doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Forging lines on old actions?

Gentleman,as Gunman said these lines are found on guns from pre-1900, and because of that,more commonly on hammerguns.Also on guns that have had their C.C.hardening worn off and likely been subjected to a liberal amount of blood, sweat, and tears, which I assume has allowed a certain amount of corrosion to act on the material in the fold lines that Hugh referred to.These lines are observed on guns by all the makers including Purdeys etc. A product of the action forging methods of that time period.

Early Savage 1899's show these "flow" marks in the receivers that are in no way scratches. They have been attributed to the forging process.

This is a minty 1899 with "flow marks" in the reciever. I suspect these are also what are showing up in early shotgun receivers.

Romac, thanks for posting these photos. I engraved an old Martini action a couple of years ago and when I had it blued and then stripped the blue on the scene area for a grey finish, differential colored lines just like that appeared where they had not been noticable before when in the polished state. Really had me baffled as to where they could have come from.

I've several guns that exhibit this feature and have seen many more. I had assumed scratches, but had trouble reconciling just how all these guns got the same stratches. I'd toyed with the idea of some common "brushing" technique, but the engraving did not bear this out. So, I'm delighted for a sensible explaination. I'll have a look under a microscope and see if I find anything worthy of reporting.

DDA

Maxm: You nailed it - Fighting Iron by Art Gogan.
Page 100 with illustrations on Page 101.
Quoting from Page 100 - "The distortion of the metal grains in the hot forging process is evident as an elongation of the grains along the axes that are parallel to the path of the plastic-like flow of the hot metal under the influence of pressure applied by the hammer or the die(s). These severely elongated grains result in residual stress gradients between the distorted grains and their boundaries or interfaces with adjacent grains. Because some corrosion mechanisms display differences in the corrosion rate that are attributable to the presence of stress, older forgings that have experienced slow, uniform surface corrosion will frequently exhibit a pronounced visibility of the "forging flow lines" as the corrosion highlights the elongated granular structure of the forging (see photos on right-hand page). These gently curving, striated surface features will often be observed on the well aged and worn ferrous forgings commonly used for firearm frames and receivers of the last half of the 19th century and first quarter of the 20th centuries. Unquote.

Ian
Thanks for once again dispelling the myths that surround the lines seen on some old gun actions. The path of these lines also indicates that the Gun makers and forge masters of the period understood the importance of correct grain flow to maximising ultimate strength of the action. For this reason todays engineers designing forged components specify by means of a diagram the grain flow they require .
Whist some Birmingham gun makers did produce small forgings for sporting guns. It is very likely that because of the size of the action body and the corresponding large capacity of the forging machines required, that this work would have been outsourced to specialist forge shops operating in surrounding Black Country towns,such as Hales Owen and Darlaston.
We tend to forget that the majority of Gun Barrels and gun locks used by the Birmingham Trade were in fact outsourced to business located in the Black Country towns.
Birmingham producers of military weapons for example; B.S.A, Webley and Scott and to some extent Greener did producer high volume forgings and gun barrels in house.

I never knew built up stress would cause the lines. Maybe one of the various stress relief heat treatment strategies should be done prior to removing any metal to stop the process rather than chasing something that could go through and through.

I have several pre-1900 Parkers with these lines. In fact, the process of drop-forging or "bulldozing" the billet into the desired shape of the raw frame block has caused a very visible uniform curve of these lines along the side of the frame up into the standing breech. If I could figure out how to post pictures here I would do it. If someone cares to give me their email address I will send him pictures and he can post them. I have never thought they were anything other than imperfections in the billet and the fact that they curve with the shape of the frame leaves no doubt of their origin.

dsromig@aol.com
Dean

Here are DAM16SXS's pictures:

Thanks Mike for posting the pictures. They don't show quite as clearly as I had hoped but are still relatively easy to see. By the way the horizontal lines curve to the vertical standing breech it is very easy to imagine the drop-forging process that formed the shape of the frame block.