WM250-VF chuck backplate problem

Hi all,

Bought a new 4 jaw sc chuck in the new year and am in the process of machiningthe backplate. Both sides faced and bored to slip over the headstock spindle. All holes drilled and tapped or counter bored for the chuck bolts. So far so good. Come to turn down the OD and realise the carriage won't travel close enoughto the headstock. Need a minimum of 40mm more travel.

I have a qctp fitted which gives a bit more overhang than the standard toolpost and the compound slide is extended as far as possible.

It appears the carriage is very near to the end of the leadscrew and that limits the travel. Anybody else come up against this problem and how did you overcome it ?

Tia

Brian

Brian - if removing the leadscrew cover does not help you could use LH turning tool in boring bar mode.

Rik

Or a boring bar at the back of the lathe with it running backwards or mount the bar upside down to use at the front again with lathe running backwards a bit like this

Hi Rik

Tried using a carbide tip boring tool upside down with the lathe in reverse. Not pleasant finish very poor. I wanted to try what you suggest but only have a small r / h knife tool. I do have some 12mm hss blanks so might make one.

Will see if taking the leadscrew out will work first

Hi jason

Replied to rik before you posted. Will try again with the boring tool but using the original toolpost and the bar at the rear of the toolpost

If you have got one of those rolled up type lead screw covers that may need removing so you can get up closer as Rik says, though the carrage can also foul on any bulges in the back of the drip tray to clear the later model motors

Brian,

A bodger's solution would be to try mounting the boring bar held by the first two screws in the holder; if that doesn't reach a longer bar surely would.

Don't try much more than light cuts with it extended that way and wrap some lead strip round the shaft, bedded well down on Blu-tack to help mop up vibration and noise.

Regards

Brian

Finished off the backplate today using upside down boring bar. Finished the OD with emery to polish out the chatter marks. The register was cut withe the same tool + new tip and turned out okay a (good fit any way).

Still feels like i bodged it a bit though.

Thanks to all

Means to an end.....you dont always have to follow text books...take pride in a mission accomplished.

Necessity is the mother of invention....there are other ways of cat skinning...

John.....cliche department..

Did you mark it relative to the mark on the lathe nose? Sorry just read it was for a four jaw chuck. ooppps

Edited By alan lloyd 3 on 15/01/2018 19:13:54

I did mark it as its a self centring chuck. Don't know if it was necessary or not but doesn't hurt.