Thread: Can anyone tell me if this is a Coti/BBW Combo

Hi Guys, I really haven't posted all that much on here so I am trying to make up for that. I recently grabbed this off of ebay. The guy had advertised a "Machinist's Sharpening Stone Lot" and among the hones was a Coti. The rest of them are pretty usless, maybe i can use them for my chisels but anywho. I'm new to honing and I can't tell if this is just a coti on a slate backing or if it is a combo. I used one of the other hones (a small Norton diamond hone to raise a slurry on the back side (I have a slurry stone from SRD for the Coti side. Here are some pics. See if you can tell me anything about the backside















I am waiting on my DMT to lap the nicks out of the Coti side. I tried different settings on my camera to try and capture the true color of it. If this isn't helpful could you tell me what I need to do to find out if it is in fact a combo. I know this isn't a Natural because of the straight seem and the fact that I can see were they joined them together. Thanks guys inadvance for checking this out.

From the pictures the slurry definitely has the purple colour indicative of the BBW. Does the slurry created from the backside look very purple in person? If so, I am pretty confident in a positive BBW I.D. Wait for others to weight in, but I'm almost certain that's a BBW!

Looks like a combo to me.

The second and third photos that show the putative BBW side are not quite in focus or don't have adequate resolution for me to tell for sure. The slurry in the later photos look dark so that is a good sign. Does the slurry appear to be somewhat purple in color? If so, then it is a bbw. Despite the poor quality photos (not a criticism) I would guess it to be a bbw and thus a glued combo.

Yea I've never been good at picture taken but it seems like my Sony Cyber Shot has been acting up on me also. Yes it does have a purplish tint to it. I'll keep trying to get better pics of it. If I can take a better one I'll post it. Thanks alot for the help guys!!

try putting something in the picture for the camera to focus on like a small ruler (scale), a key or something of the sort. I had the same problem an adding a scale to the shot fixed the focus problem. Looks like a coti/BBW to me with the pics you provided. Netter pics would help.

if the camera has adjustment for tungsten lightning use it that will correct for the white ballance. Probably best conditions for a decent picture are outside, try and take a close up of the surface of the stone.

The slurry is a reddish purple but the bbw stone without the slurry looks almost like chocolate on some of them when contrasted with the yellow coti. No question it is a combo IMO. See this tutorial in the SRP Wiki here and check out step 2 & 3. Give that a try and you'll see how it performs. Some are faster/slower than others.

With Jimmy on this. It's a combo. Looks like a glued one.

I don't know if this adds anything useful to the conclusion others have reached, but I find that the BBWs have a slight sparkle to them as you turn them in bright light, like there are small shiny dots of something embedded in the surface of the stone. I don't think you see this effect with a slate backing, but I'm not sure, because all of my stones are combos.