I'll be happy to get my little 618 Atlas rebuilt this holiday season. My nephew just brought the "new" tailstock unit over this aftrnoon. It is butter smooth. What a great deal from ebay even !!!
The lathe resto project is more like a kit-build. Many parts and tooling still needed which will mean some heavy shopping. Included on the wish list for the 618 is a steadyrest that will allow some modest barrel work. Cost over-run is a serious problem.
Well, actually, you probably *can*. It was on my list of things to do before I got sidetracked into guns again...
The trick to aligning the headstock bores to the bed is in Dave Gingery's book about building your own lathe, and it's particularly appropriate to the Atlas and other lathes that have a full-length bed and a separate headstock. Basically, you cobble up some bits to work very much like a horizontal boring mill; you need an outrigger on the headstock end to hold a center, and you put a piece of round bar through the rough headstock, between the tailstock and the outrigger. You put your boring bit in the bar, and you turn the bar with a temporary pulley rig. You shim the headstock to a snug sliding fit, link it to the carriage, and use the leadscrew to pull the headstock along the ways.
The trick here is that when you're pulling the workpiece over the boring bar, even visible misalignment between the centers makes only a tiny error in the circularity of the holes - thousandths of error turn into tenths on elliptic eccentricity.
You can pick up a replacement spindle and bearings for a larger lathe and make a bolt-together headstock to match. If you want to increase the swing at the same time, you need to make a riser for the tailstock
My idea was to use pressure-fed Ford main bearings - 351W mains are 3" in diameter - with oil seals at each end. Plain bearing headstocks can be just as accurate as ball bearing ones. The spindle could be made on your existing lathe. I also planned to modify the carriage for pressure lubricant feed, so it floated in oil, which should eliminate wear from the relatively soft Atlas ways. With the speeds and loads being negligible compared to an automotive application, there would be no problem using the cutting oil as lubricant. A piece of pipe for a settling tank and a spin-on oil filter would suffice for filtration.
I have that book. If I was converting an existing shotgun into a double (or single, for that matter) rifle, it would pay for itself many times over, just on things like the draft of the water table and bushing the firing pin holes. Good stuff.
But it doesn't help much for building the receiver in the first place, which is what I want to do. Shotgun receivers mostly start as intricate castings, finished (in the old days) on tracer mills. And then they're stuffed full of fiddly little bits, all precisely machined. It's not stuff you can do with an ordinary mill and lathe; you need the tracer or a CNC. Hell, I *have* a CNC mill, but I'm a long way from being able to write the code to make something like a shotgun receiver.
The large bore light duty lathe is a rather recent innovation. American-made metal lathes generally don't have large headstock bores until you get into the heavy industrial types. Those lathes too often have very long headstock shafts which can be problematic for gunsmithing.
Asian import light duty lathes generally from the late 1960's onward appear to have the large bores. That leaves us with a compromise on older US lathes. One solution is to select a lathe with sufficient space between centers to turn barrels or with a work-around for the often longer headstock shaft on a larger, heavier lathe or both.
Spending $2k to $5K will get you a recent asian-made lathe with a larger bore. That may exceed a home shop gunsmith's budget big time. It's always something !!!
One cute trick I've seen is to extend one of the tiny 7x10 mini-lathes by either replacing the bed with an extended one (up to 14 inches) or even more exotic to splice a left-over 10 inch bed to your 10 inch lathe bed (plus rack gear and extended lead screw.) That gives some serious length ie adding ove 20 inches to make it over 30 inches between centers !! This is not a project for the novice and you still have a small 20mm bore.
Last edited by Viper Dude; 12-25-2010 at 09:51 AM. Reason: typos...
So, two years later...
I'm occasionally making a little progress on some of the projects, but most of my time and money is going into the Auto Mag project. That's complex enough that more than half of the considerable (to me) money I've dumped into it so far has been into tool and equipment upgrades. All of the other projects are boxed up.
Lathe: replace failing 1hp motor with good 3hp 3 phase motor with VFD. Mostly finished with through-the-barrel oiler system for chambering. Finished modifying steady rest to fit. Well along with ball bearing steady rest. Have spare tailstock for lever operated tailstock. Have raw cast iron T-slot table, new T-slot cutter, need correct dovetail cutter. Oil catch pan welded up. Need to finish spider for left side of headstock. I have some of the parts collected to build the taper attachment and barrel profiler, which will use a curved pattern to shape the barrel OD.
