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Hydraulic height adjustment?

Started by Revival Sawmill, November 21, 2016, 03:16:53 PM

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Revival Sawmill

Has anyone tried a pair of hydraulic cylinders to move the bandsaw up and down in the carriage?  I've seen tons of youtube videos of acme screws and pulley/cable/winch systems, but no hydraulics... Is there a pitfall with them? Are they just too expensive?
thanks,

ladylake


Two separate cylinders wouldn't work very well as they wouldn't raise exactly the same, the newer TK mills use 1 hyd cylinder  hooked to roller chains that go to both sides raising the head even, also I think they have a check valve in the system to prevent any head drift down , Really fast up - down on those mills.  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

york

There is a mill being produced that does just that-can`t think of name of now....Mighty Mite...

https://www.youtube.com/watch?v=pH8o9O9x5vc
Albert

ozarkgem

My mighty mite is like the TK. One hydraulic cylinder and chain and sprockets. Cheap and very reliable. Its as fast as you want to make it. The other option is hyd gearbox and chains. I would go hyd if it were me. Somewhere I posted a pic of the way mine is set up. Don't know how to find it.
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

york

Yes,looks like i am wrong on Mighty Mite having two lift CYL....But look into what they call "re-phasing" cylinders .










Albert

ozarkgem

Quote from: york on November 21, 2016, 08:04:01 PM
Yes,looks like i am wrong on Mighty Mite having two lift CYL....But look into what they call "re-phasing" cylinders .
I think you can make hyd cylinders move in tandem but no need to get that complex on a mill.KISS
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

Revival Sawmill

Ok, so maybe I'll just use acme thread like everyone else!  Anybody know how much weight a 3/4"-6 thread can lift?
Thanks,

york

Acme,very slow-Both Cooks and WM use chain lift,think TK got away from using Acme...
Albert

Revival Sawmill

I'm thinking I might like a slow height adjustment... seems like it would be easier to line up the cut that way?  Chain lift is just a chain over a sprocket hooked to a hydraulic motor?
Thanks,

york

What Cooks and my TH-they use a right angle gear drive,that HYD motor drives-Cooks use a Cleveland rt. angle gear drive...
Albert

DDW_OR

Quote from: wooddust on November 22, 2016, 02:31:40 PM
.......Chain lift is just a chain over a sprocket hooked to a hydraulic motor?
Thanks,

yep, up/down speed controlled by lever.
could change the gears if that is still too fast

this photo is actually for the head carriage movement, but you get the idea.


 
"let the machines do the work"

Revival Sawmill

I'm also having a 'nightmare' scenario where the chain slips off the sprocket or breaks and the headrig drops and lands on the carriage... seems less likely with acme rod?

Kbeitz

You can buy a gear motor with a combo brake/clutch system.
When you tell it to stop it stops on a dime and will give your a
nickel change.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

ozarkgem

Quote from: wooddust on November 22, 2016, 03:15:04 PM
I'm also having a 'nightmare' scenario where the chain slips off the sprocket or breaks and the headrig drops and lands on the carriage... seems less likely with acme rod?
I just replaced my original (1985) chain. So if you just do a scheduled maintenance every 30 yrs you won't have to worry about nightmare scenario's. Acme thread has it drawbacks also. As stated slow.Needs to be kept clean. A good quality acme will be quite expensive and you will by two of them. stick with they hydraulics. cheap and simple and works. 25.00 flow control will make it as fast or slow as you want it. I can stop mine right on the money, no problem.
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

Percy

Just check out how most forklifts operate their up/down mechanism....our forklift has 12 feet of lift with a 6 foot cylinder. If I was building a mill, Id use a system like that.
GOLDEN RULE : The guy with the gold, makes the rules.

Rougespear

I used 1"-5 ACME rod... driven by a hyd motor.  My up down is plenty fast... moves about 8" in 10 seconds if I remember right, but still slow enough I can stop where I need to.

That being said, if/when I change it out, I will switch over to a chain lift for reasons of ease of serviceability... IMO, if Cooks does it a certain way then there is a darn good reason.  Look at how they do it with their AC-36.  I wish I went chain lift in the beginning, but ultimately I don't have any issue with my ACME drive.

On a related note, how is creep prevented in the hyd motor circuit so that the head doesn't slowly drop over time due to weeping seals etc.?  Or is creep a non-issue?
Custom built Cook's-style hydraulic bandmill.

york

You will get no creep,that is were the right angle drive comes into play...
Albert

ozarkgem

Quote from: Percy on November 22, 2016, 08:45:50 PM
Just check out how most forklifts operate their up/down mechanism....our forklift has 12 feet of lift with a 6 foot cylinder. If I was building a mill, Id use a system like that.
X2
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

ladylake

 
If you use as right angle gear box make sure its a high ratio like 60 to 1 or more, I think the lower ratio ones like 30 to 1 or less might not hold the load. 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

Kbeitz

If you would want to use cable then you could do like the old
elevators did. If the cable broke the part the cable hooked on
to would close up acting as a brake so the elevator could not
fall.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

bandmiller2

Hydraulic cylinder and wire cables good enough for Arial ladders and bucket trucks, likely good enough for a bandmill. Frank C.
A man armed with common sense is packing a big piece

york

Cooks,right angle drive,ratio is 30 to 1...
Albert

Brucer

Quote from: ladylake on November 23, 2016, 05:25:22 AM
If you use as right angle gear box make sure its a high ratio like 60 to 1 or more, I think the lower ratio ones like 30 to 1 or less might not hold the load.

Yeah, don't assume a worm drive won't run backwards. If it's an efficient design it will run backwards just as easily as a conventional spur gear reducer.
Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

Kbeitz

Quote from: Brucer on November 24, 2016, 12:38:06 AM
Quote from: ladylake on November 23, 2016, 05:25:22 AM
If you use as right angle gear box make sure its a high ratio like 60 to 1 or more, I think the lower ratio ones like 30 to 1 or less might not hold the load.

Yeah, don't assume a worm drive won't run backwards. If it's an efficient design it will run backwards just as easily as a conventional spur gear reducer.

The ones that will run backwards on there own has bearings for
the feed nut not bushings.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Revival Sawmill

So the chain comes from top of the headrig, over a vertically oriented sprocket on the top bar of the carriage that's attached to a geared-down hydraulic motor.  Then where does the 'extra' chain go? Does it loop to an idler sprocket at the base of the carriage and come back up to attach to the bottom of the headrig? How critical is it to keep the chain sawdust-free? How big of a shaft is needed to run across the top of the carriage top bar to synchronize the two sides?
Thanks,

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