Marlin Model 1897 Disassembly

[Pages:22]Marlin Model 1897 Disassembly

by Gary Thomann Thomann Engineering Singletrack Publishing

Marlin Model 1897 Disassembly

Introduction

This is a manual for taking apart a Marlin model 1897 22 caliber rifle. It is primarily intended for someone taking apart the rifle for the first time, when it is probably dirty and most of the screw threads are stuck. Of course it can also be used for disassembling a clean rifle. The instructions also apply to other old rifles because some time will be spent on how to remove stuck screws. There is another manual available on the internet for about eight dollars that is advertised to be for the 1897. However, it is actually for the Marlin 39A and there are several differences between the 1897 and the later version of the rifle. This manual is specifically for the 1897. There are a few recommended tools and supplies needed so let's list those next

Tools and Supplies

Patience. This is not a one night project. There will probably be a lot of stuck screws that take several days to get the loose. Don't rush!

Assortment of hex screwdriver bits or some screwdrivers. The hex bits are best, try to find hollow ground ones. These will be used to make screwdrivers to fit the rifle. If you are like me you probably already have a bunch of these around.

Gunsmith screwdrivers. Actually not needed but if some of them have thin tips they could be handy. The Marlin 1897 has very thin slots in the screws.

Bench grinder. The grinder will be used to grind the bits to the shape desired. Some other type of grinding device could also be used.

Liquid Wrench, acetone/ATF 50/50 mix, wax. Some other fluid for loosening stuck bolts could also be used. My experience is that the 50/50 mix of acetone and automatic transmission fluid is best.

Old drill press chuck. I used this to hold the hex bits and make a screwdriver. You could also use any hex holder. I like the chuck because there is no slop when turning.

Mineral spirits. Optional, but I did use mineral spirits for cleaning the magazine tube. For other parts I prefer using dish soap and water.

Dish soap and water. Check with your husband, he will know where to find the dish soap.

Small brass brush, old tooth brush, tooth picks, Q-tips, cotton rags.

Jewelers screwdriver. For cleaning out screw heads. Similar small instrument can be used.

Heat gun. Like used for shrink tubing.

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Screw Threads

As I took apart the example rifle I tried to determine what threads were on each screw in case it had to be replaced. This was not a particularly successful endeavor. At the present time the United States is under the Unified Thread Form/Unified Inch Thread also referred to as ANSI/ASME B1.1-2003 and by the term UN. The thread flank angle is 60. Normally this standard is just referred to as UNC (coarse) and UNF (fine) and apparently an 8-UN that I not familiar with. There are two modified UN threads named UNR (rolled) and UNJ (aerospace). There is an equivalent standard to UN for metric screws. If you are going to replace a screw in the rifle one of the UNF screws would probably be used.

First let us note that Marlin was founded in 1863 by John Mahlon Marlin. The company made pistols until 1875 and then began production of Ballard rifles. The first lever action rifle was made in 1881. The Model 1897 was an improvement of the Model 1892 which itself was an improvement on the Model 1891. So, the screws that were used in the Model 1897 must have been developed based on manufacturing from about 1863 to 1897, although there was probably a tendency to use the same screws in the Model 1897 as had been used in the Models 1891 and 1892.

Before the 1840's there was apparently little standardization in machine screw sizes and threads. In 1841 Sir Joseph Whitworth proposed a thread with a 55 thread flank angle and rounded roots and crests. The Whitworth system did not seem to have small sizes, although of course somebody could use his form with small screws. The standard Whitworth small screws are 1/16 ? 60, 0.10-48, 1/8 ? 40, 3/32 ? 48. The terms BSW (coarse threads) and BSF (fine) are used for Whitworth screws. The standard is obsolete but BSW and BSF screws are still used, particularly in Britian.

Standardization in the U.S. began back in 1861 with the specification of the Franklin Institute/Sellers/United States thread. This standard was mandatory only for the military and government departments. The Sellers thread had a 60 degree angle and had flat roots and crests. Apparently the use of the Sellers thread was widespread by 1880.

In 1907 ASME defined two series that used Sellers thread and numbered the sizes by gage from 1 to 30. Each gage increase was 0.013 inch. Next came the American National Standard Screw Thread by the Bureau of Standards, also referred to as CS24-30. It became effective July 1, 1930. After that came the B1.1 standard adopted in 1949. It has been updated several times. Obviously the standardization discussed in this paragraph was too late for the Marlin Model 1897.

