Full Chisel Blog

June 23, 2009

Scrapers

Filed under: Historical Material,Of Interest,Proper Tools,Scrapers,Sharpening,Uncategorized — Stephen Shepherd @ 7:16 pm

Lately I have been fiddling around with some scrapers, especially those used by luthiers.  I made a set of scrapers based on those in the Stradivarius Museum and have finally put a shape and edge to them.

 I was invited to the Utah Hand Tool Group to give a presentation on Thursday June 25,2009.  I was surprised they were still around, they use to meet at the local Woodcraft but I had not seen any mention since the store moved to the south end of the valley.  I had given a lecture and demonstration for them 5 or 6 years ago and was pleased they were still around.

They have about 30 members so it is growing and that is good.  I will talk a bit about Hide Glue (and sell a few books) but for the most part the discussion will be scrapers.  I will take a couple of my winged hand scrapers and a fist full of card scrapers.  I am going to tell them some things they probably haven’t heard, because I haven’t told anybody yet.

While cabinet scrapers (those with bodies) and rectangular card scrapers are for flat surfaces and I will touch on those subjects, I am much more interested in talking about using scrapers on curved surfaces.  I also spent my free time at work today making 6 pair of knitting needles.  I have a bunch of square blanks of curly maple and shaped then with a knife, to form the knob and sharpen the point, a small pattern-makers bronze spokeshave for rough shaping, a very small one and an oval card scraper.

Rough sawn curly maple square blanks measuring just under 3/32″ and ending up round is a challenge.  The telegraphing of the saw cuts and the curly wood was common and it required that I hold the scraper at a very skew angle to insure the rough cut and natural curl didn’t interfere with getting the knitting needles very smooth.  Then there is the fact that the blanks were 10″ long so it was not possible to apply a lot of pressure.

Now if I would have had a bench it would have been easier but all I had was my leg to support the thin pieces of wood.  But then I needed to frequently check the progress by sighting down the wood as I was working it, so moving it to my leg every time was not practical.  Then I started treating them like thin spindles on a lathe and supported them with my fingers  I am developing calluses on the insides of my fingers.

 I had also used the unusual narrow scrapers (ground to 45 degrees) in the set to work the inside of the opening in the pitman in the previous post.  And I did all of the scraping with a rough ground scrapers.  Parts of the scrapers didn’t have a burr and others did and I found that without a burr and this sharpening that I could get good curl by pushing the bevel edge scrapers.

This seems to go against all I was taught and most of what I had seen.  But then I realized that I had seen scrapers used like that before by a gunsmith, but didn’t understand how he did it at the time.  The bevel edge doesn’t even need a burr.  I removed the burr from a couple of bevel edge scrapers, actually double beveled, more like a knife blade.  They still scrape well under the proper conditions.

Stephen

 

2 Comments »

  1. Stephen,
    what you are describing is the type of scraper that I used as a patternmaker for many years. Actually, mine were hollow ground (like an ice skate blade) by setting the grinder rest to point towards the center of the drive shaft. This gave an excellent scraper for use on metal and plastic, we used them on wood too, but they did not work as well. Preferentially we made them from hardened steel saw blades that had gotten dull. Ground the sides flat on a surface grinder and hollow ground the edges and we were good to go.
    Mike

    Comment by Mike Holden — June 24, 2009 @ 1:02 pm

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