Tuesday, January 20, 2009

I made fire!

I feel like Tom Hanks shouting those words in "Castaway" every time I make a tool or a replacement part I might otherwise have had to buy.

Tonight, I used the mill to do its second-ever real, practical work, and its first-ever "project"... a replacement part for itself.

See, the sliding surfaces of a mill (called "ways") are made of dovetailed joints which are hand-scraped to be very flat and true and incidentally, to hold oil better.

It would be sub-optimal to allow chips to get into between those precision surfaces where they might wear them unduly. So to minimize the amount of crap that gets in there, the ways are provided with wipers which are just hunks of felt cut so as to fit into the dovetail spaces and retained with a few milled bits of aluminum. The felt soaks up oil and helps evenly distribute a film of oil (delivered from the oiler lines) over the ways to prevent rust. And of course, the felt keeps chips out of the way bearing surfaces.

When my mill was delivered, I noticed one of the wiper holders was broken. I asked the fellow I bought it from if he knew where I could get a replacement. He looked at me funny for a moment, smiled, and said, "but Bill... you own a mill now." Well. Changes in one's life frequently require changes in one's thinking.

So I made a mental note to make a new one as soon as I got the mill's tooling purchased. Well, I got the tooling last year and haven't done much with the mill since. I cut some u-shaped cutouts in a little heat sink a week ago, but that was a trivial thing and hardly counts. I could have done that with a rat-tail file, too.

But tonight I got a wild hair and dove into this mini-project. Guesstimating when I started, I think it took me two hours to make the thing. I could probably have tracked down a source to buy a factory replacement... but why? Maybe it would have been cheaper than my time, maybe not. But experience is tough to put a price on, and I'm still very much a noob when it comes to machining.

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