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

go down to the local co-op or tractor supply co. or such in your area and
spend a few minutes with one of their new models , looking at how they are
built and the size of their equipment will give you a really good idea



a few guidelines

a four inch bore cylinder has 12.57 square inches approximately
so for every 100 psi you get 1200 pounds of force


at 2000 psi this is a twelve ton cylinder , at four thousand it is a
24 ton cylinder ,


horsepower required to run your pump can be figured on the base of

1 horsepower = one gpm @1500 psi



most of the log splitters i see are

5-8 horsepower
two stage pump 12 gpm@800-1000 psi,2-4 gpm @3000psi
manually operated valve
a four inch bore cylinder


i built mine netirely with stuff i scrounged , though SurplusCenter is a
good place to buy, way cheaper than NT


RAMBLE OFF

On Mon, 14 Feb 2005 19:39:39 -0500, "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?

You need to match your pump in regards to yur engines horsepower. Look
at the Barnes 2 stage pumps, thats what you want to use, unless you
have a big engine, want to get into more work on hydrualics etc. The 2
stage pumps are fine, with their smaller one being suitable for a 5 or
so hp gas engine, and the next size for at least a 8 to 10 hp engine,
and the largest you need at least a 16 hp for them to work fine.
===
===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?

GPM is how much the time it takes to cycle due to flow in an unloaded
operation. More load, GPM is going to drop, and pressure will
increase..So look for a pump (2 stage) thats capable of at least 3000
psi which is more than sufficient. Lower GPM flowrate is just a bit
longer in cycling the cylinder in and out, unloaded.
===
===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?

Tonnage developped is proportional to the surface area of the piston
in the cylinder. You may have a 4inch cylinder, and you times the
square inches of that pistons face by the PSI to come up with tonnage
produced.......Its a given. However you also have a rod attached to
that cylinder which in all reality is going to reduce the pistons
surface area on the rod side, so you need to deduct the area the rod
takes up on the pistons face. The opposite side of the piston is
usually going to have more surface area as it has no rod attached to
it, so it generates greater force one way than the other.

Most log splitters you see at builder supply and garden places are
from 20 to 25 ton on average and most have anything from 4" to 5 inch
cylinders. A bigger cylinder in diameter will generate more tonnage or
force with the same pressure applied to a 4 inch cylinder, but to make
cycle times faster to make up for the larger cylinder you may need to
step up to a larger GPM pump.

To make it simple go with their 11.x GPM 3000 2 stage pump,. 5 to 6.5
horsepower gas engine, and a 4 to 4 1/2 x whatever length cylinder you
need for the ram. But the open center single spool with detent retract
position control valve and the length hoses you need, and a filter
assembly, and also a strainer breather assembly. Thats it. the rest is
steel welded up to make the design you want. Hydraulics is simple,
especially on a log splitter. Open center control valve will
continually allow fluid to free flow back to resivoir, when its not
closed by the lever to divert fluid to the cylinder. If y ou use a
closed center valve you have much faster cycle times or break out
times, as there is a pressure relief valve that holds the fluid
pressure up to or close to the operating prressure at all
times.........not needed with a log splitter, and by not using a
closed center valve it will reduce heat buildup, and wear and tear on
your hyd components.


===
===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
===


REMEMBER: "This is worth repeating for benefit of al newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

The hydraulics are just plumbing; HP hydraulic lines and fittings are
available everywhere in industrialized sections; NT notwithstanding. A
4" DA cylinder and 11 GPH pump is plenty for up to 24" dia. bucks. My
home built splitter uses a 12" stroke cylinder, which is plenty, since I
buck all my logs to 18" lengths for my fireplaces. You pretty much can't
build a splitter for much less than you can buy one, unless you snag the
major components free or very cheap.
JR
Dweller in the cellar

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




--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth
If you're not the lead dog, the view never changes
Doubt yourself, and the real world will eat you alive
The world doesn't revolve around you, it revolves around me
No skeletons in the closet; just decomposing corpses
--------------------------------------------------------------
Dependence is Vulnerability:
--------------------------------------------------------------
"Open the Pod Bay Doors please, Hal"
"I'm sorry, Dave, I'm afraid I can't do that.."

