71-72 arbor spacer thickness

[FlyingZebra]

Hi y'all


I already know how I'm going to fit my arbor spacer, but I'm curious to hear how thick a spacer y'all have needed to set your open tops straight.
For example my 1860 took .088" to get the arbor to bottom properly with an acceptable cylinder gap.

Once my 71-72 is fitted I'll post the spacer thickness here.

-FZ

[Pettifogger]

It varies from gun to gun.

[FlyingZebra]

Yes
Without a doubt.

I am interested to hear the accounts of folks here on how much they've needed to correct on their revolvers.



-FZ

[rifle]

I usually don't measure the thickness of a space/shim in the bottom of a barrels arbor hole.  I start with a small fender washer and if it's not enough I go to two ect ect ect .  Sometimes weld the end of the arbor and then shape it back and stone till it fits like what I want.

I like to see the space at the barrel/frame contact point when a shim is in the hole that is a little too thick. Then I know about how much to stone it down.

I trial and error till I work the shim to where it's right.

I use that machinists blue called Prussian Blue on the end of the arbor and "see" the fit after I install the wedge.When the end of the abor or the bottom of the hole stay blue the stuff is too thick and there's a space. When the blue gets squished away where the parts crush together then I know it's fit if......the space at the barrel/frame is proper.

It's nice to use the Prussian Blue to "see" what's up. I like a flush fit to the shim and the arbor and I can see that with the Prussian Blue.

I use a thin shim on top the arbor above where the wedge slot is to take up space between the arbor and the barrels hole also.
Without that the bottomed arbor is only partially adequate.

Even a bottomed arbor can let the barrel cant down and back at the breech end if there's a space between the arbor and the barrels hole on top the arbor and the top of the hole. You can get away with a very small space since the barrel will move to close the space between the arbor top and the hole till.....the barrels beginning of the top of the hole contacts the top of the arbor to stop the movement.
You can see it in the Prussian Blue on the end of the arbor and in the hole as the area to the top half of the end of the arbor will have the blue squished away and still show blue to the bottom half of the end of the arbor.

The immense force of the wedge causes parts to go somewhere to relieve that pressure. A flush fit arbor in the hole will let the barrel cant some and ride onto the top edge of the arbor until the space between the top of the barrels hole(at the beginning of the hole) and the top of the arbor closes and makes contact to stop the movement.

It's alright to have that extra contact point for stability when the space between the arbor top edge and the top of the barrel hole at the beginnng of the hole is small. When the arbor is too loose in the barrels hole there's too much movement and the cylinder can still get pinched and the front of the barrel cants up when the back cants down and the gun shoots higher than it should.

Actually the shim, if tight, on top the arbor to make for "no space there" is all that's needed to make the gun fit better than with just a bottomed arbor.

That means that an arbor that's real snug in the barrels hole doesn't need to be bottomed and the tight arbor in the barrel hole is better/more rigid of a lock up than just a bottomed arbor.

It's just easier to get te gun well off enough with the arbor bottomed than making the arbor fit real snug in the barrels hole. That entails making a new arbor that does fit the barrel tight and reaming the cylinders middle hole at times too.

The shim on top the arbor is a good helper and is the easiest way to get the best you can get without making a new arbor. Optimum is a bottomed arbor and a tight arbor in the barrels hole.

The thin shim atop the arbor inserted in the hole with the arbor needs to be helped along with a small screw driver so it doesn't slide back and rub the cylinder. The shims above the arbor are cut with scissors and the wider they are atop the arbor the tighter they get.

Different thickness shims are picked for the individual arbors in the barrels hole.

A gun with a tight arbor in the hole and the bottomed arbor shoots lower most all the time.

Chicoine in that book,"Gunsmithing Guns of the Old West" he says how a snug arbor in the hole is important. A snug push on fit he says. I say a snug  tap on fit.

I use copper shims or brass and make them tight so....when I tap the barrelon the arbor with a rubber hammer the shim form fits itself exactly the right size...if it's not too tight to go in the hole with the arbor.

Some guns just have a small space between the arbor and the barrel hole so it's futile to try to get a shim in there. There has to be space for the shim.

A coupla spot welds or even a long weld on top the arbor where it's in the barrel is the way to go. Weld and then file it to fit. Make sure the cylinder hole has alittle space to do that though.

Having a new arbor made that's a tighter fit in the barrel and the cylinder  is actually the proper way to do it. Makes a "race gun" out of a Colt that can make for a target grade Colt that can beat out a Remington that has a better design.

Of course there would be a few other things to do to the Colt also to tune it to be like a target gun whether it's cap&ball or cartridge.
Cap&ballers need the most "tune" usually......but it's worth it when it's done proper.

Anything eats meat likes a dead buffalo and anything that shoots guns likes a good shooter.

Gotta go run the hounds.

[Pettifogger]

Yes
Without a doubt.

I am interested to hear the accounts of folks here on how much they've needed to correct on their revolvers.



-FZ

I guess I'm not understanding the question.  Each gun is different.  It takes whatever it takes to fix the problem.  You can go here and see how I usually do it.

http://www.theopenrange.net/forum/index.php?topic=7988.0

[Coffinmaker]

A while back I found dropping  a stainless 5mm split washer done the hole worked quite well.  I've no idea how thick the washers are.  The barrel register correctly on the frame and that was all that mattered.  That, and not losing the washer when cleaning the gun.

Coffinmaker