JD 4520 weight bracket - design quality issue

[jenkinsph]

Pete,

That oughta work.:thumbsup:

 

[eepete]

Update:

If you look at the last picture of the weights, you'll see that I got 10 weights on there. Two more would not fit, and the bracket had a good sized gap. I thought maybee this bracket fit mulitple weights and tractors.

Well, after thinking about it for 4 months or so, I looked up the part number for the bracket and found out it really should hold 12 weights :confused2:. I have a few areas where I'm turning uphill on a slope with the MX6 rotary cutter and the front wheels slide a bit. So I bought two more 70 pound weights, and really wanted to put on two more of my existing 40 pound weights.

My soultion to the retaining bar bending is wrong .

The metal that was welded on should have been put above the existing bar. Here's the problem:

If you look at these pictures, you'll see where the weights have a cut-in area so that the support bars can nestle under the weights. I added my piece of metal on the side of that support bar, which pushes the weight out on one side.

(more posts to come, hang on...)

 

[eepete]

So the metal with the hole for the retaining bar needs to be welded on top of the existing bracket, and it needs to be out of the way of the top of the weight.

So I marked what I needed to cut, and cut it out. I had to get a grinder for the bottom cut (did the top cut with a hacksaw). Important safety tip: Don't use a grinder where the sparks will hit something close and bounce around wearing a cotton T shirt :laughing:. Every new tool has a learning curve...

Now it's time to put the bracket back on and see if everything fits!

 

[eepete]

Well, I got four weights to fit on the right side, but they did not fit on the left side . Turns out the bracket is about 1/8" longer on the right than the left.

You can see in the picture where the top of the weight was hitting the end of the bracket. Indeed, it was about 1/8" too wide. Since I have a grinder, the answer was to just grind a little but of the weight away.

You can see where a little bit taken off made the weight fit. When it is snug in the bracket and the retaining bar is in, there is about 1/16" clearance.

 

[beenthere]

eepete
Individual rear brakes are good for making turns too.

 

[eepete]

Now it was time to put it all together. For the "fit test", I used the 40 pound weights. But when I put the "Real" 70 pound weights on there, the right side (which had been OK) didn't fit.

Measuring the weights (yeah, I know, I should have done this step much earlier in the process...) showed enought variation that when I went to the 70 pound weights, the right side did not clear by about 1/8". So I ground down that weight, giving me a matched set of ground down left and right 40 pound "end weights" that make everything fit.

And here's a pix of the final bracket with all 12 weights on it. The owner manual ballasting for the MX6 is 12 70 pound weights or 840 pounds. I have 8 70# and 4 40# weights for a total weight of 720 pounds. So I hope I'm good to go on my couple of areas where the front wheels slid a bit.

To Summarize:

If you get this weight bracket, you'll need to weld on a little square of metal with a hole it in for the retaining bar. This must be welded on top of the existing cross supports that are on the bracket. The have to be short enough that they don't touch the weights. If you do this, the indent in the weights means everything will fit given all the slop (real machinist say "tolerance":laughing of the bracket and width of the weights. It was just easier for me to grind down the weights a bit than to re-do my retaining bar brackets. I did paint everything I ground down, BTW.

Hope everyone can learn from this. A recoverable error that everyone can learn from is a mistake I can live with :thumbsup:.

Pete

 

[jenkinsph]

Pete,
Nice write up with good documentation as always.:thumbsup:

How much was the front wheels sliding to cause you to do all of this? If I am following you correctly you have basically added two more 70# weights than you previously had.

IF it were me I would reuse the four 40# weights on your boxblade and use twelve 70# weights on the front. If you feel the need for a fully planted front end.

In my case with the heavy 8' landplane, heavy (1250lb) boxblade and the MX6 I expect a minimal amount of sliding with the six 70# weights but as Beenthere mentioned steering brakes correct all of that. The mower extends out so far behind the tractor that it will be the most cumbersome implement you are likely to have.

 

[eepete]

There are two areas where I can slide. When I slid, I had 580 pounds of weight on the front (6 70# and 4 40#). I somehow incorrectly got it in my head that the bracket was good for 10 weights when it should be good for 12.

You are correct that all I added was two more 70# weights, and as you can see the count up to 12 for a "new" total weight of 720 pounds.

When I slid, I was at about a 10 degree slope going horizontal on the slope. There are a few areas where the slope quickly gets worse, and I have to turn uphill to work around it. During this turn is when the wheels would slip a bit. When they slip, I semi-instictivly slow down, so it's OK I just want a little more margin of safety. Once again beenthere has indeed been there and is right that the brakes would help. I've got to get my "muscle memory" going enough that I can react and use them quickly.

I could load it up with more 70# weights, I'm just being overly frugal . A full set of weights is about $1K, and I already had the 40# weights for the 318. But I'll bet that if it still slips I'll probably cough up the $$s because it's not too hard to argue that slippin' and slidin' around on sloped surfaces isn't too safe .

Finally, you are correct that all the problems are with the MX6- it is indeed the most cumbersome implement I have. Add to that the fact that when I use it I'm going the fastest of all the implements I have, and you can see why the reaction time is important and why slipping is a bit unnerving. The front weight buys me some margin, I need to learn to react and use the steering brakes and I'm getting to know the property with the 4520. So it's getting better every day.

I just hope getting the grinder isn't a "gateway tool" on the path to welder adiction.... :laughing:

Pete

 

[arrabil]

I just hope getting the grinder isn't a "gateway tool" on the path to welder adiction....

Yes. Yes it is. And soon after the welder you will be looking at the hard stuff like plasma cutters.

 

[eepete]

OH NO! Metal workers addiction is in my future ?

And I just noticed that the post # where I wondered if the grinder was a gateway tool was 666.

Truly I am doomed

Pete