"Andrew H. Wakefield" wrote in message
...
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?


It's traditional to use "two-stage" pumps in splitters. The first stage
produces high flow at low pressure to move the ram quickly to and from the
work. The second stage produces very high pressures at low flow to build
the large forces necessary to actually split the wood.

Northern sells Prince pumps (not the best, but they last many years if your
wet circuit is maintained clean and moisture-free... and they're CHEAP).
They offer an 11gpm two-stage "log splitter" pump that mates well with an
8hp gas engine. Mine's an old cast iron updraft-carb Briggs.

With a 4" diameter, 24" stroke cylinder, you can generate roughly 14 tons of
splitting force at 2200psi (well within the capabilities of the pump and
engine).

That doesn't sound like much, compared to their 20 and 25 ton splitters,
until you realize that they're advertising what the press COULD do if the
system ran at the maximum pressure rating for the components -- which they
never do.

With 14 tons and a clean wedge, I can split an 18" diameter well-cured white
oak butt 20" long. (needs a wedge at least longer than the radius of the
piece.. mine's 11")

LLoyd

I have never seen Prince pumps offered by NT in 2 stage
configurations. All I have ever seen is Barnes brand 2 stage pumps.
They are a good pump. I have some over 20 years old and work fine.....
Prince is a large manuf of cylinders though, and I have had mixed
results with them, but their more than sufficient on a log splitter.

I routinely run my system at 2200 to 2500 psi not the full rated 3000
and it works just fine, and makes for lots less wear and tear on
components.

On Tue, 15 Feb 2005 12:55:42 GMT, "Lloyd E. Sponenburgh"
wrote:

===
==="Andrew H. Wakefield" wrote in message
...
=== 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?
===
===
===It's traditional to use "two-stage" pumps in splitters. The first stage
===produces high flow at low pressure to move the ram quickly to and from the
===work. The second stage produces very high pressures at low flow to build
===the large forces necessary to actually split the wood.
===
===Northern sells Prince pumps (not the best, but they last many years if your
===wet circuit is maintained clean and moisture-free... and they're CHEAP).
===They offer an 11gpm two-stage "log splitter" pump that mates well with an
===8hp gas engine. Mine's an old cast iron updraft-carb Briggs.
===
===With a 4" diameter, 24" stroke cylinder, you can generate roughly 14 tons of
===splitting force at 2200psi (well within the capabilities of the pump and
===engine).
===
===That doesn't sound like much, compared to their 20 and 25 ton splitters,
===until you realize that they're advertising what the press COULD do if the
===system ran at the maximum pressure rating for the components -- which they
===never do.
===
===With 14 tons and a clean wedge, I can split an 18" diameter well-cured white
===oak butt 20" long. (needs a wedge at least longer than the radius of the
===piece.. mine's 11")
===
===LLoyd
===


REMEMBER: "This is worth repeating for benefit of al newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

The next splitter I build will have a 2 stage pump to speed the cycle
time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
the retract time.

Current splitter has a 4 X 24 and a Vickers pressure compensating pump.
That is a rotary swash plate style and the swash plate rotates flat at
a preset pressure setting (no flow). It was built with available parts
some 20 years ago and still serves me well. Beam rotates vertical and
horizontal, Briggs model 19 7.25 HP engine.

Last fall I had 2 young men and my g/f helping. It was the easiest
harvest by far. Here is how it went;

Weekend 1 spent 2 days in the woods cutting trees, 20 -25 ft length
sections. Loaded trailer with case backhoe with 4 in 1 bucket.

At home, picked up the log with the tractor and held it about 3.5 ft.
g/f backed the Kawasaki mule under the end of the log, and I cut a
piece off 18 inches long. 4 or 5 pieces in the Mule, drive over to the
splitter and dump the pieces off to the splitter and stackers. Repeat
until wood is all in the barn. We did 6 cords in a day! No sore back!

