Pentagonal cylinder?

[r010159]

I have a peculiar problem with my Baby Dragoon that was made in 1847. This has a very early SN of 171. I am finding out that the cylinder is not perfectly round. It is somewhat pentagonal and has developed scuff marks on the cylinder where, as it turns, it meets the frame of the pistol.

Is this to be expected from an early version of the Baby Dragoon? The arbor does not evem have grooves, which I find is to be expected at this serial number.

Bob

[4V50 Gary]

Doesn't sound right that it's pentagonal. Turning an ojbect round on a lathe should be easy. However, if it's original, leave it (and don't use it).

[T. O'Heir]

Pentagonal means 5 sided. Your's may just be distorted cylinders from some twit over loading it. A dial indicator and a lathe will tell you one way or the other.
In any case, I wouldn't be shooting a 169 year old revolver anyway. Even modern BP is different than BP from then.

[Driftwood Johnson]

Howdy

Sounds like bulged chambers. The cylinder should not be contacting the frame as it rotates. There should be clearance. You can bet it was round when it left the factory.

[Smokin'Joe]

The 1862 Colt Pocket Police has a cylinder that is roughly pentagon shaped. It's a .36 cal. handgun and the cylinder would scrape the frame of the .31 cal. 1847 Baby Dragoon if improperly installed on it. Photos would help.

[r010159]

So either some idiot turned the cylinder on the lathe, or the chambers are buldging, due to too high loads of gun powder? It is original. The cylinder stamps unique to the Baby Dragoon validate this.

I will provide better plotos. Right now I will measure it with a caliper to see if the diameter remains the same. Please check back, for I will add this new inormation as an update to this post.

Bob

[4V50 Gary]

Something turned on a lathe is round or tapered.

Now, if the workpiece started out pentagonal and was turned, it would yield the curve and flats if the workpiece was not turned all the way down to cylindrical.

[jspappap]

I spent over 50 years as an aerospace machinist and the pentagonal or tri-lobal out of roundness you described has happened to me many times. Specifically on parts with varying wall thickness. I have attached a link describing this phenomenon caused while grinding. Hope this helps.
http://www.google.com/url?sa=t&rct=j...oye-Xyvj45DDtg

[r010159]

@jspap: interesting information that you have given me there.

I measured different diameters of the cylinder at different places. The variance of its diameter is at most within four thousanths of an inch, and most of the time less, at each position around the cylinder. The variability can be explained in part by my placement of the caliper. I took multiple measurements and took the smallest value. The longitudinal aberrations do go completely across the cylinder. So I then placed the end of the cylinder flat on the table, and measured that way, with the caliper also flat on the table. There the measurements were within about one thousandths on an inch.

Is this within an appropriate tolerance? I can understand trilobal physical characteristics that would maintain a specific diameter, but pentalobal? I will continue to take measurements to see if there still will be agreement with my findings. It will be interesting to see what the dimension is between the cylinder wall and the wall of each chamber...

...interesting. There is the most variability in this measurement. I also can see the difference. The measurements can vary as much as approximately eight to ten thousandths of an inch.

Bob

Update: Above variability is up to six thousands, not ten.

[4V50 Gary]

Interesting indeed, but weren't grinders like that not available in the 19th Century? That used to be a hot topic at Colonial Williamsburg. First, was that technology available and did they avail themselves to it? BTW, at school I raised the subject of progressive depth rifling and how the accomplished it.

How about some pics of the original cylinder?

[4V50 Gary]

Saw an original one today at the 45th Infantry Museum (Thunderbirds) in Oklahoma City, OK. It does appear to be pentagonal but it was turned on a lathe and then recesses between the cylinders were machined on a milling machine. I would have used one large mill bit to cut the flats (and then a round one for the recesses). Then again, if you're good at grinding bits, you could try to make one bit that does both in one operation.

