Mighty mite 1986?

[Mainecoast]

Howdy, I picked up a used mighty mite bandsaw mill. It didn't go forward when I bought it. I took the valves apart and cleaned them as best I could. Finally got it to move forward most of the time. I was reading someone on here moved their forward control valve off of the manifold and after the pump? Can someone explain that? Do I just plug the manifold and delete the $2800 flow control and replace with the less expensive inline valve? 

This mill has seen some use and I'm slowly working my way through it and breaking blades while learning (not fun) but I was happy to have a mill for less than 6k...but after the tinkering and the more to come I wonder if I should have just waited for something else. 

And just to be clear is go hydraulic carriage forward/reverse and up and down. Just need to get it done tuned. 

[sgschwend]

The one I owned had the variable speed control valve before the pump.  The issue with that is that the hydraulic press is varied but the motor will hate that method.  The valve needs to be after the motor.  That is pump -> motor -> speed valve -> return to reservoir.   Mighty Mite builds but do not add improvements so the same mistake this there forever.  

The good, very stoutly built,  very good hydraulics,  handles large cuts or logs and good power.

[Mainecoast]

So if I pull the speed control off..should I plug that port? And then put an inline speed control after the pump. 

Any ideas what type of valve? Size or flow amount?

[Iwawoodwork]

I have a 1985 model (Mighty Mite is located in Canby, Oregon) and some one hasinstalled a ball valve on the forward carriage feed with a needle valve on the other line, the ball valve is very touchy to regulate but have finally got used to it. I feel the overall construction to be heavy and well built. I broke 1 or 2 blades and bent several others due to operator error learning curve, I ended up lining the inside of the metal blade guard system with rubber belting which has save a lot of blades from serious damage.  I all so added 6 trailer tongue jacks to the frame and raised the log bunks up to the same level as my bevel siding jig that is permanently installed. my saw is a good machine and the only issues were the idler band wheel bearings  I had to replace and found the shaft was previously chewed up, so I welded it up an turned it back down and now new bearings installed and working fine.   The The double drive belts from  motor are a challenge to figure out the easiest install method so I installed a second set at the same time and tied them off to the side.  

[Mainecoast]

So your ball valve screws into the manifold? And then a speed control? 

I'd assume I should plug my speed control port. And run my speed control to the other side of the manifold (return line from the pump) 

I spoke to mighty mite a few times and really like John. He's always very helpful. 

I was curious if you could send pictures of the ball valve and rubber bumpers for the blade. 

I recently creased a blade a little. Can you still run them after? It also broke one tooth off but other than that the blade is brand new. 

[sgschwend]

Get your pump part number and see the flow rate spec.  I think in the end I put a 3/4" size fitting valve it had a micrometer type knob on it.  Something like this:  https://summit-hydraulics.com/wp-content/uploads/2019/01/LAFC-08N-2.jpg

I likely purchased it from Grainger.  In the long run I added a small gear reduction motor by removing the knob and then I added a control switch to my wired remote controller.  That allowed me to enter the cut at a slower speed then adjust the speed after the blade was fully engaged.  

[Iwawoodwork]

I believe that my mill was their #10  bsm and originally ran 2" bands but now converted to 1 1/4 +- with 19" pully type wheels. On the kinked band with missing tooth I have had that happen and took it to my anvil (any thick flat piece of steel) an used my copper 3# hammer and beat the kink out, I put it back on and it continued to saw ok but could hear the spot go around but did not seem to affect the cut, but (disclaimer) I am a very inexperienced sawmiller. The rubber belting that I installed inside my guards was used conveyor belt that I had and cut to fit behind the band wheels with a slot and cut out for the shaft then aluminum pop rivet in place, could have used aluminum or brass bolts, I also lined the front inside face of the guard and the section between the back and front plus across the bottom of the top guard between the two band wheel guards. I have had to replace one piece of belting after a couple months of hobby sawing and operator learning screw ups, just drilled the pop rivets off and new belt and pop rivets.

