Friday, November 23, 2012

Varispeed Head Rebuild

The VS head was removed from the mill when I picked it up, and included in a wooden crate alongside it. First step was removing the motor:


After removing the motor, I pulled the upper housing apart to get bearing numbers and pull all the VS sheaves apart.

Here's a few of them for any other Lagun rebuilders out there:
ballscrew end bearings SKF 7204B (x6)
Suspended sheave NTN 6012 LB
Thrust cap bearing 6007LB
bottom sheave brg 6009LB
bottom backgear bearing 6008LB (x2)
top backgear bearing 6004LB (x2)
Motor bearings 6205Z (x2)

Many of these can be sourced direct from the bearing manufacturer, eBay or elsewhere for cheaper than the OEM who is just acting as a middleman anyways.


Using my recently-purchased bigger lathe, I cleaned up all the sheaves. The outside of the suspended sheave was beat up by a bearing race spinning on it, so I had to add material with the tig welder and turn it down, then bore the inside to make it round again for the glacier sleeve. Given the cost of new sheaves, this job justified all the tooling and accessories I've recently bought for the lathe.


Split the bottom back gear assembly apart, well greased but filthy. More cleaning…


Cleanup Effort


Removed the X-axis bracket, and surprise, its filthy.


Y-axis way, before shot.


Y-axis ways, after a lot of carb cleaner and shop rags. You can still see the scraping marks, so I hope that means my gamble paid off - in spite of some rust and grime it looks like this mill got lots of lubrication while it was in service.


Table after going over twice with a razor-blade scraper, twice with carb cleaner and shop rags, then painting up good with some Chevron Vistac #68 way lube.


Resolver/Tach drive setup with cover removed


Lifting the knee up as high as I can to clean the bottom of the Z-axis ways and mill base as best I can

DSCF0992 DSCF0993

Cleaning out the sump. It was disgusting and nasty and took about 4 hours to get reasonably clean. I gave up on trying to get nasties and chips to overflow, since the mill was lifted up on the wheeled base I drilled a hole in the bottom of the sump, drained all the oil out, then simple green'ed and pressure washed the inside of the sump, and plugged the hole with a rubber compression/expansion plug.

Mill Home, Assessment

Here's a few pics after the mill was brought into the shop and before I undertook a massive cleaning effort.DSCF0962DSCF0963DSCF0964 Note the boxes screwed to the top right of the mill head. I'm guessing these were used to output a +/- (selected by switch) 0-10V signal (selected by potentiometer) at the push of the button. From what the previous owner told me it sounds like the mill was used in manual mode for a simple operation like drilling or slotting. Oddly the Y-axis motor was missing completely so I'm assuming they only had X- and Z-axis' hooked up. DSCF0965DSCF0966DSCF0967 Side mounted electronics box with very little left in it. Sure wish they would have left me a power supply. DSCF0968DSCF0969DSCF0970DSCF0971DSCF0972DSCF0973DSCF0974 Erickson QC40 spindle, had a TG100 collet holder stuck in it which was a pain to get out. DSCF0975DSCF0976