Small Projects For The Shop

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Rake Angle Control when Sharpening Saws

In his excellent (it's my primary source) write up on saw filing: Pete Taran says:
"With even a small change in the way you move your wrist, you can increase or decrease the angle by as much as 10 degrees. In saw filing, this is a huge and unacceptable variation."
In Making Woodwork AIDS and Devices Robert Wearing recommends fixing a pointer to your file handle; this greatly amplifies the visual effect of any changes in angle, making them much easier to control. But his design involves sourcing a piece of thick walled metal tubing to fit closely over your file handle's ferrule, and the use of taps and dies.

So I took his idea, but not his design, and remade it using materials and tools I did have.

I standardised on using 1/2" dowel for my file handles, since this made things simpler.

(9 Sep 2008) I've now changed to 12 mm since I can't get 1/2" any more.
The gadget is just a scrap of mahogany, drilled (with a brace and auger, natch) with a 1/2" hole to grip the handles, kerfed under the hole, and with a screw to tighten it around the handle. The sides of the hole need to be thin enough to allow a little flexing for the tightening to work. My pointer is a bamboo kebab skewer.

I clamp a reference block, whose faces are at the angles I wish the saw teeth be, on to the bench. I have a set of these blocks, whose end faces have been cut (using my mitre saw ) to the angles I need for rip and crosscut filing.

I then press a face of the file against the gauge block end, move the pointer to vertical, and tighten the screw. Keeping the pointer vertical is now a much easier proxy for the face of the file being at the correct angle.

An interesting discussion ensued when I first posted this idea to the OLDTOOLS list

If you desire even more assistance (or interferance) from jigs, Brent Beach's design may be what you're looking for.

(28 Nov, 2005) On Woodcentral, "Sandor in Boyds" posted an ultra-engineered version of this tool.

More general information on saw sharpening is now on a page of its own.
file pointer

Sharpening Nickers on rebate (and similar) planes

Recently there was a question on sharpening dado/fillister nickers on the Porch. The essential problem is that the nickers are very small, and almost any way of holding them fouls the bevel you're trying to work on. My initial solution was to file down the head of a countersunk screw, until the head was only just wide enough and deep enough to hold the nicker. However this would have left too small (and shallow) a slot to drive the screw. So I changed to a bolt with a counter sunk head which means I can tighten the nut onto the bolt - the bolt has little tendancy to spin.

When sharpening one wants maximum access and visibility to the nicker, so the nicker needs to extend as far as possible beyond the handle - this entails placing the fixing point as close to the end of the handle as feasible. However, drilling the hole for the bolt here would probably fail, with the bolt breaking through the end grain. A compromise is achieved by making the end cut on the handle at an angle.

To give some idea of the scale of all this, the wood is 8 mm thick, and the bolt's diameter is 3.2 mm. My handle was 130 mm long, which was simply the length of a handy looking scrap of mahogony.

holder for nicker sharpening
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