Marlin 1873 Hand Fabrication

[Johnm1]

In the thread "Drilling HSS" 1 I referenced that I was fabricating a new hand for the Marlin 1873 revolver. Here is a short clip of the issue:

New video by John M

photos.app.goo.gl

This occurs on every cylinder in exactly the same position. So I have ruled out the ratchet teeth as the cause of the problem. I have manipulated the hand manually and it just appears short. So this weekend I began fabricating a new replacement. I've abandoned using high speed Steel at the suggestion of another forum member. That suggestion was that the hand should probably be softer than the ratchet teeth. And I tend to agree.

I managed to post my photos with two different devices and the accounts aren't linked. I'm going to continue in the next post from my phone where the next set of pictures reside. These will entail the steps in the fabrication process.

 

[Col. Harrumph]

Keep the pics coming! A word of warning though: if you make it work you're going to become a THR resource.

 

[Johnm1]

I started with a donor piece of square tube steel from Ace Hardware. It was the correct thickness and its only description was it was weldable. It isn't very hard as a standard drill bit drilled through it with little resistance. It was covered jn masking tape and the outline of the existing part was traced on it and the hole for the pivot pin was marked.




A dremel cutting wheel took off the lions share of the excess material and a diamond dremel it took off the last of the material.




It’s very long and even though it visually matches the original part it is ever so slightly oversized in all dimensions. I have since fitted the pivot pin into the hole into the piece.

Tonight’s work will be to remove it from the holding piece and shape that area.

 

[Johnm1]

Keep the pics coming! A word of warning though: if you make it work you're going to become a THR resource.

Oh, I’ll make it work. The question is if I’m going to be able to make this version of the replacement part work or if I’m going to make a mistake (or two or ten) fitting the part and have to remake this part.

It could be fixed tonight if I get lucky or it could take me weeks.

 

[Johnm1]

Here’s the puzzle. I have no idea about what the geometry of the fit between the hand and the ratchet teeth looks like. It is totally hidden inside the revolver. I have the old hand that I can look at but we know it is short. So what did the missing top of the hand look like? Angled to the left, to the right, or did it come to a point? If it came to a point was the point symmetrical or was one side of the point shorter than the other? Was the short side on the left or right? All I’m going to be able to do, with the cylinder in one hand and the hand in the other, place the hand at what I think the angle is and try to imagine what the top of the hand should look like to engage the ratchet teeth. And doe that change as the cylinder rotates?

Any thoughts other than to go slow?

 

[rabid wombat]

You may be able to get ideas here: https://marlin-collectors.com/forum/

Separately, you are doing great stuff! Fun to watch. I wish I was as talented.

 

[SC45-70]

You may want to make the part from O1 drill rod. It will be soft in it's raw state so it can be easily drilled and shaped, but once hardened will be plenty hard.

 

[Johnm1]

Separately, you are doing great stuff! Fun to watch. I wish I was as talented.

I wish I was talanted too. I'm just a hack parts swapper who doesn't know what I don't know.

You may want to make the part from O1 drill rod. It will be soft in it's raw state so it can be easily drilled and shaped, but once hardened will be plenty hard.

I'm hoping this piece will be hard enough. In reality the only force the hand should see is the weight of the cylinder. If it fails I'll move on to a harder material.

 

[rabid wombat]

I'm hoping this piece will be hard enough. In reality the only force the hand should see is the weight of the cylinder. If it fails I'll move on to a harder material.

Make sure to get good images / dimensions on the one that works… if you have to remake it…

As @Col. Harrumph says “you will become a resource”

 

[Johnm1]

Hmmmm......

The new hand does rotate the cylinder farther but not into battery. The problem is to get the hand in the gun while on its pivot pin. The circular hole and the retaining lip for the round sideplate limit how big the hand can be. By the time I got the new hand short enough to get it into the gun it was only slightly bigger/taller than the original.

So, on to remake number 1. I did learn a lot imn the operation.

 

[Col. Harrumph]

The makers must have had a way. Perhaps slide it down in front of the cocked hammer?

