Can you put taper roller bearing(s) at the nose of that spindle? That should have you sorted.
Myford 10 has two oposing taper roll bearings on the spindle and it is pretty good. In theoriy it is not the best, but with two bearings it is pretty damn good for it's price.
http://cdn.instructables.com/F20/AN3I/HH2VZMRF/F20AN3IHH2VZMRF.LARGE.jpgMuch like this:
http://www.lathes.co.uk/elffers/img14.jpgHere is plain angular front bearing and at the back there is a pair of opposing angular contact bearings:
http://www.myford.co.uk/acatalog/H21.-HEADSTOCK-SPINDLE--A1992-1120.htmlhttp://www.myford.co.uk/acatalog/info_684.htmlI think there is a document indicating how this is adjusted. If I remember it correctly first angular ball bearing was adjusted to take up play on front bearing and then second one was "snugged" into it to take up the play on the rear. pretty good at slow speeds, the "nose" bearing limits rpm.
http://www.myford.co.uk/acatalog/Specifications_of_the_Sigma_Lathe.htmlThis should have some indication of the size of relative parts.
Do I remember wrongly or was the front conical plain bearing was replaced with a single taper roller bearing at any point?
Anyways, if you don't need super high accuracy and very high speed,
angular taper roller bearings offer very much load carrying capacity for the money. Yes they are limited on speed range and they are not cheap anymore if you need to buy "Class" over standard wheel bearing standard, and they heat up a bit because they need to be preloaded, but they take up a lot of load and abuse. AND honestly? How many of us can make a spindle and housing to required accuracy that are needed to very expensive "princess" bearings?
IMOHO. Have a good looks on taper roller bearings, design a grease nipple to them (they eat grease) and exit hole, you need seals and that should take care of it.
Pekka
* Typozzzzhh