It was 1981 and I was setting up a Hardinge screw machine to turn some stainless steel fuel nozzles. The drawing called for a 1/4 in. (6 mm) blind hole nearly 2 in. (50 mm) in depth, with a +/-.0005 in. (.0012 mm) tolerance on the diameter. There was no chance of boring that deep, so I mounted a reamer into a Brookfield holder, floated it on centre, set the length and pushed cycle start. So far, so good.
Imagine my surprise when smoke came pouring out of the machine several minutes later, followed by an awful squealing as the reamer caught in the hole and spun. The workpiece was glowing orange like a tangerine by the time I hit the panic button. Apparently I’d drilled the starter hole a bit too small and the chips packed up in front of the reamer, causing it to seize. My boss was none too happy about the overnight delivery charge for new reamers, never mind the melted holder.
Despite this memorable experience, I’ve reamed thousands of holes since then, with satisfactory results. Much has changed over the years, however. Double-margin, coolant fed carbide drills offer such excellent hole quality that reaming is often unnecessary. And ultra-precise modular boring heads are a flexible option for the hole finishing needs of many job shops, eliminating the need for reamers of every size imaginable. Some might say these multi-fluted senior citizens are going the way of disco music and floppy disks
Far from it. Mike Smith, product manager for reaming, boring and tooling systems at Seco Tools Inc. says reaming is on the upswing. “We’ve seen double-digit growth in our reaming business over the last few years. Especially with larger work, where reamers are more cost effective than boring, it’s becoming increasingly prevalent.”
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