Mill: got original 3-phase motor and step pulley out of shed. It weighs well over 100 pounds. Bought VFD for motor. Bought X and Y DROs. Have all the pieces for a "fogbuster" coolant system on hand, most of the pieces for a flood coolant system. Welded up oil catch pan to go under vise, working on Lexan box to contain flood coolant. Need to fix power feed, which requires removing table. (the old Gorton originally had built in X and Y power feeds in the knee!)
Mill: motor is too heavy to lift, table is way too heavy to lift. Bought steel I-beams to make an 8x9' gantry crane over the mill. Scratchbuilding the trucks, since they're too damned expensive to buy. Bought a 1-ton HF chain hoist on sale.
Park tank: bought stainless tank and lid from a guy on FALfiles. Bought and cut the angle iron to make the stand. Acquired a 36" gas burner log. Still have to weld it all up.
Stock duplicator: got 8 feet of 1" hardened and ground steel rod, some linear bearings, 1hp router. Project parked for now.
Heat treat oven: have all parts - bricks, temp controller, furnace cement, angle iron, sheet metal, etc. Just needs welded up.
CNC mill: I did the X2 CNC conversion four or five years ago, got Mach3 and MeshCAM for it, but never mastered any CAD software. I did three years of drafting in high school and worked as a draftsman for several years, but every CAD program I ever tried seems to be expressly designed to be as obtuse and obstructionist as possible. I finally realized that I am, after all, a computer programmer, and I can write G code in a text editor. I need the CNC operational to cut the cam tracks in the Auto Mag bolt, so I bought the materials to make a couple of pounds of machineable wax for experimenting with. I need to make a mold to cast "bar stock" blanks for the bolts.
CNC Mill: fortunately I bought the 4-axis setup from Xylotex, so it can control a rotary table or indexer. I also sprang for the high-torque steppers. I bought a 4" rotary table to use as an indexer, snagged a .250x7mm flex coupler from eBay for a couple of bucks, and sawed out the beginnings of the stepper adapter. The high torque stepper is almost half the size of the rotary table, which makes packaging awkward. I also need to buy or build a tailstock.
Tool and Cutter Grinder: I bought one of the HF "tool grinders" that looks like a big bench grinder with heavy duty tables. I have a book on tool grinding that shows how to make attachments for a conventional bench grinder; I'll be adapting some of those for the HF grinder.
I have a pile of O-1 drill rod, 4140 and 1144 bars for making parts, pieces of 1018 plate for making fixtures, some barrel blanks, etc.
I also have a fishing tackle box with new reamers, taps, drills, end mills, all purchased for this project and kept separate from my regular tooling.
I have a partial set of Auto Mag blueprints I bought from Max Gera, the original designer of the gun. Frame, barrel, bolt, receiver, some odd bits. For the 60-odd pieces he didn't have prints for, I have a small ziplock bag containing exotic, antique, collectible stainless steel bits from eBay, Gunbroker, Walter Sanford, Brian's Surplus, and a few individuals. I have never paid as much for a car as what I paid for what's in that little plastic bag. I'm making drawings so I can duplicate them later.
There's a bag of new Starline brass, several boxes of Hornady 240-grain .44 bullets, a Hornady .44 AMP die set, and a couple of aftermarket Auto Mag magazines.
For machining the Auto Mag I'll need various custom-made form milling cutters, some custom reamers, etc. They're part of the reason for the tool grinder and heat treat oven. In the evenings I'm trying to absorb all I can from my old machinist books, plus I found Google Books has scanned a bunch of old heat treating stuff in. If shop monkeys could do it a hundred years ago, I can do it too.
Various vehicles, race car parts, and gun parts were sold off to fund the Auto Mag project. I've been at it for 10 months, and I'm still tooling up; I haven't cut a single chip yet...
My goal is to make a shootable Auto Mag in three years. I have a little over two left; right on schedule, actually.
Below: what I intend to wind up with when I'm done
Last edited by TRX; 11-06-2012 at 09:47 AM. Reason: added feelthy peekchurs
I don't even remember why these projects got shelved part way through or in the case of the AKU-94 never even started even though I picked up the kit 5 or 6 years ago.