Sharpening router plane blades

[Derek Cohen]

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 ...


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/1_zps5d7f2e2d.jpg


This is used in conjunction with a sanding wheel on a drill press. Use a coarse grit, around 80 - 100 maximum.


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/2_zps6349da46.jpg


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.


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/3_zps5576ca7f.jpg


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/4_zpsc67cd1c4.jpg


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 ..


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/5_zps70904f3a.jpg


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/6_zps83e895f0.jpg


The 1/2" LV blade has a removable head, and this enables a different technique for grinding.


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/8_zpsdf68c36e.jpg


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.


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/10_zps3c0ce12d.jpg


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 ...


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/11_zpsdcb3ae76.jpg


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.


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/12_zps0044162f.jpg


The result is a really sharp edge that is easy to renew many times before any re-grinding is indicated.


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/14_zpsdda697a2.jpg


http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Router%20irons/13_zps31d7e77d.jpg


Regards from Perth


Derek

[Matthew N. Masail]

That's great! thanks! however here's a challenge... how do you handle the blade for the small LV router plane... with the round post...

[Derek Cohen]

Hi Matthew

I use a Dremel to freehand grind a hollow. One could also use sandpaper wrapped around a dowel.

Regards from Perth

Derek

[Chris Griggs]

I did this with my 1/4" lv blade a while back after some sloppy honing rounded it over. It works great. I like the jig idea. I've only ever done it free hand with a dremel. Nice write up of this Derek. Its one of those thing that seems so obvious but you rarely read about, and the first time you try it you slap yourself in the head for not thinking of it sooner.

[Matthew N. Masail]

Hi Matthew

I use a Dremel to freehand grind a hollow. One could also use sandpaper wrapped around a dowel.

Regards from Perth

Derek

Well I don't have any dremel attachments but I'll try a dowel:) thanks

[Jim Matthews]

I polish the bottom of the blade, as it is mounted in the router body.

That shows me the alignment and allows me to grind the front square to that angle, rather than skewed.
Two blocks on either side of my finest stone and a couple passes show this pretty clearly.