I've been down that road already. Have you considered sending the
sashes out to a stripping facility? It's not a bad option if you are
doing just a few sashes at a time and you can live with plywood over
the openings for a few days. Sending the old sashes out beats makinge
new ones by a mile. That of course assumes that the sashes are worth
saving...

Making new sashes is not too difficult with a very stout router in a
table or a shaper. The cutters are easy to find. Go to
www.oldhouseweb.com and check out their boards and preservation briefs.

It's nice to hear that you aren't just wanting to slap some vinyl
monstrosity up in place of the original window. Old double hungs,
properly weatherstripped and with wooden storms, are quite nice on
those cold Ohio winter nights we are still experiencing.

Jim