Sunday, August 02, 2009

Cut Pipes to Size

Today I cut the pipes that attach the legs to size.

The outer pipe is a 20" electrical pipe. As it is, it certainly sticks out way too far.

Occasionally I'm asked how long the pipe should be cut. This is difficult to answer with precision, because the distance can vary a little bit from droid to droid, due to materials used (e.g. flange width, disc width) and how far the pipe is screwed into the flange. Here's how I approached the task.

First, I aligned the outer edge of the wooden disc so that I was happy with its distance from the skins. The blueprints specify this should be a minimum of 1/2", although I have purposely decided to make it 3/8", for aesthetic purposes.

On the other side, I make a mark where the skins line up with the pipe.

Now, I need to decide how much of the pipe needs to go.

Well, for one thing I need to know the width of the other pipe's flange/pipe/disc assembly. The wooden disc is 3/4" wide. I measured the flange to be 9/16". So the disc and flange together are 1-5/16" wide. If I were to cut off 1-5/16" from the point I marked above, this would have the outer edge of the disc flush against the skins, which I don't want. I want an additional 3/8" clearance, so, I must cut 3/8" less material from the pipe. This comes out to 15/16" that should be cut from the mark I made. So I made an additional mark on the pipe at this point, marked it with a "cut here" arrow, and prepared to cut.

Rather than hack through steel with a hacksaw, I pulled out the trusty jigsaw I've been borrowing (since, oh, 2005) from my friend Kelvin, and fitted it with the vicious Progressor blade.

That blade amazes me, it cut right through it!

I want the other pipe to be the exact same length, so I measured, marked, and cut it as well.

I like!

By the way, yesterday I mentioned that I'm using electrical pipe for the outer pipe, and gas pipe for the inner pipe. Here's a cross-sectional look at the fit of these two, using the scraps.

Just for fun, I bolted the legs on to see how they look. So far, so good.

Still lots to do before I have this guy on three legs, but it's a start.

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