Getting the Walker tuned up

[M. De Land]

I've got a Uberti Walker and finally got around to measuring the arbor end gap. My other guns I can rotate the barrel 90 degrees and compare match-up. But on this gun the arbor just wouldn't go down more than half way. This one took a shim .086" thick.

The opening of the arbor well is .520" so my first shim was that diameter. It fit only a short way down the bore. So I made a .515, then a .510, and finally a .505". I'm not crazy about that much taper in the arbor bore, but nothing I can do about it. I also don't care for the angled floor of the bore. I would have preferred the shim fitting the bottom completely, but as it is, it's just around the outer edge.

What do you do, Mike? The center of the bore is another .060" deeper. Do you make the shim fit exactly?

I discovered last night when fitting a plug that my Uberti Walker arbor bore is tapered as well. I guess the next thing is to check to see if the arbor is tapered to match.

 

[Rich44]

M. DeLand

Very strange to me that disagreement on the Colt Open Tops can still exist including the use of the wedge.

The wedge is classified as one of our simple machines that were invented well before the wheel. So we are not trying to reinvent the wheel, we just are not understanding an invention that was many many years before.

A wedge can be used to pry apart or push together objects. And the wedge gives you a great mechanical advantage, with the inclined slope. Just as a bolt or screw does with tightening power, when secured tight. Sure you can use the wedge on a Colt to set what you call cylinder gap but then you lose the friction generated by the wedge that holds it in place. Because as you stated you could tap the wedge still harder and close the gap to zero. Without the arbor and barrel having a solid contact the wedge never builds up the proper friction to hold it in place. With a proper fitting arbor and giving the wedge taps with a brass piece might give 20lbs force on the wedge driving in (as a guess) but amounts to about 100lbs force of pushing together or clamping together the 2 parts for a 5 degree wedge. Without this 100lb force the friction factor will be lessened, especially after firing, allowing the wedge to be less efficient in doing its job and staying in place. I realize it is done quite often, ignoring the properties of the simple machine, the wedge. But it is just a poor approach from a mechanical stand point not to understand a machine that was invented thousands of years ago. Simply put you cannot expect a wedge to hold correctly unless it is solid. Maybe take another look at it again.

Here is an example of a 5 degree wedge and forces.


A heavy safe is being pushed away from a wall with a wedge as shown below. Assume the wedge has an angle of 5 degrees, the coefficient of friction (static and kinetic) between the wedge and the safe is 0.16, and the coefficients of friction (static and kinetic) between the wedge and the wall and the safe and the floor are both 0.35. What is the pushing force required to move the safe out from the wall?

Solution

 

[M. De Land]

M. DeLand

Very strange to me that disagreement on the Colt Open Tops can still exist including the use of the wedge.

The wedge is classified as one of our simple machines that were invented well before the wheel. So we are not trying to reinvent the wheel, we just are not understanding an invention that was many many years before.

A wedge can be used to pry apart or push together objects. And the wedge gives you a great mechanical advantage, with the inclined slope. Just as a bolt or screw does with tightening power, when secured tight. Sure you can use the wedge on a Colt to set what you call cylinder gap but then you lose the friction generated by the wedge that holds it in place. Because as you stated you could tap the wedge still harder and close the gap to zero. Without the arbor and barrel having a solid contact the wedge never builds up the proper friction to hold it in place. With a proper fitting arbor and giving the wedge taps with a brass piece might give 20lbs force on the wedge driving in (as a guess) but amounts to about 100lbs force of pushing together or clamping together the 2 parts for a 5 degree wedge. Without this 100lb force the friction factor will be lessened, especially after firing, allowing the wedge to be less efficient in doing its job and staying in place. I realize it is done quite often, ignoring the properties of the simple machine, the wedge. But it is just a poor approach form a mechanical stand point not to understand a machine that was invented thousands of years ago. Simply put you cannot expect a wedge to hold correctly unless it is solid. Maybe take another look at it again.

Here is an example of a 5 degree wedge and forces.


