doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com New (to me) Wall Thickness Gage

Since all of the input on how my other WT gage would not work, and thanks to Jim, Jack, Miller and all those of you with your input, I decided to use most of the other componants and make this one. Basically the same as Jacks. I did add a spring to hold the barrel closer to the ball bearing and it works fine. About $17.00 for metal. Had a few Starett dial indicators laying around and it's about time I used them for something.

I was concerned on this WW Greener on the barrel wall thickness and the gunsmith I can go to hasn't been in his shop lately. Now he is off in Quebec so I decided to make my own.

The smallest measurment I got was .033 near the bottom rib on the right barrel and close to that on the left barrel. Those readings were about 10" from the breech. The largest not counting chokes was .046 in a few spots with the average being about .042.

Also at the muzzle the walls read with a dial vernier caliper .072 in left and .070 in right. In between both the land measures .055. So were the sides of the barrels machined flat for a distance and then soldered together? Talk about extra steps. In looking at some other guns all American I see there is land between the two barrels, so very slight and others a little heavier. Is this a common thing for European or English guns?



Right now it is set for reading 17 3/4", and I can change that to shorter or longer.

Looks like a nice job, David.

That is very neat.

My Grandfather was a machinist, I wish I would have been able to learn something from him when he was alive. My dad has a bunch of gauges and dials and tools and different blocks of metal that belonged to my Grandpa. I don't know what a lot of them do, but they sure get the mind to turning whenever I play with them.

I am sooo envious of people with talent!!! Nice looking job David. Am I looking at this picture correctly and may I assume that this device is suspended from ??/(something) and you simply slide the barrels up or down and take the readings? I have never used one of these so if my question sounds elementary please pardon my ignorance of the procedure.

Jim, Eric and Perry thanks.
Perry it is suspended from the floor joist. I tapped a 1/4-20 hole in the end of the dial shaft and put a threaded eye bolt in it and put a "j" lag bolt in the joist. From members here this is how I came to this style as the other one I made wouldn't work correctly. Also I believe the one that they sell for $100 does not have the spring and you do not suspend it, making the readings almost impossible to duplicate.

I still would like to get a reading between the two bars before inserting barrel and then again after inserting to see how much the spring bar does deflect. I know it can not be great maybe a few thousands.

From the members here on this site, I do believe that anything can be accomplished within reason. There are people here with all the talents that could be wanted for what we love about sxs.
There are premier gunsmiths, stock makers, engravers and journeymen all here to answer questions and help one another out.

I'm still curious about the muzzle end, has anyone seen this before?
In thinking about it, just round it to .070 & .070 = .140 = combined wall thickness it would read between the two barrels and now it reads .055. that means .085 or .0425 removed off each side of the barrels. I'm impressed.

I'm going to get up in the morning and read this again and see if I understand it better.

Don't have a Greener. Do have no-name Webley&Scott. Stuck em with the W/T gauge a few moments ago. Depth of measurement only 1/2" as that's all the knife edge jaws on my dial caliper will reach. Right barrel wall .048"; left .062". Dial caliper says .1" combined thickness of both at pt. of tangency between the ribs. Only -.01" difference from combined walls outbd. to pt. of tangency. May be that the caliper was picking up the exit from muzzle (should have checked to see if there's a parallel section after the choke or straight taper to muzzle exit) and the WT gauge reading deeper in but whatever the case, I'm not getting the big discrepancy you're getting, Dave. Tubes at muzzle appear to meet at pt. of tangency on a circle. No suggestion to my eye of a flat. Does appear counterintuitive; I would have thought external striking after soldering up the ribs would produce precisely the opposite result (combined wall thickness at tangency > than combined wall thickness at a pt. where W/T gauge can be employed).

jack

I believe they did just what you think they did. Some, if not all of the older Browning Superposeds were filed flat where they came together, probably part of the regulation process. They too, are thinner(together) where they are joined than either barrel was, originally. Probably impossible to add even thin screw-ins to them.

Bill,
My phrasing might have not been too clear but Jack and Jim understood what I was talking about.
Here is a close up picture that I didn't crop just to show you what it looks like.
The washers give you an idea what I was talking about. Most guns have "land" between the barrels, these do not. In the other photo you can see what has to be done to the barrels to make this happen. So instead of the barrel walls being .70 thick all around, where they meet they are only about .027 thick.

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I like that indicator point better than the mushroom on the earlier lashup. I think you'll be happy you added the little leaf spring as you should get constant contact of the anvil on the barrel wall. Larger diameter outside rod is also a good idea and something I should have thought about when I made mine. Suspended overhead, deflection of rods should be more or less constant also unless you're making a conscious effort to use the barrelset as a lever. All of this stuff requires "the touch of a young woman" and unfortunately that touch (at least for measuring tools) seems to reside more often in men and particularly you machinists. I'm just a poor guesstimating carpenter so I hook the yoyo on the end and make a hashmark and cut it off 17 times until it's short enuf to fit in the scrapbin and start over. But I respect what we're trying to accomplish and also have a lot of respect for the late Dr. Gaddy's problem-solving. If we waited for me to invent the wheel, we'd still be on log rollers.

jack