Any mods for faster hydraulics of portable woodmizer

[MikeH]

 Anybody do this or is it out of the question? I would not mind real fast hydraulics. <---- Maybe the loading arms going about that fast.

[rbhunter]

How are you going to figure the distance for the mill to catch the log as it flies throught the air?

[MartyParsons]

Safety First!  I think Bibbyman has 6 gpm vs 4 gpm. Bibbyman it any faster? Bibby's hydraulics is powered by AC Volts and is stationary.
M

[Bibbyman]

 

6 GPM is way fast for the hydraulic system on the Super HD.  (Ever see a demo of the LT300?) 

We're sawing small logs right now and even with a year or more of practice, it's easy to over run something.  The biggest danger is lowering the back supports too fast and further than you wanted. The second biggest danger is pushing a log over the back supports if you're not watching what you're doing.

The 12 v DC pump system had a bit of a variable speed to them.  They were a lot faster when not under load.  When under load they slowed down – maybe as much as 1/3 as fast as when there was no resistance.  Thus, you kind of move fast up to something and then slowed down as the pressure increased.   Not so with the 6 GPM pump powered by 7.5 hp 3ph motor.  Things slam around quite a bit more and come to the end of their travel with a snap.  Something to consider.

I end up cracking the valves for most of the functions to slow their movement speeds.  The speed comes in handy when you're running the clamp back all the way and down,  putting the back supports up, etc.  But you don't want to go full speed when pushing a log towards the back supports – easy does it.  Or when lowering the back supports part way down.

We do not have the loading arms as we have a live deck so I don't know how more GPM will affect that function but I'd think you'd want to feather the speed back as the log is about ready to roll onto the mill.

One way to achieve more GPM on a mobile mill would be to drag along something like a firewood splitter.  Splice in some quick couplings so you can bypass your 12v DC pump and plug in the lines from the wood splitter.  I think this would be a lot of trouble and expense for the little return. 

Now if you're doing a lot of stationary sawing where electricity is available, then a power pack like we have would work.  Just keep all the 12v pumps stuff intact and put quick compliers in the lines to switch back and forth between HD sources. You'd have to switch out or remove one wire to the solenoids that start the 12 DC pumps to keep them from running when you didn't need them.   

Before going overboard on the GPM, better check and see how fast you can go with the valves and hoses, etc. on your model mill.  I've got the impression that 6 GPM @ 2000 psi is the limit on the newer LT40 Super and probably LT70.  I don't know what it would be on older LT40 Supers or standard LT40 hydraulic mills. 

Another thing...  getting HD power from an external source will allow you to use the hydraulic functions any time the pump is pumping as you're not dependant on the head being on the contact strip.  That is very handy many times but you need to be aware as you could move something while the head is "down range" and do some damage.

[MikeH]

 Sounds like you have a nice set-up Bibbyman but I go mobile quite often and dont think I want to drag a log splitter around.  ;D

[Dave Shepard]

You might be able to rig up your own power pack fairly easily. Many smaller log splitters use a two stage pump. This would allow you to use a smaller HP gas engine, and still have some speed. Then when the power unit was under load, it would drop the gpms exactly when you need it to be a little more delicate.  ;)


Dave

[MartyParsons]

[quote One way to achieve more GPM on a mobile mill would be to drag along something like a firewood splitter.  Splice in some quick couplings so you can bypass your 12v DC pump and plug in the lines from the wood splitter.  I think this would be a lot of trouble and expense for the little return.  ]

Wow! you would realy want to have faster hyd bad to go through all that trouble. the 4 gpm is not that slow. You would have more maintenance with other power source + hoses + dirt. IMO.
M

[MikeH]

 Marty, 4 gpm is not that slow I admit but neither is a 42 horse diesel and you guys came up with a 62 horse and I am just looking for a simple mod. to compliment the hydro's. Like on your 300.  Is there anything possible without using seperate power souce? 

[LeeB]

bigger hoses for less friction loss?

[Bibbyman]

Mike,

Are you sure both pumps are pumping?  Sometimes a solenoid will go out or a motor will go out and you'll not really notice it.   

