Arbor Problem?

[45D]

My take is putting a screw in the end of the Arbor is an odd way to deal with the issue.

It has to be sub size of the Arbor, it has threads that add flex and its not solid like a shim would be. In my view its a not nice correction even if it sort of or does work to the satisfaction of the person doing it.

You don't have to be perfect and you can make layers of shims with going down to beer can thickness if you so desire. One you got it sorted, glue em in place and they stay there.

And it does not weaken the Arbor which may or may not take that added stress, but the design diameter of it is there for a reason.

See post #60 above.
Also " layers of shims" is a terrible way to build a shim. BTDT.

 

[45D]

Here is the last one I made of A-2 tool steel. I make mine a bit longer and blind ended having no need for a keep spring.
Showing the two step hardeing protocol for A-2. I left out the third step temper draw in the photos.
And finally fitting it up.

The "PERFECT WEDGE MADE OF THE GREATEST MATERIAL ON EARTH" DOESN'T MAKE AN OPEN-TOP PLATFORM CORRECT!!!!!!! ONLY THE CORRECT APPLICATION OF THE DESIGN WILL ALLOW AN OPEN-TOP PLATFORM TO WORK AS INTENDED.

 

[45D]

I respectfully disagree about strength but have to admit that it appears to be adequate to the load encountered as lots of folks use and get away with the technique. I prefer to make a new,stronger and better fitting key to maintaining the original design.

A "super wedge" has nothing to do with original design!!! Correct build has everything to do with "original design".

Mike

 

[dickydalton]

Golldarnit!

 

[stephenprops1]

I like Ubertis a lot more than I do Pietta (that is not knocking Pietta quality).

It takes only a few minutes to fix the Uberti short arbors.

I have been told that old Uberti's are better than old Pietta's and that new Pietta's are better than new Uberti's. I have not done or heard of a comparison test. Has anyone else?

 

[Smokerr]

Also " layers of shims" is a terrible way to build a shim. BTDT.

If I was doing custom work like you are I would do a single milled shim per the specific application.

But as for stacking shims,actually not true it not done or advisable. I don't know if they still do it but back in the 80s they still used multiple shims on equipment. The ability to mass produce to a tolerance fine enough for one was not there yet. So you would put in one thicker one (for this discussion call it .010, thick being relative) and then have stacks of .001 to .009. Had a final drive on a BMW cycle that was just that.

Put in the thin shim to get the set and you were good to go.

Now you may think I am trying to smoke you, lo many years ago I also was directed to restore an old 10 hp Kellogg American compressor. On taking it apart I found the tapered roller bearings chewed up. Ungh.

Got the internals check and replaced parts as needed and putting back together and scratcfhing my head on finding 7 end cover gaskets. ???????? Ok, we only need one, or so I thought.

In it went and tightened down and even with a big flywheel to grasp, its locked up. Hmm, ok, back to bearing and setting end play and the lights begin to come on. They are setting the end play with a squishable gasket? No, no, no.

So, add another gasket, still locked up. Ok, add two more, still locked up. Add the rest, still locked up. Vern, I am beginning to see what the problem is. They just threw it together and the 10 hp motor started it and ground the bearings into compliance.

So into the OLD gaskets which I now realized were 7 squished together.

I added most of those before I had a free wheeling compressor and then I left it for a few days and checked again to be sure it still was free. Not only squishable, you now have how many leaks surfaces?

So yea, staking shims is not the crime that was. Clearly its not ideal, but it works and depending on the degree of precision invovled, really not an issue.

Its also what they do on prevision alighement work. You are never going to have the exact right shim. You pick the one that gets you the most and then as few as possible sub shiming.

It would be interesting to check an origianl that was fired little and see how badly off they were. I will bet my stacked shims were a miner crime against humantify in contrast (grin)

 

[Smokerr]

Mike:

This is a bit of 3D and I won't claim to be the best at that.

But if you get the spacing right, that would affect the wedge in how far you can drive it in or so I think.

Too much shim and the wedge can't go through to the little clip (or so I think).

Too little and you take up all the wedge and maybe not get tight?

