Bridge port cnc mill
They can’t imagine spending time to program a CNC machine to do that sort of work. Or, “I just need to quickly mill a little off the side.”įor most machinists, walking up to a Bridgeport Mill to drill a hole or trim a little off a part is quick and easy. “I just need a couple holes in that part.” If you drop into a vocational program at a school, you’re almost always going to see at least one Bridgeport (yup, my son ran one in school, LOL) so the new generation that’s coming up through the ranks are automatically read to go on Bridgeports for the foreseeable future. They also have their uses and they have served well over the years. They realize these mills have their limits, but that’s not the point. In general, when a machinist hears “Bridgeport Mill” they think good things. Here’s why: Universal Brand and FamiliarityĪlmost any machinist can run a Bridgeport Mill. They’re still quite popular, and many machinists have a hard time imaging not having a Bridgeport Mill sitting ready to go in some corner of the shop. Do you still use your Bridgeport Mill? What for? I did a bunch of poking around and I often ask shops I visit about the old Bridgeports I see sitting in the toolroom. Why Are Knee Mills and Bridgeport Mills Still Popular? Even so, back in the days before VMC’s took over and made them dinosaurs, there were many CNC Knee Mills available from Bridgeport as well as companies like Tree.
#Bridge port cnc mill manual
The quill has limited range, and while automating its motion in CNC is the simplest and most common, the lack of travel can be annoying.Īll-in-all, if you plan to use a manual mill as a basis for a CNC Retrofit, a Bed Mill is likely to be a better candidate than a Knee Mill. Cranking the table up and down has the most range, but it is the slowest–that table is big and heavy. This is problematic because both are needed. Knee Mills have two methods of travel in Z: their quill and cranking the table up and down. There’s one other issue for CNC applications. Bridgeport Mills are not just Knee Mills, they are Turret Mills as well. When you consider that the need for the kinds of flexibility offered by the Bridgeport Mill doesn’t come along all that often, while Rigidity can affect almost every machining operation, you can see the writing on the wall.īTW, the ability to swivel and extend on a ram the milling head is the definition of a Turret Mill. The biggest downside is the lower rigidity of a knee mill versus a big bed mill such as is found on a modern CNC VMC. Machining long parts on a knee mill is done by standing the part vertically and attacking it to the side of the table.īut, like all things, there are downsides to this flexibility, especially where CNC is concerned.
Indicate from a known spot reachable by prior travels and keep going.
This diagram should help:Īnd for comparison, I’ve also shown a “Bed Mill”. Let’s start by describing exactly what a knee mill is.
Hardinge claims over 370,000 of these machines have been built over time, and I wonder if that even begins to include the many Asian clones and knock-offs that are available? What is a Knee Mill? And Knee Mill vs Bed Mill? I don’t know how many are still being sold at that price point given you can buy a decent clone for circa $5000. MSC will sell you a knee mill made by Hardinge-Bridgeport for the low price of just over $20,000. They’re still listed for sale on Hardinge’s web site alongside modern CNC VMC’s as the “Series 1”: Here’s a drawing from the original patent filed in 1939 and granted in 1942: What machinist has never heard of a Bridgeport Mill? They became famous as the standard for manual milling machines, and that fame continues to this day. The design was done in 1936 and the knee mills went on sale in 1938. Once upon a time in Bridgeport, Connecticut, there lived a man named Rudolph Bannow who conceived the now classic Bridgeport Mill. Bridgeport Mill: Past & Future for the Classic Knee Mill