flattening chisels backs

[tablesawtom]

I like to have my chisel backs flat. I built a fixture so that I could grind the sides. I have to have then parallel within .001 or the vise can't clamp on them.

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Then I can clamp on the sides, indicate the flat flat side as parallel as I can get it andgrind the back. it took about .005 off from each to get them just to clean up. I redressed the wheel, and picked up the surface of the chisel with the grinding wheel. For the final cut the depth of cut was .0003 and then there was a total of 3 spark out passes. Now the only stone the back of the chisel will see is the 8000 grit one

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The chisels shown are Marples that I purchased new about 35 years ago for $29 and they have seen a lot of rough use.I plan on finishing the other 3 next week and give them to my son inlaw.

And then my plans are to angle the bottom of the fixture to 20 degrees and then grind the sides of a few chisels Narex premium chisels, back about 2 inches and make them into dovetail chisels. I read the information on them and they are hardened to a Rockwell "C" for 59. Being primarilly a die maker, we tempered our die steel to 58-60 rockwell, any harder and the steel tended to be to brittle and didn't hold up the cutting forces, in operation, in the press. The Narex chisels handles are wood and will the chisel will be used with a mallet so there will be some shock to the cutting edge and that is why I chose the premium chisel and not the Ricter chisel. Not to mention cost

PS The wheel is spinning the cameral stops in in that time frame.

Tom

[Philip1231]

Well that beats the hell out of grinding them by hand on a piece of emery cloth glued to the wing of my tabesaw.
Outstanding Tom!

[Handplanesandmore]

First time I saw a chisel back flattened on a rotary stone that way -- not on the flat side of the wheel.

Simon

[tablesawtom]

First time I saw a chisel back flattened on a rotary stone that way -- not on the flat side of the wheel.

Simon

It is a surface grinder. The head  moves up and down on a lead screw. The table moves back and forth and in and out.  Here is an other picture of a surface grinder. This one has coolant.

   

Tom

[Handplanesandmore]

Thanks for the explanation, Tom.

Simon

[Alan S]

That looks great. And it shows why chisels that are not expensive do not come nearly as flat.

[Danny in Houston]

This is a flat chisel back.

[MauleSkinner]

If my chisel backs were that flat, I could....

Probably still be just a hack!

[Yodascaretaker]

darn, I do it by hand on a series of 1k-4K-8k. Takes awhile.

[AHill]

Nice setup. It'll certainly save time for chisel backs that are way out of flat.

There' s a Paul Sellers video of him preparing an Aldi chisel for use. The back needed some work. It was hollowed, which is a good thing from a getting the back flat perspective. Sellers maintains (and I agree) that there's no need to flatten the entire back of the chisel. Just the first few millimeters of the cutting edge. He did progress through the grits on the back to get it mirror smooth.