Some advice on Mild Steel types please

Hello all,

My first post so please be gentle with me!

I recently bought a second hand Warco WM180 to get me started - something I've wanted to do for quite a number of years. I'm having great fun but there is a lot to learn over the next few years.

Anyway, let me start with one of the many questions that I have.

Looking to stock up on some mild steel from an online seller I have found that they have 'Mild Steel' and 'Bright Mild Steel'. The latter is about 50% more expensive than the former. No type is given for either and in fact they list EN1A and EN8 separately. Can anyone advise what might be the difference between the two types?

Oh, one other thing - Does anyone know of any metal suppliers near Bracknell, Berkshire that are model engineer friendly?

Thanks,
Paul

The "mild steel" is likely to be what is termed hot rolled and will have a black scale on the surface, alright for a bit of blacksmithing but generally not the best choice for turning. There are times when it is good to use and that is where you don't want the metal to distort when cutting large sections out of it.

The "bright mild steel " or BMS will have a smooth bright surface as it is rolled to profile while cold and this makes the scale fall off so would be the one to go for, it also usually turns a bit better than the hot rolled.

The EN1a is a free machining mild steel and if you look for the leaded option that is even nicer to turn but not so good for fabrication work.

J

Steel is rolled to make bars. Bright mild steel is rolled cold and has a reasonably bright smooth surface finish. The other type, more usually called Black mild steel is rolled when it's still very hot, which gives it a black oxidised surface.

Its easier and cheaper to hot roll, hence black MS is cheaper than bright MS.

Generally speaking, if you are going to be machining it all over, then black MS is best: it's cheaper and has far less internal stress.

If, however, you intend to use the bar surface without machining it, then you need bright MS.

If you machine all, or most of the surface of bright MS then you should expect it to distort as the internal stresses are released. This happens far less with black MS.

Hi Paul

I would go for Bright Mild Steel and try hard to get the free machining stuff, as Jason has said. If you get any old steel, getting the right conditions to get a good surface finish with our lathes can be almost impossible (for me).

BMS can distort through internal stresses when machined, but this is normally more evident with flats, especially with a longish piece when only one side is machined. With bar I never think about or have a problem in the lathe, probably because the stress are evenly distributed.

Cheers Will

Hi Paul,

Postage charges can be quite high for small quantities of metal bought on-line but Chronos include postage and packing in their prices making them quite cheap for small quantities.

Gary

Hi There

EN1A is normal mild steel.

EN3B is similar but machines very roughly.

EN8 is a through hardening steel and is quite tough.

Best for model engineering is leaded EN1A but don't weld it as the lead won't let you.

EN1A is fine for most purposes but again don't weld it as it can crack.

Thanks for the super quick response everyone. That's one hole in my knowledge filled - about a million to go!

Gary - yes I've seen some of the postage charges so I will look at Chronos. I've been on their site looking at tooling but didn't realise they sell metal.

When I bought the lathe I knew that I would spend the same again on tooling and accessories (and have nearly done so already). It looks like I'll end up spending the same again on bits of metal.

Oh, and I'm now planning a garage extension so there goes another £10k at least.

Hi Paul

Also worth considering is your local machine shop these normally have a large scrap bin full of 'off cuts' I use one local to me and never charges me so at xmas I drop in a bottle of whiskey as a thank you.

I have found M-Machine Metals, they are on the web, very comprehensive in available stock, cheerful and helpful on the phone, and delivery prompt and not too severe in cost. No connection, just a satisfied customer.

Chris