kend
Member
I need a fixture that will hold a barreled frame upright in the mill, is one available from anywhere? I checked the Brownells catalog but they don't have one.
Does A Milling Fixture Exist For A S&W Frame?
- Thread starter kend
- Start date
Big Cholla
Member
I worked on a lot of S&W pistols and never ran across one. There is a frame wrench to be used in taking off and putting on barrels that is frame size specific and could in certain circumstances be used in the mill. I got by with using various 'slugs' of precision ground steel bar in the right places pre-wrapped with protective paper. What sort of cut are you trying to set up for? ........... Big Cholla
scooter123
Member
What do you want to do? If your planning on drilling and tapping for a mounting rail you don't need an extremely rigid fixture. Get some 1x2 poplar, cut into two 6 inch lengths and groove both pieces with a 3/4 inch ball end mill about 1/8 inch deep. Now you have some soft jaws you can use to clamp the barel in the vise. When positioning the gun use a precision level to set the top strap level and plumb and clamp it firmly without being stupid about it.
BTW, if you are tapping the frame, tap size is #6-48. Tap drill size is 0.119 inch, however I would advise pre-drilling with a 0.112 drill and reaming to size with a 0.119 diameter ream. Many of the cheaper drills have a lot of runout in the smaller diameters and will produce an oversize hole. You will also want to be EXTREMELY cautious when tapping the hole, they are very easy to break and having a broken tap removed by EDM will run about 100 bucks. When I tapped my frames I put the mill in neutral and ran the tap in by hand with thumb and forefinger and back turned the tap VERY frequently to break the chips.
If you need to do some heavier cutting, get some 2024 aluminum and measure the outside of the barrel and groove the soft jaws with a ball end mill that matches that diameter within 0.03 inch. Again, don't get stupid about clamping it in place but use enough force to insure the gun won't move. You'll also want to use a NEW carbide mill running at the correct speed for the mill and diameter. You'll also want to take light cuts, no more than 0.015 per pass. If you hear the mill "singing" take lighter cuts, it's an indication the frame is vibrating and a sure way to have a cutter "bite" and cause the frame to twist. In addition, if you're working on stainless, make sure to use a mister and flood the cutting area, stainless really eats cutting tools if it's not flooded with coolant.
BTW, if you are tapping the frame, tap size is #6-48. Tap drill size is 0.119 inch, however I would advise pre-drilling with a 0.112 drill and reaming to size with a 0.119 diameter ream. Many of the cheaper drills have a lot of runout in the smaller diameters and will produce an oversize hole. You will also want to be EXTREMELY cautious when tapping the hole, they are very easy to break and having a broken tap removed by EDM will run about 100 bucks. When I tapped my frames I put the mill in neutral and ran the tap in by hand with thumb and forefinger and back turned the tap VERY frequently to break the chips.
If you need to do some heavier cutting, get some 2024 aluminum and measure the outside of the barrel and groove the soft jaws with a ball end mill that matches that diameter within 0.03 inch. Again, don't get stupid about clamping it in place but use enough force to insure the gun won't move. You'll also want to use a NEW carbide mill running at the correct speed for the mill and diameter. You'll also want to take light cuts, no more than 0.015 per pass. If you hear the mill "singing" take lighter cuts, it's an indication the frame is vibrating and a sure way to have a cutter "bite" and cause the frame to twist. In addition, if you're working on stainless, make sure to use a mister and flood the cutting area, stainless really eats cutting tools if it's not flooded with coolant.
Bullseye Smith
Member
I think it is called a vise, if it is a long barrel you will need to have a vice that is set-up on the table and the barrel can stick down thru the hole in the table top. Course you will need to make sure it is stright.
JKeefer
Member
Big Cholla
Member
Jerry: My complements on a very clean, nice jig. To coin a phrase; "Necessity is the mother of invention". You obviously are a talented designer and machinist. ............ Big Cholla
Marksman
Member
I have fixture that is held in the vise and holds the revolver by the top strap. I used it for one job and have since sold my milling machine. I am a Journeyman Tool & Die Maker and made the fixture myself. I can e-mail pics to anyone that is interested and would be willing to sell it to anyone who could use it. Contact me at my e-mail rather than PM. Thanks.
jrm53
Member
JKeefer that is a very nicely designed fixture, very professionally designed I would think there might be quite a demand for somthing like you have made, much better than blocks of wood like I used to use, I would trust a smith that had a fixture like that to do about anything for me. Jeff
JKeefer
Member
Cholla & Jeff;
Thank you both for the compliments.
That fixture is 1-1/4 inch blanchard ground 4140. The sides(edges) are ground and trued so it can be rotated and still be square. The opposite side is set up in similar fashion for machining operations on 1911 frames. The frames are supported by ground standoff buttons. There are adjustable standoffs that support various barrel lengths. It was quite expensive and time consuming to make, so I don't think it would be very marketable. Few smiths would welcome the cost.
Thanks again
Jerry
Setup can be a real bugger. I have shortened a lot of S&W barrels over the years and everyone of them is a new setup. The hand polishing done after they are machined at the factory really screws any opportunity for a consistent setup process. I will generally use a rotary table with a chuck, set up vertically with he barrel tenon clamped in the chuck. On the other end I use a center on the muzzle/bore. How I indicate it in depends on what I've got to do to it. It is a PITA. Have to be patient and sometimes just walk away. ( usually scratching your head)
There is a device called (IIRC) an angle plate. Basically, it's a right angle plate that bolts to the milling table and has holes aplenty on one face for clamps and other items to hold things vertical.
What I'd do is get a piece of 1" thick flat stock wide enough to fit between barrel boss and recoil shield, long enough to go beyond top of the frame and bottom of the frame. That would be surface ground to produce parallel surfaces. The frame would then be clamped to the angle plate for machine work using the parallel block just described to space the frame out from the angle plate.
Can't recall off the top of my head if I used studs like Jerry did to level the frame.
You might check out Enco Tool.
Depending upon what you're doing it may be possible (bull barrel, not factory) to put the barrel in V blocks in a vise. A square lets you get the frame vertical, a dial indicator on the barrel established level. But, it's a bear to do and get everything right.
What I'd do is get a piece of 1" thick flat stock wide enough to fit between barrel boss and recoil shield, long enough to go beyond top of the frame and bottom of the frame. That would be surface ground to produce parallel surfaces. The frame would then be clamped to the angle plate for machine work using the parallel block just described to space the frame out from the angle plate.
Can't recall off the top of my head if I used studs like Jerry did to level the frame.
You might check out Enco Tool.
Depending upon what you're doing it may be possible (bull barrel, not factory) to put the barrel in V blocks in a vise. A square lets you get the frame vertical, a dial indicator on the barrel established level. But, it's a bear to do and get everything right.
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