Scuff marks on cylinder of Baby Dragoon, part Deux

[r010159]

I have been having problems with my cylinder on an authentic 1848 Baby Dragoon that was made in 1847. Longitudinal scuff marks have been showing up, one before the location of each chamber. I do think this implies an irregular shape to the cylinder. So please bear with me here.

I, along with others, have given this allot of thought. The possibilities went from metalurgy to forming methods to just happenstance of scuff marks showing up in those places due to its contact with something that it has been repeatedly set on. I have come up with an explaination that I want those here to consider.

I have found the metal used for the cylinder to be very malleable. I think the scuff marks have been showing up with its contact on surfaces like a table top when it rolled right across it. The question is why the pentagonal geometry of the scuff marks. In other words, given this strongly implied irregular shape, what has given it the cylinder its pentagonal shape. We are not talking about anything obvious here, just something very subtle.

Here is what I think. I suspect the chambers were first drilled into a milled or ground round bar stock. The metal is compressible, so this could very well of distorted the metal just a bit. If drilled before its final forming, the grinder or lathe did not entirely remove its irregular shape. If drilled afterwards, then what I am seeing is the direct result of that. After all, the chambers are drilled very close to the cylinder wall.

Since a 1849 Pocket I have does not have this problem, something had changed. I believe it was the grade of the iron. For example, as documented in the book "Fighting Iron" by Art Dobson, crucible steel was used for later 1849 Pockets and the 1851 Navy. Furthermore, Colts silver spring steel, an improvement, was used by the manufacture of the 1860 Army. In addition to this, the malleability of the wrought iron that was originally used could vary from batch to batch. BTW the quality of wrought iron reached a peak that by todays standards is considered low carbon steel.

So what do you guys think? Does this make sense to you?

Bob

 

[4v50 Gary]

There is no way boring or drilling a hole into a workpiece affects the exterior such that the exterior consistently forms a pentagonal shape. To make it pentagonal is an entirely seperate machine operation.

First, reread that paper. That paper discusses elliptical holes which were supposed to be concentric. Worning bearings can cause this on the inside where the hole is, but not on the exterior surface.

Suggest you go talk to some machinists and ask them how they would machine it.

 

[rcmodel]

Could you post some photos?

I'm having a real hard time understanding what you are talking about.

rc

 

[Old Fuff]

Me also... But I'm thinking the marks on the cylinder are around the circumference, and not lengthwise.

I'm also wondering about the possibility of an misaligned cylinder arbor/pin.

But I'm open to correction.

 

[beag_nut]

Plus, whatever you describe, and its possible cause, what will you do about it? Can't send it back to the factory! Machine a new cylinder? Just sit and think about it?

 

[r010159]

Well, I have exhausted all my theories and gained as much input as I can. I understand what you are saying, 4v50 Gary. I will reread that paper. Some have said it is how I laid the pistol down on an abrasive surface. However, it has been laid down only on glass and a rubber pistol cleaning mat with the cylinder in a *locked* position. Also the much lighter secondary longitudinal scuff marks show up between the pentagonal scuff marks also in a geometrical pattern. Sum total of an odd number of lobes.

Down below is a photo of what I am talking about. Please note the two gray lines going lengthwise across the cylinder. They occur right before each cutout for the nipple. The shiny surface is due to grease used as a preservative. The misaligned arbor sounds interesting to me. What is interesting is that the cylinder is loose. IMHO I would think that this would ensure contact with the frame. Perhaps tightening up the arbor will minimize this problem?

@4v50 Gary: I have one word for the article: Bingo! I have not read the article through until now. For those interested: http://www.gagesite.com/documents/Metrology Toolbox/Geometry.PDF A centerless grinder was involved. Then the chambers must of been drilled, which explains more of what I see. Lathes for cylinders must of come later. This may have explained the mystery.

 

[4v50 Gary]

Remember what I said about technology being available and technology being used at TFL? Grinding has been around for a long time (see Gunsmiths of Colonial Williamsburg video for free on YouTube), but centerless Grinders as a production equipment was not available to Colt when the Small Dragoon was made. https://en.wikipedia.org/wiki/Cylindrical_grinder

As for lathes for cylinders being later, c'mon. Lathes were available long before centerless grinding.

 

[r010159]

According to the article, centerless grinder can produce this result. I would think grinders are a simple technology. But maybe not true. So could of technology during the earlier 1800s have created this problem? Multilobal out of roundness? Your answer to me implies a lathe. I can see this happening with a grinder, but a lathe? I guess so. My ignorance of machining can take up volumes. LOL

Bob

 

[rcmodel]

Color me blind.

But I still can't see what you are talking about.

Other then some camera glare off the shiny spots, I can't see anything out of the ordinary.

rc

 

[Old Fuff]

I think I see what he's talking about, but I'll need some time to understand what it is, or if it is anything outside of normal wear & tear.

