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Back flattening chisels with the heel of your hand

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Forum topic by funchuck posted 06-13-2011 01:08 PM 2552 views 0 times favorited 9 replies Add to Favorites Watch
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funchuck

119 posts in 2517 days


06-13-2011 01:08 PM

Topic tags/keywords: chisels back flattening tip

I’m not sure if this is a known method of sharpening, but I just discovered (or maybe rediscovered?) an easier way to flatten the back of my chisels.

I bought a set of chisels about 6 years ago and never sharpened up my larger chisels because the backs of all the chisels were out of flat. Most of them had hollow spots running all the way to the tip. Some of them had big hollows at the tips too. It took forever to sharpen up my smaller chisels, so I never attempted to sharpen the bigger ones.

For 6 years, those larger chisels sat unused, but recently, I was bored, so I decided to give it another go. I took out my granite plate and some 100 grit sandpaper. I used my fingers to put pressure on the back of a 1-1/4” chisel, then started running the chisel back and forth on the sandpaper. After a while, my fingers started aching, and I wasn’t making much progress. I could see that about 1/8” at the very tip had a hollow. I kept at it, but there was hardly any progress and my fingers were aching badly.

I thought about this process and thought that life would be much easier if I can put pressure on the back of the chisel without using my fingers. So, instead, I used the heel of my hand.

Not only did this relieve the fatigue in my fingers, but it made the work extremely quick. I could bear down all my weight on the chisel and really grind into it. It was so quick and easy that I took out my 1-1/2” chisel and did that one in the same session!

I also used this on my oilstones, but with much less pressure. It made sharpening much easier. I haven’t tried this on my thinner chisels, but I think if I skewed the chisel at an angle, it might work. The only problem I have had is that because I am using oilstones, the chisel does become kind of slippery.

-- Charles from California


9 replies so far

View Bertha's profile

Bertha

13003 posts in 2153 days


#1 posted 06-13-2011 02:09 PM

I built a little jig for just this reason! My fingers were fatiguing quicker than the chisel!

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

View Dave Pearce's profile

Dave Pearce

108 posts in 3132 days


#2 posted 06-13-2011 02:55 PM

Mike Dunbar (as well as quite a few others) has advocated using a small block of wood to apply pressure on the chisel, as you lap the back. I’ve got several sizes I’ve used over the years depending on the size of the chisel and it allows me to put the most pressure where it’s needed.

Unless the chisel is fairly flat to start with, I typically grab the block and have at it with my coarsest diamond stone.

-- http://www.pearcewoodworking.com

View funchuck's profile

funchuck

119 posts in 2517 days


#3 posted 06-13-2011 03:42 PM

Bertha: I’d be interested in seeing this jig? How is it built?

My chisels are bevel edged, so I am just wondering how it will keep from slipping? Maybe a piece of rubber?

Dave: I actually wore down my diamond stone. It’s a DMT extra coarse one too. I would think with all that pressure, you’d wear yours out?

-- Charles from California

View Dave Pearce's profile

Dave Pearce

108 posts in 3132 days


#4 posted 06-13-2011 04:05 PM

Charles,

Mine’s a DMT extra course too. So far, 4 years, still going strong. I only wish it were larger. I’ve probably flattened about 20 chisels on it, and about as many plane blades, so I guess if you’re doing alot of blades it might wear it out sooner. Not sure what the longevity is. I did take a class from an instructor who has had his diamond stone close to 20 years, and he’s still using it. For what it’s worth, I don’t use water to lubricate, instead I use a 50-50 mixture of mineral oil and mineral spirits. Seems to cut faster than the water and since my shop is not temperature regulated, stops the diamond stone from developing rust stains.

Just as an aside, another method, if you’re doing alot of blades, is to use a slow speed grinder like the Tormek and use the side of the wheel. I know high speed grinders aren’t suitable for that, but a friend of mine uses his Tormek in that fashion quite a bit.

Still other options are a belt sander or a disk sander. If you like rehabbing chisels alot, it seems like either of those options might be a time and labor saver.

-- http://www.pearcewoodworking.com

View Tedstor's profile

Tedstor

1625 posts in 2093 days


#5 posted 06-13-2011 08:35 PM

Ha. I just received a 3 pc set of vintage Buck Bros Chisels – 1”, 1.5”, 1.75”. After trying to flatten these things for over an hour, I finally cried uncle. I too was using sandpaper and a granite tile.
I just ordered a 220grit waterstone.

I’d think extra pressure would merely distort the heavy grit sandpaper, forcing it to conform to the chisel’s contours.
But I’m the furthest thing from an expert and could easily be wrong.

View Dave Pearce's profile

Dave Pearce

108 posts in 3132 days


#6 posted 06-13-2011 09:54 PM

Reminds me of an Ohio Tool firmer chisel I flattened. Great deal at the flea market, terrible deal on my fingers and shoulders. After several tries, nearly giving up, I was reminded that only a small amount of the back needs to be flattened in order for the tool to be sharpened. I ended up only flattening the last 1/2 inch or so, and finally (finally!) I was able to put on a decent edge so it would cut.

-- http://www.pearcewoodworking.com

View Mike Gager's profile

Mike Gager

665 posts in 2727 days


#7 posted 06-14-2011 05:33 AM

shoot i only flatten about 3/16” of the back. only takes a couple minutes and i only have to do it once

View Dave Pearce's profile

Dave Pearce

108 posts in 3132 days


#8 posted 06-14-2011 04:42 PM

Yeah, I think alot of us tend to want to flatten waaay too much of the backs on these tools. I’ll admit, it’s alot easier balancing an inch or two on the stones than 3/16th’s but if you only need 3/16th’s, why flatten a whole lot of metal? Slowly, I’m getting better at this…

-- http://www.pearcewoodworking.com

View funchuck's profile

funchuck

119 posts in 2517 days


#9 posted 06-15-2011 05:16 AM

I only flatten the very tip of the back too, but the problem is, the very tip had a big hollow in it. Even my smaller chisels took a long time to flatten just the tip. I didn’t want the tip to be beveled, so I kept the back of the chisel flat on my sandpaper and kept grinding with my fingers.

However, once I discovered the heel method, I did flatten the entire back because it was so much easier. It still took a bit of time, but I was so excited about this new method that I just went overboard.

I also looked up jigs that help you do this, but the only thing I found was some guy that used hot glue and glued a block of wood to his plane blades. That looks even easier to do than the heel method.

-- Charles from California

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