 

[Johnm1]

There was a spot where a hand of the correct length would fit. I just didn’t find it when I was fitting it into the revolver.

I was hoping I could slip it in from the front of the recoil shield, and then place it over the pivot pan. But there is not enough room/wiggle to do that. It would be nice to be able to place the hand in its proper position, and then place it over the pivot pin. But there is not enough room to do that. I’m gonna have to find the spot/position where a longer hand can fit in.

 

[Johnm1]

In my first attempt I used the original pin. It has a step in it to mount the hand on and the step aligns the hand with the slot in the recoil shield. For the next attempt I’ll make a smaller pin without the step in it so I can drive the pin through the hand once the hand is inside the frame. Once the hand is fitted I may be able to open up the hole in the hand to fit the original pin.

 

[Johnm1]

Well, the second attempt was an abject failure. The only positive was it only took about an hour to rough out the part. I still have not figured out how to make it longer and still fit inside the frame. I have to believe there is more geometry to this then just making it longer. On the negative side the circular hand spring decided to launch itself. It is somewhere on the floor behind the bench.

 

[Johnm1]

I’m back in business. I found the spring that launched itself across the room. The geometry of this hand still has me perplexed. I’ve roughed out and partially finished a third hand. I am fitting from the top down. Meaning, I’m trying to fit the hand so that it reaches battery before figuring out the final fit. I have accomplished that. But the hand is too long to fit in the gun and it’s too tall to pick up the ratchet tooth on the bottom side. After the gun has been fired, and the ratchet returns to its lower position. That might be a function of hand spring pressure. But I haven’t finished fitting the hand yet.

I have inspected the ratchet teeth, and they all seem very consistent. I don’t see any signs of wear on the ratchet teeth, but I have no idea what they actually should look like.

 

[JohnKSa]

Here's an auction of an 1873. If you scroll through the pictures, there's one showing the ratchet.

Lot - Marlin XX Standard 1873 .22 cal. spur trigger revolver

www.oldbarn.com

Another one.

Nouvelle page 0

And another one.

Lot - ANTIQUE MARLIN XX STANDARD 1873 .22 RIMFIRE 3RD VARIATION REVOLVER WITH HARD RUBBER STAR GRIPS

www.bradfordsauction.com

 

[Johnm1]

New video by John M

photos.app.goo.gl

I'm not sure I can explain well enough what I had to do to make this work. The thought process of just fitting it so that the cylinder reached battery appears to be the correct approach. Of course, the hand would not fit in the gun normally while it was too long. So I used a temporary pin that I could install after the hand was in place in order to make the fit. My two previous attempts I tried to trim the hand until it fit into the gun and then tried to fit it so the cylinder would come to battery. Apparently, it has as much to do with the shape of the hand as it does with the length of the hand.

By fitting it the way I did and just getting it to go into battery first the length to fit into the gun was set as well as the hand being able to pick up the correct ratchet tooth in the at rest position.

At some point I think I will attempt to make another one out of harder material. As it is I'm glad I was working with this relatively soft material. Well I was able to get it to fit was to trim it until it actually rotated the cylinder to the cylinder stop. At first, it was actually too long and the soft material at the tip of the hand would bend. I would bend it back and trim a little, and refit. I did that quite a few times. Enough times I was concerned I might actually break the piece.

Thanks @JohnKSa That is helpful. Mine looks very similar. I have two cylinders that are soft on lock up that I'll have to look at. But not tonight.

 

[BBBBill]

Not familiar with the design of the gun you're working, so generic info here. Some revolver designs depend on both length and width of the hand as both surfaces perform a function at a specific point in the rotation and lockup of the cylinder. Others depend only on the length of the hand. You might discover which your's is by doing an bit more sleuthing.

 

[OS/N]

Adding a little material to the original part and reshaping the end with file and stones may do the trick also. If its a one and done that is - if planning to produce more hands for others then setting up part duplication may be warranted.

Bolt stop could be an issue also. If it locks up by turning and is timed right then maybe just the hand.

