Clarke Lathe

[FatFreddie]

The tool is about 20mm out of the toolpost and is slightly angled to the face of 16mm stainless steel rod.

Just a thought - what are you using to shim the tool - it needs to be something uncompressible like steel strip - hard to tell what it is in the picture.

If you can't get it exactly to hight, err on the low side rather than the high.

[GeorgeD]

How do FF.

Its a thin piece of card,but to be honest I didn't think that would be the problem as I picked some tin can up yesterday for shimming and its the results are the same.

I'll get some new tooling this week and see how I fair from there,just could be the nature of the beast ie hardened stainless steel?after all these machines lack a bit of oomph in the torque/power,I mean 300watt motor...c'mon:lol:.

No problem with ally or delrin.

[irving2008]

I was thinking of grinding my own tools ie just the facing,turning and parting off ones,the boring ones I have bought in the index replacable tip type.

Would these be suitable,Irving....
http://www.rdgtools.co.uk/acatalog/S...d_prices_.html

Yes I'd imagine so, tho I bought a few ready ground but then adjusted to my own preferences and I already had a load of bits of 1/4" and 5/16" tool steel that came with the various old lathes I have acquired

[FatFreddie]

The key to getting a good finish is stopping the tool deflecting while cutting, there are several ways to ensure this...

All components between the tool tip and the workpiece must be rigid, not rigid as cant move them with your fingers but rigid as in cant move them with a crowbar! Card is a complete no no, even tin can shim needs to be flat, clean with at most three layers and the tool needs to be well clamped down.

Keep cutting forces to a minimum - deflection is proportional to force. Make sure the tool tip is very sharp - use a high power magnifying glass to examine it and sharpen if it looks at all rough or rounded. It can help to put quite a lot of top rake on for finishing but this tends to make the edge fragile so you have to be careful. You can also use a more pointy tool (technical term) but you then need a finer feed.

Depth of cut, depending on the material, a cut the thickness of paper (0.1mm) might be considered a fairly heavy finishing cut ;-)

Coolant will help protect the tool tip and keep it sharp, if you don't want to use a stream of coolant then the Rocol stuff is pretty good.

The replaceable tip tools tend to be relatively blunt as they're designed for production use on heavy duty machines. It's possible to get sharp ones but carbide is prone to chipping so they are fragile (if you stall the lathe and then rotate the workpiece backwards to free it off, you'll more than likely chip a carbide tool) so I'd recommend HSS tools for a lathe this size.

HTH

Mark

[GeorgeD]

Hi Irving

I'm struggling here on the Lathe,basically I'm having trouble parting-off...the lathe judders and for the life of me can't understand why I'ts proving difficult to part-off?

Last nightI set the gibs as they were a bit loose,today I got some new tooling and blanks,I've tried parting-off at different speeds,the tool is marginally belowthe center...I used the live center to set the tool up.

Stainless Steel bar,had to cut the workpiece of with a grinder :lol:..it ain't funny:cry:

Any pointers as to whats wrong?

[GeorgeD]

Problem solved,it would seem these Lathes struggle to part-off on hard material and the only remedy is a roller bearing change for the naff standard ball bearings
that come standard.

Now I will have to change em,thank god I don't have to turn a bit off the larger spacer on the spindle because this model doesn't have it,only the thinner plastic spacers which are easily grinded down on a table grinder.

[GeorgeD]

Forgot to mention,whilst scouring the net for info on these lathes I happen to think up an idea for DRO's on the cross-slide and compound but how to fit them?

In Lidl they had those cheap digital calipers which work on the same basis as the DRO's plus they readout inches and mm...so Lidl here I come.. :whistling:

I suppose given a little lateral thinking these couldalso be adapted to other machinery?

This will do nicely sir. :naughty:knowing my luck theywill have none left.