Tang sight threads on 1893 Marlin

[Buckshot]

...............I got an original Marble's tang sight for my 1893 Marlin, and naturally there are no screws. Also I cannot find where I put the hole filler screws to try and match them. Someone mentioned 10-32, but a #10 is too large and the 32 TPI is too course. An 8-40 WILL thread in but it's obviously not correct as its very sloppy.

When the 10-32 wouldn't go, and eyeballing the threads in the tang to the 32 TPI, I made a 10-40, and had reduced it a couple thousandths in OD, but it wasn't enough apparently. So then I made a .172"- 40 and it was STILL too large! Since I'd been humping concrete landscaping blocks all over the front yard all day, I was done in and said the heck with it.

Thought I'd check in here and see if anyone had an idea? These holes are from the factory. Guess I could just keep making them .002" smaller in OD till one goes, but I'd rather just make 2 that work! :-)

................Buckshot

[Cactus Farmer]

Is the Marloon a new one? Ergo,they may be metric.........
Otherwise measure the ID and use a pitch guage and use the Machinist Handbook to figure the OD to start with........

I do a fair amount of screw makin' and there are some propritary threads outthere that are real tough to get right.

[Pepe Ray]

Golly Buckshot, could it be a 9x40? :-D

As Cactus farmer said "There's a lot of proprietary threads in the old firearms industry."
You may have to "slug" the hole. A little imagination and some chamber casting metal should give you something to work with.

Have fun, Pepe Ray

[Denver]

...............I got an original Marble's tang sight for my 1893 Marlin, and naturally there are no screws. Also I cannot find where I put the hole filler screws to try and match them. Someone mentioned 10-32, but a #10 is too large and the 32 TPI is too course. An 8-40 WILL thread in but it's obviously not correct as its very sloppy.

When the 10-32 wouldn't go, and eyeballing the threads in the tang to the 32 TPI, I made a 10-40, and had reduced it a couple thousandths in OD, but it wasn't enough apparently. So then I made a .172"- 40 and it was STILL too large! Since I'd been humping concrete landscaping blocks all over the front yard all day, I was done in and said the heck with it.

Thought I'd check in here and see if anyone had an idea? These holes are from the factory. Guess I could just keep making them .002" smaller in OD till one goes, but I'd rather just make 2 that work! :-)

................Buckshot

A plug screw from my 1893 measures .169 for major dia. and looks like the 40 pitch guage comes closest to matching the threads. I don't have an 8-40 tap, but have an 8-36 that will thread into the hole for several threads before I can't turn it with my fingers. Can't help beyond that.

[Newtire]

Hi Buckshot,

I am also looking for a longer version of the big screw that goes thru The tang and screws into the wrist. the sight I got came with an adaptor plate that the large tang screw goes into. Could I contract you to make up a screw the same pitch as the large tang screw only 1/4" longer?

[woody1]

Buckshot, the info I get from Marlinowners is that the 8-40 was used for all Marlin repeaters after the 1881. The Ballard used an 8 1/2-40. I wonder if someone mayhaps boogered up yours?
addit info from Marlinowners: Ballard tang sight mtg screws are 8 1/2 -40 .167 in diameter and the 8-40 screws are .160 in diameter ken Mebe this'll help. Regards, Woody

[Buckshot]

Buckshot, the info I get from Marlinowners is that the 8-40 was used for all Marlin repeaters after the 1881. The Ballard used an 8 1/2-40. I wonder if someone mayhaps boogered up yours?
addit info from Marlinowners: Ballard tang sight mtg screws are 8 1/2 -40 .167 in diameter and the 8-40 screws are .160 in diameter ken Mebe this'll help. Regards, Woody

..........I figured it HAD to be larger then a #8 as it flopped around, and smaller then a #10. No #9 so prolly 8-1/2-40 it would be. Ha! Go to Lowes for THAT one :-)

Denver, "A plug screw from my 1893 measures .169 for major dia. and looks like the 40 pitch guage comes closest to matching the threads."

...........Yup. More confirmation. I just didn't want to keep turning down stock, threading and trying time after time. So I was at .172" and it WAS close! Acted like it REALLY wanted to go but I wasn't going to force it. Tomorrow I'll try the .169"x40 and see. If I only could'ave laid my hands on those dern plug screws.

Newtire, PM sent.

Thank you all, for the help!

................Buckshot

[Jon K]

Rick,

Just now saw this post.............yep, it's #8-40 tpi.

Even have an extra set of screws here.

Jon

[Buckshot]

Rick,

Just now saw this post.............yep, it's #8-40 tpi.

Even have an extra set of screws here.

Jon

...........Well as mentioned, an 8-40 DID thread in, but there was sure more windage between the threads then I'd think was right. It wasn't just a bitty 'jiggle' loose, but rather some serious floppy loose. You couldn't pull the screw out without turning it, but snugging up 8-40 screws would have been a real nail biter :-)

http://www.fototime.com/CF39D796258F85F/standard.jpg

As it was I made my own screws for it. As mentioned I made one .172"-40 and it 'wanted' to start but you shouldn't have to force it. Not the way threads are supposed to be for possible repeated assembly/disassembly. Info from Woody1 and Denver both indicated OD's in the upper .160" area.

I made one @ .170"-40 and it went in with the very slightest drag. The Marbles base has a slight reccess for the screwhead which is .346" , plus it has a tapered seat with what appears to be a 118/120 degree angle. Using .375" stock I turned a .325" length to .170" and threaded it 40 tpi. Instead of using the compound at 29.5 degrees I fed in straight for these fine shallow threads.

I then turned the .375" OD down to .344". I ground a bit to cut the bevel under the head of the screw and did that then parted it off. I clamped a drill motor in the benchvise and lightly chucked the threaded screw shank up. While spinning it I used the Dremel to dome the head, then cut a slot to use the Chapman #97 screwdriver bit. After that I polished and fire blued them. They came out a brililant bright cobalt blue, but don't show up well in the photo.

...............Buckshot

[SierraWhiskeyMC]

Looks pretty nice, Buckshot!
The Marble tang sight on my 1893 is held on with oval head slotted screws; same profile as the tang screw the rear of the sight base overlaps.

Does yours have a lever on the left that acts like a clutch? I can't see the detail in your photo; it's a bit dark.

Does yours have the flip-down aperture for low light conditions?

Mine does not have the knurled knob on the right - I presume that's a windage adjustment.

What is your Marlin chambered for? Mine is in .32-40.

[eta]
Gee, after looking at the Marble Arms site, I figured out that the sight on this rifle is a Lyman! LOL! I didn't know that Lyman had made tang sights.

[Buckshot]

[QUOTE=SierraWhiskeyMC;643451]

What is your Marlin chambered for? Mine is in .32-40.


QUOTE]

...........Thanks! Mine's 38-55.

............Buckshot

[Denver]

Buckshot,

Can't really tell from your pic and wonderin how close a new Marble tang sight comes to lookin like an original one.

[Buckshot]

Buckshot,

Can't really tell from your pic and wonderin how close a new Marble tang sight comes to lookin like an original one.

..........It's newly made but listed as original for the 1893's. My 1893 was D&T'd with plug screws in the tang and I have to believe they had to have been factory. Or the PO had it D&T'd for an original Marbles? Anyway, it fit perfectly.

..............Buckshot

[Newtire]

Just so you all know, and now I know too...The thread for the long tang screw is 1-27 TPI. Buckshot made me a perfect fitting screw and now I have a tang sight mounted & not just in a box!

Oh & Rick, the Czech's in the male.

Thanks again,
Newtire