A heavy safe is being pushed away from a wall with a wedge as shown below. Assume the wedge has an angle of 5 degrees, the coefficient of friction (static and kinetic) between the wedge and the safe is 0.16, and the coefficients of friction (static and kinetic) between the wedge and the wall and the safe and the floor are both 0.35. What is the pushing force required to move the safe out from the wall?

Solution

What is not in your example or equation is friction of wedge thickness fit to the top and bottom of the barrel slots as well as front to back, which you may remember I have brought up as important several times when describing how new tool steel wedges are made and fit. The wedges I make have not backed out and stay where they are fit to just fine with or without end fit of arbor. I don't have to keep pounding them in to stay tight and they have not shown any tendency to batter this far. Time will tell if they hold up but so far so good.
The Walker may prove to be an exception as I have not tried one of my wedges in one. The alloy used in the current wedge made is A-2 and when hardened and temper drawn are some where around 60 Rockwell which is nearly file hard. I would expect the barrel steel to yield before the wedge which may or may not prove to be a efficient working system.

 

[45D]

What is not in your example or equation is friction of wedge thickness fit to the top and bottom of the barrel slots as well as front to back, which you may remember I have brought up as important several times when describing how new tool steel wedges are made and fit. The wedges I make have not backed out and stay where they are fit to just fine with or without end fit of arbor. I don't have to keep pounding them in to stay tight and they have not shown any tendency to batter this far. Time will tell if they hold up but so far so good.
The Walker may prove to be an exception as I have not tried one of my wedges in one. The alloy used in the current wedge made is A-2 and when hardened and temper drawn are some where around 60 Rockwell which is nearly file hard. I would expect the barrel steel to yield before the wedge which may or may not prove to be a efficient working system.

Doesn't matter at all, all mine are factory wedges. That ought to save someone some time.

Mike

 

[45D]

I've got a Uberti Walker and finally got around to measuring the arbor end gap. My other guns I can rotate the barrel 90 degrees and compare match-up. But on this gun the arbor just wouldn't go down more than half way. This one took a shim .086" thick.

The opening of the arbor well is .520" so my first shim was that diameter. It fit only a short way down the bore. So I made a .515, then a .510, and finally a .505". I'm not crazy about that much taper in the arbor bore, but nothing I can do about it. I also don't care for the angled floor of the bore. I would have preferred the shim fitting the bottom completely, but as it is, it's just around the outer edge.

What do you do, Mike? The center of the bore is another .060" deeper. Do you make the shim fit exactly?

What do I do?
I never worry about "tests" to see if they're short, they are.
So, all horse pistols get a s.s. spacer made from the head of a #14 Pan head sheet metal screw. ( #12's for belts).

Put away the measuring sticks!!! When you drive the wedge in, the "thousandths" that you didn't figure in will show up. Just reduce the spacer thickness until you're close ( with the wedge driven in) and then "zero in" on your endshake spec. It's a 15 minute operation.

The arbors fit the bores pretty nicely which is why they can be rather accurate as is. Of course, charge used, bullet weight, no. of rounds fired will eventually take its toll.
With a correct length arbor, it won't matter ( especially with b.p.!).

Mike

 

[M. De Land]

Doesn't matter at all, all mine are factory wedges. That ought to save someone some time.

Mike

If you say so! I think it matters if the arbor end is short.

 

[45D]

If you say so! I think it matters if the arbor end is short.

Arbor is the backbone of the design, not the wedge.

 

[Rich44]

Trying to have the wedge tighten on both dimension's at the same time is not only hard to accomplish but also defeats the purpose of applying the pressure to hold the parts together as one piece. Which surface is really getting the pressure applied?

I fully realize some just do not get it.

 

[Pete453]

Mike, thanks, I'll look the video up.

44 is correct about wedges, they can generate tremendous forces. We use them at work for all kinds of things, they are a handy device for sure. Everything with threads on it is a wedge, and we all know what threads are capable of.

