Negative scrape turning tools

[Jeff Leslie]

A few out there are wondering why I have so many chisels. Well, this is my short/long answer.

When my club friends come out to turn on "decent" lathes, I usually (no, always) end up doing the sharpening on one of my Tormeks. It can be a log day sharpening. Black stone for the hard stuff, grey wheel otherwise. I still have another 3 grey wheels in the bank under one of the Tormek deals (It's just me with sharpening, I don't want to start a discussion about the merits of an over-priced system but for me its an invaluable tool).

Now experienced turners know how to move the tool a tad to get a fresh edge. That is not all of us. Most of my visitors probably use 1/3rd of the sharpened tool. It's a learning process. But in the end, negative rake scrapers (which are almost fool proof) need frequent sharpening. I don't use/agree with the burr process - my chisels are just sharp before use.)

I/we turn a wide variety of projects here. One thing I do insist on is the best finish possible off the tool. Thus, I have more than a dozen scrapers, some for me (aggressive) and others negative scrape for those with less feel/control.

But back to the point: negative rake scrapers are almost mandatory for beginners on face-plate work. My students (which is a joke really because I have been pupil of Vic Wood, Guilio Marcolongoand Ken Wraight for many years) need to be able to turn/scrape catch-free. They do so with my grind).

One last important thing: you may have heard that Neil Scobie is quite unwell. His son is putting a "book" together about POSITIVE things/experiences you may have had with Neil. Email me and I give you the address so you can send your stories on to his son.

I can start a separate thread if necessary.

[chucky]

Hi Jeff, I thought that you required so many chisels to even the weight in your Toyota when loading to go to turnarounds. You mentioned that you were also a pupil of the 3 best turners in Australia & they have taught you well. See you when next time your Melbourne or at the club

[Woodturnerjosh]

375823

I agree with some of what you say but in recent posts (not just yours) people seem to be under the impression that negative rake scrapers (NRS) are a new concept or an alternative to regular scrapers. Neither of these ideas is true.

The link I've attached is an article (above) by Stuart Batty (a production turner, and son of production turner Alan Batty) who, as a incredibly highly skilled woodturner, lists the advantages, use and sharpening angles of negative rake scrapers.

They do not leave as good a finish on soft timbers as a regular scraper but on burls and end grain on dense timber they leave a superior finish (I've been turning for well over a decade and learnt with regular scrapers so while I may not be a professional I am far from a beginner)

This isn't directed at you Jeff, but I highly recommend people read this article as there has been so much misinformation brought up about these scrapers that I thought people might want to read up a bit about them and the advantages they have in the right situation.

[Jeff Leslie]

No offence taken I assure you. There are certainly differing views about negative rake scrapers. The ones used by Vic Wood are sharper in the angle than anything else I've seen. He gets away with it because his touch is so fine. If you listen to those in the US, they invented them! Thanks for the link to the article, I will certainly have a read.

And yes, Ian, hope to see you, Gordon, Allan at the Club soon.

[Jeff Leslie]

Just read the Batty article. I don't agree with his insistence on a burr. Ken Wraight relates the story well enough - the burr breaks of into the wood. Not ideal. If you want proof, use the burr on something hard and put it out in the weather. In time, you will notice rust.

Now this year at the Wagga turnaround, Ken was cutting a goldfield's burl that previously he had no success with ANY scraper or gouge. He got one of his Hunter tools out (which appears to have a burr but does not) and the finish off the tool was exceptional.

We had a similar experience last year on a large salmon gum platter. That lump of wood wrecked the cutter though.

Opinion will vary on this, no question. I just do what 3 exceptional Oz turners have taught me.

[Woodturnerjosh]

My own experience and tests contradict yours regarding the burr but to each their own.

Like your teachers, Batty is a world class turner whose delicate winged vessels demand and exceptional finish off the tool.

[chucky]

I agree with you, Stick to what the 3 Ozy say Not a video, These 3 OZ turners are of world class and are prepared to give advice & show you when their attending various turnarounds.

[Woodturnerjosh]

I agree with you, Stick to what the 3 Ozy say Not a video, These 3 OZ turners are of world class and are prepared to give advice & show you when their attending various turnarounds.


A) it's an article NOT a video
B) The names of Stuart and Allan Batty are pretty well known in turning circles (well they have been cropping up in turning books for as long as I've been buying them anyway) so his point of view and information deserves as much attention as any others.
C) I've met and learnt from all three Ozzy turners mentioned and think they are great guys and fantastic turners...but from my OWN experience the article I linked speaks the most truth. If you don't agree with it AFTER trying things for yourself thats fine but saying "someone told me otherwise so I'm not going to bother trying" is just lazy.

I can see why so many leave this forum....

[Mobyturns]

I have been using a negative rake scrapers for probably the best part of a couple of decades now and long before I realized they were called negative rake scrapers. A 1" skew held flat on the tool rest or in shear scrape mode is a negative rake scraper. We even used a curved version of a skew similar to a Alan Lacer skew inside bowls.

I just checked the AAW Journal index - Stuart Batty had an article in 21:1 (Spring 2006) in which he attributes his development of negative rake scraping techniques from modified ivory turning techniques from necessity to clean up square bowls from goldfields burls he was turning at the time and experiencing tear out that both he & his father could not solve using gouges etc.

Scraping techniques have been utilized by pattern makers for probably centuries & I'm sure some of their tools would fit the "negative rake scraper" definition.

Burr or no burr - depends upon the timber. Stuart & Alan Batty turn mostly northern hemisphere timbers the 3 Aussie turners mentioned have extensive experience with our Australian hardwoods which are quite different and generally much harder, contain more silica etc than the northern hemisphere softwoods & hardwoods.

Woodturnerjosh makes a good point though - try different techniques to find the one that works best for you on each project.

Much of what has been written in the past about tool steels and burrs has been turners gut feelings and experience with little in the way of scientific validation of their theories. At the recent Turnfest, American bowl and platter demonstrator Tom Wirsing used a cheap 300 power microscope to examine tool edges straight off the grinder. Tom is a proponent of using delicate negative rake scraping techniques to refine the surface of his bowls & platters. Quite surprising to see the differences in the quality of the edge on both M2 & V10 steels from a CBN wheel and a traditional "white wheel."

[Woodturnerjosh]

just in case you didn't read the article, Batty started using the negative rake scraper technique with the burr when he encountered Aussie goldfields eucalyptus burls.
I've heard about the difference in the burr with the different steels but I'm surprised it was that significant!

[Mobyturns]

Yep, I have read the article many times as I am a fan of Alan Batty's and Stuart to a lesser extent. Both are highly skilled trade turners with extensive experience & knowledge. Stuart goes into a quite lengthy explanation of why catches with traditional scrapers occur, and why the negative rake scraper with a burr performs better.

If you follow Guilio Marcolongo you will notice that he hollows his signature offset lidded boxes with a skew chisel used as a negative rake scraper. No great finesse or fussing over maintaining a burr - just hog it out! It works well for him. I have used a modified box scraper in a similar application. It is effectively a neg rake scraper on the leading edge with a large and a much smaller bevel. Works for me but it is certainly no where near as efficient as Guilio is with his skew.

[d5k]

Very sad news about Neil Scobie, I admire him a lot. David