Of course then there is the angular aspects the the bottom of the barrel assembly contacts the frame where the pins are and you are camming it into compliance but then you have a bend to it all.

Dang, I need to get a cheap open top to play with all of that.

 

[JimCunn]

Stock wedge made out of ordinary everyday steel will withstand a 6 chamber chainfire without damage. How strong do they need to be?

 

[M. De Land]

A "super wedge" has nothing to do with original design!!! Correct build has everything to do with "original design".
Well, they fit better than factory wedges, don't distort nor back out and employ original design. There's nothing super about precision fit and eliminating the need for adjustment screws or shims so we can reuse a beat up factory wedge.

 

[M. De Land]

Stock wedge made out of ordinary everyday steel will withstand a 6 chamber chainfire without damage. How strong do they need to be?

Strong and hard enough not to distort from repeated pressure impulses. Fit on both axis is as important as what the wedge is made of. If they fit both barrel slots and the arbor slot well in thickness as well as width and are of proper hardness they well last for decades with no trouble.
I believe proper arbor end fit aids this but have seen short arbor guns with original wedges still going strong with very good accuracy after decades of use and never having seen any gun mechanic help.

 

[M. De Land]

I'm sorry, I don't "get away with it" . . . be it Uberti (plenty of meat) or Pietta (not as much).
You apparently don't understand the dynamics at play. The reason for the set screw is for WEDGE ADJUSTMENT not for ARBOR CORRECTION!!!! .

The whole reason for ANY DISCUSSION OF A SPACER FOR CORRECTION AT ALL IS . . . FOR ARBOR CORRECTION!!!!!! THE SET SCREW IS A BEARING FOR THE WEDGE . . . NOT FOR ARBOR LENGTH CORRECTION!!!!! WHY WOULD YOU MAKE A SPACER TO CORRECT THE ARBOR LENGTH IF YOU'RE THEN GOING TO INSTALL A SET SCREW FOR ARBOR CORRECTION????????? MAKES ABSOLUTELY NO SENSE!!!!!!!!

WHY CANT PEOPLE UNDERSTAND THAT A SPACER MADE FOR ARBOR CORRECTION HAS ABSOLUTELY NOTHING TO DO WITH A SET SCREW FOR THE WEDGE ADJUSTMENT?????!!!!! IT'S THE SAME AS SAYING " GUESS WHAT ?? THE SET SCREW IN THE END OF THE ARBOR HAS ABSOLUTELY NOTHING TO DO WITH THE CORRECTION OF THE SHORTNESS OF THE ARBOR , BUT HAS EVERYTHING TO DO WITH THE ABILITY TO ADJUST HOW FAR THE WEDGE GOES INTO THE WEDGE SLOT!!!!!
IF THE SET SCREW WAS THE DETERMINING FACTOR FOR THE ARBOR LENGTH, WHY IN THE WORLD WOULD YOU EVER MAKE A SPACER ???!!!!!! MY GOD !!!!!! PEOPLE JUST CAN'T READ FOR SOME REASON!!!!

The WEDGE "PULLS" THE BARREL ASSEMBLY AGAINST THE END OF THE ARBOR (WITH GREAT TENSION) SO THERE IS NO NEED FOR ANY THOUGHT OF THE END OF THE ARBOR BEING WEAK ( it is being harnessed by the barrel assy!!!!) THE FORCE PULLING THE BARREL ASSEMBLY IS CONSTANT AND WILL ALWAYS BE PRESENT AS LONG AS THE WEDGE IS INSTALLED!!!!! SO, NOBODY IS "GETTING AWAY" WITH ANYTHING!!!!!! DEFINITELY MORE THAN ANYBODY IS GOING TO TEST IT WITH BLACK POWDER WHICH WILL NEVER BE CLOSE TO +P SMOKELESS AMMO!!!!


People that use a screw past the end of the arbor to correct the length don't have a clue what they are doing !!! . . and yes, I know a so called "professional" that touts this as a "fix" ( on YouTube) . . . and it's not correct ( and he knows it !!! It's just an easy "crutch").