 

[Dude]

Mike - I'm sure you figured it out a long time ago that the Uberti Walker arbors are close to 0.10" short and about how much to remove from the #14 screw head. I just went through the whole measuring process to figure that all out. Ha ha ha.

When your screw head is too thick - how do you remove more material? When I was just making shims, if one was .010" too thick, I couldn't figure out a good way to reduce it - so just made a new one.

I'm guessing you position the rounded end of the screw head into the hole first - flat end butting the arbor. So you don't worry about filling the arbor well?

What do you do to secure the shim?

One last question about setting endshake. How will you set it once the arbor length is correct? I'd think endshake is controlled by the barrel/frame lug junction.

 

[Pete453]

Put away the measuring sticks!!! When you drive the wedge in, the "thousandths" that you didn't figure in will show up. Just reduce the spacer thickness until you're close ( with the wedge driven in) and then "zero in" on your endshake spec. It's a 15 minute operation.

Mike is telling it like it is. He's been very free with his techniques, and I can verify that they work as he says. I've done 4 spacers as he says, and it's quick. I spin the head on a cordless drill against a bench grinder and it works beautifully. It takes me 15 minutes, but with as many as he's done I'm betting he's even faster. And the beauty of the round head is that it's self centering, so no need to fuss about getting it perfect. Thanks again for all your help and advice, Mike.

 

[45D]

Mike is telling it like it is. He's been very free with his techniques, and I can verify that they work as he says. I've done 4 spacers as he says, and it's quick. I spin the head on a cordless drill against a bench grinder and it works beautifully. It takes me 15 minutes, but with as many as he's done I'm betting he's even faster. And the beauty of the round head is that it's self centering, so no need to fuss about getting it perfect. Thanks again for all your help and advice, Mike.

Pete453, thank you sir!! And, You're most welcome!

Mike - I'm sure you figured it out a long time ago that the Uberti Walker arbors are close to 0.10" short and about how much to remove from the #14 screw head. I just went through the whole measuring process to figure that all out. Ha ha ha.

When your screw head is too thick - how do you remove more material? When I was just making shims, if one was .010" too thick, I couldn't figure out a good way to reduce it - so just made a new one.

I'm guessing you position the rounded end of the screw head into the hole first - flat end butting the arbor. So you don't worry about filling the arbor well?

What do you do to secure the shim?

One last question about setting endshake. How will you set it once the arbor length is correct? I'd think endshake is controlled by the barrel/frame lug junction.

Dude, thanks for "running the numbers" for us!! Lol
The thing is, it takes longer to measure this or that just so you can take this much more off or that much more off . . . only to start over again!!!

I use a Philips head bit in a drill motor and hold the shaft side ( with shaft removed of course) against a bench belt sander ( yes. With the sander on). I'll sand some and check fit, sand more and check fit. When I get it thin enough for the barrel lug to touch or almost touch the frame, I'll drive the wedge in and see if it closed. If so, I'll check the endshake number and when that number gets to roughly .004" I'll start dressing the end of the arbor till I get my number ( .0025" - .003"). ( I dress the arbor end on a flat surface with 220 sand paper). MOUNT THE SPACER BEFORE DRESSING THE ARBOR.

As for mounting the spacer, I start a hole at the bottom of the arbor hole right where it transitions to the cone end of the drilled hole ( one on each side ( access through the wedge slot)). That gives the JB two places to flow into to help anchor the spacer in place should there ever be a failure under the spacer.

The procedure to install the spacer is to clean/degrease the arbor hole and rounded side of the spacer. Grease the arbor with Mobil1 ( of course) and enough on the end of the arbor to hold the spacer in place. Place spacer on the end of the arbor (flat side to the end of the arbor) and apply small amount of JB (mixed up of course!) to the spacer. Install the barrel assy and drive in the wedge as far as it will go. I use the 5 min. JB so 7-8 mins later I remove the wedge and barrel assy. Clean up arbor and arbor hole including any JB crumbs.

If you're going to install an adjustable wedge bearing you can do that before installing the spacer.

