Mowing Mowing on slopes

MossRoad · Oct 19, 2004

Congratulaitons on your new PT!

Those photos really show how low that machine is to the ground. Very nice.

She mentioned you have the tree shear. I'm sure we'd all like to hear about it when you get a chance... I know I would. /forums/images/graemlins/wink.gif

MikeOConnor · Oct 19, 2004

regarding the tree shear...

i got the little one. i think i shoulda waited for the big (10k pound) one. the trick seems to be to find the perfect tree. too small and it's way easier to just bash through it with the brush mower. too big and it becomes a job for Mr. Chainsaw.

that "perfect size" is a pretty narrow range with the little shear -- between 2 and 4 inches. so i think the little tree shear may go off to the blacksmith shop for some "creative reengineering." but as it comes off the line, i'd definitely recommend waiting until they get the bigger one released.

Rip · Oct 19, 2004

Congratulations Mike on your new PT-1850.... I'm sure you will get to like it more and more as you build "seat time".

Be sure to get a spinner knob for the steering wheel as the movements of an articulated machine bear little resemblence to a "regular" front steer tractor or truck, and you really have to get used to just spinning that wheel around to get the most out of the PT.

Try to locate a good welder, hydraulic mechanic, and Deutz engine machanic and introduce them to the machine. That way, whan the time comes and you need an urgent repair you avoid panic mode. With that expertise lined up before hand, plus PTs usual prompt availability of parts, you'll have many years of fun and productivity with that machine.

Regarding the tree shear, you might contact Scott soon and see about trading up to the bigger model. They might be willing to just charge you the difference in cost between the two models since you should really have had the bigger one to begin with. They also said it was "coming soon" in early summer. Tell them they really would not want the tree shear to get a bad reputation on such a high profile project!

Good luck and enjoy your great project.

MikeOConnor · Oct 20, 2004

yes! i've got the perfect 3-Stooges spinner knob rattling around in a drawer somewhere -- you're right, this is the perfect machine for it. gotta do some rummaging to track it down...

newbie question -- when i crank through a turn, sometimes i hear a sound like a 10-speed bike chain changing gears. kindof a ratcheting sound. being A Guy, i've been ignoring it (figuring; "if it's serious, something will break and then i'll fix it"). is that the pressure relief valve popping off? am i cranking the turn too hard when i hear that? no big deal, just curious...

MossRoad · Oct 20, 2004

Does the sound go away at full throttle or are you hearing it at full throttle, too?

I sometimes hear that noise in our PT425. I sounds like you describe. I don't hear it when turning, I hear it when moving forward, but moreso in reverse, and usually when I am at lower engin RPMs.

MuncyBob · Oct 20, 2004

doc, I remember reading that the RPM of the blades were high too....but when I had my blades off earlier this year to sharpen I think the blades had something like max rpm of 6200 or so stamped into them???

Schultz · Oct 20, 2004

I looked through the other sections too and noticed you torching milkweed seeds for cleaning, but I could figure out why? Does this make them easier to plant??

MikeOConnor · Oct 20, 2004

about those milkweed seeds, here's the link that Tim Shultz is referring to;

http://prairie.haven.com/modules/news/article.php?storyid=63

yep -- the reason we burn off the fluff is to make 'em easier to run through the seed drill. if they're all fluffy, they plug everything up. cool action-shots, huh? <grin>

Rip · Oct 20, 2004

Mike,

I get the same noise from my 1845 and think it is from a hydraulic shuttle or balance valve and not the pressure relief valve. So you are not doing anything unusual or extreem.

If you do not find your spinner knob, most any tractor or even garden tractor shop should have them. Buy two because most are not that strong and when it breaks you will want to replace it immediately. You won't believe the difference it will make.

tracdoc · Oct 20, 2004

Farmall,
After reading your post, I started to think more about the tip speed, and it dawned on me (duh!) that blade tip RPM must be identical to hub RPM. The high tip speed number (17,000+) is not RPM. Rather, it is actually a measurement of the traveling velocity of the blade tip measured in units of distance/time . In aviation propeller blades, the unit of tip speed velocity is MPH. For mower blades it is conventionally measured in ft/min.

There are many websites that offer calculators for pilots to calculate propeller tip speeds in MPH. One of these is Prop Tip Speed Calculator

To convert MPH to ft/min all you have to do is multiply the result in MPH by 5,280 ft/mi and divide by 60 min/hr.

The blade diameter of the PT finish mower is 16". I don't know the blade RPM at operating speed. However, we assume a speed of 4,500 RPM (i.e., about 70% of the max rated blade speed), that computes to a tip speed of 214 mph or around, 18,800 ft/min. If I am not far off on the RPM, that's a very fast tip speed, which is what accounts for the high quality of the cut that we see with the PT finish mower.

Thanks for getting me to think more about that.