The Thunderbirds also have an original Walker displayed, many firearms from our history including the earliest flintlocks made by our aresnals (no glasses so I couldn't see if it was Harper's Ferry or Springfield Armory), a Confederate Whitworth, Mosby's cannon that was captured from him, various percussion arms including an 1855 Springfield with Maynard Tape Primer (and tape), Confederate Morse Carbine with a brass cartridge, a Colt Root revolving rifle, early conversions to breechloaders, 03A4, M-1Ds, Hitlery's cape (its owner used to wear it and play Batman until his father stopped him), Hitler's silverware and table setting stuff (looted by members of the 45th while on their European Tour), original Bill Mauldin cartoons, and all sorts of neat militaria.

It is a must see museum in you're in Oklahoma City.

[r010159]

Here are two photos that may visually show the variance between the chamber wall and the cylinder. Look at the top most chamber in each photo. The apparent differences in chamber sizes is a visual distortion. At first look, it seems that the circle of chambers is offset from the center of the cylinder.

Any thoughts? Were the first examples of the Baby Dragoon, also the first of all the Pocket series, crudely formed, and then hand fitted, until the manufacturing process was refined?

[4V50 Gary]

The cylinders started out as round stock. After the chambers are bored (or perhaps before they were bored), the workpiece is placed into a rotary head and a mill bit is used create the "flats" on the cylinder. You cut a flat, back off the mill, rotate the cylinder so the next part of the flat may be generated. Think of it as putting flats on a round barrel so as to make an octagonal barrel. Same process but the machinist lower the bit (or raise the mill's knee) high enough to generate flats with sharp edges. After the "flats" are cut, then a ball mill is used to cut the cylinder flutes.

BTW, what are we doing with a AR parts drawing in the background?

[4V50 Gary]

In hindisght, I think the Colt Root Rifle had a similar cylinder. The purpose would be to lighten the firearm (without compromising its intergrity).

[r010159]

Very interesting indeed! Good infrmation in the previous post. So I can see three possabilities now. One is that the cylinder was made to be pentagonal. The second is the pentagonal shape is a "deformity" that was due to the drilling of the chambers into the cylinder. I have been told that this can happen. The third is the original owner used too much gun powder for the charge in all of the chambers.

Any additional thoughts? I am thinking that this pentagonal form has something to do with how it was manufactured than what was caused through mistreatement. But this is JMHO. Whatever is the reason, the cylinder scene remains intact except for thise scuff marks. So why these scuff marks? The cylinder not being installed on its spindle correctly?

BTW I use that mat to take apart and maintain all my firearms, while watching TV in the background. I have not found one for a Colt percussion pistol yet.

[Captchee]

Good morning .
I have been following this thread with interest as revolvers simple are not my area of expertise .
I feel however a couple points maybe of value .
First , grinders have been used for hundreds of years . Basically the only real thing that’s changed is the application of electricity allowing for the advent of smaller hand held grinders like we have today .
I would also raise the same point about the Lathe and mills.
The only real question IMO is did Colt use either and if so , when did he start .
We do know that even some 30-40 years after the date of this pistol , the US arsenals and at least one major US manufacture was still using 100 year old technology for boring . IMO it would be very unlikely that colt would not have been doing the same
This is not to say they were not using mills lathes or grinding apparatus’s of some type .

To me this begs the question as to if the cylinder in question was turned or drawn ?
If the possibility exists that it was drawn to shape , it would be polygonal .
Octagon barrels don’t start out round. Well let me clarify and say that originally they didn’t untell barrel began being mass produced from milled stock.
A forged barrel or forged bar stock is not truly round and unless a lathe is used its very time consuming to make such a barrel truly round .
Octagon barrels were far simpler and quicker to produce when using the above materials , by means of either the hammer during the forging of the stock then finished with the file or shaped with a draw file and jig .
If the later was the case with earlier colt production , then the cylinder stock would have been drilled , then shaped , then ground or turned .
This would have left the reminisce of the original draw filing to the polygon shape of the bar stock that would eventually be made into the cylinder

[r010159]

Let me see if I understand you correctly here:

Good morning .
I have been following this thread with interest as revolvers simple are not my area of expertise .
I feel however a couple points maybe of value .
First , grinders have been used for hundreds of years . Basically the only real thing that’s changed is the application of electricity allowing for the advent of smaller hand held grinders like we have today .

