Startrite Mercury MkI Spindle Bush Pulley Assembley

Yesterday I was cleaning the cast iron body, the only parts left on the body are the whole Spindle Bush Pulley Assembley, quill removed. While cleaning I noticed the following:

Bearings run tight, a flick of a finge gives less than 1 rotation. I would expect many rotations for a light bush/pulley in ball bearings. No noise or noticable sideway or up/down play in the bearings. When scrubbing the pulley from above there was a small clunk sound and i moved downwards about 1 mm. The sound was from the inner pulley hitting the top of the base. From below it was possible to see the outer race of the lower ball bearring move up/down in the houseing. When turning the pulley the outer race could also turn, but so could the inner race ie not stuck.

Checked the manual (http://www.altsawsandspares.co.uk/spares.html) and did the following:

Tigthend the grub screw through a hole in the pulley (second gear from below - see photo). This stopped the whole assembly moving up/down and the outer race of the lower bearing rotating. Loosening increased the up/down movement to ~5 mm, but it did not free the whole assembly for lifting up and out of the housing.

Removed the 2 grub and 2 set screws for the pulley and applied light tapping and light force with a puller, heat - not moving.

Just back from the workshop and events overtook this post. What I was after was info on how the bearings are seated and the spacer to best work out how to dissamble. The heating yesterday must have gotten the old grease to move so I could lift up the whole assembly until the bottom bearing was ligthly stuck at the top. A few taps with a hammer from the bottom through a pice of wood got the whole assembly to get out. Will post pictures later.

The housing do not have a seat for the outer race of the lower ball bearing to set to.

The whole spindle bush assembly is fixed to the housing by the grub screw on the upper bearing.

The spacer is for the outer races, don't know if there is support for the inner races, I guess not.

My guess is that assembly would have been something like:

Press upper bearing onto spindle bush (does it have a seat for the inner race to set to?), spacer, press lower bearing onto spindle bush keeping the spacer free to move (so tension is not put on the bearings), drown the spacer in grease so it does not rattle when the spindle is turning, place/press/tap the bearings into the housing using the outer races if necessary, fit the pulley.

I did not find an o-ring as per the manual, but what would be its purpose? Do not look like a good seal is possible, no need for a rubber guide with 2 steel bearings, what would prevent it from sliding of the spindle bush, noise damping ???

Still considering how to separate this. The spacer do not support the inner races, so it looks to me that these are 'one way' bearings - no way to get a tool on an inner race to pull it off without damaging the bearing.

The inner diameter of the pulley got values around 23.9x mm (the rim has a small taper, so I can't a proper hold) I guess this is equal to a 15/16'' bore (=23.81mm)?

On the lower end of the spindle bush I measured diameter values of 28.68-28.71mm which is 1.129'', which is close to 1-1/8''.

Anyone who know or can verify this?

Got the pulley off with a couple of heat treatments, penetrating oil and gentle tapping with a wooden dowel while hot.

So there is an inner spacer quite tight. The leftovers of the o-ring is in an inside groove on the spindle bush.

Pulled the bearings and spacers off in one go. Bearinngs are metric 47/25/12 mm and the pulley bore 5/8''

As can be seen from the pictures everything goes on from above to the seat on the spindle bush..