I like the design of the Timberwolf Manufacturing TW-6 machine.

Bob

On Mon, 14 Feb 2005 19:39:39 -0500, "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

Greetings Andy,
To figure how fast the system will work you need the GPM and the
volume of the cylinder. The volume of the cylinder is 3.1416 times the
radius squared of the cylinder times the travel. Because of friction
losses etc. your top speed will be lower than the calculated max, but
it will give you an idea. So if the cylinder volume is 1 gallon, and
you have a 10 GPM pump, the shortest time for the full cylinder travel
is 6 seconds.
ERS

On 15 Feb 2005 05:55:20 -0800, "Bob" wrote:

===The next splitter I build will have a 2 stage pump to speed the cycle
===time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
===the retract time.
snip

A 4" rod in a 5" bore cylinder.........for what reason would this be
beneficial? With so much reduction on the retract side it would be
awfully low power and slow............A 2" rod is more than sufficient
for any splitter if the moveable slide with ram or wedge is
sufficiently sturdy.

REMEMBER: "This is worth repeating for benefit of al newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

On Wed, 16 Feb 2005 08:55:16 -0800, Tom wrote:
Roy wrote:

On 15 Feb 2005 05:55:20 -0800, "Bob" wrote:

===The next splitter I build will have a 2 stage pump to speed the cycle
===time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
===the retract time.
snip

A 4" rod in a 5" bore cylinder.........for what reason would this be
beneficial? With so much reduction on the retract side it would be
awfully low power and slow............A 2" rod is more than sufficient
for any splitter if the moveable slide with ram or wedge is
sufficiently sturdy.

LOL, a little knowledge can be erroneous..

Care to share what you're seeing that Roy isn't?

On 15 Feb 2005 20:03:49 GMT, the renowned Dave Hinz
wrote:

On Wed, 16 Feb 2005 08:55:16 -0800, Tom wrote:
Roy wrote:

On 15 Feb 2005 05:55:20 -0800, "Bob" wrote:

===The next splitter I build will have a 2 stage pump to speed the cycle
===time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
===the retract time.
snip

A 4" rod in a 5" bore cylinder.........for what reason would this be
beneficial? With so much reduction on the retract side it would be
awfully low power and slow............A 2" rod is more than sufficient
for any splitter if the moveable slide with ram or wedge is
sufficiently sturdy.

LOL, a little knowledge can be erroneous..

Care to share what you're seeing that Roy isn't?

The rod subtracts from the cylinder area for retraction, so the bigger
the rod, the faster it moves for a given volume per second (you can
think of the rod as filling up a lot of the cylinder so it takes less
hydraulic fluid). The example would retract as fast as a 3" cylinder
extends. You could also use a regenerative circuit to get it to extend
faster at low power before it starts to split.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On 15 Feb 2005 20:03:49 GMT, Dave Hinz wrote:

===On Wed, 16 Feb 2005 08:55:16 -0800, Tom wrote:
=== Roy wrote:
===
=== On 15 Feb 2005 05:55:20 -0800, "Bob" wrote:
===
=== ===The next splitter I build will have a 2 stage pump to speed the cycle
=== ===time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
=== ===the retract time.
=== snip
===
=== A 4" rod in a 5" bore cylinder.........for what reason would this be
=== beneficial? With so much reduction on the retract side it would be
=== awfully low power and slow............A 2" rod is more than sufficient
=== for any splitter if the moveable slide with ram or wedge is
=== sufficiently sturdy.
===
=== LOL, a little knowledge can be erroneous..
===
===Care to share what you're seeing that Roy isn't?

