The limbs seen here are ready for “final” installation.   The fit up tests I have done so far indicate that the detached  bottom irons I’d been considering a few days ago,  no longer seem necessary for a robust capture of the spring bundle by the limb.    That sounds backwards, I know.  It is sometimes useful to reverse the usual perspective and remember that the limbs  actually do have a controlling effect on the bundle,  just as much as the bundle obviously has a controlling effect on them.    Even though the limbs are not supposed to change shape,  they are in some ways,  independent cusses.  It is important to remember that they are under a lot of stress and can have a mind of their own when it comes to doing what is expected.

In the photo below, these metal blocks that hold up the crossbar have their down slope side facing in towards the center of the spring bundle when they are installed in the machine.    The inboard half of their concave channel has been crushed by the flexing of the spring steel crossbar.    These are the perils of using mild steel in such a high stress application.

After a while this damage to the concave channel  becomes sufficient to form it into a shallow graded slope.    Eventually the angle on this slope becomes enough to cause the block to shoot out of the machine much like a bar of soap  squeezed  by slippery hands.  It seems these blocks can have minds of their own too.

The solution is to make up a new set of blocks from hardened steel.   At 60 RC,  they would not crush under load like mild steel blocks.  I will also include a deliberate back draft angle  (i.e. the bottoms of the new blocks will have a  slope cut on them such that the inboard end  is thicker than the outboard end.)  This will cause the softer bottom of the u-notch, in the ears on the washer, to deform into a sloped surface.   The sliding movement this creates will propel the blocks inboard, thus locking them in a sensible direction.

Further capture of the block can be achieved by including a large notch on the outside of the block to allow a stout whipping of artificial sinew to bind it into the ear.   It is imperative to make these blocks listen to reason.

For general reference, the  photo below is an oldie from last season and shows the blocks  fitted under the crossbars.

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