Official Luthiers Forum!

Where could I go to have a cabinet scraper cut? I'd like to make it more of an oval shape.

-John

Do you mean a card scraper or the thing that looks like a plane that holds a scraper blade?

It's easy to shape a card scraper with grinding wheels and files to whatever shape you like. Just takes a little muscle.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Hi Andy. I mean a card scraper. I didn't know it can be done that easily.
-John

Most scraper blades are made of medium carbon steel that has been heat treated to harden it. You might find your life made easier by reversing the heat treating before grinding/filing the scraper and then re-treating it afterward.

Indeed, unless you are careful, the grinding process can generate enough heat to soften the edge so you'll probably need to heat treat anyway.

To remove the hardening, heat the steel as hot as you can get it with a blowtorch, at least get it well beyond 'red heat'. Then let it cool naturally. It will be significantly softer now.

Grind or file your new profile. Get it as close to the finished state as you can in its softened state.

To harden it, heat it again but this time quench the hot metal in oil or water. Then fine tune the edge with a file and abrasive paper, then put a fresh burr on the edge with a carbide sharpener or the tang of a file.

Ian

P.S. This is a very simplified explanation of heat treating steel. Google will no doubt be forthcoming if you want to know more.

Would a french curve one do the trick ?? They are about 5 bucks at Lee Valley.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Any junior high or high school metal shop will be able to do this very easily. They will have a sheet metal cutter, which is like a large paper cutter where you slide the sheet in and step down on a bar and it will chop of the metal. If you draw the shape you want, they will be able to cut it to a general shape and then nibble off enough corners so that you can smooth out the curves with a file and then sharpen it up. This avoids heating up the steel and losing the temper. Any decent metal shop should also be able to do this (try shops that do metal forming for heating, ventilation and air conditioning ductwork or gutter manufacturers.

When you're cutting or shaping, try avoid bluing the metal. If it becomes very uncomfortable to hold onto...take your time and quench it in water to keep it cooler.

Darrin