New guy here...Some brushhog questions

[RobT]

Eric:

I was a brand new "newbie" last year and this forum has really helped me. I'm still much of a newbie, but I've spent about 100 hours bush hogging so far and have found that the shear bolt breaks if you encounter dirt, big rocks, etc.

Also, I make sure I grease up the PTO shaft connections EVERY time I go out. It takes a few extra minutes, but I think it helps (I was breaking many bolts at the beginning).

When I start out, here's my routine:

1. Raise the cutter the deck off the ground several inches cutting height
2. Engage the PTO at 550---never 1000
3. Set the tractor RPMs down all the way (or as lows as I can get them)
4. Ease off the clutch to allow PTO to start and for blade to start moving
5. Slowly increase tractor RPMs
6. Lower deck to cutting height

RobT

 

[Alan L.]

My B2710 has stabilizer bars so that the upper links can be more or less frozen in place so there is no side to side movement thus the arms never get into the tires. Maybe you have a similar situation but if the bars are just too wide on both sides I don't know what the solution would be.

 

[madpogue]

The spec for the shear pin on my KK 5-foot 40-hp mower is a simple 3/8" x 3.5", grade 2 (the softest) bolt and nut. If you're breaking shear pins immediately on engagement, with the engine at idle, something's not right. With the mower deck on blocks/stands, or the whole mower on level enough ground to have the blade free of any obstruction, can you turn the PTO shaft by hand and turn the blade? If not, your gearbox oil is probably very old, or the main vertical shaft going thru the deck needs to be lubed, or something.

In short, that pin sheared because it's supposed to. It's intentionally the weakest thing; it sacrifices itself so that a restriction or obstruction doesn't instead damage or break some other part (chew up a gear in the gearbox, twist the PTO shaft, etc.). So don't leave that harder grade bolt in there.

Now, it's possible that something with the mower was "stuck", and putting in the harder shear pin got the PTO to drive it hard enough to get it "unstuck". But to me, that means it's time to give the mower's mechanicals a once-over.

 

[Spiveyman]

I was a brand new "newbie" last year...

I'm also a newbie and have a question about your post, but first, ericinok, hopefully the folks here at TBN won't be laughing at you, maybe laughing with you as we've been there as well. I bought a farm last year, but just got my first tractor last month. I tried to get a buddy to show me how to hook up a rotary cutter and get 'er going, but he didn't have time. Asked my papaw but he hurt his foot and couldn't, so I just figured I'd give it a try. After some frustration at trying to hook it up, (my 3ph is Cat2, cutter is Cat1, and I wasn't too good at lining her up), I figured out the PTO shaft and was ready. The next part was the tricky part for me. I saw 540 and 1000 on the RPM gage, so I revved her up to 540 and engaged the PTO. My first experience with a sheer bolt was more like shrapnel! Luckily the sheer bolt did it's job and saved the tractor and cutter from another newbie mistake. Later I read the tractor manual (imagine that ) and found out that my tractor has a mid point in the PTO lever travel for getting the implement up to speed before fully engaging.

When I start out, here's my routine:

1. Raise the cutter the deck off the ground several inches cutting height
2. Engage the PTO at 550---never 1000
3. Set the tractor RPMs down all the way (or as lows as I can get them)
4. Ease off the clutch to allow PTO to start and for blade to start moving
5. Slowly increase tractor RPMs
6. Lower deck to cutting height

Here's the part that I'm curious about, step #2. engage PTO at 550. My RPM gage show's an RPM position for 540 and 1000:



Do you mean to get the RPM up to the 540 spot and then slowly engage the PTO? Step #3 has the RPM down low and #5 says to bring the RPM up. Is step 2 a parenthetical comment or is there something you are doing there?

Sorry if that's a goofy question, but I'd rather look silly here than to be getting stitches because I didn't ask the question. By the way, a pocket full of sheer bolts is now standard when I mow.

 

[Grrrr]

When I start out, here's my routine:
​

1. Raise the cutter the deck off the ground several inches cutting height
2. Engage the PTO at 550---never 1000
3. Set the tractor RPMs down all the way (or as lows as I can get them)
4. Ease off the clutch to allow PTO to start and for blade to start moving
5. Slowly increase tractor RPMs
6. Lower deck to cutting height

I'm also a newbie and have a question about your post, but first, ericinok, hopefully the folks here at TBN won't be laughing at you, maybe laughing with you as we've been there as well. I bought a farm last year, but just got my first tractor last month. I tried to get a buddy to show me how to hook up a rotary cutter and get 'er going, but he didn't have time. Asked my papaw but he hurt his foot and couldn't, so I just figured I'd give it a try. After some frustration at trying to hook it up, (my 3ph is Cat2, cutter is Cat1, and I wasn't too good at lining her up), I figured out the PTO shaft and was ready. The next part was the tricky part for me. I saw 540 and 1000 on the RPM gage, so I revved her up to 540 and engaged the PTO. My first experience with a sheer bolt was more like shrapnel! Luckily the sheer bolt did it's job and saved the tractor and cutter from another newbie mistake. Later I read the tractor manual (imagine that ) and found out that my tractor has a mid point in the PTO lever travel for getting the implement up to speed before fully engaging.




