Broken Scraper

Discussion in 'Woodturning Discussion Forum' started by Jay Pugsley, Sep 2, 2017.

  1. Jay Pugsley

    Jay Pugsley

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    I am working on a number of platters. I was using my scraper in the middle of the bottom, completing the mortise. All of a sudden, my scraper snapped off about an inch back, just about where the tool sat on the rest. When I turned the lathe off, it looked like I had a catch. Tool height was right at center level. Anyone have any ideas? It's part of a HF set, and the wood is very hard and dense. Possibly the tool quality? I was happy the piece didn't fly off, but rather just landed on the bench.
     
  2. Richard Coers

    Richard Coers

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    3 things come to mind: You had the handle lower than the cutting edge so the scraper self fed, you had the tool rest too far away, you used a cheap Chinese tool. Could be either or all of these.
     
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  3. Mike Johnson

    Mike Johnson

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    Steel was hardened and left too brittle or it could have had a small flaw in the location
    that it broke.
     
  4. hockenbery

    hockenbery AAW Advisor Staff Member

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    If the bevel of scraper is allowed to contact with the wood a catch is very likely because the wood will drive onto the cutting edge.

    I like the tool rest aabove center when working inside.
    When using a square scraper this also gives clearance to make a clean edge on the wood.
    Never drop the handle below level when working inside.

    A quality tool should not break. Too brittle or maybe an impurity or imperfection in the steel.
     
    Last edited: Sep 2, 2017
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  5. Jay Pugsley

    Jay Pugsley

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    Thanks to everyone. I suspect that it was a combination of handle position and tool brittleness.
     
  6. odie

    odie

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    I agree that the steel was probably too hard and brittle. I've never heard of a (quality) tool snapping in two like that. I buy quite a few odds and ends at HF, but I'd never expect the kind of quality I'd get with other name brand tools.

    Question: Was there a dent, or nick in the tool rest itself?

    -----odie-----
     
  7. Jay Pugsley

    Jay Pugsley

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    No, Odie, not that I can see. I actually just recently lightly filed the rest to remove a couple of spots the tools were "catching" on when they traveled down the rest. I bought the HF tools because they were all my budget could take. I have been surprised at how well they have worked, but even though they are HSS, they don't seem to keep their edge very long.
     
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  8. John Torchick

    John Torchick

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    I have the HF set and have had no trouble from them. I have been using the round nose scraper now for turning pen blanks. Sharpens good abd cuts good.
    Like anything, there could be one that has a problem. Like buying a Rolls-Royce and it won't start the next day. Don't laugh, this actually happened here many years ago.
     
  9. Mike Johnson

    Mike Johnson

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    Jay,

    Shop around and keep an eye on the used lathe tools on CraigsList & Ebay, you can find pretty
    good deals on used lathe tools most of the time. I found a large assortment of good quality lathe
    tools by filtering the query with "nearest to you" several years ago and bought a large assortment
    of Robert Sorby tools for about 10% of the new cost. Good Tool Steel never goes bad. :)
     
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  10. Richard Coers

    Richard Coers

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    I won't mention the brand name, but I had a very high quality tool snap into about 5 pieces. I was working on the back side of the bowl, shear scraping with a bowl gouge with a fairly long overhang, and just touched the chuck. It was an instant pop, and the bowl gouge was 2" shorter. I looked for pieces, finding a total of 5. One in my hand and finding some in the chips with a magnet. By the way you could see a nick in the chuck, but the cutting edge of the gouge barely had a mark. Because of the shattering of the tool, I'd be certain it had a metallurgical issue. I sent photos and had a free replacement in less than a week.
     
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  11. John Torchick

    John Torchick

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    Richard, that is good that it was replaced. As to the name of the company, it might be helpful to share it, if you want, so if the problem or any problem comes up, at least we know they will take care of the customer.
     
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  12. Bill Blasic

    Bill Blasic

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    There are no perfect tools, they do and will break on occasion. For me hanging a tool way over the tool rest and hitting your chuck is operator error and one should not be surprised that a tool can shatter in that circumstance. Proper tool usage will negate most tool breakage.
     
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  13. john lucas

    john lucas

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    Richard I wouldn't say it had metalurgical issue necessarily. Turning tools are hardened to 50 to 62 rockwell as far as I know. That's pretty hard. Not as hard a file which will easily shatter but hard enough that when it gets really stressed it could do more than just break like a tool of lesser hardness. I've taken a few hits of my chuck with brand name tools and so far no damage other than a nick it the cutting edge and or damage to the chuck. Hanging a tool very far over the tool rest of course is asking for more problems although we all do it.
     
  14. Richard Coers

    Richard Coers

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    Well the company suggested there was a metallurgical issue. And with the number and size of pieces shattered away from the break, I agreed it was a metallurgical issue. The tool was overhung to do a high angle shear scrape, not in cutting mode. There was no metal missing on the cutting edge of the tool, just a dull spot. I certainly was in error to touch the chuck, but I've done that type of high angle shear scrape for decades. But everyone can certainly have their own opinions.
     
  15. john lucas

    john lucas

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    well I won't doubt the companies word (or your either for that matter) just basing my answer on my own experience. Back when I did the article on making tools from files I purposely broke a lot of tools and files just to get a better understanding of what I was talking about and to learn what it takes to break or shatter a tool. Obviously it's impossible to test all kinds of steel. I'm just glad you weren't hurt. I've watched several video's lately of people making tools from files and it scares me because not any of them discuss tempering the file to reduce the hardness. For those who are interested if you heat a file to 425 degrees for 1/2 hour and then let it cool naturally you will reduce the brittleness tremendously and it will still be hard enough to hold a good edge.
     
  16. robo hippy

    robo hippy

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    The break was a metal issue. Any good tool in that situation should be yanked out of your arms or stall the lathe rather than break. My favorite scrapers are seldom more than 1 inch wide, and 5/16 thick. I can stall my 3 hp lathe with that, no problem. They are also my go to tools for all shear scraping.

    robo hippy
     
  17. Raul McCai

    Raul McCai

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    I'll bet there was chatter.
    I'll bet the speed was a little fast
    I bet the contact with the rest was not very close to where the tool contacted the work.

    I've done it with one of the best tools made. A little chatter, the metal starts flexing, and a wave pattern sets in, and suddenly the tool snaps where the wave is most extreme. Buh Bye tool.
     

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