Buying Vertical MillsAn Overview of Vertical Mills, Brands and Types by Speed Change Design
Vertical Mills and Bridgeport History
Cutting centers with a cutting tool oriented vertically are called vertical mills or vertical milling machines. Though standard vertical mills do not have PLCs (programmable logic controls), they can be workhorses and are popular in thousands of shops across the country for their ease of use, and relative low costs. Bridgeport Machine Company popularized small to mid-size vertical mills from 1938 until 2004. They made so many mills that its common to hear of any vertical mill machine being referred to just as a Bridgeport Many actual Bridgeports are still in use and sold on the used market.
Comparing Vertical Milling Machines
There are thousands of types of vertical mills available today from hundreds of machine tool builders. Popular vertical mill manufacturers of the Bridgeport-type vertical mill include Acra, Magna, Tree, Atrump, Sharp, Comet and many others. The machines vary greatly. Light duty machines are better for milling aluminum and soft materials, and the heavier machines can drill out titanium.
Type of Speed Changes for Vertical Mills
The type of material that you will be machining will determine the frequency and type of speed changes youll want on your vertical milling machine. There are three basic kinds of heads types to consider when shopping for a vertical mill.
- Belt or pulley change head The most inexpensive mills have belts and pulleys on them that you move to vary the speed. Its the most labor-intensive way to change speed, but if you dont vary the speed often, it will save a lot of money.
- Variable speed head This type of head has a simple handle that you spin to change speeds. It has high and low speeds and is very popular on many vertical milling machines.
- A/C Inverter head The most expensive and versatile milling head on non-CNC milling machines has a pedometer to allow for speed changes. This is the quickest of the three methods for changing speed. It also can use a 220V single-phase and 220V three-phase power.
Non-CNC vertical mills continue to be sold both as used and new because of their relative simplicity as compared to CNC Vertical Machining Centers. Vertical milling machines continue to be popular in schools, small shops and in larger production shops that use them for prototyping and small orders.