On Fri, 14 Oct 2016 18:16:19 +0100, GB <
NOTso...@microsoft.com>
wrote:
There is a bit of confusion about screw drive, this video shows what I
think you mean, the splitter is at the opposite end of the tractor to
the saw and the anvil is driven by a half nut which is released after
the split, I do wonder if it would release if jammed on a knotty bit.
Return is by spring.
https://www.youtube.com/watch?v=_gSGQPpQ6P4#t=83
IMO this would have the efficiency of a worm drive which I gather
varies greatly between 50 -90%. I gather hydraulic drives fall below
70%.
However hydraulic drives have better control and 6.5 tonnes of
pressure is adequate for most simple splitting. I use an axe at home
though I have both hydraulic and screw splitter. By screw splitter I
mean the type Tim refers to, mine is also on the back of a 35 hp
tractor pto.
I prefer the hydraulic one because it produces a much cleaner cut, the
screw splitter tears into the wood and often doesn't separate the two
bits because of stringy fibres. I find on some woods, holly in
particular it bores a hole and then gives up on a log which the
hydraulic splitter has no problems with. It does split particularly
knotty stuff which the hydraulic one stalls on but the log is often
too misshapen to get into the stove without further sawing.
Screw splitters are good on a small 360 digger for breaking down
oversize cordwood for the wood processor.
The screw splitter is also intent on removing fingers, finger nails,
hands and arms of the unwary, I have almost grown back a finger nail
lost when picking a split log off the screw and finding it wasn't
quite split as it snapped shut again.
AJH