Yea I know a bigger rod would mean less volumne needing to be filled
but its certainly way overkill on a simpole machine like a log
splitter.......I did type in slow but intended to refer just to the
low power end, which really does not mean anything on a retract cyucle
of a splitter, but heck a 4" rod.............hmmmmmmmmmm

REMEMBER: "This is worth repeating for benefit of al newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

On Wed, 16 Feb 2005 14:15:03 -0800, Tom wrote:

snip
=== Yea I know a bigger rod would mean less volumne needing to be filled
=== but its certainly way overkill on a simpole machine like a log
=== splitter.......I did type in slow but intended to refer just to the
=== low power end, which really does not mean anything on a retract cyucle
=== of a splitter, but heck a 4" rod.............hmmmmmmmmmm
===
===
===Can you think of a cheaper way of getting a faster retract cycle?
===
===Tom

Well not that I can think of off hand, but I would have to think the
price of a cylinder with such a rod in it would be pretty darn pricey
compaared to say the next higher flow pump.....I really doubt I would
even consider using a 4" rod in a 5" cylinder if I had it for free.
Heck why not grab an old Chevy 427 or even a 283 and use it with a big
pump............better yet one of the old J-79 engines that Davis
Monathan AFB boneyard is full of and use it with their high flow high
pressure hydrualic pumps that are normally installe don them for in
the old F4.....now that would be some fast cycle times, but pretty
expensive to operate...........

REMEMBER: "This is worth repeating for benefit of al newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

"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

"Roy" wrote in message
...
Yea I know a bigger rod would mean less volumne needing to be filled
but its certainly way overkill on a simpole machine like a log
splitter.......I did type in slow but intended to refer just to the
low power end, which really does not mean anything on a retract cyucle
of a splitter, but heck a 4" rod.............hmmmmmmmmmm


Roy, power does mean _something_ on the retract stroke of a splitter.

Didja ever get a slivver stuck under your guides? Sure, it doesn't take as
much power as the splitting cycle.

LLoyd

Roy wrote:

On 15 Feb 2005 05:55:20 -0800, "Bob" wrote:

===The next splitter I build will have a 2 stage pump to speed the cycle
===time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
===the retract time.
snip

A 4" rod in a 5" bore cylinder.........for what reason would this be
beneficial? With so much reduction on the retract side it would be
awfully low power and slow............A 2" rod is more than sufficient
for any splitter if the moveable slide with ram or wedge is
sufficiently sturdy.

LOL, a little knowledge can be erroneous..
Tom

Dave Hinz wrote:

On Wed, 16 Feb 2005 08:55:16 -0800, Tom wrote:
Roy wrote:

On 15 Feb 2005 05:55:20 -0800, "Bob" wrote:

===The next splitter I build will have a 2 stage pump to speed the cycle
===time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
===the retract time.
snip

A 4" rod in a 5" bore cylinder.........for what reason would this be
beneficial? With so much reduction on the retract side it would be
awfully low power and slow............A 2" rod is more than sufficient
for any splitter if the moveable slide with ram or wedge is
sufficiently sturdy.

LOL, a little knowledge can be erroneous..

Care to share what you're seeing that Roy isn't?

A 4" piston would mean a fast retract as the volume per inch
of stroke required would be 7 odd cubic inches. With a 2" rod
it would be that much slower, as 16.5 cubic inches per inch of
stroke would be required.

5" bore = 19.635 square inches
4" rod = 12.566 " "
2" rod = 3.1416 " "

The maths are quite simple..

Tom

Tom wrote:

Roy wrote:

On 15 Feb 2005 05:55:20 -0800, "Bob" wrote:

===The next splitter I build will have a 2 stage pump to speed the cycle
===time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
===the retract time.
snip

A 4" rod in a 5" bore cylinder.........for what reason would this be
beneficial? With so much reduction on the retract side it would be
awfully low power and slow............A 2" rod is more than sufficient
for any splitter if the moveable slide with ram or wedge is
sufficiently sturdy.

LOL, a little knowledge can be erroneous..
Tom

Bit of a typo in the previous! :-(

A 4" rod would mean a fast retract as the volume per inch
of stroke required would be 7 odd cubic inches. With a 2" rod
it would be that much slower, as 16.5 cubic inches per inch of
stroke would be required.

5" bore = 19.635 square inches
4" rod = 12.566 " "
2" rod = 3.1416 " "

The maths are quite simple..

