Hatton Gardens

[Doug MacQueen]

Unfortunately I don't remember what the silver steel makeup is and the term is not common at all in the U.S. The twist drills used here prior to HSS High Speed Steel were to my knowledge, a straight high carbon steel. This is not considered an alloy steel. I have taken spring stock, which was either 1095 or 1075, non alloy high carbon steel, heated it to critical temp, which is when it becomes non magnetic, and then quenched it in water. Instead of tempering, I just tapped it lightly. It did indeed shatter like glass. So I am guessing that "silver steel" is an alloy steel. Maybe chromium, vanadium, tantalum. I only wish I paid a little attention in chemistry class and I would know what these words meant. I even worked in a steel mill where alloy steels were made and I haven't a clue. I did however learn to cut 19" plate steel with oxy-acetylene, which I have to admit was very hypnotic.

[Chubby]

From wikipedia, so it MUST be correct:

The composition is defined by UK specification BS-1407, and is as follows: carbon 0.95–1.25, manganese 0.25–0.45, chromium 0.35–0.45, silicon 0.40 max.^[1] In the annealed state it has a hardness of 27 HRC. It can be hardened to 64 HRC.^[2]
The European/Werkstoff equivalent grades are 1.2210 / 115CrV3 with a composition of: carbon 1.10–1.25, manganese 0.20–0.40, chromium 0.50–0.80, silicon 0.15–0.30, vanadium 0.07–0.12

[Doug MacQueen]

That sounds like a typical tool steel mix to me. Hadfield's manganese steel did go through a refining process of tempering over a period of several years based on the patents I have found. Here is a pic of an early Diebold cannonball that was found to be not quite tough enough against a nitro attack. Later models were improved in that respect. It was found that around a 3" thickness was the most ideal in the tempering process. Safeman, you mention using a torch to anneal 5 ply so you could drill through it. What drill and rig were you using? And a better question is what drill and rig did Chatwood use to drill the Ratner plate?

[Doug MacQueen]

There seems to be a difference of opinion regarding the case hardening process. According to Price, he felt it could be used to the full depth of a steel plate. In his words, "iron" and I assume he is talking blacksmith's very low carbon iron. Pretty much every thing I find shows a limit on the depth that can be achieved. Then again he doesn't specify how thick the iron plate was, but it sounds like it would have to be extremely thin sheet.

[safeman]

That sounds like a typical tool steel mix to me. Hadfield's manganese steel did go through a refining process of tempering over a period of several years based on the patents I have found. Here is a pic of an early Diebold cannonball that was found to be not quite tough enough against a nitro attack. Later models were improved in that respect. It was found that around a 3" thickness was the most ideal in the tempering process. Safeman, you mention using a torch to anneal 5 ply so you could drill through it. What drill and rig were you using? And a better question is what drill and rig did Chatwood use to drill the Ratner plate?

I was using a Wolf 1/2" double handed drill but can't recall whether the actual drill was 3/8" or 1/2". I was in a bit of a panic at the time so perhaps had superhuman strength to push the drill without much resistance.

Chatwood just states 'hand ratchet drill'. I will attach copies of two pages
which gives some insight to the man.

[safeman]

I was using a Wolf 1/2" double handed drill but can't recall whether the actual drill was 3/8" or 1/2". I was in a bit of a panic at the time so perhaps had superhuman strength to push the drill without much resistance.

Chatwood just states 'hand ratchet drill'. I will attach copies of two pages
which gives some insight to the man.

Bloody machine!

[Huw Eastwood]

Here's another of interest while on this subject- Deloro Stellite, now under the Kennametal group. These are right under my nose every time I'm at the bench so I took a quick pic.

If someone had asked me before this thread for a rough date on when this stuff was developed I have to admit I'd have guessed at 1940s or even 50s. Turns out it was out before the First World War and made its inventor a millionaire by 1916.

It's formidable stuff and can still be bought in various grades of stock bar and plate for those adventurous enough to experiment and cut it. I have to be honest, in terms of all round hardness and heat resistance I think it's still has to be one of the best. One thing I found was It even puts up a good fight against a range of grinder cutting discs, which sets it apart from a lot of the other steels and alloys.

I mentioned a while back in a different thread that I wasn't happy with the 'spheroidal graphite iron' of the Chubb Hercules and it was this stuff that I peppered over strategic points for peace of mind.

Their drills are unmistakeable- heavy round shanks with a unique triangular section to the tip and a pyramid point end. They are considerably heavier than HSS or even Hi-Cobalt bits. Going to keep this one intact as I think it's the last of 2 or 3 we had.

[safeman]

There seems to be a difference of opinion regarding the case hardening process. According to Price, he felt it could be used to the full depth of a steel plate. In his words, "iron" and I assume he is talking blacksmith's very low carbon iron. Pretty much every thing I find shows a limit on the depth that can be achieved. Then again he doesn't specify how thick the iron plate was, but it sounds like it would have to be extremely thin sheet.

The only reference I have to the materials used states South Staffordshire Boiler Plate, which I assume to be wrought iron.

Another reference states 'about 1858, Price commenced making his doors of his "best" safes of two half-inch case-hardened plates.

[Chubby]

One material with which I used to play was "B555". It is a ballistic armour plate. Very strange. If you drill it as slowly as a civil servant on vertime it can be worked easily. But you go above that speed and it work hardens to, you guessed it, an amazing B555. It wasn't brittle though.

I had a contact who got me 6 pieces each of which was 6" x 6" with a 10mm hole centrally. I used those for hardened plates. Welded them in with low hydrogen rods. I pity anybody who came across those unknowingly!

There was some other stuff called IT100. That wasn't quite as hard as the work hardened B555 but it was hard straight off the bat. I got some cut for a friend who was patching a superb Ratner that some joker had tried to open with a OA attack through the side. Whilst the IT100 was on the bench a rep came round trying to sell some special hard drill bits which would go through anything. Needless to say my friend handed him the IT 100 and asked him to drill a hole through it. That would have been in the nineties. I think the rep might still be trying!

Good to see that stellite. I had no idea it was so old. Great stuff for hard facing the jaws of bolt cutters. Just get some stellite rods and build them up. I acquired a set of Japanese bolt cutters with tubular handles. It seemed like a good idea at the time but I then couldn't get replacement jaws as they were not imported normally. Then a friend advised on stellite hard facing. Did them once, never needed to think about refacing them again. I gave them away when I left UK. They were still good enough even after a lot of very serious work.

[Huw Eastwood]

That B555 plate sounds interesting stuff, I could've had a good experiment with that a few years ago, although I'm guessing it's a military issue alloy and not commonly available.

So it wasn't just us that gave reps a hard time if they made impossible claims for their stuff! I wonder how many drills he sacrificed before he gave up lol. The welded Stellite often seemed harder than the bar. Plus the irregular surface gave added resistance making it difficult to start and cracking the cutting edges. I made a small welded box with ground square corners so it looked like a solid block of steel. Can't remember how many laminated plates I got in there but each was hard faced on both sides. Whenever a rep showed us a new drill 'that will go through anything' it was always a case of make him a cuppa and take it in the workshop to find out...

Poor sods they never learned lol, we'd tell them not to make the claims but they'd never listen, I guess they were that pumped and enthusiastic they believed it themselves. Same for padlocks, the amount of 100 quid plus locks handed back to them 10 mins later with the shackle cut off by hand with a hack saw. We used to warn them against claims as simple as just 'hacksaw proof' because as they found out, you never know what's on the hacksaw! Looking back it's a miracle any of them ever came back, but I think most of them couldn't wait to show their boss and grill him over the embarrassment he'd put them through!