Mike and Brian, I hadthought the Witworth was mostly associated with motorcycles, That is where I learned to hate them. I about went nuts with not only the TPI, but also with the head sizes on the bolts. The one that comes to mind is the head bolts on a 350 BSAsingle. Later on, I drove a MG-GTcoupe and Ithink that there were a not of 5/16 and 7/16 screws where previous owners had bumped the size up allow for UNC threads. It's funny, we were just talking about this at the field this morning. Some of the equpment I worked on when I was on my apprenticeship back in the early 60's was manufactured in Germany and was orginally all metric, It was common practice to "Americanize" any thing that gave us trouble bolting it back together. It was a huge machine, and it was at least 10 to 15 years old and it saw maintance on about a weekly basis. Working on it required a set of metric as well a SAE wrenches. That was the only metric machine in the whole shop.

Some of the other machines I repaired were so old that you would run across a non standard screw now and then, Some of the machines were bolted together wiht Square head cap screws. Those you had to watch out for.

Don