Tom

Roy wrote:

On 15 Feb 2005 20:03:49 GMT, Dave Hinz wrote:

===On Wed, 16 Feb 2005 08:55:16 -0800, Tom wrote:
=== Roy wrote:
===
=== On 15 Feb 2005 05:55:20 -0800, "Bob" wrote:
===
=== ===The next splitter I build will have a 2 stage pump to speed the cycle
=== ===time. Also the ram will be a 5 inch bore with a 4 inch rod to speed
=== ===the retract time.
=== snip
===
=== A 4" rod in a 5" bore cylinder.........for what reason would this be
=== beneficial? With so much reduction on the retract side it would be
=== awfully low power and slow............A 2" rod is more than sufficient
=== for any splitter if the moveable slide with ram or wedge is
=== sufficiently sturdy.
===
=== LOL, a little knowledge can be erroneous..
===
===Care to share what you're seeing that Roy isn't?

Yea I know a bigger rod would mean less volumne needing to be filled
but its certainly way overkill on a simpole machine like a log
splitter.......I did type in slow but intended to refer just to the
low power end, which really does not mean anything on a retract cyucle
of a splitter, but heck a 4" rod.............hmmmmmmmmmm


Can you think of a cheaper way of getting a faster retract cycle?

Tom

Many thanks for all the helpful replies. You have confirmed some of what I
was thinking, plus given me insight into issues I didn't know enough even to
ask about!

I know I'll have a couple more questions to follow up; after I digest all
this info, I'll put up a new post with follow up questions.

Thanks again!

Andy

"Andrew H. Wakefield" wrote in message
...
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

"Trevor Jones" wrote in message
...
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 Super Split is the same thing I think. Here is a diagram of how it
works.
http://www2.primushost.com/~logsplit/principle.html

Lane

On Tue, 15 Feb 2005 03:02:28 GMT, (Roy) vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email


GPM is how much the time it takes to cycle due to flow in an unloaded
operation. More load, GPM is going to drop, and pressure will
increase..

Is this something to do witht eh two-stage pumps? Hydro pumps should
deliver constant flow, at any pressure

On Mon, 14 Feb 2005 19:39:39 -0500, "Andrew H. Wakefield"
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

http://science.howstuffworks.com/hydraulic2.htm

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.

Two stage pumps sort of shift gears, so to speak, in that when they
reach a predetermined pressure, due to load imparted on the log for
instance, they drop in GPM but go up in pressure, and remain at higher
pressure and lower flow until resistence drops, then pump cycles back
to a higher flow rate with lower pressures, sort of like a automatic
tranny downshifting.........its all done by the settings made
internally in the pump.

They allow a smaller HP motor to be used in a lot of cases to provide
the same rating, and saves a lot of wear and tear on hydraulics in
general.



On Thu, 17 Feb 2005 13:48:56 +0800, OldNick
wrote:

===On Tue, 15 Feb 2005 03:02:28 GMT, (Roy) vaguely
===proposed a theory
===......and in reply I say!:
===
=== remove ns from my header address to reply via email
===
===
===GPM is how much the time it takes to cycle due to flow in an unloaded
===operation. More load, GPM is going to drop, and pressure will
===increase..
===
===Is this something to do witht eh two-stage pumps? Hydro pumps should
===deliver constant flow, at any pressure


REMEMBER: "This is worth repeating for benefit of al newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

On Wed, 16 Feb 2005 19:54:53 -0800, "Lane" lane (no spam) at
copperaccents dot com vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email


"Trevor Jones" wrote in message
...
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 Super Split is the same thing I think. Here is a diagram of how it
works.
http://www2.primushost.com/~logsplit/principle.html


But have you seen the _prices_ of those things?

The 24 tonne one is US$4500, where I looked!

http://www.landscapingcomplete.com/M...Splitters.html

That's a lot of time needs to be saved to make up over hydraulics at
maybe $1500.

On Wed, 16 Feb 2005 21:56:10 -0500, "Andrew H. Wakefield"
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

If you are interested in the Super Split and what it takes to build
one
http://www.arboristsite.com/archive/...hp/t-6668.html

Many thanks for all the helpful replies. You have confirmed some of what I
was thinking, plus given me insight into issues I didn't know enough even to
ask about!

