chisel grinding angle

Page 2 of 2  


of
OK, the idea of a cutting action is to reduce friction to increase cutting efficiency, but I've yet to see any form of edge tool, much less an arbitrary orientation material that cuts with zero friction. There may be some super science going on with things like lasers, magnetics and possibly even superconductors, but I'm pretty sure you won't find any of those in my shop, other than the laser in my compound miter saw, and it doesn't do the cutting, just the pointing.
Cheers, Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I second that. 25 degrees then hone 1-2 degrees 26 - 27 degrees. Hollow grinding will make your chisels weak though. NO HAMMERS on them. Just wooden mallets to TAP them home. DON'T hollow grind Japanese Chisels, EVER ! Too brittle for that, they chip bad. Try 20 degrees for paring chisels. I would use a 5x11/2 or or 2 inch SLOW wet wheel and jig. Or use a lot of water to grind VERY slow, then hone up to 8000 grit water stone. I use up to 4000 grit. My chisels are so sharp that I shave my arm and the hair won't grow back for 3-4 weeks afterword. Be steady and consistant with your angles. JIGS MAN, JIGS !

angle
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

wooden
to
I
My Tormek hollow grinds everything, chisels, plane blades, whatever. My edges last a long time. I used to scary sharp. I have a full set of waterstones, and know how to use them. Heck, my mortice chisels are all done on waterstones. But the Tormek, with it's jigs and simple setup, gives great results in very little time, and I usually resharpen because I feel guilty, not because the edges are actually dull. They seem to last just about forever.
OBTW, I don't have any laminated blades, and I agree that I would not hollow grind a laminated blade.
Cheers, Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
But the hollow grind on a 10 in. wheel can be honed out too fast for me.Krenov School taught us to use a hand cranked 5 inch grinder to grind our chisels and irons. Good luck finding a hand cranker though.

Too
SLOW
up
that
gives
hollow
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Good luck finding a hand cranker though.
Hell, I see them at flea markets all the time. I have had good luck grinding on a belt sander with about 150 grit. Good luck with initial flattening on the B/S too. Tony
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

our
"Honed out too fast." Honestly, I don't even know what that means. At 90rpm, even graded to 220 grit, it won't remove material fast, and with the water bath, the irons don't even get warm. The key to the Tormek's speed is once the irons have already been done. Subsequent sharpenings need to remove nearly no material, so it goes very fast.
You talk about the weakness of a hollow grind. Well on a 5" wheel, you will get a much weaker edge than a 10" wheel gives. The larger the wheel, the flatter the bevel.
Cheers, Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

will
the
Cheers, Eric *******I see your point there, as there will be more contour, with less meat behind the cutting edge,**********
<<<<<<<But the hollow grind on a 10 in. wheel can be honed out too fast for

<<<"Honed out too fast." Honestly, I don't even know what that means. At <<<<90rpm, even graded to 220 grit, it won't remove material fast, and with the <<<<<<<<<<<<<water bath, the irons don't even get warm.
*******I think He means after you hollow grind on the 10" wheel, It will be closer to a flat bevel,(less contour) and when you then hone on a bench stone, the "hollow grind" will be removed sooner.***
thanks, Tony
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
An old boatbuilder / cabinet maker in Maine taught me to use a scythe stone to put the hollow on a chisel. Took him about two minutes to go from a flat bevel(as in no hollow) to a real nice hollow.

you
meat
for
with
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
25deg to 30deg then a micro-bevel of ~2deg
Bob S. (the other RWS...;-)

I
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi Robert,
For general woodworking, you'd grind to nominally 25 deg, then hone a secondary bevel at 30 deg. For a fine bevelled paring chisel, you'd drop these angles by 5 deg. For a heavy duty sash or mortice chisel, you'd up them by 5 deg.
However, at the end of the day, these figures are nominal. Most experienced woodworkers don't use a honing guide - they lay the chisel on the stone on its grinding bevel, then lift it by a few degrees to commence honing. I couldn't honestly tell you what my ultimate honing angle is - it's all done by feel, so it may be a couple of degrees either way from the recommended norms. Whatever you find that works for you.
It's worth while, when you start breaking in a new chisel, to hone the back it completely flat -simply lay it flat on your stone, then work away until the first inch or so at the business end is a uniform shade. For ultimate sharpness, you'd really want a mirror finish (on a very fine stone) on the back, but for general use, a uniform grey colour is fine.
Then when you hone the edge, you work away until when you run your thumb across the back of the edge (not along it!). you feel a raised burr. This means that you've honed the edge so fine that it's started to turn over under the your honing pressure.. Stop honing the bevel at this stage, then turn the chisel over flat on its back and give it a few more strokes flat on the stone to turn this burr (sometimes called the "roafe" or the "wire edge") back again. Then you can either strop it a few times on your palm or a leather strop, or gently draw it edgewise through a piece of wood to break off the burr and leave a clean sharp edge.
Beware when you're grinding on a high speed grinder - you need to keep the edge as cool as possible at all times, which means dunking it frequently. Don't let it get so hot that it starts to blue. A stone which runs at low speed in a water bath is much better, if you have access to one.
Cheers,
Frank.

I
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I use 30 degrees with good results. Exact angle unimportant, just make sure the two angles meet "sharply"
I found some old stanley 45 "irons" and measured the angle... all were exactly 35 degrees.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.