hi all
found this in some parts I just acquired. is the top one rare ?, as it looks milled to me.
bottom obviously stamped
thanks
Printable View
hi all
found this in some parts I just acquired. is the top one rare ?, as it looks milled to me.
bottom obviously stamped
thanks
Yes, it looks milled. That’s an expensive way to make a tripping lever.
Could it have just been machined to tolerance? Could it have been stamped from thicker stock and then surface ground to spec? Still, yes, expensive. Maybe it's early.
We can only see one side of one edge and those ribs aren't (?) milling machine marks in my opinion. There's only one part of that tripping lever that really need to be accurate, measured from the very loose fit and oversize (to allow for left/right articulation) axis pin hole. And I use the word 'accurate' as to indicate within +/- .030" or so. That's the sear tripping bent that you see just to the rear of the upturned part of the lever. That has got to be hardened of course. As has the actual tripping part contacted by the breech block. The top one looks like a more angled (or is it well worn.....?) later variant usually fitted to Mk5's in production.
Might it simply be that those totally irrelevant ribs are simply a visual reminder of the rolling process. The actual thickness of any tripping lever would be dictated by the width of the tripping lever slot in the change lever. I say that those ribs are just a feature of the strip rolling process. Then punched out as per usual, sear pawl bent ground and hardened.
Incidentally, if my memory serves me right - it's been a long time - this part is quite hard and tough throughout. You find this out when you try to bend it left or right a bit to get the A and/or R mode to operate correctly. Otherwise it's change the change lever
Agree with Peter, the marks are from the rollers used to roll the bar stock into a thinner sheet. I have some somewhere.
Makes more sense than machining even the prototype. I'd think the whole of it would have been made with files and such.
I agree. They are not milling marks. It’s the crisp sharp edges that show it was milled. Stamped edges are not that clean. Also, those “ribs” are very fine and would have been crushed a bit if the part had been stamped.Quote:
Originally Posted by Peter Laidler
They are not milling marks but I wonder if they are shaping machine marks? You know the machine that goes backwards and forwards with a lathe type tool doing the cutting; the machine that most of us have seen but hardly anyone has actually used. (Including me.) The marks look too wide apart to be rolling marks, although difficult to tell from a picture. If we could see the edge philb we could tell you if the profile had been punched out.
I have made quite a 'Few' of these by hand would you believe? They are simplicity itself to cut out with a hacksaw, file to profile. heat harden & oil black finish! A LOT are missing from UK Deacts, & some owners wanted the levers for their Deact Stens. Not a difficult job at all!
I suppose I didn't need to harden them. But, when you are trained to do the job PROPERLY. I guess their is only one way to do it. Correctly! :super:
pic of other side
When you say heat harden, tankhunter, I assume that you mean harden and temper rather than case harden which is also a type of heat hardening process, it could be argued?
I hardened & Tempered them F10. Case hardening would have had a similar result for a live gun. But I don't have any case hardening compound in my Workshop. So........
I tried Kasenite and had limited results. I'd rather use oil myself, you end up with a black finish too...don't know how hard it gets though, didn't Rockwell it after. My problem in all of this is how hot is hot? How long at cherry red...? I guess that takes experience.
If you are through hardening, you can suspend the part with a magnet over the oil bucket. When the part is hot enough it will become non-magnetic and fall into the oil.
It partly depends on the grade of tool steel on how hot you need to get it before quenching in oil. If I was going to make the tripping levers out of a tool steel and then harden and temper it, just basic ground flat stock (Gauge Plate) or 01 grade tool steel would probably suffice. This is a fairly basic standard tool steel and for this steel if heating in an oven a temperature of around 815 degrees centigrade would be about right. For the tripping lever you wouldn't need to hold the temperature long before dunking in oil because it's relatively thin; in an oven holding for around 15 to 20 mins should be long enough. If I was hardening the tripping lever in a flame the secret is to slowly bring it up to temperature by gradually increasing the size of the flame. You need to have the metal a little hotter than cherry red, more of a orangery yellow colour and the colour needs to be uniform across the metal. For a thin item like the tripping lever once the metal is up to this colour it would only need holding in the flame for a few minutes before dunking in oil.
Perfect. That's easy to remember.Quote:
Originally Posted by Vincent