The sows ear, a Clarke Metalworker Mill / Lathe conversion to cnc

[Robin Hewitt]

Backlash is approx .016mm on the X and Y axes and about 1 mm on the Z (and it wobbles) but that should be sorted soon. The worm gear from the existing fine feed will never provide great accuracy though so I may need to go to an external leadscrew.

Hi Mark

Nothing wrong with a bit of turd polishing :naughty:

Just a thought but you might be able to improve it a lot by changing one spring. A temporary fix perhaps so you can use it to remake the parts properly.

Usually the quill return acts on the pinion rather than on the quill.

If you put a plate on the bottom of the quill then replaced the quill return spring with a snogging great extension spring pulling up, well off centre on the plate that would have two effects...

1: The gear train would be in tension and more able to resist the tool pulling it down.

2: it would apply a twist to the quill and reduce the wobble.

If you have a sloppy quill, thick grease is your friend.

Happy polishing

Robin

[FatFreddie]

Cheers Robin :-)

I should have made myself clearer - the quill is fine (good even which is a surprise) it's the bracket that wobbles (very visibly when plunging). I've already used it to make another one in aluminium which I hope to fit tonight. There is a return spring on the quill which, as you say, could be stronger - I think machining grabby materials could be a problem but there is a lock on the quill I can use if necessary and the idea of a supplementary spring is a good one.

I should have done this years ago, it's converted a machine that was border line useful and a pain to work with into one that has many uses, is fairly accurate and is a joy to use. Turning accurate diameters was always a pain with it but now I can make a test cut, touch off to the measured diameter and press go and the jobs done - within 0.04mm first time.

Total cost for the conversion so far is about £400 - bargain :-)

Mark

[FatFreddie]

Well the Z axis bracket has made a big improvement.



Though the exposed thrust bearing with one race missing is still a bit grim :-) Must get a needle roller equivalent.



Running an 8mm spotting drill at far too slow a speed got me this



Need to look into smaller bits and a Dremel adaptor for this sort of work but I'm quite impressed so far - the EMC2 anti backlash algorithm was very evidently working during the making of this.

Mark