King Kutter XB rotary mower blades operation & removal

[yawning dog]

Hi folks, I have a couple basic questions. I just bought a used King Kutter XB rotary 3pt. mower. I don't know anything about them really. The guy I bought it from noted that sometimes the mower becomes out of balance if the two blades are not directly in line with each other (such as after a blade hits something). He showed me that although the blades could pivot around their attachment point they were basically fixed. But going online watching some videos it seems that the blades are *intended* to be loose fitting and rotate around their attachment point. I'm thinking that essentially the guy didn't know this and the blades had become so gunked with stuff that they are now essentially fixed. Question #1: should they be freed so that they can rotate freely around where they attach?

The second question is how to remove the blades. In one video showing a similar Land Pride mower, there was an access hole in the top of the unit that allowed access to the blade nut. There is no such access hole on the King Kutter XB. So must I remove the whole stump bump thing to access the blade nuts? Thanks!

 

[Flintknapper]

Yes the blades are supposed to be able to rotate around the 'shoulder' section of the bolt. It is for exactly the reason you cited (when you hit something).

IF you hit something hard enough it is possible on some rotary cutters for one blade to become wedged against the other and not return to its proper position by centrifugal force alone.

The imbalance is stark, it will nearly shake you out of your seat and you'll know right away what the issue is. Same holds true if something becomes entangled in the blades.

Yes, if there are no access holes in the top of the shredder.....you'll have to remove the entire stump jumper.

 

[ken erickson]

This is a free online manual for the XP King Kutter mower.
Yes, the blades should pivot freely at the attachment point.
This is a highlighted in bold print from the manual.
NOTE: Blade bolts are left hand thread!

XBKutter Manual 2019.pdf

 

[yawning dog]

Thank you ken erickson! That manual was really helpful. I had gone to their website and seen the IPL but I didn't think the manual would be that helpful. And the left-hand thread note is huge. I would have probably destroyed the bolts trying to get them off had you not pointed that out!

Regarding actually accessing the blade bolts, the manual didn't seem to go into that. I guess I have to remove the whole "stump jumper" part to access the bolts. If anyone has replaced the blades on their XB, please confirm.

 

[Motion]

If it were mine and the deck didn't have an access panel / hole to remove the blades, there would be. Also, the gear boxes I'm familiar with have a tapered splined output shaft, I prefer to remove and use anti-seize. If it has a shear pin, I like to remove and apply ant-seize to the input shaft and yoke. If the drive shaft has a safety clutch set it per the manufactures recommendations at the beginning of the season.

 

[yawning dog]

Thanks for your tips, Motion. It might be a good idea to take it apart anyway for the reasons you note. I was told that the stump jumper nut was actually spot welded on but I haven't flipped it over to have a look. I'm sure the weld was "aftermarket" to ensure that the nut wouldn't come off. I'll probably be having a closer look at it this weekend.

 

[Motion]

Most boxes use a castellated nut with a cotter pin, if it in fact is spot welded be careful to remove all the weld before backing off the nut, you may want to pick up another nut and pin. If the stump jumper needs to come off be prepared for war, legally I can't say how I got one off, although I can say it'll will test your religion and be a character builder. Also, the blade bolts are generic with the size stamped on the head, items you should have in hand. Thoroughly check the "U" joints. Go through everything now!

 

[yawning dog]

Great advice. Ha ha, yea, I watched a video from a guy who had cracked the stump jumper and had a really tough time getting it off. He ended up using a torch, probably MAP gas I guess, to loosen it. I'm not looking forward to the challenge! But I think I need to do it because I'm pretty sure the blades look more like rounded hunks of metal than cutting instruments and they're practically frozen on the stump jumper.

 

[ken erickson]

Great advice. Ha ha, yea, I watched a video from a guy who had cracked the stump jumper and had a really tough time getting it off. He ended up using a torch, probably MAP gas I guess, to loosen it. I'm not looking forward to the challenge! But I think I need to do it because I'm pretty sure the blades look more like rounded hunks of metal than cutting instruments and they're practically frozen on the stump jumper.

I think you will get it sorted out and will give you good service!
As a side note, I had called King Kutter years back and chatted with a customer service guy about the differences in their XP line in regards to the dimensions of the 3 pt. He was very responsive and willing to answer my questions. You may want to consider chatting with them about this cutter and the best ways to change blades , replacement blades and bolts etc.
Good luck with your repairs!

 

[Motion]

Give yourself enough room to work, remove the driveshaft, as mentioned, try to hang the deck with one side resting on the ground, if you have a cutting torch with a gouging tip wash the head off the blade bolts, then go to work on the hub. Good penetrant, wooden wedges (under the blade strong back), heat, mauls, etc., keep the nut on the threads (not tight) because when it pops you don't want it flying off. If you have a pneumatic chisel, you can try that, put it in a bind with the wedges then vibrate the living hell out of it. Remember it's tapered you only have to move it a little, but you've got to move it. FYI, Tractor Supply has a good assortment of blades and bolts. If you remove the bolts, mark where to provide an access hole.

 

[Russell King]

If the stump jumper has to come off and is not too expensive and is stuck then consider just cutting it off with an angle grinder.

I think you could get a socket on the nut and try to get it off with a break bar and pipe. Not sure how you would keep it from rotating but I think you can figure that one out.

A hole in the deck is best and you could probably figure out where to cut one. Using an extension from the top let’s you pull the wrench and then the extension hits the side of the hole and stops the rotation of the blade carrier. Then the nut will break loose (hopefully).

 

[yawning dog]

Hi folks, thanks again for all the tips. I had a look at it this weekend and it wasn't as bad as I thought. The blades were certainly dulled but I was able to hit them with an angle grinder to at least put an edge back on them. And more importantly, they weren't frozen as I had previously though. They weren't rotating like they were on ball bearings but they did move. I used the angle grinder again with sandpaper and sort of buffed out the underside of the deck to remove rust and gunk from where the blades would contact the deck. So I'm ready for a test mow now. I also changed the gear oil which did in fact look like chocolate milk!

 

[ken erickson]

Much debate here on the forum if an edge should be put on rotary cutter blades and if so, how sharp of an edge.
I personally do not have too much of an opinion either way but one thing that does makes sense to me is when cutting woody material such as small saplings. The theory goes that a sharp edge blade will leave a sapling that is sharp enough to puncture tires while a dull edged blade will leave the sapling fractured and torn. For what it's worth.

 

[RBsingl]

I engage the PTO for all implements at reduced engine RPM to reduce shock loading BUT with the rear cutter on my Deere 955 compact, if the engagement RPM is too low the blades won't swing out properly resulting in that incredible vibration described earlier. So don't try to engage the PTO with the rotary cutter mounted at too little RPM, centrifugal force is your friend in this case.

Rodger

 

[kcs]

What is the recommended RPM to start a cutter at? I have a RCR 1260
For my B2650. I engage all my PTO attachments at idle

 

[RBsingl]

For the rotary cutter and midmount finish mower on my Deere, I engage at about 1/2 rated RPM; I use just off idle for the tiller and snowblower.

I have been using a tad under 1/2 rated with my new Kubota f2690 and that seems to be a good compromise between shock loading and bogging but with only 9 hours on it so far I am still getting used to it.

ALWAYS drop to base idle to disengage PTO.

With hinged blade cutters, you could engage at just off idle and once you get to a high enough RPM the blades will swing out but I don't like all of the vibration that creates on the way to that critical blade shaft speed.

Rodger

 

[Runs With Scissors]

I also begin at idle and work my way up to let centripetal force fold the blades out properly. (centrifugal force does not exist )