On Sun, Jan 8, 2023 at 08:44 PM, Jay Perez wrote:
... have used something similar on the Z axis of my 3D printer.
There are quite a few variants and all have the same principle: a spring.
Bridgeport mills use a 'split nut' ...
Ahh, Brigdeport milling machines.
Serious stuff.
Crude but effective.
Many intelligent solutions are.
But it doesn't look crude to
me.? 8^)
... cut a gap into the nut to allow it to be compressed ...
There would be no problem with that.
Just maybe, given the size of the nut, finding a thin enough saw blade.
... a mechanism that allows you to squeeze it slightly ...
That's the exact moment at which the elephant enters the room.
Like I mentioned previously, the OEM nut is a 10mm cube and the way it moves in is 10.5mm high.
So there's only ~ 0.50mm vertical space available.
As the saddle is made from die cast aluminium, the way is shaped like a flat bottomed inverted cone
to facilitate the separation from the die during manufacture.
It measures 13.5mm at the top and 12.5mm at the bottom.
So the nut moves along the centre of the way with barely any
wiggle room.
ie: ~ 0.50mm at the bottom, ~1.50mm to each side at the top and ~1.00mm at the bottom.
I'm afraid I don't see room for a clamp + set screws there. 8^/
Idea:
I have been wondering if the M4x0.7 screw than holds the nut in place could push a very small brass/teflon/? bearing against the 8.0x1 thread and help reduce the backlash.
Or maybe the screw could be made from very hard brass and have an acute/pointed end.
ie: by design (in theory), the feed screw axis and the M4 screw axis intersect at 90¡ã and as a consequence of that, the screw's point would run
inside the thread and (hopefully) reduce or eliminate the existing backlash.
Make sense?
Obviously (if it works) such a screw would have to be replaced when the point gets worn and start to slip.
But anything is better than this incredible design flaw from Emco's engineers.
Once again, thanks for your input.
Best,
JHM
