Author Topic: Negative rake scrapers  (Read 8635 times)

Offline Haggy

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Negative rake scrapers
« on: July 05, 2014, 05:52:39 AM »
http://m.youtube.com/watch?feature=em-subs_digest&v=tdXxkr1hEPE


This U- tube link shows Mike Waldt experimenting with grinding angles on negative rake scrapers.  He is clearly impressed with what he has discovered and shows the results of his work on a platter.
Mike is inviting comments to his newly discovered grinding angles but I haven' t the knowledge to comment, I would imagine several  AWGB turners have made similar discoveries.
 Is there broad agreement on Mike's discovery or is I something new to turners?
 I own one scraper and am considering altering my grinding angles, but  am cautious as BHT has warned me not all advice is good advice on U -tube.
      Regards Haggy

Offline George Watkins

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Re: Negative rake scrapers
« Reply #1 on: July 05, 2014, 07:38:53 AM »
I've just replied on Mike's Video

I have been using negative rake on all my scrapes for about 10 years now, it’s a great technique which is especially effective on dense woods and acrylic/resins. I first saw Stuart Batty demonstrate the technique at an AWGB Loughborough seminar and I believe it originates from Ivory & bone turners, the angles aren't critical but it is important to stay between a combined angle of 40 to 70 degrees. The burr raised from grinding is most important and must be replenished often, i have not found a way of getting a good burr from anything other than a grinder.
The technique saves allot of time sanding and is very user friendly as it is a neutral cut, by that I mean it doesn’t pull you in or try to grab like a normal scraper nor does it bounce off, it just sits where you want it and beautiful little ribbons peel off the work.

More info here on a PDF Stuart put together



Offline Graham

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Re: Negative rake scrapers
« Reply #2 on: July 05, 2014, 08:02:01 AM »
To be fair Mike says he was introduced to negative rake, he isn't claiming any originality.
Regards
Graham
I have learnt the first rule of woodturning.
The internal diameter should never exceed the external width.
Nor the internal depth, the external height.
Does that make me an expert now ?

Offline Les Symonds

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Re: Negative rake scrapers
« Reply #3 on: July 05, 2014, 08:30:07 AM »
I'm with you on this one, Haggy, and will wait with bated breath until some of the more seasoned turners respond. It certainly looks interesting.

Les
Education is important, but wood turning is importanter.

Offline George Watkins

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Re: Negative rake scrapers
« Reply #4 on: July 05, 2014, 09:02:24 AM »
To be fair Mike says he was introduced to negative rake, he isn't claiming any originality.

to be fair to who? why have you made this comment?

Offline Haggy

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Re: Negative rake scrapers
« Reply #5 on: July 05, 2014, 09:48:32 AM »
Thanks for your help George, reassuring and interesting - I am excited to give this a try.
Not sure who Graham is referring to -  but I have thanked Mike for his work.
   Regards. Haggy

Offline Graham

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Re: Negative rake scrapers
« Reply #6 on: July 05, 2014, 10:05:27 AM »
I guess it was to early in the morning. I was just reacting to to the idea that Mike was claiming to have 'discovered' negative rake. My apologies.
Regards
Graham
I have learnt the first rule of woodturning.
The internal diameter should never exceed the external width.
Nor the internal depth, the external height.
Does that make me an expert now ?

Offline woodndesign

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Re: Negative rake scrapers
« Reply #7 on: July 05, 2014, 08:29:32 PM »
To be fair Mike says he was introduced to negative rake, he isn't claiming any originality.

As umbrage has been taken over my last post, as to which I'd seen as the above, a fair and understandable comment by Graham .. I've deemed it fitting to remove.  Trusting this resolves the ill feeling and any misunderstandings in the comment, which was not any attack on any party.
"It was the best of times, it was the worst of times,"  By Dickens ''''

Offline George Watkins

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Re: Negative rake scrapers
« Reply #8 on: July 06, 2014, 08:34:22 AM »
To be fair Mike says he was introduced to negative rake, he isn't claiming any originality.

As umbrage has been taken over my last post, as to which I'd seen as the above, a fair and understandable comment by Graham .. I've deemed it fitting to remove.  Trusting this resolves the ill feeling and any misunderstandings in the comment, which was not any attack on any party.

what an odd response!!

I sent you a private message to ask you to clarify privately what your post (that you have now removed) was about as I couldn’t understand it.
I wasn’t sure if I had upset you or not, but I hadn’t taken umbrage just the opposite as I was worried that I had offended you somehow.
I re-read my post over and over and couldn’t find a reason why it might have upset anyone, and still can't

I struggle sometimes with forums as I want to help people but worry about upsetting people, which is why I asked for clarification privately from you but you decided to do this instead.

I think it’s best if I leave you to it.

Sorry to Haggy for side tracking your thread but I did try and do this privately, please delete it and start again.

Offline The Bowler Hatted Turner

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Re: Negative rake scrapers
« Reply #9 on: July 06, 2014, 12:08:20 PM »
http://m.youtube.com/watch?feature=em-subs_digest&v=tdXxkr1hEPE
 I own one scraper and am considering altering my grinding angles, but  am cautious as BHT has warned me not all advice is good advice on U -tube.
      Regards Haggy
Haggy glad you are being cautious and I stand by my and other's remarks regarding U-tube "advice". Regarding negative rake scrapers, I did regrind one of mine to a negative rake a couple of years back when I first heard about them. To be honest I found them difficult to use but that may have been because I am so used to using "ordinary" scrapers. When I use a scraper I can get what I call "fairy" shavings, very soft and fluffy but definitely a shaving so I am happy with that and cannot see why I would change; but techniques do change over time as that is what gives our craft impetus, so if you try and like and get on very well with it I suggest you adopt this method. I would however take care as the tool is no longer trailing and a snatch will at the very least be loud and frightening.(this is not a negative point just a precautionary one) :)

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Re: Negative rake scrapers
« Reply #10 on: July 06, 2014, 12:16:13 PM »
Hi All,
I cannot resist my tuppenceworth on this subject.

My source of inspiration, and much of my knowledge has come from my sadly lamented good friend  Bill Jones, whose books are in my opinion the best and most interesting books on turning you can lay your hands on - that is if you can, as they have now been out of print for some time. He reckons scrapers are people, not tools, though I cannot imagine what a negative rake person would look like. My experience is as follows;

I have used scraping, actually cutting, tools for a long time now on both hardwoods and alternatives. As per Bill's recommendation I remove any burr from the tool for these materials. Not removing it makes for a much more, and often too much more, aggressive cut. The burr should be left intact for softer materials. The negative rake for best use I find is controlled by the turner (scraper) by raising the handle until best results of cutting are obtained. Even with pre negative raked tools this may also help.

Just my input, which may be of help to some turner.

Have fun, cheers, John.

Offline Haggy

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Re: Negative rake scrapers
« Reply #11 on: July 06, 2014, 09:35:24 PM »
Thank you for your replies, interesting what you say about the burr John. 
I do want to say a massive thank you to George though, because I have learnt SO much from the link you posted re: Stuart Batty and Negative rake scrapers.
 I have  put a secondary bevel on my scraper and seen a big improvement. 
I had to open your link George by re: visiting Mike Waldt's  U- tube video and reading your comment ( couldn't open it on this forum).  Mike Waldt was very grateful for the link too and wanted to share it with others- so you have done good all round. 
I am really sorry there has been a misunderstanding on this thread, particularly when George has done so much to help me.  I don't  think any harm was meant by anyone and I do want people to say what they believe even if I don't always agree!
       Regards.  Haggy