Flat bar for hardening

[Gragson]

Looking to make some steel milling vice jaws, 150 x 40 x 12mm

After cutting/drilling countersink and a bit of edge shaping to suit, going to harden & temper.
Probably not ideal but I can get mild bright EN3B for about £30 a meter 40 x 12mm.

Should I be shooting for a different grade to harden/temper? - preferably reasonably available and not cost the earth

 

[optima21]

if you harden and temper them, they'll need grinding flat as its likely that they'll distort while quenching. for hobby use unhardened will probably be ok, mine have been like that for the last 20 years. although I have used wooden lollipop sticks to protect the jaws if the surface being clamped isnt smooth (or square)

 

[Gragson]

Hadn't thought about distortion after heating/quenching..good point even at 12mm thick.
Can get them made to order for £100 hardened & ground which probably ain't bad to be fair, but wanted a crack at hardening process, especially as mrs is away end of month so oven is all mine for tempering.

Got no facility for grinding anything flat.

 

[optima21]

EN3B isnt a grade for through hardening as its a low carbon steel, but can be case hardened (just the outer few microns of metal are hardened), not sure about the chemicals that are used to do that at home these days, but it used to be kasenit, but that was banned due to the chemicals used in it.

 

[Agroshield]

...wanted a crack at hardening process...

Only if it's bad tempered.

 

[My Old Landy]

Ground flat stock

12mm x 40mm x 500mm Ground Flat Stock / Gauge Plate

High Quality Precision Ground GFS (Ground Flat Stock) Tool Steel Also commonly known as A.I.S.I. 0-1, 01, BS4659 BO1 and Werkstoff Nr 1.2510 Tolerances on metric Ground Flat Stock - Thickness +0.05mm/-0.00mm Width +0.20mm/-0.00mm Length +3mm/-0mm Oil hardening gauge plate which is supplied in...

www.rennietool.co.uk

 

[Memmeddu]

Looking to make some steel milling vice jaws, 150 x 40 x 12mm

After cutting/drilling countersink and a bit of edge shaping to suit, going to harden & temper.
Probably not ideal but I can get mild bright EN3B for about £30 a meter 40 x 12mm.

Should I be shooting for a different grade to harden/temper? - preferably reasonably available and not cost the earth

Leaf spring

 

[—Tom—]

Any movement in HT will likely not be much, and can be flattened on a piece of sandpaper on a flat surface. Will need doing anyway to clean up scale from HT.

 

[hunter27]

I have had 2 sets of jaws from a seller who makes them in England, user name gemmie14
on Ebay and have been very pleased with them.

 

[Screwdriver]

You won't harden EN3B sufficiently to make any difference to vice jaws. If I was going to take a flying guess, even case hardening will just mean the jaws will chip or crack in use. You probably want something more like EN40/4140/A2 something tough and durable.

When you're hardening, I'd be surprised if you get much distortion with chunky jaws since if you buy a suitable size, you won't need to do too much machining on it prior to heat treat. Stock removal and heavy machining is, I think, the biggest contributor to distortion as internal stresses even out.

With vice jaws (and specifically with A2), I'd be tempted to harden them then immediately temper and at the tempering temperature, quickly clamp them up in the vice. That should take out any slight twist or bend and it might even "fit" them to the vice...

 

[Kram]

GFS is relatively expensive, good stuff but, I dont think jaws need to be a high carbon steel, any common medium carbon steel should be adequate once hardened.

708M40T or 817M40T would be one of the better options if you can find flat bar or dont mind milling from round.
Old stock hydraulic bar is a good cheap source of decent steel, likely one of the above.