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Hydraulic suggestions / discussions

NoodleBender

Plastic
Joined
Nov 22, 2016
A Very long time lurker, learning something new every day here.

I have a new Son-in-Law project we are about to embark on, a home built band saw Lumber mill to compliment my daughter and his Fire Mitigation and tree felling business. After this summers wildfires in Colorado, they will have abundant wood to cut up.

Home built is slightly misleading as my shop retired Index mill and Clausing lathe are now in the garage, I have 9000#s of 8020 outside the shop and an old industrial Columbia horizontal band saw will provide many of the parts needed, after it cuts up the fabrication steel needed.

Pre Christmas eve dinner discussion, we had an idea of building the lumber mill and powering it all by the high flow remote hydraulics from his Cat skid steer 299D2.

The overall design and fabrication is something I am sure I can handle (race car designer and builder) but the hydraulics spec'ing and design.... Completely lost aside from basic functions.

The CAT spec's show 32 gal/min, 44 HP at 3335 PSI... and I know we want 4800 ft/min band speed on 16" blade wheels. We would like to god direct drive to the belt drive pully and also want to do a variable speed hydraulic motor to drive the whole carriage down the tracks. I suspect we have enough flow to do both the band and carriage at the same time.... but suspect isnt good enough at this point.

We are surfing the home build lumber mill forums to try to figure out what shaft HP at the band drive, is best. Most all those folks are running 14 HP gas engines through jack shafts....

Love to hear folks ideas on the proposed project

Dave
 
Surplus center sells a lot of hydraulic stuff that I recommend.

They also have great hydraulic calculators regarding pump power, motor torque, cylinder force and speed, etc.
Tons of information on identifying fittings and such as well.

Surplus Center
 
Driving the blade wheels directly with a hydraulic motor will be somewhat problematic due to the inertia of the blade wheels. Yes it can be done but will require some extra valving, especially to prevent hydraulic drive motor shaft shear. A sprauge clutch to allow the blade wheels to coast would be a good idea.

I suspect that if you were to use a conventional air cooled engine as others have done will likely be much cheaper than the hydraulic approach.

The hydraulic approach will require a flow divider for each load in addition to a pressure regulator and a flow control valve for each load.

I think that the high flow aux. pump is also likely a fixed displacement hydraulic pump so you will need to design the system for the full 32gpm. If it is a variable displacement pump, then the project will be slightly easier to do.

You should consider the overall efficiency of the system before you get into this very far. Hydraulic motor drive applications are notorious for their inefficiency translating to it will be a fuel hog and generate a significant amount of heat.

Costwise, the hydraulic approach will likely be at least 3X the cost of an IC engine and associated drive belts and associated components.
 
Driving the blade wheels directly with a hydraulic motor will be somewhat problematic due to the inertia of the blade wheels. Yes it can be done but will require some extra valving, especially to prevent hydraulic drive motor shaft shear. A sprauge clutch to allow the blade wheels to coast would be a good idea.

I suspect that if you were to use a conventional air cooled engine as others have done will likely be much cheaper than the hydraulic approach.

The hydraulic approach will require a flow divider for each load in addition to a pressure regulator and a flow control valve for each load.

I think that the high flow aux. pump is also likely a fixed displacement hydraulic pump so you will need to design the system for the full 32gpm. If it is a variable displacement pump, then the project will be slightly easier to do.

You should consider the overall efficiency of the system before you get into this very far. Hydraulic motor drive applications are notorious for their inefficiency translating to it will be a fuel hog and generate a significant amount of heat.

Costwise, the hydraulic approach will likely be at least 3X the cost of an IC engine and associated drive belts and associated components.

You need a motor spool valve. Motor spools leave the output ports connected so the motor can freewheel. The alternative is a cylinder spool valve, which is designed to prevent cylinders from moving without power. Do not mix the two. If you must mix the two, use an overload protection valve. Basically it's a relief valve each way that allows fluid to bypass from one motor port to the other if the pressure (torque) is too high. Do not set them higher than needed. IMO I would go with a valve approach rather than a clutch approach.

Simple flow dividers are pretty cheap and not a dealbreaker in my opinion.

But you are right. Hydraulics add up, especially to add speed controls and proper relief valves and such. Typically components are affordable, but there are a lot more pieces.




If you have fixed flow you may have issues with the motor slowing as the carriage advances.

Be aware some hydraulic motors have a case drains. On pumps, this drain is connected to the inlet. That and port fittings is the only difference. Pumps can be used as motors in only one direction. Motors intended for use as pumps or motors generally just have better seals and don't require a case drain. Those are my personal favorite.
 
A Very long time lurker, learning something new every day here.

