Model engineering metals?

Drill rod is the US term for our silver steel which you could purchase, make your tool then harden & temper. Its available in both metric & imperial.

You can also buy what are called "drill blanks" these are jobber length bits of HSS that come in teh usual metric & imperial drill sises eg 1/64 and 0.1mm increments, these are ready hardened and can be ground to shape or annealed for machining. MSC/J&L do individuals and boxed sets.

Ground Flat Stock is also known as gauge plate this is a carbon steel that can be machined and then hardened & tempered.

Jason

No, it is hardened steel used for the moving parts (keyways?) in the lock. The key will be of a softer material eg brass or mild steel so as not to damage the moving parts inside the lock.

Alan

In article , Peter Fairbrother writes

Don't know, I'm strictly a home user.

My first thought was, why not buy an economy set of drill and use these, backwards. Then I remembered that most HSS drills have the shanks left rather softer than the business end. You could try it out though.

Silver steel, as bought, is soft, and can be turned with normal tooling

- though TC tooling is preferred as it is pretty stringy stuff. You can get free turning grades though, which are better in that respect. When turned to shape, harden and temper as normal. Be aware though that it increases in diameter slightly on hardening (and decreases on tempering, but only part way back to original size). If you make a shaft a good firm fit, it won't (fit) after hardening. BTDTGTTS.

Some reports I have seen suggest it may have a higher carbon content, but I can't confirm. Try Machinery's to see if they have details.

I'm sure I have seen stuff from the US; try looking for gauge plate (or possibly gage plate!) as they might call it that. The stuff I have is a fairly sophisticated alloy, rather more complex than silver steel. If you look at the back of the J&L special offer flyers they usually have it on special offer.

Good stuff; you can make keys but life's too short...

What kind of reamer is it, and how much have you broken off? If it's a machine reamer, then a 45 degree bevel at the end is all that is required. If it is a hand reamer, a fairly long tapered lead is required*, for which you would definitely require a T&C grinder.

David

Flat stock is readily available in the US. Available in low carbon, oil-hardening (O-1), air-hardening(A-2). The Starrett stuff at least is ground, don't know about the rest. Available from MSC/J&L, ASAP, etc.

Pete Keillor

David,

The free cutting silver steel that I used to use, KEA108 apparently has not been made for 10 years so it is very hard to find. Ken Whiston used to stock it and I wish i had bought more when he was still trading. Live steam models do have a small amount left in stock. It is replaced by silver steel to BS1407 is calcium enriched to aid machineability but I have not tried it. Certainly the ps stubs stuff I have got is not very friendly to use and needs razor sharp tools with lots of rake all round and very fine cuts to avoid pinging the tip off the tool.

Bob

Is this a joke? I can't make my mind up. Most moving parts in most locks are made of brass or mazak.

Key steel is a type of steel for making Woodruff keys, etc. (e.g. DIN

Older style keys =================================== Wood (first lock ever was wooden from Egypt, if memory serves) Cast iron Cast steel Bronze Mild steel

Modern keys =========== Cast steel (nickel, chrome or brass plated) Mild steel (nickel, chrome or brass plated) Plain yellow brass Brass (nickel or chrome plated) Nickel-silver Mazak (and other zinc alloys) Aluminium alloy

In article , Bob Minchin writes

Bob, Yep, that's the stuff I usually use! I find I can use TC tipped tooling on it, but best with a new tip. I too have a small supply free-cutting, main problem is remembering to keep them identified.

David

MSC/J&L have a huge range of drill blanks, not sure if this is what you're after:

Yep, thanks (and to others) - good to know the name to Google but those prices are a bit ouch!

-- Peter Fairbrother

In North America key steel is for making the rectangular keys used in keyways on shafts! It is usually hardenable to a certain extent. It's NOT for lock keys!

Steve R.

Yes - that's my understanding as well

AWEM

No. Up until 3 weeks ago I would have thought the same but when an old Bramah security lock, which had foiled an attempted burglary, was brought in to the local college workshop by another member of the "old codgers" group we have on a Friday afternoon, as it was dismantled, another member of the group, who had worked for Bramah in the late 1950s, said that hardened key steel was used for the moving parts that had resisted drilling. (The actual key for opening the lock was of stainless steel)

I was just pointing out to Peter that there was an actual connection between "key steel" and locks (all be it rather specialised ones) as I assumed it was just a rhetorical question and that he knew of its usual use in key ways.

Alan

Why would you harden a key for a motor shaft ? My take on it is that the key is to provide drive and a shear point in a jam up. The key steel available here (Makakey )in Australia is all soft it can be had in steel and 316 stainless steel. The only hardenable square/rectangular stuff I've come across is ground stock sold by Bohler .

Ah, Bramah; They're still going and still make very high quality locks to designs which are quite distinct and unique to themselves.

However, the use of the expression "key-steel" here makes for a very tenuous connection between lock-making and key-ways for shafts.

The term "key-steel" is not used in the lock industry generally. Hardened steel sheet used to cover lock cases and within the structure of safes is called "hardplate". Other anti-drill features are generally referenced by their form or function rather than their material, so e.g. might be referred to as "anti-drill" or "anti-saw" pins. The particular material or alloy used is something of a trade secret. Of course, within the factory it might be referred to as key steel if that is what is used, but the expression has not made its way out of the factory.

Anyway, I'm still not sure whether Peter's original point was a pun. ;-(

As to your assertion that "The key will be of a softer material eg brass or mild steel so as not to damage the moving parts inside the lock." this is not true, I'm afraid. The mechanisms of the vast majority of locks are largely made of relatively soft metals, such as brass (house locks) or zinc alloy (car locks) as these materials are inherently corrosion resistant. Keys are, for the most part, made of steel because it is cheaper and stronger than brass.

Bramah would very much be the exception here and I don't doubt that what your friend said, is true. Out of interest, Bramah will make you a solid gold key if you want one. There's currently one for sale on EBay for £225.00.

They are not always intended to be shear keys! Hardened keys are used for a positive drive under moderate loads. Unhardened, the same material is tougher than mild steel. it's also cheaper than splines. A hardened key is not needed for light loads, but has less chance of wearing.

Steve R.

I was taught, in those dim and distant college days, that a key was there in a frictional drive situation of a shaft, to ensure the case of static friction pertained. The coefficient of static friction being higher than that of sliding friction. The only situation that I am familiar with where the key transmits torque to a shaft is the sliding dog arrangement in a chain drive Frazer Nash transmission. In this situation it is essential that the key is loose and a sloppy fit in the key way, the corners being rounded to allow a rocking action of the key. The shaft is hard, typically 80 ton/in2 and the key steel is 35/45 ton material. I guess there are other drive systems that are similar but I'm not sure that they are called on to transmit 100+ bhp.

No pun intended - the only thing I lose more regularly than (the keyway type of) keys is my length of 1/8" keysteel.

However yesterday a strange thing happened. I had to fit keys to two shafts/pulleys, and as usual I couldn't find the keysteel. However I did find two keys of the right size ..

-- Peter Fairbrother