Hydraulic Motor to Operate Saw Blade for Brush Clearing

http://www.sawdesigner.com/powcalc.php

https://www.blocklayer.com/pulley-belteng.aspx

https://www.omnicalculator.com/physics/pulley

Those are nice online calculators, but my main concern is coupling to the hydraulic motor, as to not compromise the shaft bearing, and what would be the best belt tightening, using a spring loaded idler, or just a sliding adjustable tensioner on the motor bracket.

I just got a full spec sheet from Parker on my motor, Real fast customer service, I had looked all over web, and just found minor specs, no wonder the motor was made in 1989, anyway they show a chart showing bearing side load ,based on 1.18 inches from mounting flange of around 600 pounds, that would be a pretty tight belt!!, so I don't think I should have to much problem tightening the belt.

Yeah those are pretty heavy duty, sounds awesome ....post a video or at least some pics once it's finished, if you can find the time....You must have a lot of land to clear...?

I have about 3000 feet of fence line, about half of it is called field fence and sets right on top of ground, so I need to cut flush or deeper as not to nick the wire. The carbide blade held up good on my trimmer cutting dirt and wood.

I'd be tempted to give it a nudge with a bulldozer...then try to drive it down...

What’s with the photo of the grader ?

It's for the Dingo's mate...

I would use at least 2 "B" sized belts,double belt pulleys, to increase life of the belts and shafts and reduce the required tension to handle load.

If you double the load on a bearing,you reduce life by 90%,doubling speed only reduces life by 10%.

Just some rule of thumb things to keep in mind when calculating cost of the double pulley arrangement.

Also by doubling your output speed,you will reduce available output torque by 50%.

Nice links

If you go to a bigger diameter saw blade then with the slower motor the peripheral speed of the blade will be higher. Old circular saw blades from sawmills could be used just a bit more sharpening and bit of lathe work to make a suitable boss to attach to the motor.

Do you really need the blade to be travelling at high speed? If it contacts a rock then a high speed projectile will be launched in some direction. It is the rake of the teeth and offset that does the work so slow and steady will still cut it for you.

What depth of cut do you need ?

Is 12” blade big enough once you subtract arbor flange radius or radius of protrusion of the motor if you direct mounted it ?

you want 2500 - 4500 RPM for a 12” blade so those motors won’t supply it from direct drive.

are you sure that 10 cubic inches displacement is correct ? That’s a very low speed ,high torque motor , if you use the other motor with higher shaft speed you can use lighter components in the transmission due to the lower input torque , you could find a short jack shaft with splined female input to match the motor shaft and put bearings outside of it for your primary shaft.

you already established the front bearing will tolerate radial load from a belt drive using 1x SPB belts or 2 x SPA belts.

Next questions are the horsepower required for the blade type you have , what is kerf width , pitch , gullet area etc ? Do you know what the horsepower requirement is for it ?

from there we can calculate pulley sizes to get correct blade RPM , and match that to hydraulic flow divided into the motor displacement so the motor can give optimum torque from the flow available without taking too much hydraulic flow from the machine controls that you need to raise / lower the hitch.

you state 18 GPM for the Aux hydraulics , is that from a pump independent of the pump used for the main hydraulic functions on the machine ?

I am modeling this after my DR Trimmer. They have what's called a Beaver blade which was a 10 inch wheel with embedded chainsaw chain. I would cut up to 4" trees but about 2 " above ground and would dull quickly if getting into dirt, so installed a 12" carbide from my miter saw and it worked quit well. The Dr has a 6.5 hp @3600 RPM with a 4" pulley on motor to a 4" pulley on drive hub. You would just push in and cut one at a time, but still a lot of work, so that's were the skid steer idea came in, but still operate skid steer same way, lot easier setting on the seat and pushing a few levers!!. I have a heavy duty lawn mower deck hub I was going to use for blade attachment, and also add a electric screw jack and brace set up if I need to push on tree if blade bogs down it gets stuck.

My skid steer is a big 7000 pound 50 hp New Holland so it has plenty of hydraulic power

Here are some photos of the DR.

Skid Steer Post Puller removes a mile worth of posts in an hour

Take from a guy who ran a tree service/ arbor care consulting company for 20 years:

Your real concern shouldn't be getting power to the blade, BUT rather keeping that nasty spinning blade from becoming the Frisbee from Hell. The mounting will be subjected to a constant micro-hammering from contact with whatever you are cutting (the big shock of a rock is the least of the hammering problems.). The standard locking gland nut and king pin will not afford you the multiple hours of runtime safety margin you need. You will need bearings and shafts in far excess of an unencumbered (by micro-hammering) unit than the books for "regular" applications call for. Finally you best better have a safety guard similar to the ones that come with your basic mini-grinder.

About the commercial units: they are safety worth the price they cost and are direct drive for one simple reason. Fewer parts = fewer points of failure and operational failure something you REALLY don't want anything to do with this type of machine.

I am planning on connecting this contraption to the underneath the forks of the skid steer so there is quite of protection there. I am out in the country, so won't have a problem hitting anybody. This probably a one shot deal, once cleared won't have to do it for several years and will probably be pushing Daisy's by then anyway, just want to have the place look nice before I crap out.

You could buy one , but making your own will stimulate your mind and keep you active which is A++ good living.

it sounds like you know how to do the rest. :)