I have a new Son-in-Law project we are about to embark on, a home built band saw Lumber mill to compliment my daughter and his Fire Mitigation and tree felling business. After this summers wildfires in Colorado, they will have abundant wood to cut up.

Home built is slightly misleading as my shop retired Index mill and Clausing lathe are now in the garage, I have 9000#s of 8020 outside the shop and an old industrial Columbia horizontal band saw will provide many of the parts needed, after it cuts up the fabrication steel needed.

Pre Christmas eve dinner discussion, we had an idea of building the lumber mill and powering it all by the high flow remote hydraulics from his Cat skid steer 299D2.

The overall design and fabrication is something I am sure I can handle (race car designer and builder) but the hydraulics spec'ing and design.... Completely lost aside from basic functions.

The CAT spec's show 32 gal/min, 44 HP at 3335 PSI... and I know we want 4800 ft/min band speed on 16" blade wheels. We would like to god direct drive to the belt drive pully and also want to do a variable speed hydraulic motor to drive the whole carriage down the tracks. I suspect we have enough flow to do both the band and carriage at the same time.... but suspect isnt good enough at this point.

We are surfing the home build lumber mill forums to try to figure out what shaft HP at the band drive, is best. Most all those folks are running 14 HP gas engines through jack shafts....

Love to hear folks ideas on the proposed project

Dave

This has GOT to be the dumbest thing I've heard in a long, long time.

Shirly there is a homebuilt bandsaw forum for you to get your design from.
 
So you need a 100 rpm on the wheels if i figured it right
12.4 cu in Bucher Hyd Motor BREL200A3810E0G | Low Speed High Torque Hydraulic Motors | Hydraulic Motors | Hydraulics | www.surpluscenter.com
This motor would be a good start for your blade motor but your going to be creating heat If your using variable flow valves. As for a skid steer being a waste to use a s a power source that is up for debate if running 8 hours a day yes but it usually always runs. my family has a woodsplitter that is powered offof a skidsteer Can split a couple cord of wood in a hour if it can be kept fed. If you need 30 gpm To run your sawmill your in the 40 tp 50 horse power that is quite the power unit On a saw mill
 
So you need a 100 rpm on the wheels if i figured it right
12.4 cu in Bucher Hyd Motor BREL200A3810E0G | Low Speed High Torque Hydraulic Motors | Hydraulic Motors | Hydraulics | www.surpluscenter.com
This motor would be a good start for your blade motor but your going to be creating heat If your using variable flow valves. As for a skid steer being a waste to use a s a power source that is up for debate if running 8 hours a day yes but it usually always runs. my family has a woodsplitter that is powered offof a skidsteer Can split a couple cord of wood in a hour if it can be kept fed. If you need 30 gpm To run your sawmill your in the 40 tp 50 horse power that is quite the power unit On a saw mill

Uhm.....don't you use the skidloader to get logs "TO" said sawmill ? I doo when I'm taking
logs from my woods. Pallet forks work great here.

Around here, they also palletize & strap the wood directly at the portable sawmill, and take pallet loads out of the woods with...wait for it...the same skid loader using the same forks.

Get a 22hp chonda engine from HF ($800) and ditch the hydraulics.
 
So you need a 100 rpm on the wheels if i figured it right
12.4 cu in Bucher Hyd Motor BREL200A3810E0G | Low Speed High Torque Hydraulic Motors | Hydraulic Motors | Hydraulics | www.surpluscenter.com
This motor would be a good start for your blade motor but your going to be creating heat If your using variable flow valves. As for a skid steer being a waste to use a s a power source that is up for debate if running 8 hours a day yes but it usually always runs. my family has a woodsplitter that is powered offof a skidsteer Can split a couple cord of wood in a hour if it can be kept fed. If you need 30 gpm To run your sawmill your in the 40 tp 50 horse power that is quite the power unit On a saw mill

I think your calculations are off. I get 1146 rpm on a 16in. wheel gives you 4800fpm. This makes the motor size off by a factor 10X.
 
I've done many jobs calling for 80/20. Some applications were OK, some not so good. When it came to sustained accuracy with high vibration and load, there were failures.
This may be one.

On edit..........these failures were "engineered"
 
I think I am with Digger Doug here...I wonder if any pre-dinner drinking had to go on to start down the path of this idea lol.

"Why use a 14hp gas motor with a few pulleys & belts, when we could use a 50hp motor in a $50k skidsteer running through tens of thousands of dollars worth of hydraulic system to accomplish the same thing?!" ..huh?

Even if having the hydraulic drives was the path I would go down it would be with an engine driven hydraulic power unit to run it, and not with the skidsteer.

Watch Matt Cremona's sawmill building videos on youtube if you haven't and do something similar to that. That would be my advice. (I do not own a sawmill so maybe I am wrong you never know)
 








 
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