Centec 2B renovation

[NilochParticipant @niloch]

I am renovating a Centec 2B with factory power feed to the x-axis via a g/box and pick-off gears. Movement of the x-axis using the ball handle having disengaged the manual rapid traverse facility is extremely stiff to the point of being unusable despite having deliberately over-loosened the gibs.

 

By process of elimination a very experienced model engineer and I have come to the conclusion that, at the very least, we need to extract the lead-screw for inspection, however, we are currently at a loss as to how to achieve our aim largely because of the g/box.

 

I am in possession of a manual which, by the way, is rather brief; I am a member of the relevant Yahoo group and I have consulted lathes.co.uk without success.

 

If anyone has any suggestions as to the correct procedure for disassembly or know where I can locate one of the manufacturers cross-sectional drawings for this component I would be extremely grateful.

 

Thank you.

[NilochParticipant @niloch]

Disassembly of x-axis lead-screw

[Laurence BParticipant @laurenceb]

It sounds like something might have seized up somewhere.I’ve just been looking at the x-axis lead-screw on my machine.Unfortunately I don’t have much information or many drawings on the 2B,so this might not be of much help,but this is what I thought.

 

In the gearbox,there are two nuts on the lead-screw drive gear.These is located in the gearbox chamber behind the ‘pick-off’ gears.Maybe if you undid those and also disconnected the lead-screw bearing housing at the other end of the table (i.e. the handle end) by removing the two allen screws.With the half nut disengaged,then the lead-screw might then come out.

 

Best of luck!

[NilochParticipant @niloch]

Thank you Laurence B for your input. I think you must, at least, be partially correct but in addition the cross sectional drawing of the g/box shown on the last page here:

reveals, with the aid of a magnifying glass, a Woodruff key securing the gear held in place by the two thin nuts.  I guess the prime purpose of these thin nuts is to take-up any end float in the mechanism. However, the matching location for the keyway in the bearing appears to be down to guesswork, although, one hopes it is at 12o’clock.

My next plan of attack is to undo the bearing on the left hand end of the table, similarly the phosphor bronze half nut, position as best as one can the Woodruff key at 12 o’clock (the key is scarcely visible by the way), undo the thin nuts as far as space allows and gently tap the spindle with a hide/nylon/rubber mallet, undo the thin nuts some more, tap with mallet etc.

Thank you.

Edited By Niloch on 06/11/2011 17:32:28

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