I would be more inclined to slit or saw of otherwise looks good to me.

David

What if you significantly 'straddle' the continuous round bar with your parting tool to reduce/ practically eliminate the interruption to the cut?

Certainly not a problem with a Q cut in the rear toolpost on my S7. I was happily parting of 1" square at the weekend. Mind you, it makes a bit of noise.

HTH,

Rod

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Edited By Sam Longley 1 on 19/09/2017 20:09:13

Is the radius critical for clearance, if not, then possibly forget the parting off that's causing the concern. Make from 1/4"x1/2" steel cut two lengths oversized, drill and bolt the outer edges, of the two plates together, then set up in the mill to profile both sides, you'll have over half a mil to play with. Then spot and bore the holes to size. The two halfs can then be cut to length and finished with a file. Or clamped in the end of the mills vise and milled off.

I think the slitting saw idea sounds best as it saves time on having to set up the work several times in the clamps/jaws.

Dave

The only times I've broken an inserted tool in my rear-tool post has been during an interrupted cut (done it twice now) – admittedly on larger work (< 2" ) – managed to break a large chunk out of them both. First time I thought it was just bad luck, got away with it on the next cut and then banjaxed a second insert on the third.

So last time I used a HSS blade (from the front) to get past the 'interrupted' section (gentle stepped cuts – in, back, feed over a bit, in, back, feed back again) and once I was past the 'knock' – I had made a wide enough channel to feed in the inserted tool straight from the rear…

A compromise solution – but I don't like taking deep cuts with the HSS tool from the front and my (inserted tip) rear tool holder doesn't seem to like being 'clunked'… although it works really well on deep parting cuts normally

Others here seem luckier with their inserted tooling but different lathes/users/tools behave differently. Anyway, that's what I do now.

Your job is a bit different in that the 'clunky' bit extends just about the whole way. So once you've moved over to the mill, I think I'd stay on it and just cut them off as other have suggested.

Regards,

IanT

Edited By IanT on 19/09/2017 22:28:27

Lathe? I would be making them, from flat, on the mill. Two pieces strapped, glued, soldered or welded together (whatever you choose) and machine them. Rotary table for the curved ends.

Very True Mick – I know I often over-complicate things (some sort of ME anxiety complex!)

But then again you can probably saw a lot straighter and neater than I seem able to do. I usually manage to skid a little off the line too – making an ugly scratch – despite sacrificing a thumb nail to try and keep things on track….

I know – practice makes perfect – but I can't see my sawing and filing skills improving any time soon I'm afraid.

Regards,

IanT

I would just part it off on the round section and then clamp it in a vice under an end milling cutter and trim it to size.

* Danny M *

I'd part it off so the tool straddles both sections, round and lumpy, only just shaving the lumpy bit. Ideally you'd have thought of this and dimensioned it accordingly. That way the tool and cross slide etc will remain constantly loaded – and you won't have any finishing off to do either.

It's not so much the insert that is the problem as the backlash and spring in the machine between the work, all the way round the machine through the spindle and bed and finally back to the tool and the insert.

Murray

Parting tools are regularly ground at an angle to either leave the pip on the part, or leave the pip on the remaining stock.