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The Bridgeport

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  • The Bridgeport

    OK, forgive my ignorance. Why is a Bridgeport (or a clone I assume) the mill that all else gets compaired to?

    I've never run a BP, I have a small knee mill that has a head like a mill/drill. This is a Grizzly, but they no longer carry this model I don't believe.

    But what does a BP have that sets it above all else? What features does it have that puts it in a class by itself?

    I will be relocating in a year or so, and don't believe I'll haul my mill, I think I'll sell it, but then I'll be looking for a replacement.

  • #2
    Three reasons I want one...#1 is the power down feed on the quill.
    I also like the fact that the head swivels in two directions.
    One shot lube.
    If you have the mill I'm thinking of, the head does swivel in one direction and it may have one shot lube?
    The BP (and clones) also have slower speeds which I'd love for boring.
    I have tools I don't even know I own...


    • #3
      They invented that particular mill design years and years ago, made a zillion of 'em, and a huge generation of machinists grew up on them, especially doing wartime production during WWII. The design has withstood the test of time, and works well. There are a zillion accessories that fit off the shelf and more being made all the time, which guarantees virtual immortality for this thing.

      With that said, there are many other similar mills available that people will tell you work just as well or sometimes better. The CNC world has come to view knee mills as "entry level" versus bed mills (quite the opposite of how the HSM world sees that issue!). There are many reasons, but a big one is the CNCers want all the Z motion on one axis, rather than separate knee and quill.


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      • #4
        Bridgeport was the first, as Bob says. They invented it. For a long time it was "the" vertical milling machine. I think it was originally designed for pattern makers, but not long after its introduction its use was expanded to metalworking.

        The American Precision Museum in Windsor, VT, has Bridgeport serial #2 or something like that.
        Try to make a living, not a killing. -- Utah Phillips
        Don't believe everything you know. -- Bumper sticker
        Everybody is ignorant, only on different subjects. -- Will Rogers
        There are lots of people who mistake their imagination for their memory. - Josh Billings
        Law of Logical Argument - Anything is possible if you don't know what you are talking about.
        Don't own anything you have to feed or paint. - Hood River Blackie


        • #5
          I think the Bridgeport Series 1 mill just became the industry standard in small knee mills because it did some things better than some of its predecessors. Bridgeport started out by making milling heads only for retrofit on other milling machines. It is certainly not the be-all end-all (it's really pretty light weight by industry standards) , but it is much copied because it was well done. I think the Harley-Davidson factor is a piece of the puzzle as well. They are one of the last American made machine tool products (although they are now produced by Hardinge).

 has a lot of historical information including some comments on what they did right in terms of versatility...something that was lacking in some other early mill designs.

          Paul Carpenter
          Mapleton, IL


          • #6
            Thanks. Would I be correct in assuming then that most all the "clones" that are available from many manufacturers are similar in design and function? I see where MSC, Enco, Jet, etc. all have what appears to be a BP in disquise.


            • #7

              Precision Machine ive heard em called by old guys. (No Offence meant to us old er guys) I machined a 24 inch by 10 inch wide fixture vee grooves and clearance slots for a customer last year. I dont profess to knowing anything. When it was delivered to there shop much to my dismay the fixture went to incoming inspection and a cmm (coordinate measuring machine) Much to my surprise the inspector told me it was well within a .001 end to end. HM this is on a old ,machine serial number 370 (gotta be old) Step pulley head circa?1960. The y was worn out so ground a file and used two dowel pins and a micrometer and a old buddy Cannibal Dave filed it for a few hours. (i was amazed at his endurance he is 69 years old) When dave finished i had a few more inches travel in the y axis and it worked so smooth and nice. Yeah i think they will last forever. I dont have the one shot lube system but i have a high pressure oil gun that works great.


              • #8
                There is another factor, when I say like or similar to a BP everyone knows what I'm talking about, same with a South Bend lathe. It is a point of reference that almost everone is familiar with.
                Herm Williams


                • #9
                  Bridgeport harnessed and rode a few important milling innovations over most of prior milling machine technology. They weren't the first, but they pretty much outran everyone else, for a long while. One technology is the quill, which makes it easy to perform operations on holes, which turns out to be a large fraction of toolroom milling machine work. Another technology is the end mill, as compared to a disk milling cutter on an arbor. The end mill became hugely popular compared to the latter becasue it was much cheaper and easier to use (and especially change). Another technology is the change to making parts from wrought bar stock as opposed to castings. The material was easier to hold and machine, so a lighter mill could succeed. Finally, a Bridgeport was simpler, cheaper, more nimble, and easier to run than most preceding mills, especially common horizontals.


