LOL! Mower hydraulics not connected in this PT demo!

[Clumber]

Folks, on frames 03 and 43 you can clearly see that the brush cutter hydraulic lines are not connected. The mower is not operating in this demo. :laughing:

‪ThePowerTrac's Channel‬‏ - YouTube

 

[woodlandfarms]

While we are at it, this is a real embarrassment

‪ThePowerTrac's Channel‬‏ - YouTube

I watched this once and this is what made me feel that I had no choice but to design and build my own. Have yet to do that, but it is on my list of things to build.

 

[Clumber]

While we are at it, this is a real embarrassment

‪ThePowerTrac's Channel‬‏ - YouTube

I watched this once and this is what made me feel that I had no choice but to design and build my own. Have yet to do that, but it is on my list of things to build.

One problem the operator is having is that the PT is on a slope. Its difficult to precisely point the cutter and apply the treadle to keep from rolling down the slope. I've been there -- with tractor on a down slope trying to dig up a broken metal post 12" away from a new wood fence. I ended up digging by hand. Just could not control the tractor rolling down motion and manipulate the bucket to dig and curl without damaging the wood fence. No problem on a flat surface.

 

[MossRoad]

That's one of the problems with making your own commercials. We see it all the time with local car companies, mom and pop stores, etc... Just really unprofessional.

Yet, I'd still buy another Power Trac. :laughing:

 

[Yellowhair42]

It doesn't look like that POS could get rid of that stump even if he were on flat ground.

 

[Clumber]

It doesn't look like that POS could get rid of that stump even if he were on flat ground.

Agreed.

 

[KentT]

It doesn't look like that POS could get rid of that stump even if he were on flat ground.

Having used my stump grinder on the PT-425 a lttle, I've found the PT stump grinder actually works pretty well, if used correctly.

What you're seeing here is a couple things, IMO:

a. Inexperienced operator having a hard time keeping the machine positioned on a slope, as previously mentioned.

b. A side-effect of the PT's lift/tilt controls being VERY, VERY sensitive when operating at full throttle (which is needed to give sufficient power to run the stump grinder).

The 30-HP machine probably only gives about 15-18 HP (if that) to the hydraulic PTO, so you can't jam the stump-grinder down into the stump -- the hydraulic motor will stall -- which he does repeatedly.

Yet, the controls are so sensitive at full throttle that it is a challenge to "lightly push" the stump grinder down onto the stump and hold it there while it grinds. Then, you have to maintain that while articulating with the steering wheel to sweep it side-to-side.

Watch him repeatedly put so much down-pressure on the grinder that he's lifting the front wheels -- in one view, the front wheel is spinning while he's grinding...

I've found the stump grinder to be one of the most challenging implements to use, but it works pretty well.

Like using my brush-cutter, it may not be pretty to watch, but it produces nice results. After many hours of using the brush-cutter, I still will lift a front wheel frequently when I set the cutter down (having lifted and carried it), because I'm running full-throttle and I can't go past down to float position fast/smooth enough...

 

[Phils]

I never even think about it anymore, but I installed a couple of hydraulic restrictors with the primary purpose of having better (slower) control when grinding stumps.

Phil

 

[SpringHollow]

I have cut out lots of stumps with my PT stump grinder - it works quite well. I start at on either the front or back edge and swing back and forth.

Ken

 

[woodlandfarms]

Ken

Do you know what kind of motor is on that Grinder? And yours is direct drive, right? Just wondering how it has been for you so far. I am going to build my own, but have yet to figure out if I am going to go direct drive, lovejoy or belt between. But with 18GPM and 3000PSI I bet it works better than the video.

 

[SpringHollow]

Hi Carl,

It is direct drive. Direct drive is simple, belt drive would absorb some of the shock but would likely slip easier. The biggest negative is that your machine can take a beating if you cut too deep but the hydraulic motor usually stalls if you do. I reversed the blade to throw away from me.

Ken

 

[woodlandfarms]

I guess the quest would be to find a motor with strong lateral loading that will spin at 800 rpm. JJ, any thoughts?

 

[BobRip]

An early PT video showed the stump grinder cutting through a stump with ease. I have stumps that go like that and they are rotten. At least these showed a real stump The small stumps, say under 6 inches go very quickly. The bigger ones (over 18 inches) can take hours, but it is still faster than any other way that I have.

 

[Gravy]

I broke the mounting ears on my my stump grinder motor (by abusing it as a trencher and hitting too many rocks). If I were starting from scratch, I would probably use a cogged belt drive to cushion the shock and allow maximum cutting depth. I would also design for lower RPM's and higher torque.

As it is, I have a spare motor that will work with a little modification.

 

[SpringHollow]

I have done stumps over 24" and none of them even took 30 minutes. I did 20 or more stumps at a friend's house in about 1/2 a day but some of those were only 8 or so inches (wider at the base but that wider part breaks off pretty easy). But my tractor is just slightly larger than yours and i was pretty hard on it.

Ken

 

[J_J]

I guess the quest would be to find a motor with strong lateral loading that will spin at 800 rpm. JJ, any thoughts?

If you need a hyd motor that will turn around 800 rpm, the displacement will be 5.77 cu in. and at 3000 psi, the torque will be 2756 in lbs.

Different scenario.

Surplus Center - 24.7 cu in PARKER TG0405MS030AAAB HYD MOTOR

This motor has good torque, but only turns at 162 rpm. Working pressure up around 3000 psi.

Anybody know the rpm of their stump grinder?


20 GPM at 3000 takes about 41 HP to run the pump. A hyd motor at 85% efficiency would develop about 34 HP

 

[woodlandfarms]

I have seen other hydraulic stump grinders running at 800. That is where I got my idea from. I found a motor at surplus that sounded good but I can't figure for the life of me how to cut and paste on my ipad

 

[BobRip]

I have seen other hydraulic stump grinders running at 800. That is where I got my idea from. I found a motor at surplus that sounded good but I can't figure for the life of me how to cut and paste on my ipad

Double tap on the area. Then drag the dots to the area you need. Then select cut. Go to where you want and then double tap and select paste. Instead of double tap you can hold your finger down for a few seconds.

 

[woodlandfarms]

BobR. The fact you have an Ipad I find wonderful.

Thanks for the advice. I am a huge mac addict and the wife got me one for my birthday, but I am pulling 16's at work and have not had the time to do much more than email....

 

[woodlandfarms]

So, I thank Bob R for the tip

Surplus Center - 4.95 cu in DYNAMIC BMS80E2GS HYD MOTOR

So what do you guys think for a direct drive stump grinder? if this is good I think I can build one with teeth and all for under 1500.

But I have never heard of DYNAMIC as a brand. White, Charlyn... Afraid this is some chinese off brand and will just shrapnel under the load.