Underrib Help!

[clayfeld]

Hi. Guys-

I'm just getting to the point of fitting the underrib to my Gemmer Hawken and I find that the distance between the top of the ramrod hole and the bottom of the barrel is 3/16", whereas the depth of the underrib, from the top of the groove to the top flat is 1/4". I know it's from something I did wrong in barrel/tang fitting, but how do I correct it? Is a shorter rib purchasable anywhere? I do have a Sherline lathe and mill, but it would be a bit of a struggle on that little machine.

Thanks,

Clay

 

[paulvallandigham]

I don't think there is anything to correct. The ferrels will add the other 1/16 inch so that when you run the ramrod through the thimbles,( ferrels) it will line up with the entry pipe and hole in the stock.

 

[SusieB]

Clay, out of curiosity, what is the size of your barrel flat to flat? Is the rib you have flat at the joint (where it matches the barrel flat) or does it have a little rib which overlaps and hides the joint? I understood your .1875 measurement of the web and the .250 thickness of the rib. If the problem was indeed opposite, the thimbles could have been the fix even though the rod would bump into the thimbles edge upon entry. This is a common problem in the industry with a lot of the ribs being to darn thick, but if I knew which type and size of your barrel, I could look thru my inventory and see if I have one thin enough. When the rib is thicker and it is the cold drawn type with no lip, use a black marker and draw your intended finish line on both sides of the rib. Use a coarse belt on either a belt sander or flat sander to remove the excess material.If it is the lipped type its easier to use a chainsaw file and deepen the groove. Adjustment at the entry nosecap if you haven't already shaped the forestock could save you time by adjusting there. I'll check in on your reply later.

 

[clayfeld]

MorningStar-

It is a Goetz 1" barrel. The flats are 0.430". The underrib is the milled kind with the little slanted overlapping walls. It measures 0.050" wide outboard and the barrel-matching flat is 0.410".

Thanks for the advice and help.

Clay

 

[Vaino]

If you correctly inletted the entry pipe in relation to the RR hole and ended up w/ a web of 3/16" and the rib at the radius is 1/4", a mismatch of 1/16" will not allow a standard RR to enter. Perhaps a rib that's 3/16" is available from a supplier? Don't know the setup for your Gemmer....an entry pipe and muzzle cap {Hawken style} or just a muzzle cap? How does fitting the tang etc. have anything to do w/ this problem?....Fred

 

[clayfeld]

Your analysis is exactly correct, Fred. A 5/16" RR will enter, but, of course, looks (and is) undersize in it hole. If I can't find a source for a 3/16" thick underrib, I'll just machine down the one I've got as suggeted by MorningStar.

Clay

 

[clayfeld]

PS: Fred, I don't actually *know* that the discrepancy resulted from my inletting of barrel and tang, I just asssumed that since I had made every other mistake, that I probably made errors in this area also, which could effect a lower barrel channel. The forend cap, by the way, is a nickel silver Hawken cap, the same form Don Stith said, as the poured pewter ones. No entry pipe.

Clay

 

[Doc Arroyo]

My only solutionwithout buying a new part is the old fashioned method. It would involve draw filing 1/16" off of the rib. :v

 

I don't think there is anything to correct. The ferrels will add the other 1/16 inch so that when you run the ramrod through the thimbles,( ferrels) it will line up with the entry pipe and hole in the stock.

Been there, done that, bought the tee shirt: it won't work very well. The ramrod thimbles have to be inleted into the rib, flush with the surface. If they aren't, the ramrod will be damaged as it is withdrawn and replaced, the finish will be scraped off and if a splinter raises the rod will be damaged and have to be replaced.

Use a round file to file the rib to match the hole and taper the end of the rod to fit. If you can, and find it necessary, increase the opening of the ramrod hole a little.

 

[John Taylor]

You got the mill, install the rib on the barrel and clamp the barrel in the mill and go after it with a 3/8" ball end mill. You might need to move it several times in the small mill to get it all done but it would be less time than hunting and waiting for another rib.

 

[Scota4570]

I am not exactly sure how it is laying out. I think the inside curve of the rib should be at the same leves as the hole in the stock. The rod should be able to lay flat against the rib and make a smooth bumpless transition to the nose cap and the stock. Make that happen. Let the barrel deeper into the stock or cheat the hole a little with a rat tail file. You may have to ajust the bedding of the barrel. Once it is working put the pipes on. Flat off the bottom of the pipes. File a corresponding flat in the rib. Let the pipe into the rib so that the rod lies flat against the rib. Use a piece of drill rod and some wire, and maybe vice grips to hold them in alignment when you solder them.

 

[clayfeld]

Thanks, guys, for all the suggestions. Since it's the rib that's too tall, I'll have to remove the "too tall" part, as you said. I don't think not having an overlapping edge will be PC-critical. From the advice given, I'll use some of all. My little Sherline mill attachment will deifinitely not carry the rib attached to the barrel, so first, I'll clamp the rib in place on the barrel and drill and tap the screw holes. Then I'll remove the rib, file off the shoulders to get a flat surface on the top of the rib. Next, I'll grind and draw file the .030 to .060 I need to remove, testing it as I go along. I'll finish up by countersinking the screw heads, then inletting and soldering the rod pipes on. Does that sound about right? (Is it always this complicated? :-( )

Clay

 

[SusieB]

Well, I bombed out. I had 3 of the 1 inch and they all measured around the same as what you have or worse. The cold drawn styles with no lips measure .225 so they are still not thin enough. Just goes to show manufacturers aint builders! If it were me, I would just mount a ball end mill and cut it down in the groove. When you mount your thimbles, they should be fit to the rib where the inside of the thimble is flush with the finish groove of your rib. This will keep your rod from stubbing its toe on the thimble as it passes. Sorry I didn't have a good rib. Our milled ribs are made to match up to Ted Cash nosecaps and they usually measure .250 on the web. He should know better too, although he isn't a builder either.Holler if you need any assistance!
Susie