Sharpening and Angles

[Big Chris]

I know there was a post here a little bit ago about angles, sharpening, and knowing the angle used.

Well today I was sharpening some big choppers and not liking the results I was getting. I decided to break out my bubble jig ( which I haven't used in about a year and a half ) and give it a try. I was really pleased with the results. I got even and uniform bevels the length of the edge.
I usually would just eyeball the bevels on the slack portion and not know what angle I was using, would just use a low angle convex. Now I can tell customers the approximate angle and be quite close, there is that bit of human error in there.

This was just a post intended to express a part of my learning curve I have experienced in my knifemaking.

Thanks
Chris

 

[james terrio]

It's very helpful to be able to measure and quantify things. It helps us learn what's really going on, how to repeat it when we get it right, and builds confidence among our clientele.

Among other things, I have a decent digital scale on my wish-list.

 

[John Katt]

I added this little jig to my platen it holds the knife at 21 degrees, this made an otherwise irritating job into a breeze, a dab of silicone spray and the blade slides across real easy, by the time I get to the 5x belt I have a very straight mirror finish on the edge, the 2nd bolt hole is long in shape and I can adjust 4 or 5 degrees in both direction

 

[Big Chris]

James: I also do like now being able to quantify these things. I think it will make changes easier in the future because the jig takes some guess work out of the equation, and gives a datum to measure from.

jonekatt: I read on here once that micarta makes a good surface to slide the blade across. BTW I like your set up.

 

[John Katt]

jonekatt: I read on here once that micarta makes a good surface to slide the blade across. BTW I like your set up.

I have been keeping an eye out for a suitable piece of plastic to help with the friction problem, I had a cutting board years ago made from some type of white plastic, that just seemed slippery like it may have been impregnated with silicone or something, think I will take a look for one the next time I go to the store

I guarantee if I get my hands on a piece of micarta its going straight on a knife LOL

 

[Big Chris]

At the machine shop I used to work at we used a material called UHMW as a wear surface and friction reducer. It was white and I think is available at McmasterCarr or maybe even Enco.

 

[John Katt]

did a quick google search and I found loads of it for sale, tons of it on ebay too, I like what wiki had to say about it, I think I am going to buy a 12x12x1/4 sheet and put it on my platen and the tool rest i use for hollow grinding

has a very low coefficient of friction; is self-lubricating; and is highly resistant to abrasion, in some forms being 15 times more resistant to abrasion than carbon steel.