Next job is to make the top half of the front cross member to replace this
With a combination of a cheap spot drill that I broke a few teeth off,
a hammer and sharpened wood chisel, made for metal
,
a cut off wheel,
and a few choice words,
I got it off and give it a clean so I could get some measurements
Found a few mud boondies sitting in the bottom section, amongst other stuff
This section was going to be a bit more complicated than I initially thought. There were 90 degree bends turning into about 60 degree bends around a radiused corner and, together with bends being close together, pretty much made my little 600mm folder not much use here.
I pondered for ages on how to do this
I thought hammer forming over a wooden form probably wouldn’t work well due to the radiuses and shrinking required, and the fact that the metal is about 1.6mm thick - I didn’t have any 1.6mm in cold rolled, so I settled for some zincalume that I have, which is harder to bend again.
I decided to make some steel moulds and use the hydraulic press. I’d never done this before and thought I’d make the piece in three sections and then weld together.
Here’s the moulds with alignment holes
and a test piece in 1.2mm cold rolled (I didn’t have enough 1.6mm to waste on practicing) next to the original and the zincalume piece I’d use
The moulds took a while to make due to the radiuses and angles
Also, the cross member tapered down from 1/2” at the front to 3/8” at the back. When I cut the steel from some 3/8” C channel, I cut “around the corner”, if that makes sense, so I had 1/2” at one end and 3/8” at the other. I could then weld a plate to these and have the required angles. Pic’s might explain better
I then drilled locating holes in the two moulds and zinc sheet, including a 11/32” where one one of the 5/16” fixing bolts go, and two 9.5mm holes for extra locating pins (3/8”bolts).
Off to the press
Almost there
Done
It got up to about 7 tonnes on the gauge, the 1.2mm test piece was about 5 tonnes
You can see some puckering in the sheet where the metal had to shrink at the corner, which is a tad less than 90 degrees
Now I had to bash, or hammer form, the return after trimming closer to actual size. You can also see the curve in the mould that I used as a form
Had to be careful at this awkward bit as a bit of shrinking had to happen. I used the ball pein end mainly here.
Trimmed again and the end tab cut out
That’s as far as I’ve got to now. For the other bits, I might experiment with wood moulds.
Cheers,
John
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