The Craftmans Shop > New from Old

The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)

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tom osselton:
Looks good and I really like that spiral bolt too!

awemawson:
Things are going painfully slowly with this project - life is getting in the way!

However today's objective was to remove the temporary manual chuck from the lathe spindle, bolt the embryo adaptor in reverse on the nose of the spindle (as both have nice flat and true surfaces) and turn the periphery truly concentric as an aid to mounting on the manual lathe in a concentric fashion for turning the A2-6 taper.

It didn't go well from the start - I'd thought that the weight of the manual chuck would be manageable, well it wasn't - the good thing is that it just missed my foot when it fell into the swarf collector (where I was standing)  :bugeye:

OK I mounted the adaptor as planned in reverse . . . .but I've now concluded that I can't tweak it easily to be concentric for turning where it is and am going to remove it, return it to the accurate jig in the Partsmaster CNC milling machine, and use a boring head to produce an accurate concentric bore to use for centring on the manual lathe - what a pain !

awemawson:
So this morning I whipped the embryonic adaptor off the CNC lathe spindle, cleaned everything up scrupulously, and sat it back on it's locating dowels in the Beaver Partsmaster ready for concentric boring.

But what to use as a boring head - I don't have a CAT40 shanked boring head  :scratch:

I've several R8 shanked ones that I use on the Bridgeport - mmm .... I wonder? Well the nominal diameter of an R8 shank is 24 mm - sit it in a 24 mm collet in a CAT40 shanked TG100 collet chuck (of which I have several) and see how a/ long the assembly is and b/ how rigid.

OK it's rather long and not brilliant for rigidity but it fits AND works. I decided to stick to low RPMs (150 rpm 43 mm diameter) and hand feed so that I had 'acoustic feedback' of how it was doing. It's not given a fantastic finish, not surprisingly, but it's OK for purpose which is merely to alow me to run a finger DTI on it on the manual lathe to ensure best concentricity. I'll see how it goes as it is.

(The nice thing about having six locating dowels on the spoil plate is that I can take it off and return it to exactly the same spot if further work is needed)

mattinker:
That's Frankenstein set up! At least you didn't have to make a n R8 to CAT40 adaptor! All the best, Matthew

awemawson:
Ah but it worked Matthew :lol:

(A CAT40 to R8 adaptor is actually available commercially but I've not seen one for sale in the UK)

So I mounted up the embryo adaptor in the 4 jaw chuck on the Colchester Master 2500, trued up the parallel faces of the A2-5 side, reversed it and started roughing out the A2-6 taper.

I decided not to finish bore it as time was getting on and there was pressure to do other things - I need to sink the test gauge about another 5 mm into the adaptor, but a job for another day. . . .

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