If you want to make one for yourself, here you go...........
>> Craft House Mana <<
This fellow is an amazing guy, he does so much with so few tools, I've talked to him on the phone, but I've not yet had the chance to meet him.
These are his "English" pages, so forgive the sometimes odd translations.
PS here is a >> link << to his drawing of the jig, it give the various dimensions etc.
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
William Arthur Ward