OK So Colt was using grinders for the cylinder stock, correct?

[snip]

To me this begs the question as to if the cylinder in question was turned or drawn ?
If the possibility exists that it was drawn to shape , it would be polygonal .
Octagon barrels don’t start out round. Well let me clarify and say that originally they didn’t untell barrel began being mass produced from milled stock.
A forged barrel or forged bar stock is not truly round and unless a lathe is used its very time consuming to make such a barrel truly round .

So metal was originally forged before a lathe was used? When a grinder is used, do you have the same problem? Getting the metal round instead of polygonal? So the question does come down to when a lathe was used by Colt?

Octagon barrels were far simpler and quicker to produce when using the above materials , by means of either the hammer during the forging of the stock then finished with the file or shaped with a draw file and jig .

What is the difference between a draw file and a grinder? What is a draw file?

If the later was the case with earlier colt production , then the cylinder stock would have been drilled , then shaped , then ground or turned .
This would have left the reminisce of the original draw filing to the polygon shape of the bar stock that would eventually be made into the cylinder

I see. So the effect of the draw file is that it forms the surface of the stock to a polygonal shape. Correct? And then the grinder would make it more round. This would not be perfect and leave a subtle polygonal shape to the cylinder. This makes sense since hamner forging IMHO would of been impractical in a manufacturing environment. Also the cylinder of my Baby Dragoon seems to support this method being used. As a side note, I imagine there would be a tradeoff to allowing the grinder to spend more time to make a more precise round shape.

So then the next question is when was a lathe employed by Colt in the fabrication of the cylinder? I wonder if the lathe was used by the time the 1849 Pockets were manufactured?

Bob

UPDATE:

Here is some very interesting information from a Wikipedia article on Rollin White. This supports my musing on that the lathe may have been used by the 1849 Pocket.

https://en.m.wikipedia.org/wiki/Rollin_White

"In 1849 he went to work for Colt's Patent Firearms Manufacturing Company as a gunsmith under contract, turning revolver barrels on a lathe."

Interesting, eh? So why not for cylinders? I do know Wikipedia articles are not entirely reliable.

Bob

[Captchee]

OK So Colt was using grinders for the cylinder stock, correct?

What colt used in that time frame I don’t know .

What is the difference between a draw file and a grinder? What is a draw file?

Draw filing is the process of using a file and sometimes a jig so as to take a barrel bank from forged rough to either octagon or round . The file is pulled along the barrel as in using a draw knife .
the blank would be put in a channel vise and one flat filed on it .
Its then rolled and a flat drawn on the other side . This is repeated until you 8 sides or an octagon barrel . To make that barrel round . You then start drawing down each of the points . The result is that each time the barrel flats get smaller and you get a more round object . This would produce your polygon which depending on the beginning dimensions of the cylinder , might not be completely removed during lathe work . If lathe work was used .
Surly at some time Colt went to using lathe production but I doubt it would have been done early on.
Grinders that I have seen were simple stone wheel grinders much like we have today . Some spun vertically , others horizontally .
Bar stock would be forged then left in hammered state for the end user OR trued depending on the product , by running it through roller mills/ presses and or grinders

I see. So the effect of the draw file is that it forms the surface of the stock to a polygonal shape. Correct? And then the grinder would make it more round. This would not be perfect and leave a subtle polygonal shape to the cylinder. This makes sense since hamner forging IMHO would of been impractical in a manufacturing environment. Also the cylinder of my Baby Dragoon seems to support this method being used. As a side note, I imagine there would be a tradeoff to allowing the grinder to spend more time to make a more precise round shape.

all bar stock would have been hammer forged . in the small shop it would have been by blacksmith work . in large scale manufacturing like at Liege , large mechanical hammers were employed .
today our barr stock is made by eather drawing or exstruding from the fernace . its then ran through roller mills to make the nice round , true barstock