I know I'll have a couple more questions to follow up; after I digest all
this info, I'll put up a new post with follow up questions.

Thanks again!

Andy

On Thu, 17 Feb 2005 12:43:29 GMT, (Kerry)
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

OK. Thanks. I had not dealt with them or heard of them. When you said
"higher pressure means lower flow" I was thinking "Wha?...." but I
live and learn.

Interesting, actually, why do hydraulic system not use springs to
retract the cylinder just as the Rack and pinion ones do?

Two stage pumps sort of shift gears, so to speak, in that when they
reach a predetermined pressure, due to load imparted on the log for
instance, they drop in GPM but go up in pressure, and remain at higher

Actually there are some cylinders that do use springs to retract them.
They are typically whjat is referred to as single action cylinders,
commonly ofund on items like power packs where there is only a
pressure or feed hgose from the pump to the cylinder. Once extended,
and you relieve pressure, it uses a spring to pull the ram back into
the cylinder, and the air is usually vented to atmosphere. If the
device has sufficent weight lots of single acting cylinders do not
utilize springs at all, and rely on weight / gravity to move them back
for another cycle. Spring retraction is doable but its slow compared
to powering with fluid.

On Fri, 18 Feb 2005 07:59:14 +0800, OldNick
wrote:

===On Thu, 17 Feb 2005 12:43:29 GMT, (Kerry)
===vaguely proposed a theory
===......and in reply I say!:
===
=== remove ns from my header address to reply via email
===
===OK. Thanks. I had not dealt with them or heard of them. When you said
==="higher pressure means lower flow" I was thinking "Wha?...." but I
===live and learn.
===
===Interesting, actually, why do hydraulic system not use springs to
===retract the cylinder just as the Rack and pinion ones do?
===
===Two stage pumps sort of shift gears, so to speak, in that when they
===reach a predetermined pressure, due to load imparted on the log for
===instance, they drop in GPM but go up in pressure, and remain at higher


REMEMBER: "This is worth repeating for benefit of al newbies!
Jo Ann asked Dr. Solo to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

On Fri, 18 Feb 2005 01:54:45 GMT, (Roy) wrote:

Actually there are some cylinders that do use springs to retract them.
They are typically whjat is referred to as single action cylinders,
commonly ofund on items like power packs where there is only a
pressure or feed hgose from the pump to the cylinder. Once extended,
and you relieve pressure, it uses a spring to pull the ram back into
the cylinder, and the air is usually vented to atmosphere. If the
device has sufficent weight lots of single acting cylinders do not
utilize springs at all, and rely on weight / gravity to move them back
for another cycle. Spring retraction is doable but its slow compared
to powering with fluid.

I have one of these spring return cylinders that I need to find seals
for. Its from a 10 ton bench top (big bench!) Italian made press
(VTA?) I scounged up last week.

The vietnamese workers took it apart..and I dont think they put all
the parts in the coffee can....

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

On Fri, 18 Feb 2005 01:54:45 GMT, (Roy) vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Actually there are some cylinders that do use springs to retract them.
They are typically whjat is referred to as single action cylinders,

Yep. Got them in many applications.


for another cycle. Spring retraction is doable but its slow compared
to powering with fluid.

Can't see why, if the spring is strong and the fluid passage easy. You
may well be right, as it's not being done, btu it seems strange.

"Gunner" wrote in message
...
The vietnamese workers took it apart..and I dont think they put all
the parts in the coffee can....

Yeah.... kinda like what they did to our swifts and UH-1s when we turned 'em
over.

LLoyd

On Fri, 18 Feb 2005 12:20:51 GMT, "Lloyd E. Sponenburgh"
wrote:


"Gunner" wrote in message
.. .
The vietnamese workers took it apart..and I dont think they put all
the parts in the coffee can....

Yeah.... kinda like what they did to our swifts and UH-1s when we turned 'em
over.

LLoyd

Sigh..so Ive heard

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"