Thread: Surface Grinder Table Lubrication

I have a Kent 200, 1984, surface grinder that I need to get working 'soon'.
The SG is the original manual version.

I have scrapped all the electricals and built a new control panel with VFD.

The chuck is off the table and stored upside down.
The table is off the cross-slide and inverted to clean the rolling glideways.

The table runs on two sets of balls with plastic retainers, 20 at the rear with a V track on the cross-slide and an inverted V track under the table.
The front has 19 balls with a V track on the cross-slide and a flat surface under the table.

The cross-slide runs on two V guides.

Lubrication is SAE30 with a one-shot manual oiler and dispensing meters to the vertical and cross-slide screws, vertical slideways, cross-slide V ways but, not to the table balls.
There are no oiling points that I can find, or identified in the manual.

The manual states that the machine is delivered with the table off the machine and anti-dust grease on the table roll ways, and requires cleaning prior to assembly.

On inspection, the balls appear to have both grease and oil in that there is a trace of clean grease on parts of the table and an oily film on the balls.
The table was 'gritty' when rolled.

But, there is no statement about lubrication of the balls.

One model in the range has flexible lines to the table ball ways from the one-shot oiler, but several others are lumped into the descriptions above, including some with hydraulic table operation.

Should the balls be operated dry, greased or oiled ?
If lubricated, with what ?

Another aspect is the position of the balls.
I am inclined to clean and re-fit each ball in its same location to avoid upsetting the wear pattern.
I this the recommended approach ?

Thanks for any advice,
John.

Some ball way machines like the cincinatti TC grinder say to keep the ball ways dry.

But then the Blohm grinder that Ueee has that also has balls ways require lubrication.

Maybe some dry lubrication like a moly type?

Yes, it appears there have been various lubricants used in this application.
My inclination is to apply a light coating of lanolin and see how it goes.
The table is quite easy to remove for an inspection.

I have cleaned all the balls and carriers and given the roll ways a first clean and inspection.
I have documented the location of every ball and every carrier, even which way was up for the carrier, so that I can put the whole arrangement back exactly as found.

The roll ways have a visible track, but any wear is not detectable with the fingertip.
The visible track is narrower at the ends, presumably reflecting slightly more wear in the middle.

I can think of no easy way for me to measure track wear.

The balls are about 15.8 mm diameter.
I have run them through my Mercer benchtop precision comparator DTI reading to 0.0001"/division.

The balls appear to show about 1 division smaller diameter at the ends.
Perhaps there has been more wear on the end balls due to higher pressures and them first encountering contaminants.

If the balls are smaller at the ends and the track is less worn at the ends, with larger balls and more worn track in the middle, then it seems wise to retain the ball locations as found.

John

*Warning. Novice commenting*

Sundry thoughts: If the outer balls are worn more, at either end of the run won't there be a clearance issue when the table is full travel. i.e, the table will tend to have a pendulum effect near the end of its travel.
If the worn outer balls were swapped with the un-worn inner balls you'd still get that pendulum effect until the base to table runner wear were evened out then it might run 'flatter'. Although, having the worn balls to the centre of the table would leave a large part of the table unsupported giving possible chatter.

YBAF,
I think most of us are novices at this level of precision and knowledge of causes and effects.

Your thoughts have gone through my head also.
I spent some time reading posts on Practical Machinist, Abrasive Machining - mind blowing details and finesse.

Trying to get a perfect result is too hard for me at this stage, simpler to just strip, clean, lubricate and re-assemble.
Some operational experience and test pieces will indicate if I have to do any additional work.

John.