Edge fixing onto the backplate?

[pgk pgkParticipant @pgkpgk17461]

I have an abundance of hot-roll plate curtesy of local scrappy but facing/thicknessing it in my mill without powerfeed is tedious and either messy with a flycutter or lots of toolmarks with the endmill sizes i have.

I get a much better finish on the lathe on smaller pieces but thinner and larger pieces in the 4-jaw I'd have to remove the gap to clear the jaws.

So I wondered about cutting some shallow slots into the edges of the plate and making up some low profile grips with countersunk heads to hold the plate to the faceplate.

say 150mm x 150mm 8mm plate with a 2mm wide 2mm deep slot in each edge with a 6mm thick holddown clamped through the faceplate so that i could skim as much as 1mm off each face and end up parallel?

The question is would that hold securely enough on cuts heavy enough to get through the millscale without the plate leavng the lathe and brown trousering me? Or is there a better way? Direct bolt-holes through the plate would lead to lots of waste to cut away.

[pgk pgkParticipant @pgkpgk17461]

[Ady1Participant @ady1]

Have you got backgear?

If your lathe is stiff enough you can remove the gap, use a decent hss tool and use the "revolving shaper" route via the backgear and your 4 jaw

safer too

Or use the backgear on your faceplate system

This stuff made hss look like cheese until I used the backgear, it had a gold coloured swarf when I finally managed to cut it

Edited By Ady1 on 14/09/2015 10:41:12

[pgk pgkParticipant @pgkpgk17461]

I'm not sure what you mean by revolving shaper except perhaps low speed scrape cutting?

The problem with using the 4-jaw (apart from potential issues replacing the gap) is that I'd need a back filler plate for the 4-jaw that's adjustable for different plate thicknesses (which means pratting about adjusting it) or setting the plate up on temporary parallels in the chuck..and I find that it's gripped just by one tooth of each chuck jaw and I've had a plate loosen like that with a dig-in on the inevitable intermittent cuts of a rectangular plate.. neither method would give as regular a plate thickness as holding it down to a freshly skimmed faceplate?

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