MIMF

A friend of mine has a nice old Star brand duplicator that does a great job carving necks. It is a hand me down from a guitar company. His is only the 2 bit model, with one bit spining clockwise and the other bit spinning counter clockwise to accommodate duplicate carving with and against the grain. These carvers have been basically replaced by CNC's, but the old manual ones still make quick work of neck duplicating. The company that made the carver is now out of business. The issue is with finding router cove bits made for counter clockwise cutting. Know of a source? Thanks, Bob

Perhaps you can get your local sharpening service to grind one appropriately for you?

My service is always willing to grind and try out something. Have had router bits modified and a circular saw blade ground down to do fret slotting.
Cost me around R100 each (around $5US)

I don't think it can be created by grinding a regular bit. It would have to be built from the ground up.

I have never seen this kind of router bit.

You don't say what size you need, but might any of these be useful?

https://drillsandcutters.com/carbide-si ... end-mills/
https://www.kodiakcuttingtools.com/view ... left-hand/
http://toolinghouse.com/lefthand-squareend.aspx
https://www.endmilldiscount.com/end-mil ... ls-795.asp

A Google search for “custom router bits” turned up a large list of makers.