Do I need to lap these chisel backs flat?

[Warren Mickley]

You have to look at how the chisel behaves when you sharpen and use it. In sharpening we usually just work the last inch or two of the back. If abrading on the back on your fine stone does not touch the burr or even polish the area near the burr, there is a problem.

If you really use the chisel, and abrade the back near the edge, after five or ten thousand sharpenings the whole back is no longer flat. This is of no consequence as long as the area near the edge can register flat on the stone. And if you are really going to use the chisel, time spent in preparation will not be wasted.

[Frederick Skelly]

Still not clear on the "conversion to diamond plates" thing for the Makita, I didn't find anything about that.

I was assuming they meant something like these Doug. LINK Don't know if I'm right. But I've used a similar brand on my Worksharp and flattened my Narex Paring set with them. One of the guys here introduced me to them.

[bridger berdel]

I was assuming they meant something like these Doug. LINK Don't know if I'm right. But I've used a similar brand on my Worksharp and flattened my Narex Paring set with them. One of the guys here introduced me to them.

Yep, that's the makita, and the diamond plates are like those but bigger. I made a backer disk for them from i think 1-1/2" thick acrylic. I run the machine in a deep laundry sink.

[John C Cox]

I will pile on with many others.

Just sharpen up the bevels good (ignore the backs for now) and see how they do... You can get them really sharp just honing the bevel and then when you do final stropping - run the back over uncharged leather strop to wipe off any feather edge.... If they work well in your hands and you don't have trouble with them pulling up out of a cut or cutting crooked - then let them be.

If they don't - then it will be time to sort out the backs.

Chisels humped like that take me an hour to an hour and a half to sort out. I finally sorted out a method that works well enough after taking the plunge into vintage chisels again... And 100.00% of the ones I have came in with a hump in the back...

Perhaps we need to work up a tutorial for sorting out vintage chisels.

[Mark Gibney]

Mike Brady - Isn't that a firmer chisel; and if so, to what use would you put it?

No, the lands are sloped, it just doesn't show in the photo.

As to what I will use them for - ask me again in a year!

[Andrew Pitonyak]

There are two reasons (off hand that I can think of) for flattening the back. First, because the edge on the back and on the face of the chisel must meet in a nice line. For that, you can flatten a very small portion of the back. Second, if the back of the chisel registers against something. So, if that large warp on the chisel is not registering against something, then it really does not matter to take that bow out of the back. I would be afraid of over-heating the chisel.

[lowell holmes]

I hone the back 1/2" of my bevel edge chisels on a diamond hone and put a micro back bevel on them. They will pare translucent shavings.

Try it, it works.

[James Pallas]

When tools are old you don't have any idea of how they were used. I have read on this forum even that one of the good things about patern maker chisels is flexibility. That being said maybe those chisels were flexed often and steeply and took a bit of a set that way. Tools do do that.
Jim