Bud,
This subject came up years ago when the 5.5"Z retrofit kit came out, and a lot of questions came out when Z bearing block bearings fell out.
Turns out a lot of people had been using WD40 on the rails and it degraded the factory grease.
(happened when I got back the second Desktop from up North and did his Z upgrade, and turned out he'd ignored my advice on WD
The felt wipers on the ends of bearing blocks are key.
Every 30-40 hrs of cutting, center machine(for X,Y) and wipe rails clean with light oil(sewing is good,and been using 3-1 for 5 yrs), then drop 2-3 drops oil on upper rail,
and a saturated paper towel on underside. Then I make radio button 1 0,0 and radio button 5 at 24,18 and go button 1 and then 5 about 6 times....then wipe excess off!!
Felt wipers Need to be moist to clean debris off completely!
On Z rails, got to max height/clean rails...with bit out go as low as you can, wipe rails...3-4 drops on each channel(and let it roll down channel) then raise and lower 6 times and get
all excess off. That's all the maintenance to do.
A mandolin Desktop owner asked about the grease fitting, and Brady Watson(was a Shopbot Technician/Guru at the time) explained that those bearing blocks were also used in wet environments(thus the fitting), and nothing needed to be done in dry environment except keep felts moist(he said it could actually be Bad for the factory grease).
Have to admit on the Northern Desktop where WD had eliminated factory grease,I used to have a high end bicycle shop and had sealed bearing grease(Phil Wood N/A now)..
and gave the bearings a light coat(and no problems in 5 yrs).
A little worried about that brake cleaner taking out all factory grease...NOT up on quality greases now as I still have Campagnolo lithium and Phil Wood.
Maybe someone else could recommend a top quality grease?
MAYBE just weekly oiling of felts will be good enough for the bearings? (If so I'd say weekly oiling is now a Must)
Hope this was any help Bud.
scott
scott P.
2013 Desktop/spindle/VCP 11.5**
Maine