Tuesday, November 3, 2009

I'm Not the Scraper Maker, I'm the Scraper Maker's Son. . .

As a rule, I leave tool making to the professionals. 

Like its cousin jig-making, tool-making requires a dogged focus on performance, but with the added pressure to make it look nice.  The jigs in my shop resemble modern art -- found objects that work only when used in a completely non-intuitive fashion.  They are like some sort of lethal puzzle jug, except that instead of getting wet, you lose a finger.

So imagine my surprise when quite out-of-the blue I decided to make a scraper plane.  It's not that surprising, actually, since I do have a desk top to finish.  But Woodwork magazine came to my rescue with just the right article.

Ejler Hjorth-Westh wins the award not only for the best plane article, but for the best name, and the best hair of the June 1995 issue.  His plane consists of six pieces - two cheeks, two infill blocks, one wedge, and one pin.  The only critical angle is the "ramp" upon which the blade rests.  In this case he recommends an angle of 95 degrees.  He also suggests that you use an angle of 50 degrees on the front ramp -- and leave plenty of space for shaving clearance.

I had a block of hard maple that I  fashioned into the infill blocks.  The blocks are 2 1/2" high by 2 7/8" wide.  The width is determined by adding 1/8" to the width of the blade you will use.  The cheeks are some 1/2" QSWO I had left over and the wedge and pin are also oak.

Once these have been cut to a rough form, it is time to mark and drill the hole through the cheeks to hold the pin.  While he suggests filing the posts of the pin, I actually turned each pin to 3/8".  I first gripped a 3/4" block of oak in the little jaws of my chuck, held it between centers, turned one pin, then flipped it around and held the completed pin in a keyless chuck and turned the other end (again between centers.)  I rounded, slightly, the edges away from the ramp and tested the fit.

Ejler suggests making two 1/8" registration holes on the cheeks, with matching holes in the inserts (above the dotted line arc) that will allow you to insert a dowel to keep the parts lined up during construction.  As you will be cutting away this portion to give the plane a sleek look, they will not be seen in the finished item.  It is good practice.  So I chose to ignore it and proceed with the glue up (remembering to capture the pins between the cheeks.)

Upon unclamping I found that one cheek had shifted up by about 1/32" , but one "death-or-glory" pass over the jointer set things to right.  My advice -- use the registration dowels. 

I always save any curve I fair in mdf for a router template as they come in handy for drawing arcs in situations like this.  I found one, drew it, and sent the plane through the bandsaw.

Tradition would dictate that you use the scrap from the infill to make the wedge.  I, however, used a scrap of the QSWO cheek, shimmed it by 1/4", turned it on its side, and passed it through the bandsaw.  The photo of this procedure looks so dangerous that I refuse to post it.  It would be more sensible to use a handplane or start with a longer piece, shim it on a sled, and pass it through the thickness planer.

I must admit that this was a charmed project -- everything went right.  All the pieces fit on the first try, the bandsaw cut a perfect arc in the final shaping, and sanding took about five minutes down to 400 grit.  This, of course, ensures that it will not work.  I'll wait until the Hock blade arrives to give a final update. 

This won't be the last plane I build.  There is something very satisfying about completing something in just a few hours.  I'm also chuffed about the way it looks; it reminds me a bit of an old Kharmann Ghia I once owned.  Let's just hope the doors don't fall off this one.

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