Hydraulic cylinder design question???

[torker]

Hey guys! I'm about tired of looking for a cylinder for the feed control on my Wells bandsaw.
I want one like the factory uses on most saws. They have the tube going from one end to the other and the needle vavle in the middle to control flow. I'm thinking I'll just build my own.
Simple enough. But... What kind of plunger should I use?
One like a hydraulic brake cylinder uses with the rubber cup? Only problem I see there is mounting it so it can use a "flap" disc that falls away as the saw is moved up out of the cut and would allow the oil to move freely so the saw can be raised quickly.
The other way I'm thinking is a plain disc with an "O" ring around the outside. The flap disc would be easier to mount with this type setup but how well would the "O" ring work? Would it be easy to raise? Would it seal well enough? Would it have too much friction to ever work smoothly?
Thanks for any ideas!
Russ

[Joel]

Go to McMaster Carr and take a look at U cups.
I would post a link, but I can't remember how to make a direct link to an item on that site.

[Your Old Dog]

I thought those valves had a ball-bearing sitting on a spring as the relief when going the back to neutral positon as in lifting up the blade. I'd try the O ring first, if it leaks a little what does it matter? It ain't a jack so it might work.

[Bruce Griffing]

Look at the grizzly catalog and find a similar saw. Order the part from that saw - should be reasonable.

[Flying-Phantom]

The valve you are looking for is a hydraulic flow control valve. Try parker hydraulic fittings and controls.

[torker]

Hmmm.. Grizzly doesn't ship to Canada I don't think. I asked Busy Bee and House of Fools...err Tools up here if they could get me a cylinder for one of their saws. Maybe... in about two months.
A check valve in the line? I'm thinking about that one but don't see how it would work. The oil has to flow through the line both ways no matter what you are doing. A check valve wouldn't allow that would it?
The "disc" I'm thinking of at the end of the plunger would fall away(exposing oil passage holes) on the upstroke and allow the oil to flow faster....correct?

[smiller6912]

A flow control valve is used to allow (near) free flow in one direction and is regulated in the other. Try this link to McMasater-Carr these are air but you get the idea.
(I've had problems with the links to their site, good luck).
http://www.mcmaster.com/nav/enter.asp?pagenum=955

[torker]

Ah... ok I got it now. The link works BTW.
And I did find this but it's for a 7X12 china saw. This ol' Wells is a lot heavier.
http://www.accuramachinetools.com/ne...-band-saw.html

[torker]

Ha.. this just gets better. I found this ..of all places... from here. A discussion I was even involved in a few years ago.
BTW.. the door closer worked ok but the control left lots to be desired.
It wouldn't be heavy enough for a 9X16 saw anyway.
http://bbs.homeshopmachinist.net/sho...c+modification
Russ

[torker]

Now I'm getting somewhere.. I found all the stuff I need to build a good heavy duty cylinder from Princess Auto up here. The speed control valve is $7, 1 1/2" bore- 9" stroke double acting cylinder $63, and a needle control valve from the hardware store, already have a bunch of hydraulic jack oil. Should be into the thing for about $80. I'll order the parts in a couple hours.
Thanks for your help guys.
Russ