There’s always new and exciting equipment to talk about at Fronhofer Tool. This quarter we’re highlighting our Dainichi (live tooled) lathe. Many of you understand the concept and the difference between milling and lathe work. On a milling machine, the tool spins and the work stays stationary. In a lathe, the work turns and the tool stays stationary. Both work using the same principles of surface feet per minute to optimize efficiency. Recently tool manufactures have come up with a new concept to marry the best of both worlds in one machine. While these machines are still very expensive the price, like in all commodities is coming down as manufactures find better and more efficient ways to build these machines.

The new, live-tooled machines have small drive shafts in the tool turret. With convenient tool holders that accept these drive shafts, the tools are able to spin as if they were part of a mill operation. These holders accept virtually every tool that a milling machine would use. When these tools are spinning, the chuck (which normally spins all the time) turns into an axis of its own. It only rotates now to allow the machine to do milling work the way the table of your milling machine would react in a milling operation. It is slightly more complicated than that because as it turns the turret has to move in and out so straight lines can still be milled. However, with the sophisticated software and programming systems that machine shops use today, this really isn’t any problem.

What makes these machines so attractive, is jobs that used to require multiple setups can now be done in one. And as I’ve stated in previous articles, setups cost lots of time, money and accuracy. Although the initial cost of the machine may seem high, we quickly regain that investment through higher accuracy with cycle time reduction.

When a machinist needs to drill a hole in a precise location he should make a mark that the drill will follow without “walking”. The spot drill’s angle allows the drill to start in location and track square through the part. Center drills have a steeper angle than most drills; this does not nest the drill tip, as does the spot drill.

A lot of force and heat is generated at the tip of any drill. Center drills have a long weak tip that must travel much further into the work to produce the same diameter on the surface. Spot drills are tougher, can be pushed harder, and do not need to drill as deep. Their shallow angles tend to leave burr free edges making them excellent for pre-chamfering, especially reamed and tapped holes.

Select the proper tool, use center drills for center work and spot drills on surfaces that have to be drilled again.