Back hoe/digger bucket theory.

[Marcle]

I've seen a number of bucket designs by fellow members, many seem to be of an angular design. This has got me thinking, as I've always made mine with a rounded back and flat top as shown in the image below

My reasoning for the flat top is that its then easy to see the bucket is flat and ready to draw back toward yourself.

My reasoning for the rounded back is mainly for the easy flow of soil into the back of the bucket, though I suppose an angular design would help break-up the soil. Another feature of my round design is to maximise the area within the 'swing' area of the bucket so it continues to dig without being pushed out by the back of the bucket.

A note of caution. many mini diggers come with buckets that are far too small, so a bigger bucket reduces digging time, but... do be careful not to oversize your bucket as if your digger has short out-riggers/steadies, its quite easy to tip your machine over by having an over-weight bucket with soil out-side the safety lift zone of your out-riggers.

What's the experience of others?

 

[DJ54]

I guess it depends on what you are digging. I have used both a trench bucket, and the shorter bell type bucket, with round radius for cleaning ditches along highways. The trench bucket with the flat bottom is I'm presuming, designed so as to ride the heel of the bucket, keeping a flat bottom trench.

The bell type makes a nice rounded ditch, curling the bucket when side digging.

 

[R W]

The angular design is probably easier to construct in a home workshop than the rounded type, would be one reason if not the main reason for them being popular on HM machines.
From what i've seen most factory made buckets are of the rounded design.

 

[Marcle]

I appreciate the rounded back can be an issue, the way I over come the curve is to use strips of flat and weld them all together.

The radial lines are just to emphasise the flats on the curve. The flats are obviously the width of available stock.

 

[DJ54]

Actually, I'm thinking the rounded type bucket would be easiest to build, as far as cutting the sides. Depending on your cutting tool, I have made a circle cutter for my torch, actually from scrap in the shop. A piece of 3/8" rod, and 3/8" ID box tubing. The tubing slipped over the rod, cross drilled on one side, with a nut welded on for a jamb bolt, to make it adjustable. On the cutting end, a nut large enough the tip fit through. On the pivot end, what ever you can come up with to clamp to your material, and keep it in place, but yet let it pivot. I cut a piece of sheet metal to replace the manger bottom in my 2 horse bumper pull horse trailer. It is a 6' radius.

When I bought my plasma cutter, I got the optional circle cutter. On the pivot end, it has a pointed piece of square stock, that slips through a magnetic holder. Center punch your stock, place the pointer in the punch mark, and set the magnet. Fully extended, it will cut a 36" circle. If you want larger, you're just limited by the length of 1/4" square stock you want for a pivot arm, if needed larger.

Looks like it would be much simpler to cut a semi circle out of proper stock, then cut in half.

Even if you wanted a flat bottom you could backset, to get your flat bottom, then adjust the radius point to round out the back.

 

[spo307]

the problem for me if i were to build a round back bucket, is how to bend 3/16 material around the radius, i know i can heat, bend weld but thats a lot of work

 

[Marcle]

the problem for me if i were to build a round back bucket, is how to bend 3/16 material around the radius, i know i can heat, bend weld but thats a lot of work

That's why I used strips of flat stock (3" or 4" x 3/16").

 

[Jesse masterson]

the problem for me if i were to build a round back bucket, is how to bend 3/16 material around the radius, i know i can heat, bend weld but thats a lot of work

I built my 12 inch round for my rhino backhoe by taking a 12 inch wide flat stock , tacking it at both sides plates of the bucket. Then I used my front loader for pressure to push around sides moving a inch them tacking it in position then changing the backhoe buckets position then pushing again with the front loader in proper position then tacking again , repeating procedure till done , did use heat and sledge occasionally did a pretty good job and I used 1/4 inch Steele plate.

 

[ray66v]

I have always used 3/16 steel for most of the bottom, and mostly use the heat from the welder, to allow me to bend it, as I weld it.

You can use the opposite end of the plate as a lever, applying pressure to it with a long pipe wrench, a small chain come along, or pipe clamps, to close the gap as you go.

I add a thicker piece of steel, where the bottom meets the cutting edge.

Another twist, is to add a taper to the bucket making the back part narrower than the front, and you can also make the top narrower than the bottom. This allows the bucket to be easier to maneuver in the trench, and allows you to make turns, without knocking the sides down.

I made this bucket with both tapers.

 

[kateean2]

The angular design is probably easier to construct in a home workshop than the rounded type, would be one reason if not the main reason for them being popular on HM machines.