machining a curve ...

OK guys heres a question ..

This is a safe key circa 1750 or so, the clever thing about this type of key is that the ward cuts curve through the bit, in ' parallel ' (not the correct term in this case I think) to the key shaft.

Now originaly these keys were cut with chisels, custom made by the person who cut the key - however I lack both the time and skill to make such chisels and then cut the warding in such a way.

From time to time I have to make such keys, and herein lies the problem I have to make the cuts square, and as a consequence slightly wider than the original which can in the case of a complex ward result in a weaker key, so I have been looking into producing the curved cuts on the lathe and while I can start the cut easily enough the carbide tipped tools the shape of the tool prevents the cut exceeding more than a few mm deep.

I had considered using some holesaws mounted in the tailstock, but the problem with such an approach is that the position of the cut can be in almost any position and holesaws will not (unless I am missing something) be suitable given the limited range of sizes, and also it would cost me a small fortune in holesaws !

In terms of equipment at my disposal I only have a myford super 7 & rodney milling attachment. I have a swiveling verticle slide & a dividing attachment also.

Any suggestions as to a technique would be appreciated.

Paul