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Can or should Hydraulic cylinder's be used to raise/lower saw head?

Started by GAmillworker, July 13, 2011, 06:59:02 PM

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GAmillworker

Can or should Hydraulic cylinder's be used to raise/lower saw head?  Has anyone done this before?  Would it be accurate? 

Thanks
Daniel
Thank the Lord for second chances

Magicman

What is going to hold it in place and keep it from creeping?  This is where worm gears really work well.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

GAmillworker

Thanks for the reply Magic man.

Read your post on cabin addition.  Great work. 

The cylinders would be pushing chain up like on a forklift.

Dont know if I can incorporate some type of lock.
Thank the Lord for second chances

tyb525

LT10G10, Stihl 038 Magnum, many woodworking tools. Currently a farm service applicator, trying to find time to saw!

ladylake

 The TK 2000 uses a hyd cylinder for up-down, it has a check valve to keep the head from dropping. If I was building a mill  I might use a hyd motor driving a worn drive gearbox running a roller chain, no creep with the realiability  of hydrailics, so long as the gearsbox would stand up to constant up-down.    Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Kcwoodbutcher

The TK 1600 uses one ( pulls a roller chain), have never had a problem with creep. It's a very robust and reliable system.
My job is to do everything nobody else felt like doing today

GAmillworker

Thanks for the replies.

Does anyone have pics of the TK setup?

I'll do a search.
Thank the Lord for second chances

bandmiller2

Dan, you bet it works and it works well too.Thats what I used when I built my bandmill,let me explain.A good cylinder and valve, creep is no problem.I used 3/8 wire cable reeved to give me 2" up/down travel for each 1" cylinder movement.Think of it like a rope through a pulley if you fasten one end of the rope and move the pulley up1" the outher end of the rope will move 2".The hyd. cyl. is verticle with two cable wheels in the yoke the cables are fastened to the frame at the top through the wheels to each side of the band head.The feed uses the same hydraulics to move the carriage with a hyd. motor and drum for anouther cable, just kinda pulls itself along.Sorry about no pictures not up to speed on that. Frank C.
A man armed with common sense is packing a big piece

Larry

On the TK 2000 there is not much to picture.  The hydraulic cylinder resides inside some tubing on the carriage.  The only thing visible is a short section of roller chain.

Its one of those things that is simple and works quite well.  Drops with the setworks are right on and rock solid.
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

sgschwend

MM uses a hydraulic cylinder for the setworks.

The valving is such that when the valve is closed the the cylinder is locked from both hydraulic lines.

The challenge I found with the Mighty Mite was manually stopping one the scale.  In this type of manual setworks there is a minimum time the valve will open and hence minimum step size versus cylinder speed.  The slower the speed the smaller the minimum step size.  To control this issue I adjusted the hydraulic flow rate in the cylinder with two flow control valves.

The advantage of this system is the matching lifting force on the sawhead, with a minimum of parts.
Steve Gschwend

sjgschwend@gmail.com

Brucer

There's a simple, off-the-shelf device to prevent creep in hydraulic cylinders (and motors). It's a 2-way pilot operated check valve, and it will prevent oil from returning from one side of the cylinder unless the other side is pressurized. Costa about $50 in Canada.

Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

ladylake

Quote from: sgschwend on July 13, 2011, 10:04:27 PM
MM uses a hydraulic cylinder for the setworks.

The valving is such that when the valve is closed the the cylinder is locked from both hydraulic lines.

The challenge I found with the Mighty Mite was manually stopping one the scale.  In this type of manual setworks there is a minimum time the valve will open and hence minimum step size versus cylinder speed.  The slower the speed the smaller the minimum step size.  To control this issue I adjusted the hydraulic flow rate in the cylinder with two flow control valves.

The advantage of this system is the matching lifting force on the sawhead, with a minimum of parts.

  I know what your talking about, my old Oliver 770 with a loader has check valves in it's system, the loader will stay in one spot forever but there is no way to lower it a inch or so without it jerking. The TK 2000 has check valves but also has a manuel lever where it can be inched up-down as slow and as little as you want. No idea how it's plumbed.    Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

bandmiller2

My bandsaw setworks is simplicity in itself an aluminum yardstick and pointer.Its very easy and precise to feather the spool valve and drop the head down to the next mark.Hydraulics make head movement effortless,easy to make multiple cuts lifting the head to go back and over.Feed is easy to control with a cheap needle valve, infinately adjustable feed,full speed gigback.I don't think a solenoid type valve would give fine enough control of the bandhead hight 1/32" control is desireable. Frank C.
A man armed with common sense is packing a big piece

argyle1

I'm using a cylinder to raise and lower the head on my circular dimension mill, but instead of cables over pulleys I'm using 80 pitch drive chain over sprockets.
There is no creep at all, even tho it has a very heavy saw head--if you have a good cylinder and valve, there won't be a problem with creeping

Magicman

We are all learning a lesson, especially me.   :-[    :)
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

ladylake


  Seems to me even brand new tractors, skidlaoders etc will let a loader go down over time unless they have some kind of check valve.  If you have every thing in good shape there sure wouldn't be much creep in the 20 seconds or so that it takes to make a cut.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

tyb525

One of the basic rules in hydraulics is that you can't trust them to hold up a load 100% of the time. Maybe 99% of the time they will hold just fine, but once a hose breaks or a seal/valve blows or leaks, its game over. That's why a mechanical holding device of some type will ensure there will be no falling saw heads, ever.

I personally knew a guy who was killed when he was working on a planter. The tractor's hydraulics were holding it up, and out of nowhere it dropped fast, he had no time to move out from under it. This was a fairly new tractor, too. I've heard similar stories from other people also.

Does it matter on a saw head? Maybe not. Would it be a great idea to incorporate a mechanical holding device of some sort, since you're in the process of building the saw anyways? I'd sure as heck do it now, rather than in the future if you realize you need it.
LT10G10, Stihl 038 Magnum, many woodworking tools. Currently a farm service applicator, trying to find time to saw!

Dave Shepard

A system like bucket trucks or LULL type forklifts uses might work. They have a valve in the cylinder that requires full hydraulic pressure to activate the cylinder. It cannot come down by gravity, even if a hose breaks.

Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

beenthere

I have that lock valve on the hydraulic top arm cylinder on my 3 pt tractor hitch. Surplus Center has the lock valves for about $100 or a bit less. I have no problem making very fine (and slow) feather adjustments to that top arm. SC also has the cylinders that include that lock valve plumbed in.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Dave Shepard

Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

GAmillworker

Thanks for an education.

I dont have a lot of knowledge of hydraulics.

The cylinders I'm using are from a forklift so I will check to see if I need to add valve or not.
Thank the Lord for second chances

Log-ic

Hi, on my Pezzolato mill the up/down functions of the headrig are controled by 1 double acting cylinder.  Larger Pezzolato types have two.  I never had any troubles with this and I must say  it works very accurately.  The headrig is connected with a linear wire encoder that controls the mill computer.  This way, the computer always "knows" the exact distance between the blade and the bed of the mill.  Any hydraulic cylinder with internal or external leakage will become unreliable and inaccurate, but that is an issue of maintenance. The computerized hydraulic functions of the mill are not controlled by lever distributors but only by electronic solenoid valves
Pezzolato HD8 40HP diesel (2" bands) and Pezzolato MP-800 40HP Deutz diesel (4" bands)
Avant 635TDL articulated loader with various attachments
Loroch JLM-V sharpener, manual saw setting pliers
Vollmer VWM planing bench and rolling machine
Husqvarna chainsaws...

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