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negitive rake scraper

Stuart Batty sells them but I think right now his site it not up and running. I think I heard that he is going to have a big release of his new tool line and all at the AAW symposium and After that the site will be going again after that. I would think though that you might be able to contact him directly and purchase?

Stacey
 
S. Clark said:
You can but the real key is the type of steel. Carbon steel or even M2 won't hold the bur long enough to be effective. Stuart's found the key by moving to 10V.

- Scott
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Sorry, I guess my idea of "long enough" and Stewart's are a bit different. I have been using them for quite some time making my own out of O1 and M2 and find you just have to sharpen more often. The cost of the more exotic steels in the quantities we need, kind of preclude us from buying the raw blanks.
 
If I'm correct I think Stewart said his scraper was made from V15 steel that was really expensive. I think you could make one out of any good steel you will just have to sharpen it very often. One of the reasons is the negative rake scraper that is shaped like Stewarts has a very acute edge. This raises a really good burr but doesn't last long at all. I would have to make 2 identical scrapers with different angles to figure out the difference.
I have to flat scrapers, one home made. The homemade one doesn't raise a burr as easily and the burr is smaller but it lasts a while and cuts really clean. The store bought scraper raises a big burr easily and cuts really well at first but has to be sharpened more often. I think the difference is hardness of the metal. These are sharpened at about 45 degrees.
The negative rake scraper Stewart showed is sharpened on the edge and looks more like a skew with a really acute angle.
 
S. Clark said:
You can but the real key is the type of steel. Carbon steel or even M2 won't hold the bur long enough to be effective. Stuart's found the key by moving to 10V.
Click to expand...
That was a misprint -- if you look on the AAW home page, you will see a correction to the article:
Note: The Spring 2006 issue of the American Woodturner, page 9, misidentified the steel these tool are made from as "10V". They are actually made from M-4 steel.
​
A number of the turners in my club have been using negative rake scrapers for years and one of our members showed Stuart Batty some new ideas for negative rake scrapers such as not using symmetrical angles for the top and bottom of the scraper. M2 steel works just fine and since the main advantage of the negative rake scraper is getting an ultra smooth finishing cut, the life of a burr is really not an issue.

Bill
 
Bill - that correction was specifically for the commemorative gouges - which are M-4 steel. The info might also apply to the negative rake scraper, but it also might not.

Also I agree with your comment about M-2 being sufficiently hard for a good scraper. I've had good luck with regular old carbon steel too.

Mostly I only have to start sanding with 200 grit just like all the other turners on this forum........right. 😎
 
boehme said:
That was a misprint -- if you look on the AAW home page, you will see a correction to the article:
Note: The Spring 2006 issue of the American Woodturner, page 9, misidentified the steel these tool are made from as "10V". They are actually made from M-4 steel.
Bill​
Click to expand...


I spent two days with Stuart; it's 10V. The other point that may be missed here, and I think he mentioned it in his article, is that he is using this tool on exotic HARDwood. He turns a lot of cocobolo. You need a bur that'll last. He showed me how with regular HSS steel you lose the bur after a single pass if even that. Count to 3 and it's gone. If you are scraping common woods, there is little need for a negative rake. Shear scraping is adequate for what most people are turning.

- Scott​
 
Stuart demonstrated this scraper at the Southern States Syposium last April - he was custom making them and selling for more $$ then I could afford. I took a piece of carbon steel when I got home and ground one out followed by a cutting torch hardening and quench. I absolutely love the finish it gives - really does let you start sanding at 220 grit. I do have a problem even with the hardening I did with the burr not lasting long at all but it is very easy to put a new burr onto this scraper. I am hoping the new company will be able to mass produce this at a lower $$/scraper cost so I can buy one made out of the better metal!

Wilford
 
The Austin local chapter is sponsoring a well known woodturner from Colorado this week and I went to the all-day demonstration today. There was lots of usage of negative rake scrapers. All of them were custom. Mostly of them only had a 5 degree bevel on the top. Mostly they were all M-2, and I'm not sure if any were Powdered Metal or other "exotic" beyond M-2 in hardness.

It was a good session for me. But no one seems to know for sure why they work better than a standard 90 degree scraper. And none of this scraping was done riding the bevel.
 
Jeff,

Sounds like perhaps Trent Bosch. He was our demonstrator last spring and while he was here a couple of our members who have done quite a bit of experimenting with negative rake scrapers showed him what they had learned about them. I don't know anything about Trent's prior usage of the tool, but he seemed interested in what they had to show him.

My thought about the advantage of the negative rake scraper over a standard scraper is that it presents an edge to the wood in the same fashion as tilting a regular scraper downward towards the wood -- the main difference being that the negative rake scraper is held flat so that most all of the force of the tool on the rest is straight downward whilst the force on a tilted tool can be resolved into two components -- one component being downward on the rest and the other pushing back along the tool. This second component of force is the problem because it requires the user to counteract the force and the reaction time of a human does not allow one to control both force and position accurately simultaneously. This results in a dynamically unstable control loop -- whenever the turner applies more force than required, a dig in may result -- pulling the tool away from the turner -- a sudden reversal of forces that the person can't handle fast enough.

Because of the relationship of the cutting edge to the tool rest when using a negative rake scraper, any force applied by the turner that would push the edge into the wood causes a reaction from the wood to push the tool back away so the system is inherently stable with no sudden force reversal.

BTW, your observation is the same as mine -- definitely no bevel rubbing. And regular M2 steel is just fine. I think that the bevel rubbing idea is related to using a scraper like the Sorby hardwood scraper.

Bill
 
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rbagley said:
Jerry Glaser builds the scrapers for Stuart Batty - or at least he was a year ago.
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They will re-emerge as CET cutting edge technology (at the AAW symposium). Not sure where everyone fits in, but Stuart is the VP of R&D. There is also a company Cryosteel involved .

Had I known it was for sale, I would have busted my piggy bank (ok, so everyones piggybank).
 
Bill (B) - I think that sounds like as logical of an explanation as any explanation that could be. It's interesting to me that a minor 5 degree relief cut on the top provides so much flexibility. Maybe this "newly refound" technology will sweep thru the woodturning field faster than bowl gouges did a few years ago.

ALL - Jerry Glazer is 85 years old (or somewhere around there). While he is doing good for that age, at some point nature takes a turn. Currently he is planning to be at the symposium.
 
rbagley said:
Jerry Glaser builds the scrapers for Stuart Batty - or at least he was a year ago.
Click to expand...

Just a note when I saw Stuart's scraper in the magazine it just appeared to be a reground glaser scraper A11 scraper. It would be nice if they do start selling them rather than me buying another high end scraper to regrind.

For those who think your M2 negative rake scrapers are "good enough" it is most likely because you have not used one of the high end ones. You can get a good enough scraper out of M2, but a negative rake scraper really is a different animal. Comparing an M2 NRS to one made out of asp 2030, 2060, or A11 and saying the m2 is good enough is like comparing an RX7 to a Ferarri and saying the mazda is good enough without ever having owned much less driven a Ferrari.
 
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