It often happens, when there is a very important piece of work-to be gotten out, the reamer of the size you want is broken, lost or under size. In a case of this sort the writer worked out the following reamer of simple construction, which may be useful to others: Use a piece of drill rod the size you are to ream the hole, place the desired length in a speed lathe, and crown the end. Then grind one side at an angle of about 10 deg. Care should be taken not to grind below the center, as the reamer will not follow true with the hole if the cutting edge is below center.

Fig. 111 - Emergency reamer.