Bow Frogs

When I started making renaissance bows, I quickly adopted the loose-frog-without-screw system. Actually I went through all the stages of Medieval bowmaking, from hairs attached with a piece of rope to miniscule simple frogs and click-in frogs.

I adore the simplicity of this way of giving tension to the hair and I even left the clip system behind because it limits the flexibility you can have when you can slide the frog in exactly the right position. To prevent it from slipping away you simply put some rosin between frog and bow.

Pull the frog in the right position

Rosin as anti-slip

The hair is fixed on both ends the same way, with a small piece of wood in the mortise made for it. You simply pull the frog to get the right tension. The acaciawood keeps its tension very well, so you don’t need to relax the bow each time you stop playing.

piece of wood blocking the hair

loose

half way

good tension

lower walnut frog

higher maple frog

If you want more or less space between the hair and the stick you can put in a higher or lower frog in two seconds.

Wikipedia on baroque violin bows : The screw mechanism for changing hair tension is first mentioned in a French shop inventory of 1747 !!!