HINT!! - Dressing the arbor is the "easy" way to get to your clearance spec. BUT !!! the more you have to dress the arbor to get to your clearance spec, the more likely you'll need the adjustable wedge bearing. In other words. If you don't want the wedge bearing, you'll need to be more ACCURATE with the thickness of the spacer. Dressing the arbor makes the wedge slot larger overall.

Mike

 

[M. De Land]

Boy that was fast from Midway and it appears to be quite well made with good timing, fit and finish. I started on the pre-shoot tune up smoothing spring,wedge corners and notch in hammer so it won't tend to pull caps. The wedge fits well and from the file test on one corner feels quite hard.
I checked the end gap on the arbor with a caliper measurement of the well bottom corner and it appears to be right at .060 which I will make a spring stock plug for, to fill the gap, install and begin testing full power loads. I've read that is 55 grains of 3F when using a 1/8th felt grease wad.
The trigger is a bit heavy so will install a sear lift to lighten and make it more clean breaking.
The wedge angle is the same 5 degrees as the ones I make and the arbor slot is flat most of the way across hopefully matching up to the wedge angle flat. Lot of cross wedge contact area.
We'll see what the wedge does as far as backing out and or battering !
I still need to check alignment, cylinder mouth diameter and uniformity along with bore level and diameter using a machinist plug gauge. Enjoying the new gun already !
The loading lever spring seems quite stout but I'm going to make a lock for it if it pops loose under recoil like most do in the videos I've watched.

Trying to have the wedge tighten on both dimension's at the same time is not only hard to accomplish but also defeats the purpose of applying the pressure to hold the parts together as one piece. Which surface is really getting the pressure applied?

I fully realize some just do not get it.

The other reason wedge thickness is important is bullet induced barrel torque which puts most of the pressure on the lower lug pins with loose wedge fit. Snug wedge thickness fit in both barrel and arbor slots helps the lower lug pins support radial torque pressure as well as providing a friction load against backing out.
The photo shows a good wedge thickness fit up.
I did measure the cylinder throats last night with a plug gauge and they are a consistent .449. The land diameter (bore) is .438 and very level breech to muzzle.
I'm turning a precision plug tonight in the lathe once I get an accurate compressed end fit thickness, figured out. I also got the sear lift made and installed in the hammer last night ready to be stone to final fit.
I think the only thing left after the plug is made and fit is to de-grease, re-lube and reassemble.
Oh, I do need to either make a cerosafe cast or drive a slug through the barrel to get the groove diameter for my records.

 

[SDSmlf]

The I did measure the cylinder throats last night with a plug gauge and they are a consistent .449. The land diameter (bore) is .438 and very level breech to muzzle.
I'm turning a precision plug tonight in the lathe once I get an accurate compressed end fit thickness, figured out. I also got the sear lift made and installed in the hammer last night ready to be stone to final fit.
I think the only thing left after the plug is made and fit is to de-grease, re-lube and reassemble.
Oh, I do need to either make a cerosafe cast or drive a slug through the barrel to get the groove diameter for my records.

Curious as to what you measure. The last Uberti 45 caliber bores I measured had bore diameters around .438” with groove diameters running around .458” (rifling was about .0095” deep) and their cylinder chambers .4495”/.4500” diameter. A lot of windage in their bores between cylinder and groove diameter if you are looking for accuracy, at least what I found. Probably too much detail to discuss until we can chase down arbor length and wedge fit one more time.

 

[45D]

I also got the sear lift made and installed in the hammer last night ready to be stone to final fit.

I'm not sure what a "sear lift" is? Could you explain?

Mike

 

[M. De Land]

The other reason wedge thickness is important is bullet induced barrel torque which puts most of the pressure on the lower lug pins with loose wedge fit. Snug wedge thickness fit in both barrel and arbor slots helps the lower lug pins support radial torque pressure as well as providing a friction load against backing out.
The photo shows a good wedge thickness fit up.
I did measure the cylinder throats last night with a plug gauge and they are a consistent .449. The land diameter (bore) is .438 and very level breech to muzzle.
I'm turning a precision plug tonight in the lathe once I get an accurate compressed end fit thickness, figured out. I also got the sear lift made and installed in the hammer last night ready to be stone to final fit.
I think the only thing left after the plug is made and fit is to de-grease, re-lube and reassemble.
Oh, I do need to either make a cerosafe cast or drive a slug through the barrel to get the groove diameter for my records.

