at their cost if you pay for it in advance.
 

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Discussion Starter · #13 ·
I went down to the shop with my son yesterday and saw the lathe in operation. The machining part was what I expected but the readout on what was happening was much more detailed than on the Okuma mill. I was wondering how we would be able to precisely locate the center hole on the stub since the chuck is hydraulic or air (can't remember) and limited in adjustments but wookie76 gave me an idea on that. A custom, stub specific spider can be made to dial in the center hole. Thanks wookie.

Steel is really the least of the problems in making the stubs or anything else actually. Steel is delivered to my friends shop two or three times a week. I checked with him on pricing and 1018 and all mild steel is approximately $1.60 per pound. He doesn't use much 4140 so couldn't quote a price off the top of his head. A 12 foot length of 1018 1 1/8 by 1 3/4 will be ordered next week. Radius cutters will also be ordered on the next tool order. The 1 1/8 by 1 3/4 size will require precise location but will minimize stock removal.

I keep telling myself that this is way cheaper than messing with race motorcycles or race cars :) :) :)
 

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WLB, if you are going to make the stubs to fit a particular frame I first fit the stub to the frame so that there is 0 clearance between the breech end of the stub and the face of the frame. Then, lightly let the hammer fall on the firing pin marking the point where the center of the barrel axis will have to locate on the stub.

If you are going to make the stubs generic leave a little extra length to fit and use SWAG to determine the center of the barrel axis. As much difference there is with these frames one to another the worst that can happen IMHO is the firing pin strike will not be perfectly centered on the primer. Piney Creek
 

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Well, if you use a frame to mark the center of the stub all of them will have the same errors as the frame you use to mark the master. Could be good and could be bad. Larry
 

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Discussion Starter · #16 ·
Piney, my plans are to make them generic. Obviously, with the wide variances in dimensions of the H&R there will have to be fitting. On all the actions I have measured the only constant is the dimension from the center line of the bore to the center of the hinge pin. Everything in a vertical direction will be located off the center of the barrel hole. On the rear of the stub excess material will be left in the vertical direction for latch fitting. I made a tool to measure the distance from the rear of the hinge pin to the breech face. After I get enough measurements I'll establish a dimension for the length of the stub.

Big Question: Would it be better to leave excess overall length on the rear that could be filed or milled to fit or machine to a length that would fit all receivers and let the barrel protrude through the rear to get a tight fit. I would think for most people it would be easier to adjust the fit by letting the barrel protrude a few thousandths. Some where along the process of barreling a stub a lathe has to be involved. I would suspect more people have lathes than milling machines so it would be easier to get a good fit by turning the barrel in or out than milling or filing the whole rear of the stub.

Any opinions?

Bill
 

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Bill, for a good overview on your problem see Mike Bellm's website and articles on how he looks at and handles headspace with break open guns. IMHO to adjust headspace by screwing the barrel in and out would require a locking nut like Savage plus problems with extractor cuts. Best case as I see it is to machine stubs to a min. length and then the rest of the details concerning breech face to barrel face distance and cartridge depth to correct headspace is the responsibility of a hopefully competent gunsmith. Regards, Piney Creek
 

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WLB said:
. . .I keep telling myself that this is way cheaper than messing with race motorcycles or race cars :) :) :)
because it is. maybe i never saw enough, but i've never seen anybody come out on
the good side of selling used high performance gear. me and a friend (several actually)
messed with drag, dirt, some off road, etc. all of our adult lives. (i started in my teens)
if you miss a race, you're put back at least one spot. so there goes all your spare time.
our joke for the last 3 decades: what's the last part to go on a hot rod ? - a for sale sign . :(
i can always leave my firearms lay 'till i feel like messing with them. ;)


good luck with your venture
 

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Discussion Starter · #19 ·
PineyCreek22 said:
Best case as I see it is to machine stubs to a min. length and then the rest of the details concerning breech face to barrel face distance and cartridge depth to correct headspace is the responsibility of a hopefully competent gunsmith. Regards, Piney Creek
Thanks Piney, that's pretty much what I had in mind except I forgot about the extractor since I just use a fingernail notch. I read over Mike's headspace info. Interesting way he sets headspace by shortening the barrel and/or shimming the firing pin bushing.

Ranger 99, didn't mean to imply I was doing any serious racing. Haven't raced seriously since my motorcycle drag racing days back in the early 70's. In recent years I have bought and sold a number of roadracing and oval track cars that I got to play with a little when my serious racing friends rented various tracks for practice or I helped a race car rental business with their programs. Sold the last race car in February. Couldn't fold up enough to climb through the window any more. I've had H&R's and NEF's as far back as I can remember. Them and my trail scooters (think fat tired 2 wheeled ATV) are now the focus of my tinkering.

Bill
 
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