[Mainecoast]

I am currently set up to run 2" blades. I never really gave it much thought when I bought it. But it'd be nice to swap to 1 1/4 blades but I'll never see the return on investment. My plan is to use the saw to custom saw for small timber frame projects (live edge timbers, octagonal) stuff like that and my general use around the future farm/homestead. Maybe I'll need it for the kids houses if lumber prices never go down

I'll have to try your method of insulating the front guards. I suppose I'll need a copper hammer. I did use my small steel sledge. 

Now one question, John at mighty mite said I have to change my rollers and wheels to swap blades. I believe him but while looking in my cooks saw mill catalog they advertised wheel retro fits. Their claim is the wheels work on a range of blade 1 1/4-1-1 1/2. I thought they had one listed for 2"bands and 1 1/2...if thats so why couldn't I just change out my guide rollers? 

Thanks for all the input folks. I'd really like to figure the flow control valve situation out. I do currently have a speed compensation flow control valve. It's on the right side of the manifold with an adjustable knob for speed control. They cost about 2800$....mine has been sticking. So if I can plug the manifold and add the new inline control after the pump it'd be helpful. 

Im also going to be replacing the switches on my hand controller some of them are a bit worn out. You switch forward and have to tap the side of the controller. 

[Magicman]

Your blade wheels may not allow a 1¼" blade to run without the teeth contacting the blade wheel which would remove the set from that side of the blade.

[fluidpowerpro]

Although I am not familiar with the exact details of your hydraulic system, I am fairly knowledgeable about hydraulic systems and how most function. That being the case,  I suspect that the factory flow control that is installed ahead of the motor is a 3 ported priority flow control. When you set the valve you are setting the amount of flow you get out of the Priority flow port, which would be plumbed to your motor. The flow out this port should remain the same regardless of hydraulic motor load and engine RPM. Any excess flow is sent out the by-pass port to tank at low pressure.
In this type of set up, your system pressure will be relatively the same as the load pressure of the hydraulic motor, because thats how much pressure its taking to do the work.

If you mount an in line flow control (2 ported) on the outlet of the motor, yes, you can control the motor speed, but instead your system will run at whatever pressure your system relief is set at. Thats because the only place the excess oil can go is over the system relief valve at max pressure. That arrangement will very likely result in your system overheating.

Just for example, if the main system relief is set at 2500 PSI and your the load on the motor results in 1000 PSI of hydraulic load, you will need to provide an additional 1500 PSI of back pressure on the motor to slow it down. If your pump flow is 5 GPM, but the speed you want from the motor uses 2 GPM, that means 3 GPM is passing over the system relief at 2500 PSI. 
3 GPM x 2500 PSI / 1714 = 4.37 HP of wasted energy which will be going into heat. 
(The actual flow and pressures of your system may be different, the numbers above are just shown as an example)
To minimize heat you could turn the system relief pressure down to match the load pressure of the hyd motor, but then its likely you wont have enough pressure to do other functions.  

[longtime lurker]

Your blade wheels may not allow a 1¼" blade to run without the teeth contacting the blade wheel which would remove the set from that side of the blade.

Totally dumb question Lynn but why is that? Are the wheels not crowned, or is there some other reason? Curious...

[sgschwend]

On my 2006 system the control after the pump had no effect on system pressure but it did provide constant pressure to the motor which results near constant motor torque.  Additionally on my machine the wired remote allowed the addition of a bidirectional motor controller for that valve which provided adjustment to the new valve, hence remote control of the feed speed.   

[Magicman]

Totally dumb question Lynn but why is that? Are the wheels not crowned, or is there some other reason?

Not a dumb question, how much crown and how much is the blade being pushed back? 

[Mainecoast]

I found an issue I was having. So the flow control valves on these particular units run around $2800. So if I can get by without that repair I'm a happy man. I did test the wire that was for forward continuity. There must be a break in the line somewhere. So I am now trying to source the correct wiring for the control pendant to the solenoids. Hopefully this has been the issue and not the $2800 dollar valve they use. I know when I was speaking with mighty mite they mentioned that they have been considering moving away from that expensive valve and going to a normal flow control because this very reason. $65 dollars vs $2800.