Friday, April 9, 2010

Bender's foundations - feet, legs, base - part 2

Once the pipe for the legs was cut and curved, I welded the cuts and welded the legs to the foot cups on the base. I didn't think to photograph it, but the next step was marking the top of the legs to be level with the base, and at the appropriate height. To do this marking, I used the trick used by cabinet makers, (and dressmakers) of using a block of "stuff" with a pointer and marker contacting the legs, and then rotated everything around to completely mark the legs. In this case the block of "stuff" was the body previously made, packed to height with some pieces of timber.

Once the legs were trimmed to the correct height and level, I tested the fit with a plywood disk I used to test the body of roundness.

A photo of the "high tech" tool stand I used to keep the tools off the welding table whilst I was working. The three grinders proved quite useful since the 9" (230mm) grinder was used with the 2.2mm wheel, the 4.5" (115mm) with a standard grinding wheel, and the 5" (125mm) with the 1mm cutting disks. Yes, I used the faceshield and earmuffs... I value my eyesight and hearing, and see too many of my friends from industrial backgrounds with hearing loss from exposure to these kind of jobs.

The leg joint plate was made by placing an appropriate strip of sheet on top of the crotch plate and drilling all four clearance holes at once. I then marked through the curved (elliptical) ends of the legs, and split the strip with two tabs - one on each leg, both pointing towards the middle of the crotch plate. I then welded captive nuts, and bolts in the joint plates so each leg has one bolt, and one nut for securing it.

The welds were ground back and touched up prior to painting, but the above photo shows the captive bolt on the left, with a nut spun on, and another bolt spun into the captive nut on the right.
I choose a single bolt for each leg to make alignment during assembly easier, but I wanted the extra strength of two bolts, hence the second bolt added into the captive nut.

As always, I like to stack the pieces together to see how my progress is going. This what Bender looked like at the end of the day making the legs. It's obvious I had been picking at all parts of Bender instead of completing one part, and then another.
Until the next installment...

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