OK, now the welding. But first, I wanted to take the opportunity to
adjust the straightness of the dozer section. It was bowed in about 1/2"
in the center.....not too important, but it is accessible now. The first
photo shows how I bend buckets. I use some chain, an I-beam and my
trusty HF 20T jack. (This cool air-over-hydraulic jack is another HF bargain:
about $60 and VERY useful.) This precedure is hard to do precisely, and
I tried it 4 times before I got it close enough. The steel is very springy
and it springs back to the original bend if you don't over-bend it. Sometimes
you can can hit key parts of what you are trying to bend with a sledge
hammer while under tension. Done correctly, this can cause the steel to
take the bend, without springing back as much. This trick has worked for
me before when straightening m/c frames.
In the 2nd photo, you see my clamping arrangement, with 2 squares
for plumb and true. I
cut 2 wood blocks to get the spacing correct. The
pin holes have been
cut to 1.5" to allow the DOM bushings to fit loosely.
Alignment is managed by running a chunk of DOM all the way through, and
a temp pin w/ the bushings in the other holes. I don't want to use the
25mm pins here because they are not tight enough for good alignment.
I was running out of DOM tubing, so I used a temp pin that was 1.000, filed
down to barely go inside the DOM.
Heat management is extremely important, if you don't want to ream out
the bushings after welding is done. I used to have to do that before I got
better at managing the inevitable distortion in the steel. Note that the
bushings are not welded in before the brackets.
Once I was happy with the positioning, I tack welded the brackets,
alternating from side-to-side quickly. A tack weld on only one side will pull
the bracket out of plumb as it cools. It helps to tack the top and bottom
first, and hold the bracket in place very firmly.
When all was tack welded and in the proper position, I completed the welds,
but still alternating from side-to-side. While the brackets were nice and hot,
I welded the bushings in, using my temporary pin for alignment. I have had
MUCH better success with alignment of welded-in bushings when the
surrounding metal is very hot. Less distortion that way.
The last photo shows the completed brackets and a chain lift slot and
reinforcement plate I added in the center because every bucket should
have one.