                  • #10
                    Originally posted by Herm Williams
                    There is another factor, when I say like or similar to a BP everyone knows what I'm talking about, same with a South Bend lathe. It is a point of reference that almost everone is familiar with.
                    That's exactly it, IMHO. If you search ebay for Bridgeport, you'll get hits for any number of accessories for a "knee" type mill design. I'd bet that most new "Bridgeport-type" or knee mills sold today are definitely not actual Bridgeports, but clones. Being both made in the US and carrying the Bridgeport name makes real Bridgeports sell for a lot more.

                    And of couse, having said all that, I have to admit that when I got my mill, I sought out Bridgeport because it was what (little) I knew. There used to be one where I once worked, and I knew some about what it was and what it could do.

                    There must be a lot of people out there who started as I did, with a Bridgeport series I and a South Bend 9 lathe. If and when I upgrade to better machines, I'll probably go with carefully selected new import machines. Now that I've had machines, I know what features I like and which I'd like to have in the future.

                    As for the power downfeed on the quill - I suppose it's a neat feature, but I don't really use it in "power" mode. I use the quill "wheel crank" to get a nice slow and accurate downfeed. OTOH, power feed on the X, Y, and knee are very desirable features.



                    • #11
                      BP was a staple of industry long before it added power downfeed and one-shot lube. It sat in a particular sweet spot of performance and price. While other similar machines came along soon after, they really had no edge on BP, so the typical shop stuck with BP, to such a degree that nobody except serious machine geeks has ever seen anything else. I've often heard people use "Bridgeport" as a synonym for "mill," as they might use "South Bend" as a synonym for "lathe", though with far more justification in the BP case.

                      There was never any other vertical mill which hit the equivalent lower-level spot which South Bend hit in lathes; BP was stretched to cover that market as well. If BP had been a bit overpriced, then maybe something like Mill-rite or Rockwell could have snuck in there; but that's not how it happened. And nowadays when stocking a shop with tools, the dominance continues - I must see hundreds of used Bridgeports for every used Rockwell or Mill-rite I stumble across.

                      A cheapo shop, like maybe an industrial maintenance shop, would have an SB and a BP. A fancier shop for higher-precision work would have a Monarch or Hardinge and a BP. A shop for heavier work would have a Leblond and a BP. A shop for much heavier work would need something bigger than a BP - perhaps it would just keep its old horizontals. The BP is not a heavy duty machine, and was never intended to be (although it's often abused as if it is). It was intended to be flexible (with loads of head angles and positions) and easy to use - just clamp the part and the table and go; no assembly of the table like, say, a Deckel.

                      The BP was just the perfect machine for so much general shop work that it was crazy for just about any shop to not have one. A combination of thoughtful design, excellent build quality, ruggedness, ease of use, and relatively reasonable price turned out to be unbeatable. The variety of heads for the same basic machine was a big selling point, but I doubt that it was actually significant, as I just about never see the C, R, T, or E heads, just the M and J.

                      In fact we now know that they were overbuilt for their function. I have one that's over a half-century old, and although there's some wear it still needs no work that I consider important enough to justify the effort and downtime of a rebuild. That longevity, of course, did the original buyer no good - he paid for durability which he didn't use. Hence my claim that it was overbuilt. Though many of them are simply clapped-out by now, as they saw very heavy use. That's the price paid for being so useful.


                      • #12
                        I think there is another factor in the dominance of the BP. I've used some of the competetors mills. And frankly they are just clumsier to run. Tree had that quick release collet system that would be a PITA when the whole thing started to wear out. Gortons and Trees both had much harder quill depth stop adjustment. The Kearney& Trekers are whole different ball game as they lacked the tilting heads in the Rotary Head models but before CNC they only way to do arc or radius works was on them or a rotary table on a BP. But BPs do have their faults. The R8 collet system for one. The wear prone VariSpeed drive system. With the cost of VFDs today way anyone still sells the mechnical system is beyond me. Plus some of the atachments seem to trying to stretch the design farther than it shoud go IMO. The shaper head looks neat but I question just how much it beats on the machine. The Knee Screw, Nut and Bearing are taking the whole load of the cutting action. Granted it should not be large cutters but then I have seen people swinging 5 or 6 inch flycutter set-ups in a BP. The Horizontal Head Attachements are pretty much useless without the riser block for the turret.
                        I think there was another factor at work to beyond price. "We're Americans damn it and we ain't using any of that fancy foreign machinery like Deckels."
                        Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.