Friday, January 30, 2009

Weldors, machinists, and diversity - Part 2

One problem with horizontal band saws is the vise that holds pieces of metal that are being cut. It does not work well and it only holds pieces of metal that are at least 4 or 5 inches long. What do you do when you want to cut a piece that is only 2 or 3 inches long?

Machinists have three solutions. One is a kind of vise jaw extender. It sits inside the vise, but is longer and extends right out to where the saw cuts. The second is to use milling clamps, which all machinists with a mill have on hand. You have to drill and tap holes in the table of your saw and then you can bolt the clamps down to hold the metal you want to cut in place. The third is a pretty neat idea which involves putting a smaller vise inside the larger vise in such a way that the small vise sticks out to where the saw cuts. The photo shows the small vise holding an odd shaped aluminum casting. The jaw of the saw vise itself is on the Left side of the small vise.

The weldor's solution was to take a piece of angle, drill a couple of holes through the angle into the bandsaw base to make a small shelf that sticks out. Then he just used a Vice-Grip 'C' clamp to hold the small piece of metal. This probably took ten minutes.

The weldor may have thought of this solution because weldors have lots of these clamps in their shop - it is the most used method of holding pieces of metal together to be welded or ground. On the other hand, machinists do not have these kind of clamps in their shop. Even if they did I think they would be uncomfortable with the lack of elegance. These clamps do not hold as well as a machinists vise or milling clamps which are designed to exert thousands of pounds of force. Of course the Vice-Grips hold just fine for the bandsaw but I that might well be irrelevant to a machinist.

I was explaining this to my wise wife who told me there is a lot of research on how people form mental models, and how difficult it is to think 'outside the box.' It is one of the strengths of diversity she said.

Maybe I should join a jewelers forum, and an auto body forum, and a sheet metal forum, and ...

Thursday, January 29, 2009

Weldors and machinists - Part 1

I have mainly learned everything about metal work from trial and error, and the web. I am a member of a welding site, machining site, and horizontal band saw site. When you work in metal you need to cut it. For several years I used a chop saw which uses a big, thin, movable grinding wheel that grinds through the metal. Works just fine but it throws metal sparks, dust, and grit everywhere. Worse, it is not very precise -- especially when cutting angles that have to fit together.

A nicer way to cut metal is with a horizontal band saw which is quiet, much more accurate, and makes very little mess. They come in two flavors; small, really cheap, and poorly made or big and expensive. I did my research by lurking on the horizontal saw site which is devoted to methods to make poorly made saws work well and to improve them.

This is rambling background coming to the point that both welders and machinists use band saws. However their approaches to modifying and improving their band saws could not be more different.

Welders are to the point; make something that works and be done with it. It may be because many of the welding site members are professional weldors, and in many cases, time is money.
Oddly enough, their solutions, usually involve welding!

You might think this unremarkable, however machinists rarely think of welding anything! If they have to put two things together they mill them so they fit within a few thousandths of an inch, drill precise holes and tap them so they can be screwed or bolted together. Machining is a hobby for almost all the site members and many are retired. Designing, machining, and assembling an elegant modification that takes hours or even days strikes them as the natural way to do things.

That is why I was struck by a welder's elegant, simple solution to the problem of holding pieces of metal that are too small for the band saw vise. The machinists have at least three different solutions to this problem but none of them of come close to the weldor's solution. (to be continued)