Hand adjustable reaming

If you wish to contact me with a valid e-mail address, I'll send you a picture of one. They have a threaded body with screw on end pieces to lock the blades in place The blades ride in tapered grooves and are themselves tapered so the diameter of the reamer can be changed by re-positioning the blades. They are turned by hand with a tap wrench. Make gentle cuts. They don't like aggressive cuts.

Ted

I know of no such book, there's some description of adjustable reamers in some of the textbooks, but they really don't tell you how to use one, just not to turn a reamer backwards in the hole. A lot of the technique you have to pick up by using them, just like any other hand tool.

There's two types that are commonly available, one is constructed rather like a solid reamer except the flutes are cut through to a center hole and has a threaded tapered plug for expansion, the other has a number of loose blades that slide in tapered grooves, two cylindrical nuts at the ends of the blades provide both adjustment and retention. Neither is a precision tool, they will not provide a really good surface finish like a solid reamer should and the resulting hole will usually not be parallel from end to end. You can stone the blades on the separate blade sort to all cut at the same time, most of the cheap ones only have 3 blades that cut simultaneously out of 6. That improves the hole finish and with some judicious stone work, you can get a pretty parallel hole, but only for one set size. Stoning is not for the tyro, either. You've got to watch your cut, about .0005" at a time is the max, so if you've got to remove more than that, it gets a little tedious to make the run through the hole, remove the reamer, brush off the chips, turn the top nut, turn the bottom nut, relube and do it again. These are not power-drive tools, either.

What they are good for is enlarging holes for studs and fasteners that are just a little larger than standard sizes or where you want a really close fit on a bolt or stud. They get a fair amount of use around my place.

Stan

What he said. Also, what they really excel at is doing the last fitting of a shaft into a bronze or oilite bearing. You can get a really top-notch fit this way, and I don't know of any other.

Grant

Stan Schaefer wrote:

Machine Tool Operation (Vol II) by Burghardt and Moltrecht (Vol I) both have a few pages on reamers. Burghardt may be out of print but the Moltrecht books are still available.

Thanks Mike for your references and to all those that responded

John.