Question about sharpening chisels ?

[jay hanks]

I am new to sharpening and I am using scary sharp but my question is really about lapping the chisel. I have some older stanley chisles that have light pitting farther back from the edge. My question is this how clean should I make the back with lapping, should it be smooth with no pitting visible, or is that just personal prefrence as to its look? I dont think it would hurt performance since the area with pitting is smooth to the touch. Thanks Jay

[Alan Turner]

I am new to sharpening and I am using scary sharp but my question is really about lapping the chisel. I have some older stanley chisles that have light pitting farther back from the edge. My question is this how clean should I make the back with lapping, should it be smooth with no pitting visible, or is that just personal prefrence as to its look? I dont think it would hurt performance since the area with pitting is smooth to the touch. Thanks Jay
Jay,
I am an old tool guy. My Wiitherby's and Stanley 750's are the best chisels I have. They do require some initial time investment, as you have discovered.
Truly sharp is when two planes intersect at a thickness of one atom (plus or minus, of course). So, if there is pitting at the actual cutting edge, that spot will not be sharp. In terms of lapping, all you need to be really polished on the flat side is a very little bit. Theoretically, 1/64" would be sufficient. I rarely go back more than 1/2" or so as lapping is boring and quite time consuming. If you have pitting that is not actually at the cutting edge, then don't worry about it till you grind far enough back to hit it. Then just go a bit further.
Alan

[jay hanks]

Alan, Thank you for the reply. That is kinda what I thought but being new to sharpening chisels I didnt want to get started on the wrong foot. Thanks Jay

[Tyler Howell]

[OK you guys. another Newbee! What is Lapping? I don't remember the term from the scary sharp articles??

Tyler :confused:

[Don Henthorn Smithville, TX]

Lapping is the process of flattening the back of the chisel. As has been mentioned only a small area of the back needs to be lapped, but it needs to be done very precisely and with progressively finer grits. The finer the final grit, theoretically the keener will be the finished edge.

[Tyler Howell]

Thanks Don,
Knowledge is power! I'm going to give some "scary sharp" tuning a try tonight. Hopefully with proper Lapping.

TJH

[jay hanks]

Tyler you might want to get the Lee book on sharpening, there is also a DVD I dont have it but I am sure it will help visually. Thats where I started with learning about the shapening process. Jay

[Scott Quesnelle]

If you have a blade that requires a fair bit of lapping. Get some of the drywall screen. 80X and 120X (should be available in just about any hardware store). Put it down like your other scary sharp paper and lap away.

Another handy hint is to get scrap of wood maybe 1"x1"by 9" long. Put this on top of the blade and then you can use 2 hands to apply pressure. One on either end of the wood. Just make sure your glass/granite is held in place firmly.

[Tyler Howell]

You guys are the best. Thanx again.
Working my way through some of my dads old chisels and some others I've hosed up with a bench grinder.
Knowledge is power.

TJH