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Scraper tools for clueless newbie

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  • Scraper tools for clueless newbie

    I've seen a few different types of scrapers in pictures, but I've never done any of this. What are the tools pictured below used for? Are they just general purpose scrapers or are they for a particular scraping operation? How do you manipulate the tool - sideways motion, just with the tip, never the tip,...? Are these tools just called scrapers but used for something else and I'm just getting them mixed up since I know squat about how scraping is done? Do I ask way too many questions?

  • #2
    I believe those are woodworking tools. Probably for carvers. Scraping as it pertains to metalworking involves straight edges that are dragged sideways across a flat surface, and will 'scrape' off fine shavings, in order to get the surface flatter. Think of applying drywall mud with a trowel. As you wipe off the excess as a finish pass, you're 'scraping' it away, and the flat edge of the trowel is imparting it's flatness to the drywall mud left behind. Certainly there's technique involved, such as the angle the scraper is held at, amongst other factors, but that's basically it. Kind of like how a squeegee is held and dragged.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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    • #3
      darryl,
      Thanks for the reply. I think you must be right about these being woodworking tools since Millers Falls tools are mostly for wood. However, they are called "bearing scrapers" and I thought they might be for metal, maybe with limited usefulness.
      I am somewhat familiar with scraping in theory. The shortest tutorial would probably be to "hit the high spots" with the scraper. I also know that it can become quite involved and to get into it very heavy is likely to lead to aquiring another expensive set of tools, so I may never delve very deeply.
      I was curious about these tools because I've had a couple like this in an attic box for years and wondered if I they would be useful for experimenting, if they're for metal.
      I wonder if there are any scraper specialists who wouldn't mind me quietly staring over their shoulder for a few hours. In this country alone there must be at least... a half-dozen still working.

      p.s. I just did a little searching and found that these are likely for deburring and scraping camshaft and crankshaft bearings - oddly enough.
      Probably only useful on soft material like babbit. I'll probably just continue using mine to help hold the bottom of the box to the floor.

      [This message has been edited by vinito (edited 04-22-2004).]

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      • #4
        Those blades are probably harder than the hammers of hell. Babbitt is composed of a matrix of soft tin or lead and crystals of much harder material such as copper, antimony or nickle.
        Free software for calculating bolt circles and similar: Click Here

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        • #5
          Vinito,

          They are bearing scrapers, used for fitting bronze or white metal (babbit) bearings. They were often used for fitting big end and main bearings in car engines before the days of renewable bearing shells. The bearing was bored very close to size, then was lightly blued, bolted onto the crankshaft and the shaft turned to mark the high spots.
          The rod or crankshaft was then removed and the high spots scraped down with the bearing scraper using the side of the scraper blade, and with the blade alnost flat on the surface of the bearing. This was repeated until the bluing marks showed an acceptable fit. I did a 1920s Chevrolet engine a couple of years ago. It's a very slow process by the time you do four rods and three mains!

          The scrapers are sharpened on an oil stone, holding the two flat faces both in contact with the stone while sharpening.

          FWIW both my bearing scrapers - dating from the 1910s and 1950s - are ordinary carbon tool steel.

          franco

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          • #6
            I stand corrected. Bearing scrapers they are then. I bet there's a knack to using them properly without distorting the bearing shape. A newbie might tend to overdo it, I can see that happening quite easily.
            It seems that the tool would be doing a combination of scraping and skimming, and that it would be active over only a short length of it's cutting edges at any one time. I can imagine that considerable care is required in it's use.
            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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            • #7
              Hi Darryl,

              In my previous post I forgot to mention that, before the bearing was bored, a number of shims were placed on each side between the bearing cap and the other half of the bearing. In the case of the Chevrolet engines, one thick one (about 1/16 in, from memory) and several of about 0.0015in. were used. If the bearing wore in service, or, as you suggested, too much metal was removed while scraping, a couple of shims could be removed from each side, and you could start again. If you ran out of shims or none were fitted, the bearing cap would be rubbed down on emery cloth on a flat surface to reduce the clearance before scraping.

              What you say about the method of use is pretty right - it's easier to do than to explain. It is a fairly tedious job though. Each time the bearing is blued to check the fit, the cap bolts need to be correctly torqued. With the rod bearings, the piston has to be on the rod with the rings in place to preserve the correct alignment.

              Regards, franco

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              • #8
                Yes they are bearing scrapers and IMHO just about useless as is. Over the years I have found that to be really usefull bearing scapers have to be at least 15 to 18 inches long. The longer handle actually gives you more control of the cutting edge as the longer the your scraper the les actual stroke length you get for the same linear movement of the hand doing the work. Now for really serious bearing scraper work you need a two handed scraper. I'll see if I can post a picture of the one I've got at work tommorow. Just the thing for scraping bearings in presses
                Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.

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