Thread: Flattening a Hard Silicon Carbide Honing Stone

Crystolon" is a trademark of Norton Abrasives for man-made stones of Silicon Carbide that are vitreously bonded. In other words, they are heated to such a high temperature that the grains fuse together. Other companies can make similar stones but cannot call them "Crystolon". Silicon Carbide has a mohs hardness of 9.5.

I wonder if the Atoma plates might work better due to the design with the diamond grain more exposed.

I used two grades when doing my stones Stewie . I can't check to see exactly the grades now . They were either 60 and 80 grit or 80 and 120 silicon carbide . It breaks down so quick that an 80 will be a 120 in not much time at all. I lay the glass flat on a piece of manufactured board so it can take a fair bit of direct pressure . I was using 3mm glass . A shoebox lid size piece . And making sure the circles and straight passes were covering the whole piece of glass for even wear down . I'm not sure this mattered the wear would be so fine but I did it anyway . Nice flat fresh faces cut the steel well!! I've done silicon carbide stones , a few Norton's, I think they were , my pride and joy Camberwel market find 5 or $10 Black Arkansas and some green Charnly Forrest Ebay buys from the UK . The same grit cut them all well.
Most would know? It's pretty important to keep them flat as a curved stone will curve the bottom flat of a blade and this is not so bad on a plane iron but it is bad on a chisel for true paring and makes a difference , specially when paring end grain joints to a dead on scribed line
Rob

Rob; as we have both highlighted the silicon carbide powder does break down quite quickly when used on these extremely hard Norton Crystolon stones, so its important to replenish the powder to speed up the flattening process. It cost me $86.00 to purchase the 1250mm x 300mm x12mm laminated glass (12mm rubber seal included). The reverse face of the glass will be dedicated to flat sanding. A cheap outlay when you consider the benefits gained by having a large area of flat surface to work with. The rubber seals serve their role of containing the flow of the slurry.

Stewie;

Those *very* dished ... 5-10mm deep old school oilstones ---> concrete slab, and for the fine finish ... a limestone block

Cheers,
Paul

Originally Posted by hiroller

I wonder if the Atoma plates might work better due to the design with the diamond grain more exposed.

All of the electroplate diamond hones are pretty short lived if they are exposed to crytolon and india stones, as well as very coarse waterstones.

Best to find something cheap (like really coarse sandpaper or loose grit) to do the work on the stones as they're hard on anything.

Trialled 150 grit sic powder to flatten the reverse side of the Norton Crystolon Honing Stone. (1/16" hollow down full length of stone). 15 min work.

Stewie;

All of my oil stones have now been flattened using 150 grit sic, this was followed by a good rinse and wipe down using a mix of household detergent and warm water to remove any contaminants. The stones were then treated to a good soaking of Dan's Honing Oil.



I also worked the sole of my Stanley #4 for 15 min using the 150 grit. The critical areas are totally flat. I will be ordering some 60 grit sic to flatten the remaining soles on my Stanley bench planes. (No LV or LN bench planes in my workshop.)




Phillip; before I started working the sole of the No.4 , the hollow stretched from the front toe - to just shy of the heel. Not ideal.

Stewie;

Stewie,

Have you noticed any deterioration in the surface of you glass plate?

Regards,
Rob

depending on how fussy you want to be, I find the cheap 4 sided diamond plates from Aldi with a little turps makes short work of things

shedbound; add some real value to this forum and forward a thread (with photo's) detailing your sharpening technique.

Stewie;

Originally Posted by rob streeper

Stewie,

Have you noticed any deterioration in the surface of you glass plate?

Regards,
Rob

Rob; there is a cloudy appearance to the top surface of the glass that indicates abrasive wear, not enough to have any effect the overall flatness of the plate. To minimize the long term effect of abrasive wear, the strategy I am following is to not localize, but work the sic powder across the whole surface of the plate. Its likely I will get 1 -2 years of use, before I need to flip the glass over to a new surface. Up until then; the other side will be dedicated to flat sanding, using spray adhesive and sanding paper. At only au$80.00 for the sheet of 1250mm x 300mm, 12mm laminated glass plate, imo it was a sound investment.

Stewie;

Ok, here's my process, the stones were not too bad as I try to keep them reasonable,
SAM_1896.JPGThis is the cheap diamond stone from Aldi, This one has flattened countless chisels, plane irons and sharpening stones and is still good, yes I am singing my praise for these things I love them for $10,
SAM_1898.JPGthe bucket lid is just to dip the diamond stone, I work the stone back and forth length ways alternating angles etc
SAM_1901.JPGSAM_1904.JPGHere is the end result after 5 minutess work, the grey stone is very fine and very hard its a "something" #1 it just polishes the tool really, I like a ever so slight camber (up) in the stone over its length. I know this method may not suffice for the aficionados, but I class this as acceptable for myself, even if you want to use the method to hog of the worst of things and then finish on glass.
SAM_1905.JPGFinally some of the slurry
cheers Joel

This afternoon I flattened the sole on my Stanley #5C, a fairly quick process with a corrugated sole. A quick resharpen of the blade, and set the cap iron clearance by eye to around 0.8 mm. Very nice shavings.

Stewie;