Building a Band Saw Hydraulic Downfeed with Lift Function

[ratbldr427]

Air over hyd is the simplest as mentioned . You only need one cylinder and a directional flow control and an accumulator or small tank,a piece of capped pipe would be cheap. Air regulator for lift control speed.A three way exhaust valve to supply air and exhaust when down feeding. Air to tank forces fluid past the check in the flow control, lift speed is by regulator setting. The manual valve exhausts and blocks air in for down feed which is controlled by the adjustable flow control from the cyl. Apply air and the flow reverses past the check for speed up. You could get fancy with a solenoid for air control for p/button operation. You could put two meter valves(wo checks) in parallel for hyd control up and down.

 

[memphisjed]

Perhaps larger saws with 2" wide blades work that way? Can you specifically list some brands/models of saws that are Hyd down feed? I've never seen one.
Here's my Welles 1270, it runs a 1.25 blade. The head weighs around 400lbs. There is a lift cylinder that's single 'up'
acting.... to raise the head.
The weight of the head is more than enough to make the blade cut up to 12" OD steel barstock.
View attachment 387264

hyd mech s20, newer hem, pedinghaus, meba, all the controlled automation saws.... amada on their high end saws.. any of the industrial grade saws. Even a horizontal should be running just over 5 ipm cut rates. The width of blade has little to do with this, width allows thicker cuts (space between guides and lesser amount wheels).

old saws are pretty, and many can be upgraded like op wants. Electrical is easier than hydraulic imo for how, but if you have the pumps and valves might as well use that. Also add in hydraulics for the vices while running lines and cylinders.

 

[john.k]

One warning from experience,if the saw head assy balances in the open /up position,be very careful that hydraulic lift doesnt leak down ,as after a weekend the whole sawhead can come crashing down ,generally busting the bade ,but also busting the whole head casting.

 

[dkmc]

hyd mech s20, newer hem, pedinghaus, meba, all the controlled automation saws.... amada on their high end saws.. any of the industrial grade saws. Even a horizontal should be running just over 5 ipm cut rates. The width of blade has little to do with this, width allows thicker cuts (space between guides and lesser amount wheels).

old saws are pretty, and many can be upgraded like op wants. Electrical is easier than hydraulic imo for how, but if you have the pumps and valves might as well use that. Also add in hydraulics for the vices while running lines and cylinders.

Nothing I need to think about implementing. Gravity works fine on my saws.
High production with a 2" or larger blade cutting large bar, is where I guess down force comes into play.

Most commenters in this old thread seem to think gravity is sufficient.

bandsaw downfeed force

How much force should I be able to apply to a horizontal bandsaw blade? In reworking my bandsaw I got curious about how much pressure I should be able to supply to the blade so is there a good rule of thumb for this? The blade is 1", 8-12 pitch and the main materials are 4140 or 6061...

www.practicalmachinist.com

 

[Garwood]

My 330 CNC Cosen is pressure feed and so was the 1960's 12x24 Kalamazoo it replaced.

 

[M.B. Naegle]

Thanks for all the comments so far.

I might be using the wrong terminology, but with a hydraulic assist, I'm looking at it as a way to limit and meter the fall or the arm, not push it down faster. All of our horizontal saws have needed some reduction in the fall of the arm to keep the blade from getting stuck in the work, but they've also all been slower speed saws with a single speed, or cone pulley speed change. I'm adding a VFD to this saw for variable speed to match material and tooth pitch, but expect it to stay on the slower side of cutting as the drums are running iron on iron and being driven by a big pinion gear, so I don't see a need to push the arm down any faster than gravity takes it.

I'm presently getting the drum and coolant motors re-mounted as I wasn't happy with the hack job the prior owners did (long ago this saw was originally a single speed overhead-shaft driven machine FYI), so once the blade is turning again, I'm going to focus on getting mounts for a cylinder made. I'm thinking I might start with pneumatics if only to prove the mechanics of the system, and then if needed I'll switch it over to hydraulic, air-over-hydraulic, or whatever will work best. The control aspect IMO is easiest to do trial and error, while mounting the cylinder takes a little fabrication.

 

[Garwood]

You need downforce when you are sawing thicker stuff. It makes a big difference.

Not that the Mayflower's bandsaw needs hydraulic down feed, but it is a real, useful thing.

I think you'll be pretty disappointed with air. It's way too springy. I had one of those Carolina things long ago and it had an air cylinder on it. What a pile that thing was.

As I mentioned before, consider mounting the cylinder on the outboard end. Lots of new saws do it this way and for good reason- You never load material through that area anyway and it gives the greatest control, with a smaller cylinder, moves the cylinder out of the nasty swarf zone and all the pivot points have an easier life.

 

[Strostkovy]

You need downforce when you are sawing thicker stuff. It makes a big difference.

Not that the Mayflower's bandsaw needs hydraulic down feed, but it is a real, useful thing.

I think you'll be pretty disappointed with air. It's way too springy. I had one of those Carolina things long ago and it had an air cylinder on it. What a pile that thing was.

As I mentioned before, consider mounting the cylinder on the outboard end. Lots of new saws do it this way and for good reason- You never load material through that area anyway and it gives the greatest control, with a smaller cylinder, moves the cylinder out of the nasty swarf zone and all the pivot points have an easier life.

I recall a cheaper band saw at one of my jobs that people would rip teeth off the blade of. It had a hydraulic system that had air in it so it would build up force. If cutting square tubing it would build up pressure on the flat and then shoot through the side walls of the tube that the teeth would remove themselves. doesn't help the blade was always too coarse but that alone wasn't enough.

 

[dgfoster]

I recall a cheaper band saw at one of my jobs that people would rip teeth off the blade of. It had a hydraulic system that had air in it so it would build up force. If cutting square tubing it would build up pressure on the flat and then shoot through the side walls of the tube that the teeth would remove themselves. doesn't help the blade was always too coarse but that alone wasn't enough.

Cutting square tubing positioned with two sides horizontal and two sides vertical is a PITA no matter how you slice it. I made a a couple of simple fixtures to hold the sides at 45’s. That way the blade is cutting a nearly constant cross section of metal through the entire cut. On the odd single cut I don’t always use it and just hand feed. But most of the time I make life easier and use it. Not an original idea by any means, but one worth thinking about.

Denis