So what was Marlin using? I would guess the Sellers thread. In the screws on the Model 1897 it is the pitch (threads per inch) that don't seem to match the modern screws. The diameter was less of a problem. My rifle had all fine threads, the modern UNF screw threads are shown in Table 1. The screws in the table are what we would like to use if we had to replace a screw in the rifle. As we will see substitution doesn't always work. The diameter shown in the table is the major diameter, the value at the outside of the threads. The diameters shown in the table are actually maximum values. A more complete thread table is shown in Appendix A.

2 Marlin Model 1897

Table 1. Modern standard UNF screw sizes and major diameter.

Size 0 - 80 UNF 1 - 72 UNF 2 - 64 UNF 3 - 56 UNF 4 - 48 UNF 5 - 44 UNF 6 - 40 UNF 8 - 36 UNF 10 - 32 UNF 12 - 28 UNF 1/4" - 28 UNF

Dia, in 0.060 0.073 0.068 0.099 0.112 0.125 0.138 0.164 0.190 0.216 0.250

Getting Stuck Screws Loose

When I began to take my 1897 apart I found that about two-thirds of the screws were stuck. I have a set of the eight Grace gunsmith screwdrivers. The next thing I found was that they would not fit the rifle screws, the slots were much too narrow. I took a couple cheap screwdrivers and ground the blade narrower on a bench grinder. Gunsmith screwdrivers are supposedly hollow ground. The Grace ones were actually flat ground. I tried to grind mine in a flat profile also. I then tried some intermediate pressure on the stuck screws, but they did not budge. I did not want to put any hard pressure on the screws; I was afraid the bit would slip. Some of the screw heads were already damaged. At that point I slopped some Liquid Wrench on the screws and retreated to the internet to find the best way to loosen stuck screws.

The classic method to loosen a rusted bolt is to heat it red hot with a torch. While this is ok on a car muffler it was certainly not something I was going to do on a fine rifle I paid $600 for. I was willing to apply a bit of heat using a gun I have for shrinking tubing. I looked for reviews on the best solvent to use. Apparently before they had Liquid Wrench and its siblings wax was used. That was interesting. Then I ran across a review that claimed the best solvent was a 50/50 mixture of acetone and automatic transmission fluid.

In the meantime I was giving some thought to the screwdrivers. I decided that using the quarter inch hex bits would be the best. I already had a large collection of them in a tupperware container. Some of them were even hollow ground, although the blades were too thick. I did some grinding on the flat side of the wheel and tried the screws again. I needed something solid to hold the bits that had a handle diameter that fit my hand well. I decided on an old drill chuck I had. Figure 1 shows the chuck and some of the bits I eventually made. The photo also shows the two cheap screwdrivers I initially ground down.

3 Marlin Model 1897

Figure 1. Homemade screwdriver bits and drill chuck handle.

The drill chuck fit my hand well. For each screw I was working on I tried to make a bit that was the right thickness for the slot and with a width to go completely across the screw head. Of course I was making bits throughout the disassembly process.

By the time I got all this going the screws with Liquid Wrench on them had been sitting there for about a week. With my new bits I tried again to loosen them, again using only intermediate pressure. No luck, they were still stuck. Apparently Liquid Wrench doesn't work well on early 20th century corrosion.

So I went to the auto store and bought a quart of transmission fluid and in a small wash bottle mixed a small amount with some acetone. I put a drop or so on the screws I was working on and let them sit a couple of days. And some of them came unstuck with just medium pressure! On the ones that were still stuck I heated the area with my heat gun until the metal was just about hot enough you couldn't leave your hand on it, put some more mixture on, and waited another day or two. And these screws came undone. I continued the process as I took the rifle apart, eventually getting all the screws out without additional damage than had been done by the previous owner(s). Why this mixture works I don't know; the acetone and transmission fluid are not even soluble in each other. After the bottle sits a while the two fluids separate.

So that is the method I would recommend. Make a bit that fits the screw nicely. Put on the acetone/transmission fluid mixture and wait. Apply a bit of heat if needed. Have patience. One thing though. Transmission fluid smells bad so don't spill any on your wood work bench or you will be stuck with the smell. When I used it I place aluminum foil under the rifle to catch any drops. Other times I put the whole assembly (like the right side of the receiver) in a zip lock bag before applying the solvent.