Here's the part that I'm curious about, step #2. engage PTO at 550. My RPM gage show's an RPM position for 540 and 1000:

View attachment 84411

Do you mean to get the RPM up to the 540 spot and then slowly engage the PTO? Step #3 has the RPM down low and #5 says to bring the RPM up. Is step 2 a parenthetical comment or is there something you are doing there?

Sorry if that's a goofy question, but I'd rather look silly here than to be getting stitches because I didn't ask the question. By the way, a pocket full of sheer bolts is now standard when I mow.

First, I think that 540 RPM is the standard PTO speed, never 550 RPM.

I think he means that you want to lower your revs down to a fast idle and engage the pto slowly as you said you do.

Then, once the cutter is spinning happilly, crank the revs up to 540 RPM on the tacho.

I think you are doing it right allready.

The difference with what Rob said is that his tractor has a lever that engages the pto. But you then have to let out the clutch for it to start up.

 

[sandman2234]

Just to make sure everyone is clear on this, the speeds noted for pto on your tachometer are for the engine rpm to make the pto spin at that particular speed. Or in other words, the speed the engine has to turn in order for the pto to be turning the rated speed.(540/1000, etc)
Those are NOT engagement speeds and are subject to tear something up if your not extremely lucky. Engage the pto at the slowest possible speed, lowest possible load, and increase speed/load after it is engaged.
Just wanted to make this clear,
David from jax

 

[ericinok]

ONE PROBLEM SOLVED!!!

I read all the replies here, and also started thinking about it. Even with a HST tractor, it would still make sense to use the clutch and ease it out when engaging the pto. Like I said earlier, I am waiting on my manual, but was too excited to get going. Anyway, I tried getting it going and easing out the clutch at a low rpm, and it worked like a charm. Several times. Now, I'll go buy some shear bolts and take out that hard one (that didn't sound right, did it?).
Thanks for all the help on that one.

As for my other problem, I have still not conquered it yet. This weekend I'll get under there and see if I can reverse the arms or if there is a pin I can set to keep the arms still. However, it seems like you would not want them to be entirely still, and I only have about 3" of clearance right now on both arms before they hit the tire?

If I can't figure it out, I'll take a picture and post it here, so you guys can see exactly what I'm talking about.

Another question - what kind/type of oil do you put in the gearbox? I'm sure this hasn't been done in many years.

 

[Spiveyman]

First, I think that 540 RPM is the standard PTO speed, never 550 RPM.

I think he means that you want to lower your revs down to a fast idle and engage the pto slowly as you said you do.

Then, once the cutter is spinning happilly, crank the revs up to 540 RPM on the tacho.

I think you are doing it right allready.

The difference with what Rob said is that his tractor has a lever that engages the pto. But you then have to let out the clutch for it to start up.

Cool thanks! At least that's something I'm doing right. 1 down, 14,756 to go.

Just to make sure everyone is clear on this, the speeds noted for pto on your tachometer are for the engine rpm to make the pto spin at that particular speed. Or in other words, the speed the engine has to turn in order for the pto to be turning the rated speed.(540/1000, etc)
Those are NOT engagement speeds and are subject to tear something up if your not extremely lucky. Engage the pto at the slowest possible speed, lowest possible load, and increase speed/load after it is engaged.
Just wanted to make this clear

You know what they say, God watches over fools and little children. I think I've squeaked under that first category more than once. Luckily that sheer bolt just snapped clean so I didn't tear something up.

... see if I can reverse the arms or if there is a pin I can set to keep the arms still. However, it seems like you would not want them to be entirely still...

Yep, you have to be careful there. I realize we likely have very different systems (Blue Vs. Orange), but... do you have telescopic stabilizers? Does your attach point have upper and lower holes? On my tractor you can let the stabilizers allow some sway, and attach the stabilizers to the upper holes and this will limit the sway, or you can use a solid position and eliminate the sway but you have to use the lower positions, there are cautions with either way... you know what... I'll just scan that page from my manual. It will do a better job with pics than I can do with words. Maybe one of you Orange guys could do that to hold ericinok over until he get's his manual.

 

[ericinok]

I appreciate the help, Spiveyman. Our set-ups look pretty much the same, so I'll pretend I have a Ford until I get my manual.

Is my monitor blurry, or does your dashboard show 4000 hours? Wow, that's what I call getting your money's worth out of a machine. I was feeling bad about putting 10 hours on mine already, kicking it up to 613 hours.

Thanks again.

 

[JoeinTX]

Really nothing to do with the poster's issues as you're simply feeling your way out and rightly so, but, I've never sheared a shear pin in my life.


Shredding.......digging post holes......spreading......etc......never. I've used a variety implements and units ranging from the 8N Ford to the 120hp MF to the old Corsicana 5ft shredder and 10' Mohawk cutter.....never a blip. Digging through our dry hard clay and rock down to 3-4' or using the 5' Howse to pulverize brush and roots and 2" overgrown growth......never a shear pin replaced in 20 years.


I'm envious of the process.............what are you guys doing doing to split pins at such a regular rate??? I need to know.