If one reads up on firearms manufacturing in this country , it is very quickly noted that even our Arsenals were using technology that was 100 to 150 years old .
While we had the best Iron in the world , we couldn’t make steel for crap .
When we did learn the process of steel manufacturing which we got from the English , we couldnt make proper barrels from it . that’s why complete barrel manufacturing companies were purchased and moved to the US. Again those companies were in England

Again in not saying this was how your cylinder was done . Simply put I don’t know .
But it was the common way of making barrels in this country tell the mass importation of barrels and barrel blanks began to flood the market in the 2nd half of the 19th century .
I seemed to recall reading of Colt having to admit the use of imported barrels and barrel stock during congressional hearings

[Hawg]

I don't know how Colt made their barrels and cylinders but they use wrought iron for everything prior to the 1860 army. After 1860 they still used wrought iron for the frames until the 1880's.

[r010159]

What did they use for the barrel and cylinder with the 1860 Army and later?

Bob

[4V50 Gary]

We should pose the question to the experts at:

Springfield Armory National Historic Site or Harper's Ferry NPS.

[Hawg]

What did they use for the barrel and cylinder with the 1860 Army and later?

Colt called it silver steel but that was just marketing hype, it was actually Bessemer steel bought from Thomas Firth & Sons in Sheffield, England.

[4V50 Gary]

on barrel making.

Early barrels were either folded over a mandrel along the length of the barrel and then rounded OR several pieces of equal length iron were wrapped in helical fashion over the mandrel until the length was made. The barrel was then bored and then grounded. Turning it concentric on a lathe made grinding the flats easier later.

Forging dies allowed for forging of flats and depends how well it is executed by the craftsmen involved. This would simplify the barrel making process.

Making a barrel from a solid, octagon (or round) bar stock is possible but boring it concentric isn't. The bore can be off but this can be easily fixed when the barrel is turned round on a lathe. We see this even when modern barrels are made. Of couse, once the barrel is shortened and then turned on a lathe, it is concentric. It then has to be milled for flats. I did this with the half-round barrel, flintlock style 10/22 I made.

Returning to the cylinder. It's round when see from the top (chamber end).

[r010159]

@4V50 Gary: Can questions be asked online to those two orginizations?

@Hawg: So Colt did use steel before the 1880s, correct? However, I do not think they used steel for all parts of the firearm, correct? Is there a book that has this information?

OK now, at this point, I want to restate my original question. There are scuff marks occuring at the same location after each cylinder stop, forming a pentagonal pattern. So what is causing these scuff marks? This is why I think the cylinder wall is slightly deformed into a pentagonal shape.

What do you think has caused the pentagonal form of my cylinder on the Baby Dragoon? Either it is a natural outcome of the manufacturing process, or a mistake was made during its manufacture. Perhaps when the chambers were drilled? What can I measure to determine which one? How about a method to just determine what is creating these longitudinal scuff marks? If the chambers were drilled into metal stock before it was formed into a cylinder, then it may be due to the manufacturing process. Otherwise, perhaps something went wrong when the chambers were drilled? After all, the cylinder does have five chambers. That may not be a coincidence. Perhaps something else?

Here is a mediocre photo of the problem. Do you see the marks across the cylinder before each chamber? Fortunately, these marks have not defaced the cylinder scene under magnification. I have a coating of grease on the pistol.



FWIW This has been the most enlightening discussion I have had here. BTW I just purchased the book "Fighting Iron: A Metals Handbook for Arms Collectors" by Art Gogan. This should give me the metallurgical side of the picture.

Bob

[4V50 Gary]

Contact them through their respective National Park Sites. The National Park is more than Jellystone, Ranger Rick, Yogi & Booboo. Rangers do their best to answer questions relevant to their park site.

BTW, that cylinder does look round with partial flats. As to the cylinder notches not being concentric, that is normal wear from the bolt striking it and peening the material that way.