Well I think she's as ready as she's ever going to be for 55 grain charges of 3F , a grease wad and ball.
The sear lift yielded a 1.5 pound trigger pull with no discernible creep.
The plug wound up and amazing .092 thick to produce a solid .0025 barrel cylinder gap.
I've always read this is way to tight for black powder but we'll see what happens.
The seven groove left hand twist barrel has a groove diameter of .4532 and bore of .438 so that yields a groove depth of a bit over .0075.
The chamber mouths are .449 and the groove is at .4532 so am curious how accuracy will turn out. May be just fine with ball shooting, its bullets that prefer to be at groove diameter generally.
The alignment is about as good as I've ever seen in a revolver as the .437 plug gauge would inter each chamber mouth by tipping the barrel upward.
Turns out the arbor is tapered from the end of the cylinder to the end of the arbor. It mic's .528 at cylinder and .499 diameter at arbor end. The portion of the arbor under the cylinder bore is level and even at both ends at .520.
Here is a couple of shots of the pre-fit sear lift and final fit plug I lathe turned ,draw filed and diamond honed to proper thickness. It mic's a very uniform .0915 to .092 depending on mic used. It's tool steel left annealed.
The hole is for hook retrieval if it gets stuck in with grease or bullet lube.

 

[M. De Land]

Arbor is the backbone of the design, not the wedge.

I agree but the wedge connects the arbor to the barrel and sacrefices itself to make it work.

 

[45D]

I agree but the wedge connects the arbor to the barrel and sacrefices itself to makes it work.

Wonder why mine and my customers wedges don't? It's a mystery . . .


Round and round and round . . .

Mike

 

[Rich44]

The other reason wedge thickness is important is bullet induced barrel torque which puts most of the pressure on the lower lug pins with loose wedge fit. Snug wedge thickness fit in both barrel and arbor slots helps the lower lug pins support radial torque pressure as well as providing a friction load against backing out.

This is exactly where you are making poor judgment. In this application of barrel retention on an open top Colt, Samuel had it correct.
Arbor, barrel, and barrel location foot against frame must make solid contact. All at the same time. For the wedge to hold properly it only needs pressure applying front and back. Defiantly not top to bottom which is counterproductive to the holding power of the wedge. If you feel you need to fit the wedge tight top to bottom to get it to hold, you are actually robbing the holding power of wedge from front to back which is the proper force. Your statement of " Snug wedge thickness fit in both barrel and arbor slots helps the lower lug pins support radial torque pressure as well as providing a friction load against backing out." Are you trying to kid me, do you have any idea of the shear strength of those 2 locating pins that are off center line of the bore? Please. Proper metal to metal contact/fitting and with a wedge that builds pressure and actually compresses the parts together with proper friction is all that is required.

 

[45D]

This is exactly where you are making poor judgment. In this application of barrel retention on an open top Colt, Samuel had it correct.
Arbor, barrel, and barrel location foot against frame must make solid contact. All at the same time. For the wedge to hold properly it only needs pressure applying front and back. Defiantly not top to bottom which is counterproductive to the holding power of the wedge. If you feel you need to fit the wedge tight top to bottom to get it to hold, you are actually robbing the holding power of wedge from front to back which is the proper force. Your statement of " Snug wedge thickness fit in both barrel and arbor slots helps the lower lug pins support radial torque pressure as well as providing a friction load against backing out." Are you trying to kid me, do you have any idea of the shear strength of those 2 locating pins that are off center line of the bore? Please. Proper metal to metal contact/fitting and with a wedge that builds pressure and actually compresses the parts together with proper friction is all that is required.

By George, I think you got it !!!!

Mike