Not The Same Old  Grind    

     Some of us are old enough to remember the introduction of “throw away” carbide inserts. What an idea that was! Instead of removing a turning tool from the machine and regrinding it, the cutting point became a replaceable carbide insert.

     Although this concept has been around a long time we have now become a “throw away” world. This philosophy has extended to other types of tooling. We use a variety of disposable tooling in our machine tools. Drills, taps and end mills are now treated by machinists as throw-away items.

    The first company I worked at had a large tool room that built fixtures and provided a complete regrind facility to support the production machines. Today I’m in a smaller company, like many of yours’, not blessed with a tool room for regrinding used tools.

     In our facility we’ve got coffee cans – the disposal center for used tooling. The used tooling would sit in the can until we’d send some out to a regrinding service or simply purchase new tools.

    Recently we were fortunate to discover a universal tool-grinding fixture that enables simple regrinding of drills, taps, carbide bore bars and end mills. Together with our small surface grinding machine, this fixture is turning the coffee can of used tools into a tool supply source.

    A friend introduced us to this “handy-dandy” regrinding fixture called a PC-101 supplied by BMC Tool Company (www.bmctool.com) based in Quakertown, PA. This unit allows for the regrind of taps, drills, end mills and solid carbide boring bars.

     The challenge of regrinding tools has always been providing the correct tool angles and the accurate radial relief required to produce a good cutting point.

     This fixture is designed to accept a standard 5C collet, accepting a range of shanks to 1.125” diameter. We also purchased a cup and standard type diamond wheel. To complete our investment, a set of angle blocks were needed to define any “back” angle that may be required for regrinding small boring bars.

     The fixture has a small dividing head unit that provides simple 12 position spacing capability suitable for indexing in 30 degree increments. Any tool with 1, 2, 3, 4, 6 and 12-flute spacing can be accommodated. The ability to provide easy radial relief is a key advantage of using this fixture. To generate the relief you simply rotate the body of the fixture by hand.

     When using this grinding fixture you must be very careful as your hand can get pretty close to the grinding wheel during this manual relief operation.  Exercise caution and keep hands clear of the grinding wheel.

     This fixture provides us with the ability to regrind many of our previously thrown away tools. This is a definite saving as we can regrind tools several times. We accept that a reground tool will probably not last as long as a brand new tool, especially when regrinding titanium coated tools. On the other hand, we do not have to wait for the UPS truck when we are out of a specific tool. Just find a used tool and regrind it.

     To get the in-house capability for regrinding required an investment in two types of diamond wheel, a set of angle blocks and the purchase of this “handy-dandy” regrinding fixture. These purchases now provide the same kind of regrinding services only previously enjoyed by larger size companies.  Makes sense to me.