English-pattern Mortise Chisels

[Dakotapix]

I started grinding my 3/8" English mortise chisel yesterday and it became very apparent I will need to remove a lot of steel to achieve the 20 degree primary bevel. I'm maybe half way there but had to quit because of other things going on. I'll resume at some point today. What became apparent because of the thick stock on this chisel is the need to NOT over tighten the left-hand knob. Doing so would definitely cause a definite uneven grind. Seems to be going well so far. Just tedious work.

[Ken S]

Jeff Farris did a PDF on how to use the older square edge jig. He discussed tightening. I was unable to locate it in a search today. Your observation about overtightening the left screw is valuable. A few quick passes with the dry grinder would speed up the reshaping. Just stay in the area of the bevel with lots of metal to absorb the heat and work carefully.

I checked up on the twenty degree bevel angle. The one dealer website gave a good description of the chisel and the reason for the twenty degree bevel. It sounds logical, although I was surprised that it was not beefier. After all that work, I hope you like your newly sharpened mortise chisel.

The good news is that subsequent resharpenings should go much more quickly.

Ken

[Elden]

Jeff's pdf:

http://www.sharptoolsusa.com/squareedgeweb.pdf

[Ken S]

Thanks, Eldon, that's it!

Ken

[Herman Trivilino]

If anyone is concerned about the slight hollow being less strong than a flat ground,

I thought this was well-understood. If Dakotapix proceeds to grind at what he's measured to be a 20 degree angle using the Angle Master he will leave more steel on the heel of the bevel than if he had ground it flat at 20 degrees. Another way of saying this is that when he's finished grinding the 20 degree bevel with the Tormek and wants to remove the hollow with a bench stone to produce a flat 20 degree bevel, he'll be removing steel from the heel of the bevel.

[Dakotapix]

I finished the 3/8" mortise chisel today. It was going very slow so I switched over to  25 degree base bevel and then finished the working edge at 35 degrees. I'll try to chop a mortise tomorrow. I appreciate your tips though. I read through Jeff's PDF on using the square edge jig and that was pretty much how I set up this chisel. Not always though. I had my share of trouble getting square sharpenings until I began to understand the tightening sequence on both the new and old jigs.

Next is a 3/16" mortise chisel (aka pig sticker).

[4-Square]

Changing the primary bevel on an English pattern mortise with a Tormek is not really the right tool for the job... It can be done, but that's a lot of steel... An awful lot of steel... Ad if it's Ray Iles, then it's an awful lot of D2...

The 20d primary is a design feature inherent in the proper use of the tool – Chris Schwarz has several articles on the two or three most accepted workflows – and they all benefit from the shallow primary. I suspect 25d will work, just not as well...

When I've got my jig done, I'll post a photo.

[Ken S]

Jeff Farris made an interesting comment in the gouge section of his turning video which might be useful here. When doing a major reshaping, Jeff suggest doing it in stages. Reshaping the primary bevel on your mortising chisels might seem less arduous if you approached it in stages. Five or ten minutes now and again would not be such a chore, and you would get a feel for how your chisels work at different bevel angles.

Ken

[Herman Trivilino]

Another tip is to keep a tool in need of this kind of shaping in reserve. If you find yourself sharpening something like a kitchen knife when the grindstone needs truing, you'll need a chore like this to get the grindstone back in a smooth-enough condition to be able to continue working on the kitchen knife.

If you try to sharpen a kitchen knife on a freshly-trued grindstone you'll not be able to get a refined edge as the grindstone's surface  will be too rough.

[4-Square]

==>When doing a major reshaping, Jeff suggest doing it in stages. Reshaping the primary bevel on your mortising chisels might seem less arduous if you approached it in stages. Five or ten minutes now and again would not be such a chore, and you would get a feel for how your chisels work at different bevel angles.


An interesting idea... But the primary on single-bevel bench tools and the double-bevel carving kit is apples to oranges. Something can be gleaned by varying bevel angles on carving tools, but many bench tools are designed around a narrow window of acceptable primary bevel angles... Incremental grinding is simply not a viable option.

I know this is a Tormek forum ---- but.... For heavy metal removal, it's not the right tool for the job... It can be done, but that doesn't mean its the best tool for the job... You're asking to remove too much steel in a user-acceptable time window... There's nothing wrong with establishing the primary on some other media, then refining and/or finishing with the Tormek -- it's what I do now... In the spirit of full disclosure, the Tormek plays an intermediate-role for my western-style chisels (O1, A2, PMV-11) and plane irons (A2). I prefer a hollow-grind to facilitate a hand-finish on magnesium-matrix waterstones (Chosera 10K). My Japanese chisels are never hollow ground... The rest of my bench and carving kit is sharpened and finished on the Tormek...

To establish the primary on my English-pattern mortisers, I'm going to use a stationary sander... Nothing is wrong using scary-sharp, bench grinder, bench stones, belt-sander in vise (does that have a name?) and/or some other time-acceptable method for heavy steel removal... Spending thirty+ minutes establishing a primary on a big mortiser is counterproductive... Again, it can be done -- but life's too short...

[Ken S]

You are quite correct, 4-Square. Confronted with a big mortising chisel with major grinding, if no one was looking, I would sneak over to my belt grinder or dry grinder. My dry grinder has a Norton 3X 46 grit wheel. I use the dry grinder for heavy work. I like the 46 grit wheel.

I am curious about the primary bevel on your chisels when you acquired them. I believe the Ray Iles mortising chisels leave the factory at twenty degrees. Someone put some work in for you to redo.

Keep us posted.

Ken

[4-Square]

I've maintained the factory angles... All primaries are at 20d, secondaries around 33d and tertiaries at 35d give or take -- maybe the 1/8" is a bit different, but I'd have to check... The issue is after four or five sharpeningings, the secondaries start to creep and need to reestablish the primary...


My reflection on bulk steel removal was more in response to the post earlier in the thread where the user was attempting to reestablish a primary using the Tormek and had to give-up at 25d... I think this reflects a negative bias on alternative bulk steel removal strategies – there really is nothing wrong with an alternative primary strategy for big steel... After all, on a single-bevel bench tool (with few exceptions), the primary is really just a platform for the secondary... I don't care how my primary gets established (except fine dovetail chisels, Japanese chisels and maybe one or two other items) – as long as it's straight and square to the long axis – who cares? I might not admit to scary-sharp on woodworking blogs --- I'll let the joinery speak for itself

I'm finishing-up a couple of occasional tables today. I should get to the 20d jig by Wed or Thurs... I'll post a photo...