Third session: heat correction (sideway) with heatgun for string alignment.
Hard to do meaningful pics, but you can hopefully see there is still a lot of problems in this stave. Both limbs are off, looking at the handle. A short measurement (bow in vice, back up) with a cord tied on one tip, aiming over the handle middle shows a results of 8 cm off at the other tip. The amount is about 50% at lower and 50% at upper limb. At both limbs the side bends are relatively sharp and at the fades.
I begin with the lower limb.
The stave is fixed in the vice, belly down, and gets heat from belly side. To control the amount of movement a standing yardstick works perfect. I stop the process when 4 cm are achieved with my adjustable support (a tool from drywall works).
The lower limb (in foreground) is corrected and looks quite good, the upper limb is still off.
The side view shows the reflex in upper and deflex in lower limb.
Fourth session: Just the same procedure as on the lower limb now on upper limb.
The only difference is, I will parallel heat out a part of the reflex in the same session. So we need two forces, a weight for moving the front profile down (string alignment) and rubber bands pulling parallel horizontally to reduce the reflex. (I will heat the lower limb later to reduce the deflex here later (sixth session) – in the end upper and lower limb should look balanced in the side profile).
Here is the set up, the black plastic clamp is for the standing yardstick. The rubber straps produce a horizontally force and second horizontally laying yardstick will show the amount of deflexing.
The same, just another angle
Photo after the heat corrections shows tips and handle good in line. If this would be a straight flat bow, I would leave it. But being a recurve I will correct the little sabre in both limbs, the portions are marked with masking tape.
Fifth session: Heating out the remaining rest of the sabre in both limbs.
About 2 cm in the upper limb and about 1 cm for the lower limb, both are located midlimb. Not a great deal. Bow is clamped sideways, weight load is now 2x10 lbs. The clamp sits already in the curve of the recurve, so one weights is hanging in line with the force line of the limb. The second weight (that with the brown leather loop) is farther away from the limb and will induce a light torsion for a little additional untwisting. Yardstick is leaning against the clamp and works as my reference (read 170cm now). And yes, the sabre needs to be bend out over the long side of the rectangle cross section, it needs just a bit longer heating with a bit lower heat.
Upper limb, 2 cm necessary
Lower limb 1 cm necessary
The set up with the different attached weights
Set up, another point of view
Sixth Session: Heating in reflex (or reducing the deflex) in lower limb.
It’s off about 3”!! I will do the last bit of untwisting in the same session to get the recurves in line at the end. Set up is the same as in the fourth session.
Here is the result:
Front view or back, upper limb is right
Side view, upper limb is right
Lower limb is in foreground
Lower limb is in foreground
Well, i was a bit lazy with posting here, but not in the workshop. Meanwhile the stick was in the fuming pipe for a week and is now resting another week for evaporating the damps.
