Thin cutting edge for tractor tree spade?

[Justin00Stang]

I have a small tractor that I am making a tree spade for. It will attached to an existing 4ft bucket. It will be about 30" wide and stick out 26" from the cutting edge of the bucket, in a triangle shape. It will be made from 1/4" steel, with some breaks in it and steel strip welded to it for strength.

I would like to weld a cutting edge on it, to help it break through roots when transplanting small trees. Most of the stuff I find online is for huge equipment that uses 1" thick x 7ft wide cutting edges.

Any idea where to find something smaller? I would prefer to buy it then hand grind an edge on 4-5 linear feet of steel.

I thought about using lawnmower blades since they are thin and have an edge already on them, but how hard are they?

[Doughboyracer]

They don't need to be all that hard (you are cutting wood) and if you worry about them being "sharp" you will wear them out that much faster...I guess what I am saying, sharpen what you have and use a "replace/repair" plan. After all how often are you going to use this very fine idea of a project?

[gwiley]

"sharp" edges will blunt and even bend when you use them to cut roots. The root cutting "spades" that I have used on the Bobcats have from 1/4-3/8" thick material with cutting edges that range from steep taper to none specifically to keep the edge thick to avoid damage from rocks.

You are better off serrating the edge and leaving it pretty thick than honing it to an edge.

It might not be helpful to compare with a small tractor, but my Bobcats have 36-45HP and haven't done serious damage to the edges even in rocky Virginia soil.

[chewinggum]

I built a spade for my Kubota sub-compact and just used 5/16 steel plate with a single bevel edge. It is not hardened, but has held up well. I don't think you need to worry about a hard edge.
JD

[Justin00Stang]

I picked up the 1/4" plate from the waterjet shop yesterday and took it by my buddys shop to put a 15* brake in each side of the spade for strength. I will just grind a little bit of an edge on it and see how it holds up. We have mostly sand here in FL.