Wednesday, December 22, 2010

Started Working on Foot Hoses

Today I worked on the hoses that run between the battery boxes and foot shells.

I'm using 3/8"-diameter brass braided hose that I picked up at Lowe's. Each hose is 20" long. The blueprints call for the hose segment to be between 11.5" and 12.5", so it needs to be cut down.

The first step is to wrap the hose with tape, to help prevent the ends from fraying when they are cut. The brass fibers are sharp too.

Next, I used ye olde tin snips to cut the end off. I think the last time I used these was when I was working on the hoses for droid #1.

Although the hose is spec'd to be between 11.5" and 12.5", I measured off 14.5" and wrapped masking tape around the other side to be cut. The extra length accounts for the the fact that the knurled cable fittings will cover a couple of inches of the hose.

Then, I did something different from droid #1. I pulled the inner tubing out of the braided hose. I did this because it is very difficult to jam the hose into the knurled cable fittings. I replaced the tubing with a thinner one, as I'll show momentarily. I had actually tried jamming everything into one of the fittings at first, and I succeeded, but I decided this is not the way I want to go this time.

I purchased some vinyl tubing from Home Depot. The dimensions are 3/8" outer diameter x 1/4" inner diameter x 10'. I'll use this inside the braided hose instead. It's just a little thinner than the braided hose, but enough so that the knurled cable fittings can fit over the hose. The tubing is required to give the hose inner support. I plan to do as Mike Senna did, and use an expander to force the tube up against the braided hose to prevent the tubing and knurled cable fittings from sliding about.

I measured and cut the tubing to length, and threaded it into the braided hose.

Finally, I slid the knurled cable fittings on. Unlike the fitting on droid #1, these did not put up much of a fight.

Three of the four hoses are done. I want to redo the first one. I made enough of a mess of it when I was jamming it into the knurled cable fittings with the original tubing inside, that I'll pick up a replacement and then finish it up.

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