Replies

1. 
   ricky | Mar 28, 2015 06:37am | #1

   Mortise bevel

   I have the Robert Sorby and Ray Iles "pigstickers". The Sorby I keep at 30 degrees and it works for me. I've been trained not to do a secondary bevel but instead do a hollow grind so that when I hone on my waterstone, the tip and heel of the bevel is polished. As I work, i return to the waterstone only until the hollow grind is worked out, then I take it to the wheel for another hollow grind. I've done everything from hand-cranked grinders to the Tormek for acheiving the hollow grind. It doesn't matter as long as the hollow doesn't touch the ends of the bevel, your angle is maintained. Since I don't use a jig at the waterstone, I find this method gives me better registration of the bevel to the waterstone than trying to balance on the tiny secondary bevel.

   If you want to try 30 degrees but don't want to regrind from the 25 degree bevel, you can just add a 5 degree secondary to get 30. Then as you go along chopping and sharpening, the secondary gets bigger and bigger until it becomes the primary. From there you can do the hollow grind or 1-2 degree secondary.

   The Iles have the factory 20 degree primary with a 35 secondary and that seems to work fine for their type of steel.

1. 
   jimpetillo | Mar 28, 2015 09:52pm | #2

   Mortise bevel

   Thanks Ricky.  That's exactly what I'm going to do. Leave the 25 degree bevel and add a 30 degree secondary bevel.

2. 
   PJohn | Apr 09, 2015 02:41pm | #3

   Bevel on Mortising Chisels

   Hi, Jim -

   I agree that simply adding a 10 degree secondary to the tool as-bought is the first thing to try - that's good advice. If you've no difficulties, then there's your answer! Especially since this is your first mortising chisel, I'd suspect that it may be a while before you've used it enough to to gain the confidence to "really beat on it" to maximize productivity.

   Remember that a secondary should be only 1/32 - 1/16 wide so that you may impose a few touchups to the bevel before having to re-grind the primary. That ash is hard like rocks, so you're likely to be touching up chisels, planes, and scrapers fairly often. (But it does make for gorgeous product and considerable bragging rights.)

   I don't own any Narex tools, but suggest to you that the initial grind angle will affect the strength of the sharpened section of the tool. If it's extremely shallow, as for a paring chisel, the "abuse" of mortising may just cause the edge to break off or chip. That's good reason for a steep primary angle (which steepens because of probable loading from paring at about 15-20, bench 25, firmer 30, and mortising 35.)  If you should encounter that problem, the easiest "fix" will be to go to a 35 degree angle with a 2 degree secondary.

   My personal preference is for the absolute repeatability of the "scary sharp" method using float glass and wet-or-dry sandpaper in concert with a reliable jig such as the Veritas. It allows for very simple, repeatable, and accurate grinding of both secondary and primary bevels.

   Good luck!