Also, people that think the "perfect" wedge is all you need are clueless!!!

Mike

The end of the arbor is still strength compromised by your adjustment bearing screw threaded through the end of the arbor slot even if it bumps up to your screw head spacer to make end contact because the joint negates any barrel separation strength enhancement you think your getting by end fitting. If the end of the arbor slot lets go the barrel will head down range and it won't care that it was pressed up against the end of the arbor.

 

[JimCunn]

Explain to us how the shear strength is affected by the arbor screw. Feel free to use equations if it will help.

I'm also interested in why regular wedges are capable of withstanding undamaged the loads produced by 6 chamber chainfires, but are not capable of coping with normal use.

 

[JimCunn]

"and that new Pietta's are better than new Uberti's".

How closely does the Pietta 1862 Police revolver replicate the original Colt?
How closely does the Uberti 1862 Police revolver replicate the original Colt?

 

[M. De Land]

Explain to us how the shear strength is affected by the arbor screw. Feel free to use equations if it will help.

I'm also interested in why regular wedges are capable of withstanding undamaged the loads produced by 6 chamber chainfires, but are not capable of coping with normal use.

Very simple, solid steel is stronger than the same depth of drilled and threaded steel of less diameter.
As a wedge progressively deforms its support strength is increasingly compromised as tolerances are moved out of design specification.

 

[45D]

If I was doing custom work like you are I would do a single milled shim per the specific application.

But as for stacking shims,actually not true it not done or advisable. I don't know if they still do it but back in the 80s they still used multiple shims on equipment. The ability to mass produce to a tolerance fine enough for one was not there yet. So you would put in one thicker one (for this discussion call it .010, thick being relative) and then have stacks of .001 to .009. Had a final drive on a BMW cycle that was just that.

Put in the thin shim to get the set and you were good to go.

Now you may think I am trying to smoke you, lo many years ago I also was directed to restore an old 10 hp Kellogg American compressor. On taking it apart I found the tapered roller bearings chewed up. Ungh.

Got the internals check and replaced parts as needed and putting back together and scratcfhing my head on finding 7 end cover gaskets. ???????? Ok, we only need one, or so I thought.

In it went and tightened down and even with a big flywheel to grasp, its locked up. Hmm, ok, back to bearing and setting end play and the lights begin to come on. They are setting the end play with a squishable gasket? No, no, no.

So, add another gasket, still locked up. Ok, add two more, still locked up. Add the rest, still locked up. Vern, I am beginning to see what the problem is. They just threw it together and the 10 hp motor started it and ground the bearings into compliance.

So into the OLD gaskets which I now realized were 7 squished together.

I added most of those before I had a free wheeling compressor and then I left it for a few days and checked again to be sure it still was free. Not only squishable, you now have how many leaks surfaces?

So yea, staking shims is not the crime that was. Clearly its not ideal, but it works and depending on the degree of precision invovled, really not an issue.

Its also what they do on prevision alighement work. You are never going to have the exact right shim. You pick the one that gets you the most and then as few as possible sub shiming.

It would be interesting to check an origianl that was fired little and see how badly off they were. I will bet my stacked shims were a miner crime against humantify in contrast (grin)

I'm only talking about the "subject at hand" not shims in general (come on, I was raised in a garage!! ).

Mike:

This is a bit of 3D and I won't claim to be the best at that.

But if you get the spacing right, that would affect the wedge in how far you can drive it in or so I think.

Too much shim and the wedge can't go through to the little clip (or so I think).

Too little and you take up all the wedge and maybe not get tight?

Of course then there is the angular aspects the the bottom of the barrel assembly contacts the frame where the pins are and you are camming it into compliance but then you have a bend to it all.

Dang, I need to get a cheap open top to play with all of that.

Smokerr, you're thinking in the right direction!! The "determining factor" of shim thickness is the amount of "endshake" you're looking for - pure and simple. Of course, the end result can leave a wedge slot too large for the wedge to fit ( like you describe), which is precisely why the "adjustable wedge bearing" is installed. It allows the original wedge to remain with the revolver and also allows you to determine how far the wedge will insert (such as interference with re-holstering). Options make life easier . . .

