Tuning Card Scrapers
by Bob Smalser
This article first appeared as a thread on theWoodNet woodworking forum. It was compiled and reproduced here for easier public consumption. All Text and Images are the property of Bob Smalser.
In previous articles, I described rehabbing older Bailey-pattern planes acquired from Ebay to replace all the family's ancient wood planes.the ones I'm getting tired of inlaying mouths in every decade or so as they wear. I'll rehab these oldies one more time and pass them on to my oldest boy who's interested in luthier work.he'll be the 5th generation of craftsman for some of these. I'll describe resoling these woodies in another article, but as my card scrapers are essential tools for this work and mine all need a tune-up, I'll walk you through that process today.
I pull the mahogany filing block out of the bin.any hardwood block the length of the file with a dead square rabbet to serve as a shelf for the file will do. and while holding the chalked file in place with my left hand I run the scraper down the teeth until I've filed away all the old wire edge and have a nice fresh, square surface to turn a new edge from. The chalk aids in preventing the single-cut mill file from clogging and I'm careful to not slide the scraper backwards against the file's teeth..a practice that dulls files exactly twice as fast as necessary.
A nice, fresh, dead-square edge.
Then moving both block and scraper to the Arkansas stones, I hone the edge dead smooth on coarse and fine stones. The smoother and squarer the edge, the better and more durable the eventual cutting edge.
Then I clamp the scraper to a hard, flat surface and use a burnisher to turn a wire edge inwards on both edges as shown in the sketch. The burnisher? The one I'm using is a luthier design by Timberline Tools of Mendanales, New Mexico, but any hardened and smooth steel will do..like the back of the old Buck Brothers gouge shown or a valve stem or pushrod from your local junkyard. The burnisher should be oiled for best results.
Then I simply affix the scraper on edge and turn those wire edges outward to make two hook edges as shown in the second sketch. The purpose-built burnisher does that automatically and rapidly..when using the gouge, I use two hands and rub the edge on a diagonal with the burnisher beginning horizontally and pushing the gouge twenty or so degrees downward during each stroke.
The result? The scraper, held in both hands and sprung a bit toward the body as it is pulled toward you, cuts this hard maple sole like a plane..only with more control and precision. Learn to use scrapers, and you'll cut your abrasive paper outlays to a pittance and even that varnish finish coat that egg-shelled on you won't be a burden. That's right.properly tuned they can cleanly remove as little as one layer of varnish.
I'm not into unnecessary tools, but this luthier's burnisher halves the time and effort of tuning the scrapers. You can either buy or make one. How do you harden the 5/16ths drill rod? After it's cut to length and the edges eased, simply grab it with soft-jawed pliers, heat it to cherry red with a propane or MAPP torch, and toss it in a can of linseed or motor oil.
Return to How-To Index
Return to Woodworking
©2004 Cian Perez / www.CianPerez.com