His handlebars had started slipping. Not badly, he said, just a little when you shoved hard on them. I warned him not to use hisadjustable wrench on the tightening nuts. It was likely to damage the chrome and start small rust spots. He agreed to use my metricsockets and box-ends.When he brought his motorcycle over I got my wrenches out but then noticed that no amount of tightening would stop the slippage,because the ends of the collars were pinched shut."You’re going to have to shim those out," I said."What’s shim?""It’s a thin, flat strip of metal. You just slip it around the handlebar under the collar there and it will open up the collar to where youcan tighten it again. You use shims like that to make adjustments in all kinds of machines.""Oh," he said. He was getting interested. "Good. Where do you buy them?""I’ve got some right here," I said gleefully, holding up a can of beer in my hand.He didn’t understand for a moment. Then he said, "What, the can?""Sure," I said, "best shim stock in the world."I thought this was pretty clever myself. Save him a trip to God knows where to get shim stock. Save him time. Save him money.But to my surprise he didn’t see the cleverness of this at all. In fact he got noticeably haughty about the whole thing. Pretty soon hewas dodging and filling with all kinds of excuses and, before I realized what his real attitude was, we had decided not to fix thehandlebars after all.As far as I know those handlebars are still loose. And I believe now that he was actually offended at the time. I had had the nerve topropose repair of his new eighteen-hundred dollar BMW, the pride of a half-century of German mechanical finesse, with a piece of oldbeer can!Ach, du lieber!