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Colhester chipmaster bearings

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Steenkamp:
Hi All
I have recently acquired a Colchester Chipmaster as my primary lathe by trading in my ML7 and related rooling. I have had this niggle for some time now of not getting a decent finish using negative rake carbide, positive rake carbide or even with a tangential cutter or super sharp hss. I started playing around with tipes of material im cutting too. Known stock that used to give a mirror finish on the Myford doesnt even come close to shiny on the chippy. So i started checking all the gibbs and other adjustments that can have an effect. Still same old. Even locking cross and topslides makes no difference.

I then tested a 0,01mm finger guage against the spindle bore and i get no movement on the guage whatsoever. But if i slowly rotate the spindle by hand i can feel little rough spots while turning, and the rough spots are at random places, ie not repeating on the same place.

Can someone who know these machines perhaps give me a pointer as to what direction to go in now?

Could it be the bearings in the counter shaft that the clutch and brake system utilizes that makes such an impact on finish?

I have already contacted Nobilla tools in Uk and they quoted me £420 excluding shipping to SD!
If i convert that to our currency its more than what i paid for the whole machine! In fact i can buy a similar new asian machine for the price of second hand bearings.

Sorry , rant over.

Can somebody please direct me to an alternative make of bearings as nobody in SD  or SA can even find these Gamet bearings.

awemawson:
When I was rebuilding a Round Head Colchester Student twenty years ago to my horror I found that one of the hollow rollers in the front spindle bearing had collapsed and knocked a hole in the outer race. Like the Chipmaster the Student uses Gamet, and even then I could find no equivalent or any at a sensible price. In the end I found a used but ok one.

Have you had the bearing out yet for inspection? If yours has a similar issue but hasn't gone too far you may get away just changing the rollers.

Steenkamp:
I haven't removed anything at all yet, bit scared of what i might find. there is no noise or heat buildup around the spindle bearings. I used a screwdriver " stethoscope" to try and hear anything and the only place i think i could hear anything was on the drive-shaft containing the clutch and brake. I guess i will have to dismantle the headstock and take dimensions so our bearing suppliers can look for an alternative. Will a bad spindle bearing still make no movement on the spindle taper when testing with a finger guage?

awemawson:
Certainly with mine there was no unusual play apparent, but there was a graunchy bit at one point in the revolution.

loply:
If you're getting random tough spots are you rotate the spindle, is it possible there's some swarf or suchlike in the bearings?

I would inspect them and see if you can wash out all the grease fully then regrease them. It should be clear what the problem is once you've cleared the bearings out.

If it is the bearings, I'd be hopeful you could find a sensibly priced alternative without too much difficulty.

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