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Thread: OK, some Bridgeport questions
02-18-2012, 11:11 AM #1
OK, some Bridgeport questions
There are a couple of current threads about Bridgeport's accuracy, stiffness and so on. I have a couple questions about them but didn't want to hijack another thread. So:
If one needs to do work that would be otherwise done on a Bridgeport, on what machine should it be done? By that I mean making one or two parts in a shop that can't justify the cost or space of anything bigger, stronger, faster, more powerful . . .
It seems that a knee mill is a good machine for doing a lot of things because of its versatility. Is there something better for that kind of work than a knee mill, or is it just Bridgeport that so many are dumping on?
Does the Series 2 Bridgeport have the same limitations as a Series 1?
As background, my business is mostly designing and making one-off items - assembly machines, test equipment, prototypes, replacement parts and modifications to existing machinery. Most of what I make I also have designed, so I design with the limitations of my equipment in mind, although a few times I have sent work out to a CNC shop. Most of what I make is not very price-sensitive. Being a one-man operation, the majority of my time is not running machines; it's dealing with customers, designing, bookkeeping and working with other tools in the shop. My knee mill isn't a Bridgeport, it's a PAL, made in England and, I think, somewhat stiffer than a Bridgeport Series 1, although it's about the same size.
Edit: The last job I sent out to a CNC shop was paid for directly by my customer who is (was?) a friend of the shop's owner. For the price I would have gladly spent two days on the PAL turning cranks on multiple setups.
02-18-2012, 11:39 AM #2
In one of the other threads, I was poking fun at Bridgeports, but considering what they are & what they're capable of, I like them just fine. They have a relatively small footprint, they can be manipulated to do just about anything you can think of, and they aren't that expensive (comparatively speaking). There are 5 of them in the toolroom that I work in, and I think that they are indispensable. The downside of them is their rigidity, but that can be compensated for easily enough. All it takes is paying attention. Personally, I've run an Index that was, to me, better built than a BP, but it was still a knee mill. In my opinion, a shop like you describe can utilize BP's or the like just as well as any other knee mill.
02-18-2012, 11:54 AM #3
My only gripe about Bridgeports is that while sold in the hundreds of thousands, so they are not rare, the lore keeps the price well above able equivalents and their little accessories must be made of gold.
Take the right angle attachment and tail stock. There are people who wax poetic about them but in truth, they are no more useful than the frequency that you see them installed, not 1 in 1,000. I can hear the howl already, "hey, I use mine all the time as a little cut-off saw....." I rest my case.
I paid much less than the going price of a BP rt. angle attachment for a 1,500# horizontal hand mill of the #1 US Machine Tools variety and it's dramatically stiffer.
I've seen asking prices for more than I paid for my K & T 2H universal. You want solid?
The slotter can be useful, especially if your BP has the double ended ram and you can leave it mounted but the price asked would buy a real slotter, like a 20 to 32" shaper or an orphaned P & W 6" slotter, well, those have gone up, they truly have become rare.
Not even going to address the 3D head, those guys are nuts..... not the sellers, the guys that shell out the bucks.
There is just not enough bang for the buck in a BP for me to tumble out of genuflecting reverance. But if you need someone to just get one out of your way, give me a call, anytime.....
02-18-2012, 03:32 PM #4
My standard comment on such threads is to consider a CNC open bed mill.
Good CNC (hurco, centroid, I imagine others) combined with a much stiffer machine and open access. You can do one-off work quickly with them. The ones you might want have hand wheels, modes that behave like a single axis power feed, and so on.
The reason I harp on this is that I don't think people have seen these machines, and think "that will be much harder than a knee mill" - when that's not necessarily true at all.
Are you really going to rotate the turret so the head is over the floor and use it a like a radial arm drill? Tilt the head out of square rather than using a sign bar? Or turning the part on its side and using CNC? Will you buy and USE the slotter attachment?
If so, by all means buy a knee mill.
If not, there are other things to consider.
(Yes, I know, most of the lower cost machines one sees are knee mills - they must be relatively cheap to manufacture for some reason. Sigh.)
02-18-2012, 05:11 PM #5
If you are doing modifications, repairs, its a very nice, versatile, reasonable-cost machine.
For constantly cranking handles I would probably be looking elsewhere.
02-18-2012, 05:32 PM #6
So how is the Series 2 BP for stiffness? They look massive compared to a series 1, but then you'd expect a lot more out of one.
Not that I'm in the market for anything. I've had my PAL for close to twenty years, and regarded it at the time as a huge step up from the Chinese mill-drill that I had been considering. That was when I was still a full time computer programmer and the mill was just going to be a hobby toy. Little did I know . . . I would love to have an open bed CNC, but as close as I am to retiring that isn't going to happen unless I hit the lottery. But I understand you have to buy a ticket for that to happen.