 

[DT Guy]

New video by John M

photos.app.goo.gl

I'm not sure I can explain well enough what I had to do to make this work. The thought process of just fitting it so that the cylinder reached battery appears to be the correct approach. Of course, the hand would not fit in the gun normally while it was too long. So I used a temporary pin that I could install after the hand was in place in order to make the fit. My two previous attempts I tried to trim the hand until it fit into the gun and then tried to fit it so the cylinder would come to battery. Apparently, it has as much to do with the shape of the hand as it does with the length of the hand.

By fitting it the way I did and just getting it to go into battery first the length to fit into the gun was set as well as the hand being able to pick up the correct ratchet tooth in the at rest position.

At some point I think I will attempt to make another one out of harder material. As it is I'm glad I was working with this relatively soft material. Well I was able to get it to fit was to trim it until it actually rotated the cylinder to the cylinder stop. At first, it was actually too long and the soft material at the tip of the hand would bend. I would bend it back and trim a little, and refit. I did that quite a few times. Enough times I was concerned I might actually break the piece.

Thanks @JohnKSa That is helpful. Mine looks very similar. I have two cylinders that are soft on lock up that I'll have to look at. But not tonight.

You might look for case hardening compound (this is more than you'd need, but an example: https://www.amazon.com/CHERRY-RED-T...sr_1_1?keywords=kasenit&qid=1707659258&sr=8-1) and just harden the one you have working.

Larry

 

[Johnm1]

Not familiar with the design of the gun you're working, so generic info here. Some revolver designs depend on both length and width of the hand as both surfaces perform a function at a specific point in the rotation and lockup of the cylinder. Others depend only on the length of the hand. You might discover which your's is by doing an bit more sleuthing.

In this case I angled the top to match the angle on the ratchet teeth in the cocked position. I'm not sure that is correct, but it is working for now. There is precious little information on this particular firearm on the internet.

Adding a little material to the original part and reshaping the end with file and stones may do the trick also. If its a one and done that is - if planning to produce more hands for others then setting up part duplication may be warranted.

Bolt stop could be an issue also. If it locks up by turning and is timed right then maybe just the hand.

I have not had luck adding material to pieces. All I have to accomplish that is a map gas torch. On larger pieces I can actually weld/braze material together. Smaller pieces are very difficult for me. I have not found a micro welder here in the Phoenix area. The one attempt I made to have a regular welder do work didn't turn out well.

The bolt stop on this firearm functions well. All I have to do is get the cylinder to rotate far enough and the bolt stop will hold it in place.

You might look for case hardening compound (this is more than you'd need, but an example: https://www.amazon.com/CHERRY-RED-T...sr_1_1?keywords=kasenit&qid=1707659258&sr=8-1) and just harden the one you have working.

Larry

I need to get some of that material anyhow. But in this case, I'd like a harder piece for its rigidity and not necessarily its surface hardness. Although hardness wouldn't be a bad thing here. As long as I can keep it softer than the ratchet teeth.

 

[Johnm1]

Well the softer steel failed after multiple test cycles. I stopped fitting when 2 of the cylinders came up just short of lock up by the tinyest amount. At that point the other 5 cylinders were actually in a bind between the hand and the cylinder stop. Although the tip of the new hand would bend slightly, the force put on the hardened pivot pin 'wollowed' out the pivot pin hole in the new hand loosening the hand and allowing the hand to rotate off of its pivot pin after multiple test cycles. At least with the sideplate off. It might hold with the side plate on.

I'll re-make the hand out of a harder steel for this part. But I now have a shape and a length that I can duplicate albeit slightly long. Searching for appropriately sized 01 drill rod now. As long as the heat treat temperature doesn't exceed 1800 degrees F I can harden it myself in the jewlers kiln I own.
For that matter, I need sheet spring steel. I have to make a cylinder stop for a suicide special I've had for a while. It also wouldn't hurt to have various thicknes of hardened/hardenable sheet steel.

 

[Big Bore 44]

Save yourself some money and hassle... Go to the local Pick n Pull yard and grab a car leaf spring. You'll have a decade worth of good steel that'll take almost any heat treat you want. Most automotive springs are i the 1085-1095 range.