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The Disassembly

Initial Breakdown

Start with the main holding bolt on the right side of the receiver, as shown in Figure 2. Unscrew the bolt, it will not come completely out of the receiver. You should be able to loosen the bolt with just your fingers. If you need to use pliers, wrap a rag around the bolt so you don't mar it.

Put the hammer at half cock or full cock; I found that it works best with the hammer at full cock. Hold the stock in your right hand and the rifle forearm in your left hand. Bend the stock to the right and the rifle should come apart. You can also lay the front of the barrel on the table with the right side of the receiver up and push down slightly on the receiver. The rifle will come apart at the receiver with the right side of the receiver connected to the stock and the left side connected to the barrel. The bolt and firing pin will still be in the left side; slide it to the rear and remove to the right. A photo of the bolt just before it is lifted out is shown in Figure 3. When you set the bolt down the firing pin will probably fall out. That is not a problem.

Figure 2. Main assembly bolt on right side of receiver

Figure 3. Bolt pulled back and ready to be lifted out.

5 Marlin Model 1897

Next remove the rear most screw on the upper tang. This is shown in Figure 4. The On my rifle this bolt was not stuck but the end had mushroomed very slightly, so I had to loosen and tighten it several times to get it out. As you can see the head already had some damage. When you have this bolt out, slide the stock out of the receiver. Two sight screws are also shown in the figure; these will be discussed later.

So now lets start discussing screw threads, beginning with this stock screw. The major diameter of the thread is 0.204 in, a little smaller than that of a 12-28 UNF screw. On my thread checker, the screw fits both the 12-28 and 12-32 holes. This is probably because the stock screw is a bit smaller than a #12 and also because the thread checker is only 1/16 inch thick; it does not provide much resolution.. At this time I do not have either a modern 12-28 or 12-32 screw to try in the tang - I am trying to find them. Another interesting feature of the stock screw is a tapered shaft. At the end of the threads the diameter is 0.208 in, just under the head it is 0.229 in. The taper must be to draw the stock in snug. Obviously it complicates things if you need to make a replacement.

Figure 4. Stock removal screw and screws for sight.

Next the magazine tube and forearm will be removed. At the front of the forearm remove the two screws in the collar ? the right side collar screw is shown in Figure 5. Although the forearm will be loose you cannot yet remove it; the magazine tube is holding it on.

Figure 5. Right side forearm screw.

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Marlin Model 1897

The diameter of the forearm screw is 0.137 in, the same as a #6 modern machine screw. It will go about 2 turns into the 6-40 hole on the screw checker before it jams. A modern 6-40 screw does screw into the forearm mount so that size could be used as a replacement.

Next the magazine tube needs to be removed. At the front of the barrel push in the magazine tab, shown in Figure 6, in and pull the magazine tube all the way forward. There will be a click when it reaches the limit, there is a crude mechanism for holding it open.

Figure 6. Magazine tab and the dovetail the tube screws into to.

At the front of the barrel under the magazine mounting dovetail that is shown in Figure 6, a hole in the outer outer cylinder of the magazine tube will allows access to the mounting screw. Figure 7 shows what you should see. Notice that the screw on my rifle is a bit boogered up. Using a bit of the proper size bit unscrew it bolt from the dovetail mount in the bottom of the barrel. However, I recommend that you do not pull the screw out of the inner tube, tube; just get it out of the dovetail in the barrel. You can now now remove the magazine tube assembly from the rifle and can then remove the forearm.

At this point you should have five parts/assemblies. First, the rear stock and its mounting bolt. Second the right side of

Figure 7. The magazine screw seen through hole in outer magazine tube.

the receiver. Third, the left side of the

receiver and the barrel. Fourth, the

magazine tube assembly with the mounting screw still in it. Fifth, the foream, its collar and the two

collar screws. You can lay the wood pieces to the side, we are not concerned with them.

It is ime for some initial cleaning. Using a toothbrush, maybe a dish washing brush, and perhaps a cheap paint brush, clean the left side of the receiver and barrel with warm water and dish soap. Wipe

7 Marlin Model 1897

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