Just picked up my first framing slick on Ebay and I've noticed a very slight banana bend on the business end of it. I'd estimate it at about 1/32 - 1/16". I assumed it should be flat like a chisel's back. This is fair amount of metal to remove, if it needs straightening. Should I get a smith to flatten it, grind it, send it back to seller, or keep and use it as is? I haven't had time yet to sharpen it and give it a try...

YES!
If it is used for framing, not finishing, the back should be flat.

I'm not totally sure what Mark is saying yes to, but not all slicks are flat on the back side. Some are bent a little. This is by design and should be used this way.

I think he is saying Yes that his is flat on the back. Tools are made for independent people and there lies the heart of the issue. Use the tool and sharpen it the way it works best for you and the results you want. I see it impossible to have a truly flat back on a slick no mater how you look at it, IMO.

Tim

Which direction is the curve? Is should be flat left to right, but all of mine have a slight curve front to back. I think it gives you greater control over the depth of cut. You have the ability to "climb back out" if you can push down on the handle and have the cutting edge point back up a little. My $0.02 worth. CB.

I have a slick I use for framing(joinery) that is flat on the back, so I can produce flat surfaces... This slick has a truly flat back, IMO.

I also have a slick that I use for finishing(after the adze or broadaxe) that is not so flat on the back, so I can smooth things out while minimizing tear out. The finishing slick also has a crescent shaped edge for the same reason.

What Daiku said.
Slicks, and even framing chisels, may have a slight curve upward back-to-front on purpose. It's personal preference and you learn to work either way. If you want to hollow out slightly a broad surface like a scarf or big tenon (so that it goes flat with tangential shrinkage) the curve lets you control the cut better and climb out as necessary. A perfectly flat chisel is more likely to dig in when paring the sides of mortises, so some (not me, but Jack Sobon does) prefer a slight curve to them as well.

I prefer a belly side to side at the cutting edge, unlike Daiku's flatness from side to side. With a straight edge against the bottom you will see a slight gap at the edges. This is where I see it is difficult to have a dead flat slick even if it was flat front to back. Still personal taste, some are more adamant about it than others.

Tim

My slick has a curve in three directions. From side to side. From the cutting edge towards the handle, and the cutting edge itself is a radius. I had my slick sharpened by a retired machinest. It was absolutely flat, square and perfect, and almost unusable.

Well bloody hell, that's a lot of encouraging advice. I think I'll use it as is, and probably like it a lot. I can always flatten it a little bit if necessary. Thanks all!