"Back on Face" Problems

[Cold Spring]

Ithaca and Fox hinge pins are straight, not tapered. When working on a gun with a tapered pin, you mill to the small diameter, then match the taper using files and scrapers. Much more complicated and time consuming. For those who asked for a pic of the fixture, here's the best I can do. Fixture is in my cabinet at the machine shop 30 miles from here. I don't have a print. I made it up some years ago while fooling on the mill. First pic shows the complete setup on the mill, with fixture clamped in the table vice, and barrel in the fixture. Also shows the outrigger I use to support the mid part of barrel during the machining. Again, you need "witness" coordinates for the barrel hook radius before doing any welding, so you can revert to the EXACT coordinates after barrel is welded and replaced in the fixture. Then you make table adjustments on the X and sometimes the Y axis for the actual off the face on that particular gun.

Second pic shows the original condition on this gun. .004" thick steel feeler gauge is a tight fit = .0035" off the face IME.

Last pic is for those who do their own soot fitting. Be sure to use a good dust mask to keep the airborne carbon out of your lungs.

[Autumn Daze]

Frank, Great pictures and tutorial. Thanks! I remember when those Kurt Anglelok vises first came out. Thay added so much versatility to the Bridgeport mill verses the old Bridgeport vise. Another nice feature of the Kurt vise is that for every pound of force along the axis of the screw the vise exerts a half pound of force down. Just sayin....

[Eldon Goddard]

Frank,
Thanks for all the help I have decided to use dycem blue as the soot method is just to dirty. Got black on everything from the garage door to my work bench and everything else. The old hinge pin I took out was tapered I checked it with my calipers, however I do not know if it is the original but I would assume it is as the finish on the gun I am pretty sure is original.

[Cold Spring]

Eldon, I am happy to help. Ya know, I should have qualified my earlier statement about Ithaca and Fox hinge pins. I know for a fact that A H Fox and Ithaca NID hinge pins are dead straight because I've rejointed a few of each. HOWEVER, I've never done the earlier Ithaca Flues model and for all I know its hinge pin is tapered. Any Syracuse Arms enthusists out there? SAC used tapered hinge pins and are a challenge to get back on the face because of that design. I did one SAC gun and all I have to say is, never again. Possibly the best way to do that is press out the old pin, fixture the barrels so they are dead on the face + a little bit for wearing in, then line-bore/ream on the mill for an oversize straight or tapered pin. Of course the new pin will have to be dressed off on the sides of the frame which would be very difficult without marring the frame colors on both sides. Just thinking out loud..... Good luck with your project.