Dependant on any fine features you would probably better with EN8 or 16. They would be better in unhardened state than En1 or 3, but could be heat treated to suit requirements.

Peter

En3b is much the better for parts that are to be case hardened as opposed to through hardening carbon steels,

In my experience it does not machine badly but no where as well as En1a.

Tug

EN8 (080M40) machines nicely and can be hardened quite easily.

Silver steel machines reasonably well, and can also be hardened. Between the two, my choice would be EN8 because it machines to a better finish. I believe EN8 is stronger than silver steel, but could be wrong about that. If screwcutting, I would use EN8.

EN24T also machines easily to a good finish, and has a greater strength than EN8. The T indicates the material is supplied in a hardened and tempered state, but it still machines nicely.

I have bought both EN8 and EN24T from M-Machine Metals, with whom I have no connection other than being a satisfied customer. Other suppliers are available, etc…

Marcus

+1. The answer depends on the purpose the pins and set-screws are put to. Do the items need to be hard, or tough? Does it matter if they're brittle?

The reason different alloys exist is because their properties meet the need in hand. Last pin I made was Brass, not Steel, because it's a Shear Pin, designed to break first in the event of a head-crash.

Most of my pins are made of EN1A-Pb because it's easily machined, and strong enough for most purposes where safety doesn't depend on the pin. It's unsuitable for anything remotely safety critical.

Mild steel is rather soft, so not ideal for bearing surfaces, and, although tough it bends easily. Case hardening creates a thin hard surface on easily machined mild-steel parts, improving their wear resistance. Good for moving parts in clocks, guns, models and other mechanisms. But, because a thin hard layer may not last long in a hard working machine, it's often better to make the part out of a hardenable steel. The disadvantage being that these alloys are more difficult to machine and have to be quenched and tempered properly. The result is inclined to be brittle, especially if tempering is botched.

Although it's often machined, with the exception of the leaded variety, mild-steel is a cheap structural metal rather than an engineering material. Drills, saws, and welds without bother making it good for building ships, tower blocks and car bodies but it's not suitable for bolting wings on aircraft! EN3 is cheaper than EN1A, but it doesn't machine so well. Machines just about OK, but I find it tends to tear and smear making it hard to get a good finish. Leaded EN1A machines extremely well, but the finished part is about 20% weaker than EN3.

The important question is 'does it matter?' If Peter wants to case harden otherwise satisfactory pins just to resist scratching, then I'd stick with EN1A. Apart from availability and cheapness I see no advantage in EN3. And if the pins have important hardness, toughness, and strength requirements, then mild-steel of any type is probably unsuitable.

On the subject of specifications, no-one makes EN1 or EN3 steels. Although extreme resistance to change means many British customers and vendors still call steel by those designations, they've been obsolete since 1972. What you get when "EN3B" is ordered, will be one of several slightly different modern equivalents. Doesn't matter for most purposes, but steel bought for safety critical applications should be ordered more carefully. The correct steel depends on the requirement.

My home workshop requirements aren't demanding and I don't weld, so most of my steel is EN1A-Pb (probably 11SMnPb30 in real money). As only Peter knows what his pins and set-screws are for, he's in danger of getting some duff advice.

Dave

Edited By SillyOldDuffer on 26/12/2022 10:24:09

There is some really useful info in this thread though some might be just opinions or feelings and need verification.
It would be great to have a single sheet guide pinned on the workshop wall. I wonder if someone with the right additional knowledge could produce a guide/table in MEW that we could photocopy to hang up?

En1a isn't leaded, that's EN1a-Pb, or whatever SOD quoted above in modern terminology

A slight thread drift. I have to make some special bolts to hold the balance weights on my 6" traction engine crankshaft. The drawing says to use "High Tensile Steel". Normally in this situation I machine down some tensile bolts. However, this time the shape of these bolts is outside the scope of modifying an existing bolt. I will have to start with some steel stock.

So my question is what is the spec for high tensile steel please?

Les

OK thanks, I'll start another thread and scan the drawing to give folks an idea.

Les

Kennions sell En1a and it’s a leaded steel. En24T is a reasonable machinery steel for pins bolts gears etc which has a good wear resistance and can be surface hardened.

If Kennions are selling steel with lead in it, it is EN1a pb. If you look at High Peak Steels website you will find En1a pb has 0.25% lead, EN1A hasn't got a column for lead, and it is quoted as suitable for case hardening. I haven't worked out how to do links on a phone

Edited By duncan webster on 27/12/2022 01:22:57

My point was that some suppliers sell leaded free cutting steel and call it En1a so be careful.

regards Martin

ps you are right in specifying the +pb of course 

Edited By Martin Kyte on 27/12/2022 08:00:31

You could always ask for a material cert, this will list thr properties of the metal.

Any company should be able to give you this.

The vast majority of certs I see at work are from China nowadays

Jim