Butt Joint Gap Or is it called Barrel lug/ frame Gap?

[Curtis Lee]

Here is my question. How do I fix the BUTT JOINT/Frame GAP in my #2 1861 Navy?
Photo context.
#1 the measurement method I am using for reference.
#2 Is the Amount of "Frame Gap" with revolver assembled.(.008)
#3 Is the amount of shim(.008) needed to achieve a .001 cylinder gap (NOT PICTURED) which as I am aware is called END SHAKE.
NOTES
#1 All measurements are taken with wedge inserted with the retaining spring just engaged.(AS IN PICTURE)

 

[Larry Akers]

There are two points of contact that determine cylinder gap--the point that the barrel assembly contacts the frame below the cylinder and the end of the cylinder arbor where it should contact the bottom of the hole in the barrel assembly. The contact point on the frame acts as a pivot so any gap at the bottom as you show is inconsequential. For the revolver to be able to be assembled with a repeatable cylinder gap the arbor MUST bottom out in its hole. Determine the difference between the length of the arbor and the depth of the hole, add the width of the desired gap and make a shim of that width to add to the end of the arbor. An alternate method is to drill and tap the end of the arbor for a screw which makes the gap adjustable.

 

[wiscoaster]

Curtis, do a search on "short arbor" and you'll find enough content to keep you reading for weeks.

 

[Colonial Boy]

Curtis, do a search on "short arbor" and you'll find enough content to keep you reading for weeks

Or maybe months

 

[Curtis Lee]

Curtis, do a search on "short arbor" and you'll find enough content to keep you reading for weeks.

SO true! I have seen the screw in the end of the arbor method.

 

[Curtis Lee]

Or maybe months

TRUE DAT! I will let Y'all know how I solve it.

 

[Curtis Lee]

There are two points of contact that determine cylinder gap--the point that the barrel assembly contacts the frame below the cylinder and the end of the cylinder arbor where it should contact the bottom of the hole in the barrel assembly. The contact point on the frame acts as a pivot so any gap at the bottom as you show is inconsequential. For the revolver to be able to be assembled with a repeatable cylinder gap the arbor MUST bottom out in its hole. Determine the difference between the length of the arbor and the depth of the hole, add the width of the desired gap and make a shim of that width to add to the end of the arbor. An alternate method is to drill and tap the end of the arbor for a screw which makes the gap adjustable.

The screw method or making a wider wedge seem to be the prevailing methods for correcting frame gap. The gap is only .008. As for the arbor and barrel hole assembly ,that measurement reads good . NO over or under(DEPTH) when using the insert 90* out and rotate to see the depth measurement of the arbor to hole. Hope I explained that adequately,

 

[Curtis Lee]

Mostly this gap is $A!@ING WITH MY OCD. When I shim the B/wedge i achieve a perfect cylinder forcing cone gap. So I am not to far out of spec.

 

[45D]

The screw method or making a wider wedge seem to be the prevailing methods for correcting frame gap. The gap is only .008. As for the arbor and barrel hole assembly ,that measurement reads good . NO over or under(DEPTH) when using the insert 90* out and rotate to see the depth measurement of the arbor to hole. Hope I explained that adequately,

The set screw method is no good. It reduces the diameter of the arbor to that of the set screw. Not to mention, why would you want to "adjust" it?

The 90° test is not a viable test (only on really old copies . . . maybe).

The first point of contact is the frame/bbl lug. If the forcing cone is too proud to allow frame/lug contact, reduce the forcing cone until its not an impediment.
If the arbor is too long to allow frame/lug contact ( is it a Pietta?!), reduce it until contact is made.
AFTER you have frame/ lug contact ( WITH WEDGE IN PLACE !!!!) THEN adjust arbor length for endshake (either further reduction of the arbor or forcing cone or both).

Mike

 

[45D]

Mostly this gap is $A!@ING WITH MY OCD. When I shim the B/wedge i achieve a perfect cylinder forcing cone gap. So I am not to far out of spec.

What is your "perfect gap"?

Mike

 

[Curtis Lee]

What is your "perfect gap"?

Mike

.003 I remember you like .0025-.003

 

[Curtis Lee]

OK Mike, It's a 2020 1861 Uberti.I was holding off doing the screw method. So here is what i did do.
#1 Found some ss stock that came off an old wind shield wiper.
#2 sanded it down to .006
#3 cleaned the arbor wedge hole and super clued that puppy in on the front side.
Badda Bing! no frame lug/frame gap and a .003 FC "end shake gap".
And I don't have to install the wedge in any further than when the wedge spring locks.

 

[45D]

OK Mike, It's a 2020 1861 Uberti.I was holding off doing the screw method. So here is what i did do.
#1 Found some ss stock that came off an old wind shield wiper.
#2 sanded it down to .006
#3 cleaned the arbor wedge hole and super clued that puppy in on the front side.
Badda Bing! no frame lug/frame gap and a .003 FC "end shake gap".
And I don't have to install the wedge in any further than when the wedge spring locks.View attachment 304707

Ok. What you did was help the wedge pull the barrel assy on further and close up the lug / frame gap (so something is lacking there). That is essentially what the wedge bearing that I install does in these revolvers.

The problem is, when you drive the wedge in further than you did, it's going to continue to pull the barrel on more and your .003" of endshake will close up to 0.

What you're looking for is a rap of the wedge with a hammer and NO change of wedge position or the endshake measurement (so you still need a spacer in the arbor hole).

Mike

 

[Curtis Lee]

SO how do I achieve what you're explaining?

 

[45D]

SO how do I achieve what you're explaining?

A spacer to correct the "short comings" of the arbor (preferably mounted in the arbor hole).

