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

The Craftmans Shop > New from Old

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awemawson:
I think that it would be wise to try and manually drive the Z axis to see how stuck or free it is. By dangling my iPhone into the works I've managed to get a picture of the servo motor name plate - if I'm reading it correctly it's developing 15 Newton Metres of torque at 2000 RPM and taking 25 amps at 150 volt to achieve that :bugeye:

The actual ball screw is coupled via a toothed belt drive to the servo motor - I'l try and get time tomorrow to remove it's cover and probably have to fabricate something to engage one of the pulleys

nrml:
I am surprised that you don't have an industrial grade bore-scope in your box of toys. It would make inspection of these tight spaces much easier and i-phone dangling unnecessary.

To be honest, I don't understand a lot of what you are doing but that doesn't diminish my interest in the slightest. This is truly a worthy sequel to the Traub epic.

PK:

--- Quote from: awemawson on July 02, 2018, 09:35:06 AM --- There is a series pass regulator comprising three 2N3055 power Transistors with load sharing resistors in the Emitter circuit, and this group of three is driven by a fourth 2N3055 making a 'super alpha pair' (well quad in this case!). The base of the fourth 2N3055 is driven by a UA723CN voltage regulator IC

--- End quote ---
What vintage is this machine Andrew?
I can remember building power supplies like that 30 years ago, and they were a little dated then.....

awemawson:
Spot on PK, it's 29 years old !

awemawson:
This morning, bright and early, I whipped the cover off the Z axis ball screw pulley and tentatively tried turning it by hand. It turned remarkably easily, but before any significant travel I needed to move a pile of tooling that came with the machine, and clear as much of the rust on the ways as I could.

Then grasping the pulley I moved the carriage to it's extreme travel towards the tail stock, revealing the expected rust under the moving element. Nothing major, and a bit of judicious scraping and stoning and it will be fine. No doubt when I move it back towards the head stock end more will be revealed.

I need to clean up the ball screw as it also has suffered - again nothing major but it needs cleaning,

. . . quite a pleasing start to the day - now off to do some fencing !

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