Prompted by Bob's excellent video on split point drill bit sharpening at http://www.homemadetools.net/forum/s...arpening-70940 I present my own simple tool modification for the same purpose.
Bob talked about drill point geometry and split point sharpening so I won't repeat that although I use the 4 or 6 facet geometry explained in my earlier post at http://www.homemadetools.net/forum/h...6205#post83247 .
Web thinning at the point of the drill enables a more accurate start to a hole and reduces wander, it also removes or reduces the need to drill a pilot hole with a smaller bit because the point of the drill is in effect the same as a smaller drill.
I had a little grinder designed for sharpening chainsaws which I used sometimes for web thinning but the blade was at an angle and was movable, this made it less than ideal for drill bit work. This is pictured below.
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Click thumbnails for full size images.
To improve its utility I made this simple holding support from some bits out of the scrap bin.
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The next pix show the grinder mounted on the support. It is now very convenient to use.
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The wheel that came with the grinder is 3 mm wide which is fine for larger bits but too thick for smaller ones. Fortunately the hole diameter in 1 mm angle grinder cutoff blades is the same and so I change over to those for smaller bits.
Showing a 3 mm blade mounted with a 1 mm cutoff blade below.
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