 

[r010159]

Thank you!

Bob

 

[beag_nut]

According to the article, centerless grinder can produce this result. I would think grinders are a simple technology. But maybe not true. So could of technology during the earlier 1800s have created this problem? Multilobal out of roundness? Your answer to me implies a lathe. I can see this happening with a grinder, but a lathe? I guess so. My ignorance of machining can take up volumes. LOL

Bob

Ceneterless grinders were not available when that pistol was made. So that hypothesis is irrelevant.
Much more likely: holster wear or bad storage.

 

[r010159]

I have ordered a dial indicator and its stand. There being a variance in the chamber walls with the cylinder wall tells me more is involved, but that may not have anything to do with the scuff marks. The scuff marks are recent. The pentagonal nature tells me it is not holster wear. Each is in same location just before the cutout for each nipple. Either it is how I had laid the pistol down on the table, or there is some characteristic of the cylinder that is causing this. I have only laid down the pistol on glass and a rubber pistol cleaning mat. The cylinder has always been in a locked position when I have laid it down. So I do not think there is anything there that could of caused this, particularly over a very short period of time. The cylinder is loose. That may have something to do with it.

I think the dial indicator is the next step. This will also determine if any part of the cylinder has been flattened. It is on sale at Brownells. However, I do not know how to test for any odd lobal characteristics of the cylinder. Now if only a grinder is able to create this problem, then this must be not the problem. As some posters have mentioned here, grinders were not available back then.

Bob

Additional note: Measuring the diameter may always show the same reading. But instead, if I move the dial indicator offset from the diameter, thereby measuring a mathematical chord of the cylinder, this may tell me what I need to know. If the measurement is consistent there through the circumference, then the cylinder is round. This will eliminate almost all of my current ideas. I suspect this will be the case.

 

[r010159]

Here is an update.

I first placed a paper wedge between the cylinder and the frame, just enough for the paper to move in and out freely. Then I slowly turned the cylinder to find there are points where the paper wedge moves with some resistance. So this verified that the cylinder is rubbing against the frame.

I can now see where on the frame this is happening, right next to the slot for the cylinder stop bolt. This is not good. Also the arbor is a bit loose. I think this is part of the problem. Furthermore, the cylinder is definitely not perfectly round. However, I see only about up to two to three thousandths of an inch variance, the best that I can tell. But considering that the overall cylinder to frame clearance is quite small, this may all be that is necessary for the scuff marks to happen. The clearance may be even less there.

I find it difficult to believe that too little clearance was a design flaw. So I will see if I can tighten the arbor, but how to do this? I do not see where I can do this.

Bob

 

[Old Fuff]

I can tell you what has to be done, but recommend that you don't do it.

Cock the hammer and you can see the back of the arbor. At about 12:00 is a small pin on the outer circumference of the arbor. This pin is in a blind hole and must likely be drilled out. Then the arbor can be unscrewed and removed from the frame.

Then the threads on the arbor and in the frame can be cleaned. Apply a thread sealant to the arbor threads and screw it into the frame. Wrap some masking tape on the cylinder just enough to insure when it rotates it won't rub on the frame. Reassemble the cylinder and barrel, and wait for the sealant on the arbor to set. then replace the small pin that was previously drilled out with a new one. Be careful to insure that no sealant gets on the arbor where the cylinder is, or into the frame's hand slot.

Now, consider that what you have is a valuable historical relic. Hopefully you have no intention of shooting it, and revolving the cylinder should be held to an absolute minimum. I would recommend a gunsmith who specialized in refurbishing antiques such as the one you have, but unfortunately he has passed away.

I suggest that you sit down and consider what the consequences might be if a mistake occurred during an attempt at fixing the problem went seriously south.

 

[Jim K]

^^^^^^^^^^^^^^^^^^^^^^^^

Destroying the gun in order to fix a problem that doesn't bother anyone but you would not be a really great idea.

Jim

 

[r010159]

I agree gents! Hands off on this one.

I wonder how much the not perfectly round cylinder played a role in this? I also wonder how much of its value dropped due to my woeful ignorance?

@Old Fluff: Thanks for the description. Any alteration would dramatically decline its value. I would never shoot such a piece of history. That would be senseless.

@Jim K: I would never think of doing such a thing. I agree with you. Besides, I have spent much too much money on this to risk it.

Bob

 

[Old Fuff]

Keep in mind that what you have is one of Colt's earliest revolvers. He, and an engineer named E.K. Root designed a lot of the machinery used to manufacture revolvers from scratch after Colt moved into a new factory in 1848.

So it should be understandable that the better precision that came later, not to mention what is available today, is not always reflected in what was made during the late 1840's and early 1850's.

Add to this the additional wear and tear it went through during it's lifetime to present, and ask yourself, "If it could talk what stories would it tell?"

If you want a perfect gun with no stories to tell, buy a replica.