American Hone Company's 1915 CARBO questions

Hello today I found something very special to me at least. It's what would be my Great-Grandfather's/Grandfather's old 1915 Carbo hone that also pre dated the move to Iowa. It's in great condition for surviving both wars. But since i have reserched the caracteristics of this hone I have been finding very little information. There was a older forum on the hone itself but what I wanted to ask was slightly OT. I was wondering if anyone new about its method of use because I dont expect to get a reply on the other forum.

A few things I did find out were that:
-it supposedly is similar to a 5000 so it is an "intermediate" hone (anyone confirm that?)
-It is very hard apperently (in terms of lapping purposes)
-Judging by the lack of info on this hone is it possibly rare? However i do now that another hone made by the same company is a little more popular (00 frictionite).

The dimensions are 13.5 cm length 5.5 cm wide and 1 cm deep. Agian It was used in both wars so it has been around the block. But i would really like to now how others are using it, do you soak it vs using it dry, water, lather, oil. Using a slurry stone perhaps? I now how to hone but i am new to honing a razor itelf (I'm not an expert but I know the logistics of it).

I think most folks use barbers hones dry, with lather, or with water only. A few report using them with oil. Some hones' instructions say to rinse very well with cold water after using with lather.

Here are the instructions that came with a new 00 Frictionite, posted by hi bud gl. I've got a Frictionite, and have used it every way but with oil. I've never soaked it, nor used it with a slurry stone.

I don't know anything about its rarity. Given what you know of it's history, I'd treat it as rare.

If it really is ~5k, you probably won't get a very satisfying shaving edge off it. Use a very light touch and only a few laps to hone with it; barber's hones are usually quite fast cutters.

That hone was made by the American Hone Company. They made both a 5 1/2" & 6 1/2" long model. The abrasive is silicon carbide and the binder is earth based type (think clay type of stuff). The grit was rated at 3F but during the manufacturing of the hone the abrasive was crushed under high pressure so the end grit size cannot be determined. In comparison to other barber hones this would not be rated as a fine grit hone and should be used as an intermediate hone.
Rare it is not.

Hope this helps. :D

amazing that you have this knowledge randy..
im thinking that 3F refers to the "flour rate" of the abrasive, taking 3 hours to settle in water? something like that? please explain.

I do not have any definitive information as to the methods used to grade the abrasives. The options they had at the time was the method you have mentioned which is the sedimentation in a fluid technique and other fluidr based separation techniques. Of course they also had the sieve method. From what little I know there were no standards established like we have now.

One document I have seen was an internal memo from the Carborundum Co. to its sales reps giving them guidance as to grit size. They said that a 3F rating was equal to 400 grit and finer, a 4F was 500 grit and finer etc. Please note that it meant the coarsest grit was 400 or 500 etc and also had everything that was finer. The question that arises is what was the distribution/percentages of the finer grit sizes?

Of course this is all interesting but what really counts is how the razor shaves! :D

I FINALLY, got the chance to gice a go with this hone and I can't say enough about how well it performs. THIS HONE IS AN ABSOULTUE GEM IN MY OPINION!!!!!! For a little side note about my previous questions:

The lather on the hone method (i used proraso) yeilded an effortless glide in fact i was worried I was applying to much pressure.

A definite barber's hone, three strokes got my bismark back in the game but the extra three strokes were just gravy.

Like hinted in other forums the thing is very very very hard, I gave up with the norton lapping plate 5 min in beacuse i was dishing it out so i settled for 400 grit wet or dry sand paper. After which it came out smoother than i thought it would, so smooth that no further progression was required. However I do think I will invest in a DMT 120 or 325 to lap my lpping stone and this (any recomendations?). I did not keep track of the time seeing as I did this in the afternoon in preparation for using the razor the next morning.

The final word on this stone that I have is, in combination with the right stones, or for touch up sharpenings, the 1915 CARBO will redefine the term comfortably sharp.