riser block length

[Justynwithay]

I am looking for advice on what the length of a riser block should be. I have made several board bows and a couple laminated bows with a power lam in the handle section and now I want to take a shot at hybrid bow. I'm trying to ascertain the length of the riser block. Is there a certain ratio of overall bow lenght to riser length? Any advice would be greatly appreciated.

[Hamish]

What's your definition of a hybrid bow? One that looks like a laminated fiberglass bow, but is made of natural materials?

[Justynwithay]

Fiberglass and wood

[stuckinthemud]

For the length of riser block.  Minimum is 8”.  4” for the grip and 2” for whatever method you intend to mount the limbs above the arrow rest and below the grip.  Better is 12”as a minimum

You need to balance draw length against the angle the limbs mount on the riser and the profile of the limbs, so no hard and fast rule as there are a lot of variables - straight, deflex, reflex, r/d, recurved?  Then you say hybrid, so materials will increase the options.  I would recommend a certain amount of time is spent messing about with designs before work commenced, I wasted many hours and no small amount of timber the first time I experimented with 3 part take down bows.

[Justynwithay]

Thank's for the input stuckinthemud!

[Hamish]

Does your hybrid design have glass on the belly as well as the backing? I ask because those bows behave differently to a traditional wood bow, with just fg as a backing.