Mike

 

[45D]

Curtis Lee, I'd also remove the shim from out of the wedge slot. If it comes loose, the wedge will be too. You don't want to shoot it in a "loose" condition. It would be better to build up the side of the wedge or install a wedge bearing and not worry about any more wedges.

Mike

 

[Curtis Lee]

a Wedge Bearing goes in the hole of the barrel assembly that the arbor sits in? If yes I finally follow your concept. I 'll remove the wedge slot shim and install a ,006 to .007 shim in the arbor hole . I was a little slow in school as well.

 

[Curtis Lee]

Curtis Lee, I'd also remove the shim from out of the wedge slot. If it comes loose, the wedge will be too. You don't want to shoot it in a "loose" condition. It would be better to build up the side of the wedge or install a wedge bearing and not worry about any more wedges.

Mike

Mike; I removed the slot shim and cut a .010 shim from paper installed in arbor hole. Bing Bing Bing, we have winner.NO frame gap and the End shake is .003. NOW I SEE THE FLAW IN MY ORIGINAL FIX. So know all I have to do is make quasi permanent arbor shim. I think I will cut one from and old feeler gauge set and super glue in the bottom of the hole. Why super glue? Because I had a "heck"(THAT ONE IS FOR THE ADMINS) of a time removing the slot shim. I don't think this guns problem is severe enough to use your special screw fix. Thanks again Mike. Now the aft side of the wedge forces the two parts together solidly.Additional,with very little change of loosing the shim and shooting a loose gun.

 

[M. De Land]

Mike; I removed the slot shim and cut a .010 shim from paper installed in arbor hole. Bing Bing Bing, we have winner.NO frame gap and the End shake is .003. NOW I SEE THE FLAW IN MY ORIGINAL FIX. So know all I have to do is make quasi permanent arbor shim. I think I will cut one from and old feeler gauge set and super glue in the bottom of the hole. Why super glue? Because I had a "heck"(THAT ONE IS FOR THE ADMINS) of a time removing the slot shim. I don't think this guns problem is severe enough to use your special screw fix. Thanks again Mike. Now the aft side of the wedge forces the two parts together solidly.Additional,with very little change of loosing the shim and shooting a loose gun.

Well technically end shake is a term used for revolvers with bushings on the end of the cylinder and is a separate measurement from barrel/cylinder gap which will be bigger/wider than true end shake gaps.
End shake gaps set up with cylinder bushings typically are no more than .001 often half that where as the smallest barrel cylinder gap I have ever seen is on Dan Wesson smokeless cartridge revolvers set at a very tight .002.
Also barrel cylinder gap is almost never equal distant at 3,6,9, and 12 o'clock (especially with open frames and arbors) usually being tighter or looser at 6 and 12 o'clock which has a lot to do with if they shoot high,low or off to one side.
This is why when a very large gap has to be tightened up than the lower lug (pivot point) needs adjusted as well to keep the barrel/cylinder gap as equal distant as possible as the wedge draws up the barrel on arbor to the frame.
The wedge is so powerful in it's cam action and off set from bore line that it can actually pull the muzzle out of line if the arbor end is not fit up tight in the well. So the arbor should fit the end of the well and the lower lug should butt up tight at the same time ideally leaving the barrel cylinder gap equal distant around it's perimeter at what ever gap one prefers.
I personally always prefer to set the gap at the top a bit tighter than the bottom as when the ball hits the forcing cone and the arbor radial tolerance slack is removed the gap will be more coaxial/equal distant (in line) with the bore.

 

[Curtis Lee]

1;Well technically end shake is a term used for revolvers with bushings on the end of the cylinder and is a separate measurement from barrel/cylinder gap which will be bigger/wider than true end shake gaps.
2;End shake gaps set up with cylinder bushings typically are no more than .001 often half that where as the smallest barrel cylinder gap I have ever seen is on Dan Wesson smokeless cartridge revolvers set at a very tight .002.
3; Also barrel cylinder gap is almost never equal distant at 3,6,9, and 12 o'clock (especially with open frames and arbors) usually being tighter or looser at 6 and 12 o'clock which has a lot to do with if they shoot high,low or off to one side.
4;This is why when a very large gap has to be tightened up than the lower lug (pivot point) needs adjusted as well to keep the barrel/cylinder gap as equal distant as possible as the wedge draws up the barrel on arbor to the frame.
5;The wedge is so powerful in it's cam action and off set from bore line that it can actually pull the muzzle out of line if the arbor end is not fit up tight in the well. So the arbor should fit the end of the well and the lower lug should butt up tight at the same time ideally leaving the barrel cylinder gap equal distant around it's perimeter at what ever gap one prefers.
6; I personally always prefer to set the gap at the top a bit tighter than the bottom as when the ball hits the forcing cone and the arbor radial tolerance slack is removed the gap will be more coaxial/equal distant (in line) with the bore.

M. De Land​

1; typical of people,how they tend to use a word or phrase that is similar to item discussed.
2; SO, I ended up with .003 :cylinder/barrel gap. I which I am content with.
3;I will keep that in mind when I finally get to sighting in.
4;And that process it a bit over my pay grade.LOL! BUT noted! What I have achieved is the wedge going in no further than it take for the latch spring to engage.
5; Thankfully that's what I have after Mike walked we thought the concept.
6; Not to be flip,but this part is way over my head. My goal is to have well timed,smooth functining,reliable big boy toy. Not to forget and learn something along the way.
But along that vein I am interested in Bore clinder alignment. I have done some
reading/research here and looks like I may need a pin gauge of some sort.

Thanks for the feedback.I will be sure help some like wise.