Box Scraper Adjusting Three Point Hitch for new Box Blade

[kvmapr]

Last Friday I picked up a 6 foot box blade, took it home and before sunset had it mounted on my Jinma 254's three point hitch. First thing I noticed is the links between the lift arms and draw bars were too long (I had put them out at full length while using my middle buster to rip trenches in sod). I shortened those up and the box blade now rides at a good elevation.

But then I ran into a problem that I think I need some help solving. I noticed that when I look at the profile of the box blade, that is the side view, the front end of the box is higher than the back end, where the scraper blade mounts. I tried a few test runs and the blade couldn't get a bite in the ground. Something wasn't right.

I recall some photos here on TractorByNet of properly mounted box blades. I think it was 3RRL's that I was looking at, and in those photos the box is canted the opposite of mine. That's to say, the front end of the box is lower than the back end of the box. In that manner the ripper's should engage easily, and the scraper blade should get a nice bite.

I looked at the 3 point hitch and could see that the box blade rotates forward and back on the two mounts at the ends of the draw bars. And it's the top link that controls the pitch, or how far forward or back the box is canted off of level.

I looked at the top link, and it is shortened up as short as it will go (about 19 inches on center between the two eyes). But if the box blade is to be angled so it will get a bite in the ground, that top link will need to be much shorter, maybe four or five inches shorter.

So now my questions...
Am I seeing the problem correctly, or have I missed something here? Lord knows I have yet to master the three point hitch system.

And if I'm on the right track, is a shorter top link the right answer?

Thanks all for your advice.

 

[Leon Wittner]

Not sure about your tractor but on mine with the blade on flat ground if you look at the side plates on the blade. There is about 3/4 of an inch clearance (front to back) when the blade is on the ground. When I first tried mine I had the front and back about the same height and all that happened was the side plates left two lines down the road.

My L-2800 Kubota has like four holes where the top turnbuckle attaches to the tractor and the manual says to use the second hole from the bottom for a box scraper.

Not sure if this will help you but I am pulling a six foot King Kutter box blade with rippers.

 

[Dyer retired]

kvmapr,

Sounds like the top link is your problem all right and a shorter adjustable link is certainly available. I have a rear blade that will turn 180 degrees, but when raised much off the ground would not do so because the top corner of the blade would catch the lower control arms....because the top link was as short as it could be adjusted and would not allow it by. I could play with the height adjustment some keeping it close to the ground and more level with the bottoms of the control arms, combine that with enough play in the blade swivel to lift it and get it turned, but it's been a pain since I had it. I didn't want to spend the 24 or so bucks for a new shorter adjustable top link, so I was able to cut a minor 45 degree corner off both sides of the rear blade top and it swings great now for me, with zero effect on the blade of course.

O.K. that was way more response to your question than you probably cared to hear about, but check out a TSC or any supply place site and you'll see the offerings. Unless, I've missed the whole question all together, then disregard. Good luck. John, retired

 

[greg_g]

is a shorter top link the right answer?

Yes. Easy for me to say though, 3RRL and I have hydraulic toplinks. We can adjust the length on the fly, without leaving the tractor seat.

There should also be more than one set of holes through which to pin the end of the toplink. Ideally you want to select the set that puts the toplink approximately parallel to the lift arms when the implement is in the working position. In your case though, select the set that angles the front of the BB down farther.

Agri-Supply has Cat 1 toplinks that have 13" bodies (yours is probably 16") and run about 12 bucks.

//greg//

 

[kvmapr]

Leon - I like the way you describe it. Looking at the side plates on my box blade, the lower front corner of the plate is about 3 inches higher than the lower rear corner. So high my rippers can't even engage the ground when let out to full depth!

Dyer - thanks for the suggestion, and TSC was the first place I stopped. They had cat 1 top links, but only in the size I already own. Nothing shorter.

Greg_g - I saw that too, there are two holes where my top link attaches to the tractor. I can drop the top link down to the lower hole and that will help the geometry some, I'm sure. Then, when that 13 inch top link I just ordered from Agri-supply comes in, I hope to have the entire situation remedied.

I'll post back later with the results. Thanks all for the great (as usual) input.

KVMAPR

 

[Soundguy]

i agree.. sounds like your top link is set too long.

soundguy

 

[john_bud]

You want the front of the box to be 1.5" to 4" lower than the rear depending on soil, job etc. Normally it's in the 1.5" range for scraping.

Measure your top link (from the lowest 3pt hole on the tractor side) to the box mount with the box tilted to that 4" angle. That will be your extreme shortest top link.

If you are having a hard time getting one that short for some reason, you can buy some of Pat's Quick Hitches as seen on this site. That will move the 2 mounting arm points back about 3-4".

jb

 

[kvmapr]

OK, success! The 13 inch top link came in from Agri-supply and I got it mounted with no problem. After setting it into the lowest mount hole on the tractor, and pulling it in to its shortest length, I connected it to the box blade. The front corners of the side blade are now about an inch lower than the rear.

So I put the rippers out to full length and put it to the test. Boy does it work nice, I'm in love. First thing I did was cant the blade to the right about 3 degrees, and then started scraping out the floor of my pole barn. The floor of that barn has had a 10 degree slope, left to right, in it since it was built (long before I bought the farm). After a dozen passes I had the slope down to about 3 degrees.

This is the best implement I've bought, outside of the FEL and toothbar. Between the two, I can now move a lot of dirt.

But John Bud is right, I'll have to buy a set of Pat's Quick Change Hitches to extend those lower draw bars back another 3 or 4 inches (unless I can find a top link even shorter than 13 inches).

Thanks for all the input. I'll try to post some photos of the job when it's finished.

KVMAPR

 

[john_bud]

I've heard good things about the Pat's system. They will also make hooking up much simpler.

jb

 

[Soundguy]

I'll have to buy a set of Pat's Quick Change Hitches to extend those lower draw bars back another 3 or 4 inches (unless I can find a top link even shorter than 13 inches).

You can always 'make' your toplink shorter by cutting and welding.. but 13" is pretty short as it is.

One thing.. to help prevent confusion in the future.. your lower links are called 3pt lower lift arms.

a 'drawbar' is bar that is either 'swinging' from a bracket ont he back of the tractor, usually under the diffy.. or is a '3pt' version ( 11-hole for cat-1 )that mounts betweent he 3pt lower lift arms.

properly identifying the lift members will help others help you.

soundguy