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This mount appears to be original but I'm not sure. At any rate it has be altered. it looks like the original S/N was removed with an end mill and a new number (AM 7421 ?) was added. Any idea what the hash marks under the rear ring represent ? How about the partial number under the front ring ? I assume the cut out in the rail was to accomodate some scope other than a No.32. The cutout is well done mill job not a bubba hack saw special. Any thoughts ?
The hash marks you mention ARE the original numbers roughly barred out and usually the second or subsequent number would be placed near here. Why it would be placed near to the front thumb screw is a mystery but it has been milled out with a small milling cutter mounted into the pantograph engraving chuck, then the last AM number engraved at the same time. THEN commercialised by having a chunk taken out - none too carefully, with a grinding wheel that needs dressing off! What makes you say that it's a well done milling job? It looks awful from here!
It could be worse, lol, thats a fine professional job compared to out here in bubba land! Any chance that was to fit a military scope while in service?
I was just thinking about silver soldering (hard soldering.....) a section into the recess to bring it back to normal. But........... Has anyone out there in forumland got any experience of hard soldering cast impure wrought? Will it distort at that temp.........?
Any thoughts out there........ JM....? Breaky?
Brazing will work, My uncle used to do it, but it WILL distort at least a little. Enough to render the bracket US? That depends!
Was it wrought Iron or low carbon mild steel ?Quote:
Originally Posted by Peter Laidler
This is something I was looking at a bit a go regarding a casing for a lathe. (see link below )
MIG Welding Cast Iron
My Dad is a retired welding Engineer and upon seeing the pictures of the bracket in question his advice was that if it's useable as is leave well enough alone. Silver soldering cast won;t work, the solder won't flow or bond well to cast. If the attempt were made to repair the ground out spot JM's brazing method would be best, but it's not an easy thing to do. The first thing to be done is to heat the part hot enough to burn out any grease or oil that has been absorbed, about 900 degrees. Easiest thing to do is make a bed of coals in the BBQ grill and clover it up for 10-15 minutes. Next, clean the area to be braised with a sandstone grinding wheel or a rotary file. If possible it would be good to make up a jig to keep the bracket rigid while the rapair is done and as it cools off. After jigging the entire bracket needs to be heated to a uniform temprature close to the melting point of the brazing rod, after the repair is complete heat the bracket uniformly again without causing the weld joint to come apart. Now cover it again with the hot coals and let it all cool down together. Good luck.
Bigduke6, I read the link on MIG welding cast, the guy did a good job but I think he had a lot of luck on his side. His decision to braze it was a good one but MIG welding it with stainless wire ( 309L) would have worked too if done correctly. One thing he did'nt do was heat the part long enough to burn out any oils that were absorbed by the cast, thats why he had pits and holes in the brass joint. When I make a repair of this type, providing the part isn;t too big, I have a bed of coals handy to emerce the part in until it stops smoking, that tells me all the oils been burned out. If I'm brazing it I try to fill the whole crack in one pass, when arc welding it I peen the weld after each pass. Peening stress relieves the weld joint and reduces the chances of it cracking. An important thing to remember when repairing cast objects is to keep the whole thing hot the entire time the repair is being made, then when done immediatly cover it again with the coals and let everything cool down slowly and evenly. If it has'nt cracked by the time the coals burn out it's not likely to ever crack.
Big Duke, the material spec for the original brackets is malleable whiteheart (PURE) or blackheart (impure) cast iron.
I seem to remember during my apprenticeship that you can braze it (that's why I was thinking hard silver solder might be suitable....) providing that the whole item is deep cherry red. The metallurgy labs explained why........
I remember it being discussed at some length overcracked/snapped/broken MGB GT V8 exhaust manifolds but that's going off the subject a bit I suppose
I reckon the MGB exhaust manifold repair is directly relavent. Near as I can tell the brackets could be a form of nodular cast iron, but have never felt like sacrificing even little bits for analysis. (It does machine like cast iron, as I had to repair an oversized spigot locating hole once. Didn't save any swarf, though...)Quote:
Originally Posted by Peter Laidler
A useful tool in my box these days for removing oil and contaminates from all metals, is pressure pack carby cleaner, have brazed a lot of cast iron and it's not so hard. (including manifolds)
I'd mount the bracket by the mount holes, lay it flat and just braze the piece in, there is not enough metal to stop the heat flowing throughout the surface, so there's no need for all the extra preperation.
