Size
In a typical home-engineering workshop progression, you buy a bench vice, some hand tools, and possibly a bench grinder. After you buy a small pillar drill then comes a big leap — buying a centre lathe.
Along the way you acquire more small tooling, drills, turning tools, etc. You make many useful items and produce a fair bit of scrap.
But then you find that the lovely pieces you are turning out on your lathe require other features, especially holes more accurately positioned than you can mark out and drill on your pillar drill. As good as you have become with a file, that flat section needed on the shaft really needs to be machined. And how are you going to make a slot for that keyway?
Milling machine
Another even bigger leap is now required — a milling machine. With this, you will be able to accurately pitch out holes, machine flat, machine slots, machine angles, square-up edges, and maybe start that model steam loco you promised yourself.
This leap often seems to be very daunting and it actually may be, in part due to the different milling-machine types — all centre lathes are basically the same layout and just vary in size.
There are two main, basic millingmachine configurations, horizontal and vertical (referring to how the spindle of the machine is mounted), with a few that are both.
In this first article of our introduction to milling, we will look at the most useful type for the home workshop: the vertical milling machine. So, once you have made the case for buying a vertical milling machine, new or second hand, what you should be looking for?
Whatever you plan to make, don’t forget that when friends find out about your purchase, they will always have car and boat parts for repair or modification. So, unless you are going to be a clockmaker, you may want a machine big enough to cope with some of the typical sizes of car or boat parts. However, no matter what size machine you buy, you can be sure that the first jobs you are asked to do will be too big for your new purchase.
Unless you have lots of space and money, though, don’t get carried away with size. When you have a typically small job to do, a very large machine can be very ungainly to use. The working footprint of a milling machine is also generally larger than its base size, so don’t forget that when you plan the machine spot in the workshop, you need to allow space for table movements and the possibility of a workpiece overhanging the table.
Power
Do you have single- or three-phase power available? Single phase makes things easier as you can plug in and go. But check the current required, as a 10A supply may not be suitable and you may need to upgrade the wiring. If you have three phase, this will open up your options with the possibility of using ex-industrial equipment.
You get better starting torque from three phase than from single phase and three phase is much easier to run in reverse. This is very useful in some processes, for example, reversing the spindle to wind out a tap if you have been tapping under power.
Converting ex-industrial equipment to single-phase motors is not always an option due to space limitations, as singlephase motors are usually larger than their three-phase equivalents. But the use of a single-to-three-phase converter may be an option, as most smaller machines tend to be single phase. If you buy new, you may be able to choose single or three phase.
New or second hand?
Is the well-used Bridgeport mill at that price as good as a new, imported machine with a warranty?
There are some very good second-hand machines out there, but worn out is worn out, no matter what the name on the side. The latest machines coming out of Asia are now well worth considering. You may also be able also to do a deal on a starting tooling package with your new machine.
When looking at a machine, be it new or second hand, find yourself a friendly toolmaker, miller, or model engineer to help you assess the suitability of your prospective purchase.
When you have a typically small job to do, a very large machine can be very ungainly to use