When fitting the spacer, the contact at the barrel lug and frame is established first - that's the "constant" in the setup. Then you "fit" the needed spacer until you reach your endshake tolerance ( with cyl pulled to the rear of course and wedge in tight. Another nice time to have the adjustable bearing!!).

Mike

 

[45D]

Strong and hard enough not to distort from repeated pressure impulses.

There isn't any distortion with a correct length arbor ( echo), the "impulses" pass through without interruption which is exactly the reason for the end contacting the barrel assy under tension.

Fit on both axis is as important as what the wedge is made of. If they fit both barrel slots and the arbor slot well in thickness as well as width and are of proper hardness they well last for decades with no trouble.

Apparently not necessary, my setup retains the use of the original wedge and both wedge and tolerances are maintained ( unless the particular wedge is soft, then a new factory wedge is installed).
I still have factory wedges in my converted revolvers that shoot that smokeless stuff . . . and the wedges are in perfect shape. A much better testament than the use of bp.

I believe proper arbor end fit aids this but have seen short arbor guns with original wedges still going strong with very good accuracy after decades of use and never having seen any gun mechanic help.

Proper "end fit" is not only "PROPER" ( by design), it is imperative for a repeatable assemblage.
You can in fact "get away" with the "Uberti fix" ( taper fit) in belt pistols with less than max loads for a long time but it's definitely not an "as designed "build". You can't do that with a Walker or Dragoon. You fixed your own Walker accordingly so you must have some doubt in Uberti's fix.

I won't even go into the need for a "gun mechanic". You don't "know" till you know, some folks like a "custom" revolver, some are rough and loose right out of the box . . .

Mike

 

[45D]

The end of the arbor is still strength compromised by your adjustment bearing screw threaded through the end of the arbor slot even if it bumps up to your screw head spacer to make end contact because the joint negates any barrel separation strength enhancement you think your getting by end fitting. If the end of the arbor slot lets go the barrel will head down range and it won't care that it was pressed up against the end of the arbor.

Proof that you still don't really "get" the design concept. Not only is the arbor the "backbone of the design, it is also the path for the transmission of the "impulses" you mentioned above. The impulses are the most damaging forces when there is a break in the "transmission". The joint
is protected from the destructive force BECAUSE of the pass through. That's why the wedge doesn't get mangled because it can't move. It's tight in its position. The impulses go cleanly through the whole assemblage without interruption. The end of the arbor is obviously the MAIN connection of the two assemblies which is why a single spacer works better than a shim stack. Shim stacks suffer from compression over time in this particular application.

It's the arbor screwed into the frame that keeps the barrel from going down range. As long as the wedge is making a solid connection under tension, it won't be compromised.

Mike

 

[Bad Karma]

Needed more photo room for the fit up. Notice there are no gaps top or back only the added clearance slotting to the front for the wider wedge/key in the barrel slots.

That Centaure was certainly well used by the time you took it in…

 

[Bad Karma]

There isn't any distortion with a correct length arbor ( echo), the "impulses" pass through without interruption which is exactly the reason for the end contacting the barrel assy under tension.


Apparently not necessary, my setup retains the use of the original wedge and both wedge and tolerances are maintained ( unless the particular wedge is soft, then a new factory wedge is installed).
I still have factory wedges in my converted revolvers that shoot that smokeless stuff . . . and the wedges are in perfect shape. A much better testament than the use of bp.


Mike

It’s a shame there’s no more documentation from the period but one of the War Department’s chief complaints with the Colts was the wear and replacement of wedges.They ordered thousands of replacement frames and separately wedges. I’m sure some wedges were lost as well as battered and requiring replacement.

 

[Bad Karma]

I have been told that old Uberti's are better than old Pietta's and that new Pietta's are better than new Uberti's. I have not done or heard of a comparison test. Has anyone else?

No but Uberti are still better fit and much closer to the original size and shape of the original Colt. So, I’d still pay more for the uberti. If you want to fix the arbor length, it’s really a simple operation taking no time or particular skill.