Winchester forging grain lines

[Pat C]

I know most here have seen old Winchesters with what appeared to be scratches in the sides . Some people even called them forging lines. What is actually happening is during the high heat from forging and subsequent slow cooling the grain becomes very coarse .

The forging dies cause the steel grain to flow around the basic shape of the frame. These lines are the end grain boundries from the coarse grain structure. Where it terminates at the surface it break down and causes the charcoal blue to flake along these boundaries.

Interestingly almost 30 years ago I restored an old 1892 rifle I had traded for .Did the entire project myself . And when finished I sent the polished parts to Doug and Terry Turnbull for charcoal bluing,rust bluing.

When they came back I noticed a few dark streaks along the sides . But really hard to see unless lighting was correct
I thought they were streaks from break clean or acetone when they decreased them prior to bluing.

Wrong they were the forging grain lines showing back up.
Fast forward to today. You can see a few places where the blue is stating to flake along these lines.

I bet I polished .010'' -.015" off the sides , you cannot get away from this,it's in the steel forever. You cannot feel them ,only see in strong lighting.

[Pat C]

Here is an 1892 well worn and grain lines prominent

[Sixgun]

Old head Winchester guys know that…the untrained eye thinks there’s something wrong. …..someone might say, “my rifle don’t have those” but sintered metal or investment cast dont which is about everything made in the last 50 years.

[JRD]

I wonder if back in the days of forging lines in Winchester receivers, they didn’t have the technology or knowledge to normalize forgings before machining.
Normalizing is a heat treatment process which doesn’t harden the forging, but makes it uniform hardness throughout for more consistent machining. S&W forged revolver frames are normalized prior to machining so there are no hard or soft spots in the forgings from differential work hardening.

[Pat C]

The reason behind it was the older poorer quality steels and no subsequent heat treat . Basically the receiver were heated to pretty high heat and die forged then slow cooled so grain stayed at its larger size. The were machined then open hearth charcoal blued or later charcoal blued in gas furnace.

This poorer quality steel but strong enough because of the forging.

The topic is of interest to me because the lines can never be removed permanently they come back to be seen again just like this one has done

[marlinman93]

I've seen these forging lines on a lot of old lever action repeating rifles, and always on blued receivers with a little or a lot of wear. Can't say as I've ever seen them on color cased receivers, and I think it's because the bluing salts can get into microscopic pores and highlight the forging lines.
In the past I've listened to guys talking about these lines and passing up on guns that had them because they felt they were flaws in the forgings. I had to chuckle when I hear those kind of statements as I've never heard of any ever failing.
This isn't just a Winchester thing. It appears on other rifles that have large flat sided blued receivers also.

[Pat C]

I've seen these forging lines on a lot of old lever action repeating rifles, and always on blued receivers with a little or a lot of wear. Can't say as I've ever seen them on color cased receivers, and I think it's because the bluing salts can get into microscopic pores and highlight the forging lines.
In the past I've listened to guys talking about these lines and passing up on guns that had them because they felt they were flaws in the forgings. I had to chuckle when I hear those kind of statements as I've never heard of any ever failing.
This isn't just a Winchester thing. It appears on other rifles that have large flat sided blued receivers also.

Wouldn't be anything to do with bluing salts as they were not used during this era . The early guns were open hearth charcoal heat blued then early 1900's Gas furnace charcoal blued in rotary retorts.

Color case guns still show them too but not as much because the surface has been hardened and grain structure finer.

DuLite corporation developed hot salts bluing late 1938 the steels and processes had mostly been improved by then pretty much gone by then.

Anytime you look at a fresh break on these older firearms you'll see what I mean when I say coarse grain structure
That is the culprit .Steel when heated multiple times as they did to high heats and low carbon at that the grain structure will remain very coarse .

