Patchbox inlet chisel.

[varsity07840]

What's the appropriate chisel to use on radius inlets such as the ends of a southern mountain style?

[David Rase]

A sharp gouge the same sweep as the patchbox radius.
David

[Ky-Flinter]

Or a forstner bit of the appropriate diameter.

-Ron

[okieboy]

 You can also create radii of various sizes by going the opposite of a larger gouge of forstner bit and following your line (scribed with a sharp knife) with a very narrow and very thin chisel. Narrow is .125-.062" wide. It is not a very fast method, but it will deal with any curve, even irregular ones. Chisels like this are generally homemade, but not difficult to make at all. Flatten a piece of music wire and shape with a sharpening stone, then a piece of hardwood dowel for a handle to tap with a light mallet, such as a piece of maple about 3/4 x 1 x 6".

[B.Habermehl]

I usually screw the patch box finial in places first, then I scribe around it with a sharp scriber. Then I remove the metal part. And trace in my scribed line with a super sharp pencil. Then I take my radioused chisel, and roll it into my scribed line. My radioused chisel can be made from a flat chisel by simply grinding the end to a radioused edge, then sharpen from one side keeping one side as flat as possible. My tool has the approximate radius as my little finger tip, the chisel blank was hand forged and tempered from a hay rake tooth, no measurements were really taken. The cut is achieved with a rolling motion of the wrist. The bevel of the chisel faces the outside of your scribed line as you roll cut. You will find a ton more uses for this tool. BJH
PS. You are likely to make several of these in different sizes for different jobs.

[Mark Elliott]

I use an approximately 1" old fashioned spur bit (with a brace)  to rough out patchbox cavities.   If I want round ends,  I just don't square them up.    I keep it simple.

[Herb]

You can make any radius chisel you want from a hacksaw blade or the blue steel banding or "strapping"  from lumber yards. Score across, break into two inch pieces, grind the teeth off the working end for 1/2" and hammer it around a drill bit of the size you want.  Don't need to heat it unless you make a small radius, 3/8" or so..  Then grind or file  a long bevel to sharpen it.  I use a small hammer to drive it in on the scribed line.  This material also makes good patch box springs.

[smylee grouch]

I have done what Herb suggests and it has worked for me. I also have made scrapers from the old saw blades in many different sizes and shapes, easy to make and in a sense free.