Tractor backhoe - homemade

BFreaky · Feb 7, 2014

No, I googled the name before answering so I know what you're talking about.

hddnis · Feb 7, 2014

Been watching this thread with great interest since the beginning, but figure I should subscribe so I don't miss anything.

Mr. HE

BFreaky · Feb 9, 2014

Some progress... 2nd picture shows the hose protection cover. I installed the pumps in place

rScotty · Feb 9, 2014

toddler said:
BF,
Any relationship to Mike Mulligan? Because I foresee a similar lifelong relationship in your future.
Todd

You must mean this Mike Mulligan....

BFreaky · Feb 12, 2014

Main frame is hooked up on to the tractor. The second photo shows a powerfull magnet and inlet filter inside the oil tank. It should help collect small metal particles

Spitzair · Feb 12, 2014

Looks great! Can't wait to see the finished product!!!

GolfAddict · Feb 12, 2014

Whoowee, closing in on it now!!

Beltman60 · Feb 12, 2014

I can see it tearing up the turf
as soon as it thaws

KubotainNH · Feb 12, 2014

That looks like a beefy setup even for that big tractor. It'll be cool to see some action video. Amazing workmanship.

rScotty · Feb 13, 2014

BFreaky said:
Main frame is hooked up on to the tractor. The second photo shows a powerfull magnet and inlet filter inside the oil tank. It should help collect small metal particles

Mornin' Freaky,
I'd recommend that you put some thought into the magnetic filter. Off the top of my head I'd prefer to use magnets of alloy Sm2CO17. Magnetic strength and material friability of neodymiumFeB magnets isn't as well controlled. Not only are they physically weak, their field strength also drops off variably at high temperatures. On the neo type magnets, it depends a lot on which neo magnet chemistry is chosen and how it was manufactured. Keep in mind that on neo magnets especially many of them have a knee in their temperature spec that occurs within the operating range of your hydraulic oil. The resulting demagnetization is not recoverable; it is permanently gone.
One more magnet chemistry to mention: the old alnico alloy magnets were strong physically and had decent performance well above the temperature of hot oil. But alnico tends to self-demagnetize when installed in a variable flux path such as you are expecting. That's another way that field strength is permanently lost. Overall, I think the SM2CO17 is your best bet, having decent physical and temperature strength. That SmCo chemistry is not usually nickel plated - but you can plate it yourself or otherwise encapsulate it if worried. Note: plating doesn't stick well to sharp machined edges. Most things - magnets included - are tumbled before plating. Yes, that applies to painting too...just not as much.

Whichever you choose, think it through in detail. Magnets are not equal and their effects on particles can be even more strange. One thing that I've seen happen is that as particles collect, they will continually align themselves along the major flux paths until field saturation occurs. Basically at that point the particles have almost short-circuited the magnet so any additional particles will only attach themselves to the fuzz until some small force knocks them off.....forces such as fluid flow and particularly pulsed fluid flow. That's OK when the pump is off and fluid is just sitting there resting, but turn it back on and these particles - now tiny magnets themselves - will be knocked free to circulate and attache where they will. Now that they are magnets they are no longer flushable.

IMHO, the big key to magnetic filtration is that the magnet be in an easily serviceable position, well away from the fluid flow and particularly away from variable fluid flow, and be cleaned often. Clean it very often during break-in or after any events.
The upside to all this is that I think you said you will have one or probably several media-type filters in the system and those should trap most everything.

BTW, Your project is tremendously impressive. Beautiful curved lines. I'm enjoying it immensely.
Good Luck!
rScotty