Dave Lammas tool post

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 19/06/2016 07:43:59:

Lynne, before you go rushing out to buy a bit of Cast iron round think about the grade. I don't know what the supplied castings are done in but may be worth a couple of quid more to get a piece of SG Iron bar, It would be heartbreaking if an overtightened screw snapped a corner off the toolpost. Or even a bit of free cutting steel, bit more work but cheaper than cast by half.

What do the metalergists think?

.

I can't claim to be a metallurgist; but I'll have my say, anyway

The overall proportions look a little light, to me, and I would be happier with steel.

In fact, I think the optimum might be a fabrication, with steel [gauge plate if you can find an off-cut] top and bottom, and cast iron as the core.

MichaelG.

[LynneParticipant @lynne]

Thanks to everyone who has responded with respect to suitable material. The material I found on ebay, which satisfies the 90mm criteria, is described as BMS to 080A15/EN3A.

EN3A is described as having good machinability,weldability,lowtensile, and can be case hardened, which to me would be an ok material. I have not so far in my internet searches, found an other material which meets the 90mm criteria.

Puzzling in some ways as 080A15 is cross referenced to EN3B, but in my view is still an ok material. RegardsLynne

[Clive FosterParticipant @clivefoster55965]

Lynne

EN3B is bright mild steel, EN3A is black. Same steel but bright is cold drawn so will be pretty much on nominal dimension and can be used as is. It will have some locked in stresses due to processing so you need to take the usual precautions when using for parts significantly assymmetric relative to the centre of the bar. As bright steel goes it not too bad in that respect, some of the higher end steels are much more wiggly. Black bar still has the mill finish on it which needs to be removed before you can do anything with it. Messy and you need to start oversize. Negligable locked in stresses so its pretty much proof against wiggle when machining. Due to processing differences EN3B is closer to 080A15 book properties than EN3A. Nothing of great import but its quite common to cross reference only the bright version of steels.

Its pretty weak as steels go, under 1/3 rd the strength of EN16T / EN19T but it gets the job done. Good for welding beacuse it pretty much won't heat treat whatever you do to it, the melting, fusing and cooling cycle doesn't make much difference so it tends not to crack.

Anthony

I currently run a Smart & Brown 1024 but had 3 SouthBends previously. A 9" change gear only model C replaced by a similar model A, giving me a gearbox and power feeds, which in turn was swopped out for a late Heavy 10 Toolroom version with D1-4 spindle. Some wear on the 9" machines, rectified by a bit of Boxford cross fertilisation, but spindles and headstock bearings were excellent on both. The A had worn its feed drive key down to nearly nothing so clearly had done plenty of work. The Heavy 10 was near mint save for a seriously yucky paint job on the cabinet stand in a purply-blueish-mauve colour so horrible that no camera or printer appeared to be capable of accurately reproducing it. In the few pictures I have it doesn't look too bad. The camera lies! Heavy 10 had to go after I popped a drill chuck out of the silly far too short travel tailstock one time too many. The 1024 went straight into the same hole.

Clive

Edited By Clive Foster on 20/06/2016 17:52:51

[LynneParticipant @lynne]

Clive, Thanks for the information. I have asked the ebay supplier to clarify whether it is Bms, or Black

I think that the material is ok for a toolblock. Regards Lynne.

[John Stevenson 1Participant @johnstevenson1]

EN3 whatever will be fine for a toolpost. Far stronger in shear than a casting or lump of durabar.

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