BTW, a great collection of smilies here!
02-18-2012, 06:36 PM #7
One crude proxy is weight.
A series I apparently weighs about 2,000# depending on which ref you find.
A series II (which Hardinge no longer lists?!?) apparently weighs between 4500 and 5200#.
So one imagines that a series 2 would be more robust. (But it's the wrong structure to go one on one with a bed mill or horizontal.)
For perspective, MSC lists knee mills from about 2000# to about 3000#.
And some manual open bed mills runnning from 6600 to 7250.
Kent USA lists a knee mill (KTM-5AVKF) with a net weight of 6000#.
(That's all just web surfing, I don't have use experience with any of these.)
02-18-2012, 09:16 PM #8
Hi Jim, like Bryan mentioned, a good open bed mill will get you a lot more. I'm currently upgrading from a Bridgeport style machine to a Hurco bed mill CNC. This is a type I have run in the past and can say, it's dead easy to learn, for conversational programming. They do cost some money up front, I was able to get this one for $2,250. I will easily put another $2,250 to power it up and tool it, but then I will be set for my needs. You might have heard the saying, spend the money and cry once.
02-19-2012, 02:01 AM #9
I do 99.9% aluminum and a BP does a wonderful job. If I were messing with large steel parts it might be another story. I know a guy who has a couple Abene mills with the slanted ram. Never used one, but the things look way rigid and moving the ram in closes up the work envelope and would increase rigidity. I'd love to own one in decent shape but I think they're rare as hens teeth. There are quite a few other obscure mills to look at, but BPs seem most common around here. I hardly ever see or hear of a K&T or other "heavy" mill for sale.
02-19-2012, 03:22 AM #10
What model is that Hurco? Spindle taper & table size? I don't think I've seen one like that before. When people mention "bed mill", I think of the Okuma's that I've been around. Good conversational machines, just big.
02-19-2012, 03:46 AM #11
BP/turret mill bashing seems to be a popular sport with some folks. Your operation as a one man shop from floor sweeper to designer to CEO with only a fraction of time for cranking handles might be challenging.
No BP booster or basher here, in the right hands on appropriate workpieces in one-off shops they have a place. They're inexpensive and versatile.
The real question is would another approach be more productive (lower overall cost, more work output) for you than using a BP or similar for your work. Included in those costs are everything: your time to research a better approach; money spent to purchase, install, power, tool; time to learn the new whatever it might be; etc.
Would it make you more competitive or profitable? Only you have a view through that window.
02-19-2012, 06:03 AM #12
I think of my series 1 B.P. as an all around tool, it is kinda my swiss army knife of the shop. It is great for just about most one off things, i.e. repairs, prototypes and the like. As far as production goes, as others have said there is way too much hand turning and tool changing is a PIA if you just have the standard R8 set up. I would love a cnc but right now I am limited by $$$ and space. Scratch that if I found one cheap enough I would find the room, who needs a coffee table anyway ?
02-19-2012, 10:51 AM #13
The model is a Hawk 40 with the Ultimax 4 dual screen. It has a CAT 40 spindle.
The table is 13" x 58", but it has an aluminum waster plate on it 2"x21"x43"
02-19-2012, 11:37 AM #14
67Cuda, isnt $2250 a rather ridiculously great deal for that machine, as in, one would have a better chance buying a lottery ticket?
I ask simply bc I have seen quite a few of those for sale, but theyre always in the $12k+ range. Admittedly, I never pay attention to what they sell for, but if theyre that cheap regularly I would love to pick one up once I clear a few things out.
02-19-2012, 01:29 PM #15
If I had a crystal ball. I could have had this machine for $600.00. The next highest bid was $550.00. I bid what I could afford, which was a great price.
02-19-2012, 02:40 PM #16
Take good care of our tax dollars there.
02-19-2012, 03:13 PM #17
Last year a buddy who works in maintenance at the Federal Reserve Bank told me that they had "an old lathe" to get rid of for the effort of hauling it out. It turned out to be a Harrison M300 with all the tools and accessories except DRO. It was from the mid-80s and probably didn't have fifty hours on it. It didn't have a nick, ding or scratch anywhere, and some of the accessories still had the cosmoline on them. Back then they had a guy in the department who wanted it, so they bought it. He left a short time later and it had been sitting under a custom vinyl cover ever since, depreciated to zero and taking up space. The next morning I took a trailer and a couple of buddies over and hauled it away. It cost me lunch for three, and $40 to get the cabinet lock picked and a key made.
02-26-2012, 06:22 AM #18
A Harrison M300 for 3 lunches and 40 Bucks?
Some people have all the luck!
02-26-2012, 06:51 AM #19
I got this for $400. Better than a Bridgeport. Still want a Bridgeport (or comparable).
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02-26-2012, 07:19 AM #20