"Back on Face" Problems

[Eldon Goddard]

I have been attempting to put my Ithaca flues back on face. I had my friend tig weld the hook and it was going well till I started on the breech face got most of it to contact using my oil lamp and files, but then I noticed that it was begining to come loose... so I must have taken to much off the face. I think my problem was that I did not get enough contact on the hook before I started working on the breach face. Long story short I get to start all over again. Calling my welder friend tonight.:banghead: I would like to say to all the gunsmiths on this forum that whatever you are getting paid to put a gun back on face it is not enough. It is alot of work and I have the black hands to prove it.

[calvin humburg]

Eldon, Have you got a gunsmith giving you help? Not sure but I don't think the hook is perfectly round. I've herd of people doing it and getting there gun stuck shut. Just stuff rolling around in my finite mind to ponder. Are you using candle to black the lug? GOOD LUCK

[Ed Blake]

That's why the Brownells shim stock and soft solder on the hook is so easy and effective. Very little fitting and filing.

[Harry Collins]

There is a video on YouTube of putting a Parker back on face. It shows wedling and smoke and filing. There was no need to file at all. That had been done at Parker years ago. All that was needed was to dress down the weld unless I am missing something.

Sorry about your bad luck. I hope you get her back on face.

Harry

[John Campbell]

Eldon:
I'm sorry for you. And the gun. Now, all you can do is rebuild the hook and refit. BTW... one should NEVER be filing on the "breech face" (standing breech) of such a gun for any reason.

It must be clear to you by now that certain jobs are a bit beyond the reach of the average gun hobbyist. Even through they seem simple at first. This is not a criticism. Just a sad truth that I had to learn myself... the hard way.

Good luck.

Best, Kensal

[Bruce Day]

.....started on the breech face got most of it to contact using my oil lamp and files, but then I noticed that it was begining to come loose...


xxxx

[Frank Srebro]

I've rejointed a number of guns, and I concur that the back ends of the barrel breeches should never be filed, They were contact fitted when the gun left the factory, and there's no need to try filing them to get new contact with the standing breech. When re-doing a barrel hook by welding, the EXACT original X and Y axes must be maintained. Even a .002" difference in location in either axis will make a huge difference on the fit of the barrels against the standing breech. And a compound error (both axes off center) is a MAJOR problem. Trying to do it without a witness location (pre-welding) and with files is just asking for big trouble. I do it on a vertical mill equipped with a digital readout (DRO). The hook axis center is located before welding, barrel removed for welding, then replaced on the holding fixture on the mill, with adjustment made using the DRO for the off-face dimension plus a thou or two for fitting. New hook radius is cut with an end mill ground to the exact diameter of the hinge pin. Readers please note I only work on my own guns, no exceptions. I am not posting this to solicit work.

It's just my opinion but soldering or gluing a shim to the hook radius may apparently get the barrels back on face but it usually results in "point contact" at the top and bottom of the shim because the hook radius is then smaller than the hinge pin diameter. The hook radius is usually not worn uniformly round. Short term fix only.

All that doesn't help you now with the Flues. Best you might do IMO is to reweld and just work the hook radius only, being careful not to make its diameter any larger than the hinge pin. That can easily happen and you'll end up with very limited bearing against the hinge pin. Work very-very slowly while watching what's happening with the barrel contact. Once you get it very close (touching at the bottom of the barrels, maybe .001" off face at the top) you can soot fit the back end of the barrels which you said you've already filed. Keep in mind that will likely tighten the headspace and the rim cuts will probably have to be redone with a rim cutter. One last tip, the oil lamp soot tends to build up and it should be wiped off each and every time you check for fit, then resooted. Otherwise you'll get erroneous readings of " good fit" because the soot is so thick.

[Eldon Goddard]

Thanks for all the info guys. I did not file on the breech face. I just sanded down the barrel faces very lightly to get it to contact the breech face. I bought the gun for the specific purpose to learn how to fix it. I figured that you had to clean it after smoking it but now i know for sure. The pin should be round as my first attempt at fixing it was to replace the hinge pin, only to find that the hook was to worn down even to contact the new pin, so I decided to weld the hook. I have never tried this before so I did not expect to get it right the first time.

[charlie cleveland]

one things for sure your not affraid to takle a bad problem...i think you will win in the end and be ready to use that gun... charlie

[Bill Murphy]

How in the world did you manage to replace the pin? Where did you get a pin the same diameter as the original? When you found that the original pin was still fairly round, why did you replace it with another pin?

