Negative rake scrapers

[Reed Gray]

Well, I have been making some threaded boxes, and putting a negative rake scraper to use. It isn't some thing I use much, but have been using it on the lids of the boxes to clean up end grain tool marks. I also started using it for the sides, and it works really nicely, I only have to touch the box up with 220. The problem was with having to put a new burr on it so often (I have my mini lathe set up so I can sit). Well, I have burnished burrs on my big scrapers, why not a negative rake scraper. Tried it and it works great. I do this by hand, with a triangular card scraper burnisher. Bevel angle is 40 degrees, and keep the burnisher only a couple of degrees sharper than that. The Veritas burnisher would not work, and would put too much curl in the burr. I was needing a NRS for going to the right and the left, and would burnish one side of the scraper for one direction, and then turn the burr back to the other side for going the other way. Getting tired of that, I took an old skew and converted it to a left NRS. It really is pretty easy to turn a tiny burr, and it cuts as well as the grinder burr, and lasts much longer.

robo hippy

[Jeff Gilfor]

Reed, do you have the NRS set with a larger bevel on the bottom and smaller one on top, or are they equal, meeting in the middle? Just curious, as I made one from one of my old scrapers a while ago. Ground top and bottom to 30 degrees each (for a 60 degree total angle). Works pretty well but, and this may sound like I'm an airhead, I have a hard time remembering which side is "up" after I burnish it (I do use the Veritas). I'm thinking about simply continuing to sharpen on one side only, so that a top and bottom will become more obvious. They do work really well for light cleanup work, don't they?

[Jack Gaskins]

Reed, would you mind showing your NRSs. I want one but not sure what you mean by one for the right and left sides....Thanks, Jack.

[Reed Gray]

I will have to go with a description, no picture taking or posting skills. Like standard scrapers, they are swept back to the right and left sides in a 1/4 round profile, or like a skew that is rounded rather than a straight angle. The boxes are on waste blocks, and the swept back to the left one goes from the center of the lid around to the side, and the swept back one goes from the base and on up the side. I have kept the angles the same so it was easy to change back and forth depending on right of left. I will probably keep them that way.

I have tried them on bowls, and with harder woods, they do work okay, but I can do better with standard scrapers and gouges. For the boxes, and end grain turnings, they are really great.

robo hippy

[Jack Gaskins]

Thanks for the description. Think I will go looking around the net for some photos.

[John Keeton]

Jack, I suspect Reed is talking about something similar to this set -264953

These are from Penn State, and do not yet have a negative rake, which is a 10-15* angle ground on to the top face.

[Bill Bulloch]

I use scrapers, but have never used a Negative Rake Scraper before. I have been looking at Stuart Batty's Negative Rake Scrapers and have them on my list of items to check out at the Symposium this weekend. He has so many different sizes that it is just about imposible to tell which I might need or want without holding them in my hands. The ad for these say: "The skewed blades have a slight radius edge making it easier to traverse long cuts. It can be used on either side up." I take this to mean that you can use it on the inside of a bowl from bottom to top, then turn it over and use it on the outside of the bowl from bottom to top also. I'll wait until I see a demo before I buy.

[Reed Gray]

Thanks for the picture John, those are pretty close. I like the tip to be a bit square for getting into corners like some of the bowls turned from a plank with wings on them. Also great for my boxes which are on waste blocks, and I can cut clean all the way to the block before parting off, and you couldn't do that with a round nose.

All negative rake scrapers have two bevels just like gouges, one top, and the other on the bottom. Some people like a more blunt bevel on the bottom, like standard scrapers, in the 60 to 70 degree area, and a tiny secondary bevel on the top, more in the 40 to 45 degree range. To turn the burr, you put the bottom bevel on the grinder platform. If you have a 40 degree bevel on both top and bottom, you end up with more of a skew chisel type grind, which makes it easy to flip over for either side up. You do have to grind or burnish the bevel if you flip it over. If you watch Stuart's demo (his booth set up is great, many video screens and cameras) he explains more about 'included' angles, which means both of them, top and bottom. He did make a comment once that a negative rake scraper works the same as a shear scrape. I am not sure I buy that one because one is a scrape: cutter is at 90 degrees to wood rotation, and the other is a shear cut with the cutter at a high shear angle 45 or more degrees to the wood rotation. For me, shear angles always cut cleaner, no matter how light of a cut you take. A scrape 'pulls', and a shear 'slices'.

I haven't really found them too useful on standard bowls. I do need to experiment more with them though. For sure, they are better on harder woods.

Really try to take in Mike Mahoney and Stuart doing their 2 ways to turn a bowl demo. I watch it every chance I can get.

robo hippy