Looks like something has been done to the "thumb screw" holes as well, as they have slight raised "lips" around them on the side against the pads.
My wonder would be how well the grinder bloke cooled it as he ground, otherwise he may have warped it already!
To redo, better to mill out square and insert a block with a couple of screws, fill the screw slots and gaps with solder or any filler of your choice and paint over.
Number partially ground out looks like M7421 and the milled out number you could probably determine with the aid of black light or whatever it is the police labs use.
---------- Post added at 08:57 AM ---------- Previous post was at 08:55 AM ----------
Just mind you don't have any carb cleaner still there in pores or pockets as heat turns it into Phosgene apparently and the smallest whiff can make you a very sick man indeed.Quote:
Originally Posted by muffett.2008
Surpmil, it's an optical illusion. There are no lips. Don't think it was done with a grinder, it's not warped and when mounted on the rifle it's dead on. It appeaers to have been milled out and finished up with a file. Looking at a 2D picture is not like having the real thing in your hands. And just for the record, I'm a retired Mech. Eng. that started out as a machinest/tool maker and now a full time tinkers mate with a complete machine shop, so I do have little knowledge about what I'm doing. I do think your suggestion is the best for restoring it to the proper look. I think that welding/brazing/soldering is a fast track to disaster.
To be fair Charlie, we all gave you our thoughts - just as you asked - and..............
Just one further point if I may........ Is it numbered/matched/mated to your rifle?
If it were mine, I would bronze braze a patch in and then have Brian Dick suncorite over the patch to disguise it. Before doing so, I would clamp a large steel bad of the proper diameter into the rings and build a heavy steel plate with shim pillars to attach the mount to in order to mitigate the chances of warpage.
I'd then heat the part with OA and braze away. Should work, nothing ventured, nothing gained.
Peter, the just for the record remark was not intended to be snarky, it was just meant to advise that I do know some small amount of what I speak. In answer to your question, while this mount came with the rifle the numbers do not match. That's why I was suprised to find that it lined up so well. I made up a test bar with a laser bore sight that mounts in the scope rings and a second laser bore sight mounted in the bore. Set up in a rifle rest it's right on at 50 Ft. in both axis.
I'd just dam it up and fill the gap with steel filled epoxy, dress it up and paint it. There are no heat issues and you'd barely be able to tell.
Exactly what I did for the IWS brackets, though not having your background or resources, my setup probably wasn't as good!Quote:
Originally Posted by Charlie
Hey Charlie is this not the same bracket that's now numbered to a certain L42A1 being evaluated in another thread?
Good eye VintageHunter. The missing chunk seems to have been replaced, and quite neatly with only a colour change revealing the repair.
VH, Yes it is.
This thread goes back a loooooong way and I ain't reading that far back again but is there any dispute about that butchered brackets originality in respect to that particular L42? I would say with more or less certainty, based on nothing more than a couple of years service and another couple of years of the same as an Armourer that the bracket was not butchered like that or matched to that rifle in UK service. If it was and was butchered like that, you can be rest assured that there would have been some searching questions to have been answered - followed by what we used to call '..... a long report on a short bit of paper' followed by a NM&D (neglect, misuse and damage) report followed shortly by a hefty bill for the miscreant
I agree, but the question at this point is/was about all other aspects of the rifle and kit but the scope mount. And of course you know the scope is genuine because you recently did a complete refurb on it.
Send me the number and I'll confirm it. Not disputing that it ain't one that I've done in the past but you'd be absolutely gobsmacked by the amount that have a black and shiny finish with my name attached to them, sometimes by by fair means but others........, well............ Some of 'em don't seem to feature on my work sheet library though. Must have done them in my sleep!
Charlie, you'll find that many on this forum, including me I hasten to add, tend to wander off at a tangent. It's not to everyones cup of tea of course but life's a bit like that
Scope # 22595 (AK&S)
Yep, rebuilt by me from dire condition