"Andrew H. Wakefield" wrote:

I've been looking at the possibility of building a log splitter, vaguely
following some old plans from Mother Earth magazine. The metalwork presents
no problems (perhaps famous last words!) but I have never messed with
hydraulics. I've been looking at the parts that Northern Tool sells, and am
not entirely sure what I am looking at.

For the hydraulic pumps, there seem to be two styles, one that is rated in
GPM and one that is rated in cu. in. Why the different ratings? Are these
two different types of pumps, intended for different uses?

For pumps that are rated in GPM: If the max PSI is the same for two
different pumps, would they both be able to create the same amount of
splitting force -- but the one with higher GPM would move faster than
other -- or am I totally off track here?

NT also sells a variety of hydraulic rams, ranging considerably in price.
They all seem to have three specs: max PSI (generally either 2500 or 3000),
stroke, and bore. Okay--how do I compare these specs to the commercial log
splitters advertised as "20 ton splitter" or "25 ton splitter"? Is the
overall force exerted related to the PSI--but the rams and pumps all seem to
have similar maximum PSI?? Or is it a function of PSI and bore size?

I guess what I need is a quick course in basic hydraulics. Is there a good
website to read up on this stuff? Many thanks to anyone who takes pity on my
ignorance!

Andy

I rented a splitter last year that spoiled me. I'll never even consider
hydraulics for splitting wood again.

The splitter was "Gripo" brand name. It used a rack driven by a pinion
on a shaft with a fairly substantial flywheel on it.

The cool part was that it had a cycle time of around a second a shot.
Place block, lift toggle handle, SHUNK!, place block. The ram was
retracted by springs and was ready to go before I was in all cases.

No problem blowing through the knots or crotch wood. Blew through a
couple blocks sideways to shorten them, it grunted at that.

All on a 160cc Honda motor.

Wish I had taken some pictures of the linkage that connected the rack
to the pinion. I've been keeping an eye out for a suitable rack and
pinion set since then. I figure a flywheel is easy, as there is usually
a scrapped out baler at most farm auctions I've been to.

Hmmmm.... A google search finds Super Split made in the US that uses
the same mechanism. Cool stuff!

Cheers
Trevor Jones