[Eldon Goddard]

Lets see.... I thought I could fix the problem with a new hinge pin as I am a terrible welder and I do not have a welder in the first place. So I put in a new pin from brownells, but I failed to fix the problem in doing so. Then my friend told me he could weld the barrels for me I decided to try that instead. I probably should not have replaced the hinge pin in the first place, but if I had a dollar for every stupid thing I have done I would probably own an Invincible grade not a VHE.:rotf:

[Bruce Day]

You probably found that the barrel hook does not directly engage a hinge pin; it engages a guide roll through which the hinge pin extends. This is shown in the diagrams in TPS and in Parker catalogs. Replacing the hinge pin does not fix looseness because it is not the bearing surface.

When Parker repaired loose guns, they had jigs that held the frame and prevented it from being bent while the hinge pin was pressed out. The guide roll was removed and a new one inserted in the frame channel, then the hinge pin re-inserted through the roll. Because so many hinge pins are extremely difficult to remove today, the preferred practice today is to weld new material on the barrel hook, then round file to shape, which takes skill and a fine hand.

As an expedient today, some will glue a shim into the barrel hook. This can last for years and costs almost nothing. My personal view is that this is not the best fix but something temporary. I realize that temporary goes on for years for some owners. I should further add that i have never personally done this work, but this is my understanding based upon reading and talking to gunsmiths who do this work as a matter of course. I have had one gun loose on face and fixed by the hook welding method, but I think by the time a gun gets loose on face due to guide roll/hook wear, there are many other wear issues with the gun.

[Frank Srebro]

Several friends asked for more info on my technique. Here's a photo collage showing work on a 16 gauge Fox. Same technique would apply to an Ithaca Flues, subject of this thread, except that the end mill would be sized same as the Flues hinge pin.

Just as an aside, I'll add that I started doing this work on my own guns because of sloppy workmanship, multiple times, by gunsmith XYZ who does rejointing work. I worked part time as a machinist while in high school and college, and nowadays have access to a large machine shop owned by two friends. Sorry, I won't badmouth this gunsmith on the world wide web. Please don't ask for his name. Maybe he does better work for others? Last comment, there's no reason why most any gunsmith who owns a vertical mill can't do similar high precision work.

After TIG welding
http://i1044.photobucket.com/albums/b450/silvers897/post1-4.jpg

Milling machine adjusted for +.005" on the X (long axis). In this case it was .0035" for "off face" measurement + .0015" for final fitting
http://i1044.photobucket.com/albums/b450/silvers897/Post1-1.jpg

New radius milled in the hook using an end mill sized for a 16 gauge Fox hinge pin
http://i1044.photobucket.com/albums/b450/silvers897/post1-2.jpg

New radius is cut and is ready for fitting. Note how little "heat" propagated to the barrel hook
http://i1044.photobucket.com/albums/b450/silvers897/post1-3.jpg

Fitting about 1/2 way complete using oil lamp soot
http://i1044.photobucket.com/albums/b450/silvers897/post1-6.jpg

I like to use Dykem (machinist layout blue) for final fitting. Dykem is much thinner than soot. Almost done here but I'll add that most factory done work will show even less contact than in this pic..
http://i1044.photobucket.com/albums/b450/silvers897/post1-5.jpg

[Larry Frey]

Frank,
Thanks for sharing your procedures in pictures. I’ve made a couple of new roll joints/guide rolls for both hammer and hammerless guns and by adding the needed material was able to achieved the same result with no file fitting. I would be very interested in getting more details on the fixture you used to hold the barrels while machining in case I decide to try the welded hook method. Thanks, Larry

[Tom Carter]

Yes, please show the fixture. Thanks, Tom

[Eldon Goddard]

I did not have that much contact on the hook but I did have a good amount in the center of the hook. Are not most hinge pins tapered? How do you account for that when milling as end mills are not tapered? I agree that using a vertical end mill would be the best choice and I do have some experience machining. I have access to a vertical mill and even a cnc mill but since it is at my school bringing in a set of barrels is out of the question. I may be able to get the permission, but I doubt it.

[Frank Srebro]

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. :nono:

http://i1044.photobucket.com/albums/b450/silvers897/post1-7.jpg

http://i1044.photobucket.com/albums/b450/silvers897/post1-9.jpg

http://i1044.photobucket.com/albums/b450/silvers897/post1-8.jpg

[Dave Suponski]

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.

[Frank Srebro]

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.