I'm a self employed machinist. Because of this I purchase more cutting tools than I make. One example of this concerns reamers. If a job requires several small reamed holes it's cheaper to spend 30 bucks on a reamer than it is to make a D shaped reamer. But yesterday I needed to make a piece of tooling where a reamed hole would be best. This tool is 1.75" long. The ID is .2720" (nominal) and 1.5" of the length of the OD is .290". The remainder of the OD is .500". The ID needed to be .2720 to .2723. The length and odd size of the ID, and the possibility that this tooling may need to be duplicated in the future, made a reamer the best choice for me. Since I needed the tooling right away I had to make my own. Using 5/16" W1 drill rod I found that the tool grew about .001" in diameter when hardened. My experience with O1 has always been the reverse, the drill rod shrank when hardened. I drilled the tool with a .265" drill and then turned it to .300", then reamed it with the just made reamer and finally finish turned it to .290". The "D" reamer cut the hole to .2722" and left a very nice finish. The reamer took less than 45 minutes total to make. I'm writing this so all you hobby type folks are reminded about "D" reamers and how easy they are to make. For deep holes they aren't as fast as regular reamers but for the home shop and people who like to make their own tools they are great. ERS
- posted
17 years ago