[MartyParsons]

Change the hydraulic oil to the J13 winter grade oil. Clean the motor burshes every 850 - 925 hours. Hydraulic filter change at 500 hours. The electrical system can not handle any more amp draw, so adding more pump or more motors are out of the question. Some customers change to the winter grade oils to speed up the pumps. If you are in a realy warm climate I am not sure what the effects of wear to the pumps may be? If you do this make sure you get all of the original oil out.
M

[bandmiller2]

M ike,you could go to synthetic hydraulic oil and gain some speed in cooler weather.Are all functions slow or just one, possible kinked hose or restriction.Watch anouther mill of the same type and compare speed.You may have to just slow down and smell the roses.Frank C.

[beav39]

i agree with bandmiller the lt40 hydros only go so fast the only thing i would like to see a little more faster would be the loading arms   like band miller says smell the roses     or trade up.

[MikeH]

 Thank you Marty, thats what I was wondering.

[MartyParsons]

It looks like you have a LT70 walk mill. Have you ever changed the hydraulic oil? How many hours on the meter? If MN is Minnesota you should try the Winter grade oil. If any WM hydraulic owner has installed any other oils in the hydraulic system it will s l o w the system way down. I see this from time to time. We drain the pumps and purge as much oil out of the system and add the J13 oil and it speeds things way up.
Glad to try and help!
Marty

[logwalker]

Marty, can we use J13 in the summer months? Joe

[Bibbyman]

One thing that would speed up the loading arms function would be to replace the lift cylinders with ones with a smaller diameter.  But smaller means speed, larger means power.  You can't have both (with the same GPM and PSI). If you saw only small, light logs, this would work. I'd think?  :

[beav39]

marty where do we get the j13 oil from woodmizer?

[MartyParsons]

Part # P12822 Exxon Univis HVI 13   Recommended for:
Cold-weather applications
Here are the temp ranges for recomended oil.
1. Dextron III  30 degree - 120 degree F
2. Exxon Univis HVI 26  minus 20 -- 100 degree F
3. Exxon Univis HVI 13   minus 30 degree --   60 degree F

I can not answer your question if it is over 60 degree F will it protect your pump at 100 degree F ?  I am also not sure about the syntethic.  :-\

Maybe Sparks would know.

Marty

[Brucer]

One thing that would speed up the loading arms function would be to replace the lift cylinders with ones with a smaller diameter.  But smaller means speed, larger means power.  You can't have both (with the same GPM and PSI). If you saw only small, light logs, this would work. I'd think?  :

Actually, you can have both. Here's an old-timer's trick. All you need is a 2-position, 3-way valve, a T connector, and three short hoses.

Arrange the valve so that in one position it connects the regular control valve to the lift cylinders in the normal manner. You'll use this position to retract (lower) the cylinders and to extend (raise) the cylinders at the normal, slow speed (with full lifting force).

In the other position the valve will connect both ports of the lift cylinder to the pressure line from the control valve. The return line to the control valve will be isolated.

"What? Connect both cylinder ports to the pressure line? It'll never move!", says a friend of mine. Oh yes it will, and very fast, too. It will extend at the same speed as a cylinder with the same diameter as the cylinder rod in your lift cylinders. That's about 6 times faster on my mill. Naturally you'll have only one-sixth the lifting force.

You just gotta remember that the cylinder will only extend with the new valve in the high-speed position. To retract you have to switch the new valve back to the low speed position. Mind you, cylinders always retract faster than they extend (under the same load).

[logwalker]

That is pretty clever Brucer, if I see it correctly you are using the oil from the return side to boost the extend side. The larger piston surface on the extend side overcomes the retract side and uses the extra oil to boost speed. Who thought of that one? I think you can do anything with hydraulics if you are smart enough. Joe

[Brucer]

Yep, that's it exactly, Joe.

It certainly wasn't me that thought of it. First heard it mentioned by a mechanical draftsman who'd been trained in Holland. He knew more about practical hydraulics than any of the millwrights or machinists in our company.

Many years later I found it discussed in "Industrial Fluid Power - Volume 2". It's called a regenerative circuit.

[Dan_Shade]

do you have a picture for this hydraulically challenged guy?

[logwalker]

Think of it this way: the extend side of a cylinder is empty in that there is no rod extending thru it. That makes the piston surface larger on that side then on the retract side. Apply the same pressure on both sides at the same time as Brucer's valving circuit does and the larger surface area of the extend side will overcome the retract side. Because he has connected both sides together the fluid on the retract side is forced into the extend side and extends the piston about 6 times faster. Clear as mud, eh?

[Dan_Shade]

what about the other direction?