Rehabilitating an Old Oil Stone

One of the treasures from Orvil Heft's tool collection was a nice Pike's Lily White Washita oil stone.  I've never worked with oil stones, so I contacted Bob Rozaieski, who I support through his Patreon page.  Bob had some good recommendations for me and most of what I've done below incorporates his suggestions.

The stone as found

It came in its own wooden box - in fact it was glued into the box, which I thought was weird.

The inside of the box lid

The box itself was interesting.  The sides of the box were joined with tiny rabbet and dado joints that were pinned with a couple tiny nails.

One corner of the box's lid

Not every joint was still perfect ...

... and predictably with this tiny joint the dado blew out in two corners of the top

An internet search indicated that Pike's Washita stones are well thought of.  My understanding is that it's a relatively soft stone used for fast metal removal.  In 1932 Pike was bought by Norton.  Here's a great 1985 article written by Robert Topping if you want some history on Pike Manufacturing Co. and the abrasive industry in general (that's for you, Bob).

The stone was heavily dished and dirty.  And apparently it was glued into the box!  I thought maybe it was just stuck from all the muck.  But it really was glued in.  I got it out by clamping the stone in the vise and gently tapping the edge of the box until it released.

Stone clamped in vise, tapping the edge of the box with small hammer and block

Unfortunately, some of the stone stayed with the box.
The light areas show glue residue.

Side view of stone face-down on benchtop.
Notice the air space under the center of the stone - about 1/8"!

The first step in cleaning up the stone was to soak for a few days in mineral spirits to try to loosen up some grunge.

Could have used a better plastic container - this one got soft from the mineral spirits

I had read somewhere that you can roughly flatten a dished stone on a concrete block.  So I tried that, but after a few minutes, the block was smooth as a baby's butt and didn't help flattening the stone any more.

Flattening using a cinder block

After a few minutes I was still only getting the ends of the stone

After a few more minutes

I decided to face the wrath of the wife and use the driveway as a flattening stone and that worked MUCH better.  I cleaned the driveway with water several times in between rubbing sessions.

After a few minutes on the driveway

Finally got it as flat as the driveway

Then I took it inside and cleaned it off and used a coarse diamond plate to get it flatter.

I did this in the kitchen sink where I could clean away the debris often

Lookin' a whole lot better now - can see how it gets the name "Lily White"

Here's the stone standing on end in its box, looking straight down from above.
I was shocked to see a reflection off the dry stone of the red lettering in the box lid!
I guess it's pretty smooth.

The next thing I did was to boil the stone for about an hour and a half with some liquid dishwasher detergent.  This got more of the deeply embedded oils and swarf out of there.  Then I let the stones dry in the sun for a few days.

Finally,  I soaked the stone in mineral oil for a few days.

Soaking up some mineral oil

The stone should soak up some oil and hopefully that and the use of fresh oil when sharpening will keep the metal swarf from clogging the stone.

I haven't used the stone yet for sharpening - I'll do that soon and report back.