Sharpening Router Plane Blades
A recent post on a router plane reminded me to post the method I use for sharpening router plane blades. This topic comes up regularly. I am not sure if anyone else prepares their blades this way, but I swear by it.
As with the preparation of any plane blade, the method consists of two parts - grinding and honing.
Grinding
I hollow grind all my blades - including the router plane blades - as this reduced the amount of steel to remove and enables the bevel angle to be repeated each time. To do this I built a very simple jig. This is good for Lee Valley and Stanley blades, with their angled sides. Grinding Lie-Nielsen does not require a jig, but follows the same principle.
The jig is a simple V-grooved section with one corner bevelled ...
This is used in conjunction with a sanding wheel on a drill press. Use a coarse grit, around 80 - 100 maximum.
The size of the wheels depends on the depth of the hollow you wish to create. The Lee Valley/Stanley blade heads are longer than those on the Lie-Nielsen, and the latter must use a narrower diameter wheel.
The aim is to use the V-groove to keep the bevel square to the wheel. Ensure that the direction of the turn is into the bevel. This is a LV 1/4" blade.
It is easy to maneuver the jig and blade into the ideal position. Use light pressure and keep the blade cool. Here are a few overhead shots ..
The 1/2" LV blade has a removable head, and this enables a different technique for grinding.
The blade head is attached to a holder. This enables it to be treated as a common plane blade. Here it is set up in a Tormek. It could as easily be ground on a high speed dry grinder.
Honing
While the 1/2" head may be honed in a guide, all other blades need to be freehanded. That is my preferred method anyway.
Freehanding the 1/2" blade (using the holder). Pull the blade sideways on the sharpening medium. Honing on a hollow is quick work ...
Honing the other blades simply requires balancing on the hollow, which is considerably easier than attempting to hone on a flat bevel. The hollow acts as a jig.
The result is a really sharp edge that is easy to renew many times before any re-grinding is indicated.
Regards from Perth
Derek
September 2013
EDIT to add a video on this method by Vic Tesolin: https://www.youtube.com/watch?v=cuNu-GlgH88