[Grizz]

this is very interesting. it is correct that heating metal and cooling can increase grain size, but annealing steel involves changing its crystalline structure into a very soft state. does anyone know what metal these frames were made from, was this perhaps iron, which has grain throughout? or what the modern equivalent metal is? does anyone know to what temperature they were heated before forging? annealing, hardening and tempering, and spring steel were very well known processes at the time these receivers were made. are there any photos of the pre- and post forging stages? or of the dies? are there any photos of blown up receivers that had these stripes?

curiously, grizz

[Sixgun]

Like MM says, you can see them on guns that have lots of wear or no wear…….

What looks like horizontal scratches on this 1873 are forging marks and this is a 98% gun made in 1891.

[OldWin]

From an NDT/MPI standpoint, these marks would be regarded as "surface indications" only, and in no way compromise the steel. They would show up significantly under MPI inspection, but as long as there is no porosity in depth, it wouldn't be an issue in THIS application. There are cases where it would be, and especially if running across the grain. One could argue there is a difference in strength when compared to a later production receiver without the forging striations, but it doesn't matter for this application. Other areas of the rifle would fail first, which I'm sure Winchesters engineers were aware of.
As we are aware, Winchester utilized everything they could in regards to production, especially back in the day.
For myself, I never even thought of these marks. It's "part of the charm" of the rifles from the era.

[Pat C]

From sometime in mid 1870's Steel was the material . But these earlier steels especially the receivers were just a low carbon mild steel . You don't see the lines as much with color case hardened receivers because the surface is hardened making the grain finer. But they do still show occasionally.

[OldWin]

Some of it is "folds" or laps in the steel when it was forged. The forging process was improved over time, as was the pour, and the alloy, eliminating these imperfections.
As you mentioned, it isn't as prevalent in the color cased receivers. I'm not sure if it is purely surface hardening, receiver selection to color case, or a combination of the two.

[Pat C]

Winchester used dies to forge, simple round stock placed in the die and drop hammer conformed the barstock into rough forging. No seams or folds in the metal. What your seeing is the grain boundaries following the contours of the raw forging.

[Grizz]

Winchester used dies to forge, simple round stock placed in the die and drop hammer conformed the barstock into rough forging. No seams or folds in the metal. What your seeing is the grain boundaries following the contours of the raw forging.

thanks for the info. I'd like to see those dies and watch the process. There are some interesting industrial forging videos on tube. Fascinating topic

[OldWin]

Winchester used dies to forge, simple round stock placed in the die and drop hammer conformed the barstock into rough forging. No seams or folds in the metal. What your seeing is the grain boundaries following the contours of the raw forging.

Yes, I know. Those conditions are there from the pour. The forging process at that time didn't remove them. The terms can be misleading.

[Pat C]

These photos are from Winchester in late 1930's prior to WW2
Same forging equipment was being used at turn of the century and probably earlier. Most open die forging have progressive dies to go from bar to finished forging which is usually close to final size.

[Grizz]

Thanks very much for the photos. Helps to see it.

[Pat C]

This is what the inside of most Winchester parts looked like very very coarse grain structure. This is a broken 1876 lever from 1883. You can see the very tin case hardened smooth layer but the core is coarse grained steel. Levers were forged like frames.

Scale does get embedded into the surface of the forging and this voids the surface . And does contribute to this I believe.

The poured hot ingots/bar are not refined until they go into the forging die. Then the grain is refined to the shape of the given dies. This is what gives it strength to final shape..

[Sixgun]

Early 1873’s up to the second model in ‘79 were iron. (I think it was ‘79) I had a first model made in ‘74 that I’d shoot from time to time.

These pics are from an 1886 in 45-90 I blew up 20 years ago ….case is still stuck in the barrel…..the barrel was NOT nickel steel. This rifle was made in 1903.

[Grizz]

THANKS for the photo. glad you survived that! That's very course grain. Is it possible that there could be case hardening where the finish is? New files are case hardened where the teeth are and have course grain inside . .. . that's a lot of damage, did the bullet exit the barrel? Oops, was that the magazine?

[Pat C]

What did you determine caused this 1886 failure ?