Thread: Norman patent rear tool post.

Hi Guys,

I turned the post down to size today !

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The finish is horrible compared to the one inside the tool holder block. However it fits really well, even if it feels a bit rough. I had considered using some fine emery paper on it, but I wonder if its worth it. I'm very tempted to chuck it in the bin and get something else to use for the post.

.

Originally Posted by BaronJ

So I set it up in the lathe between centres.

After setting it all up, it took a 10 thou cut to get the piece of bar truly round and parallel.

Hi John
I am finding that I have to do this more and more. There was a time when you could just chuck a bit of bar and it was reasonably close.
Not so anymore I'm afraid.

Phil

Hi Phil, Guys,

Yes I dumped that horrible piece of bar and got a new piece of free machining bar. Its a bit bigger in diameter at 45 mm but it turns very nicely, with a much better finish.

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This is the piece of bar that I got. It has a very smooth black finish on it, like some kind of coating, possibly some kind of anti rust treatment. Someone said that it would rust as soon as you looked at it
Ignore the other bits in the pictures, they are for the clamp bolt. I just used them to stop the bar from rolling away.

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This is after I turned it down to size. I took the last couple of thou off using a shear tool. Its a much better finish than the other stuff, and the tool block slides smoothly up and down on it. The through hole is for a 7/16" (11 mm) bar that will be used to clamp it down to the lathe cross slide. It drills very easily as well.

Hi Guys,

Well I've now got the rear Norman patent toolpost finished.

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In order to make the clamping stud to hold the toolpost onto the lathe cross slide, I used a length of 11 mm diameter bar salvaged from an old daisy wheel printer. The other piece is a 4 mm thick piece of mild steel. I didn't have any 4 mm flat material so I made some by machining, on both sides, from a piece of 6 mm thick bit of flat bar that I had in the bin. Its 55 mm long and cut so that its width fits into the bottom of the Myford "T" slots on the cross slide.

I turned one end down for about six or seven mm, and cut an M8 thread on it, then above that I turned the bar down to 9.5 mm for a distance of 5 mm, to suit the top part of the "T" slot. After measuring and marking the centre point of the small bit of plate, I drilled a 7 mm hole and threaded it M8 for the bottom of the clamping stud to screw into.

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I fitted the plate to the stud and turned off the excess threads so that it wouldn't catch on the bottom of the slot. After a test fitting making sure that it would fit either way round, I put it back in the collet chuck. It was at this point that I turned the bar around and single point threaded the other end 7/16" X 18 (7/16" BSF) with the threading tool that I found. I loctited the M8 thread into the piece of flat bar.

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I also made the brass washer using the "Wax Chuck" technique and also a 7/16" hex nut to fit the top of the post fastening stud.

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These pictures show the test fitting of the nearly completed assembly, with the existing rear parting toolpost next to the new one. At this point I still needed to fit anti rotation pins in the toolpost, so that it cannot rotate when the nut is tightened and cannot rotate under cutting loads, although when parting there wouldn't be any high forces. The forces in that case would be in a direction to lift the post up and push it backwards.

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Here I've made and fitted the two locating pins. I've made them from some 9 mm chromed brass bar that also came from an old printer. They are 5 mm high and have 6 mm by 6 mm long pins on the bottom loctited and press fitted. They needed a quick rub with a file to remove the high spots left after parting off.

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The final product ! Actually no I realised at this point that I need a ring or tube under the tool holder for the hight adjustment screw to bear against. That or a very long screw.

Hi Guys,

Just to finish off this job, having thrown away the first mounting post because of a poor finish and made another one, I also decided to throw away the tool holder that I had made and make a new one of those as well. Basically everything in the pictures in the first post, got binned.

However this time I made a clamp that could be fitted into the tool holder and would secure the parting blade by compression from the clamping screws that would normally hold the lathe tool.

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These are pictures of the tool block with the parting blade held in the clamp. I machined a groove for the parting blade and then machined the holder so that it was a loose fit into the tool holder, after which I drilled full length with an 8 mm drill. I used a 1 mm thick slitting saw to cut the slit into the 8 mm hole. This allows the three clamp screws to compress the metal onto the edges of the parting blade.

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This picture was taken whilst setting up the new post and tool block. It is essential that the parting blade is dead square to the work, so I used the chuck jaws to align the holder and set the distance of the post from the top slide edge. Also the centre hight was set at this time. 2 and one eighths of an inch looks an awfully long way from the top slide surface.

I've still to get a piece of tube to go over the post so that the hight adjusting screw has something to bear on.

If anybody wants a copy of the drawing for the blade holder just let me know.

Thanks guys.