Bridgeport Terminology

[Leaky88]

Bridgeport Terminology
If for no other reason than reputation, I am pretty set on buying a Bridgeport Vertical Mill for my personal Home Shop use. Since I am certain it will be a USED one, I want it to be something current enough to get parts and tooling for.
R8 Taper and a DRO are pretty easy, what’s clouding the process is terms like:
J-Head, Series I, Series II
Should I be looking for specific serial numbers?
ANY assistance would be greatly appreciated.
Thanks.
Leaky

 

[zkling]

Bridgeport is like Kleenex, a name brand that is commonly used to describe a certain item. What you are looking for is a vertical knee mill.

As for specific bridgeports to look for. Get the largest, heaviest one you can find/fit/move. The smaller M heads are OK, but their step pulley and round ram are not as nice as the variable speed machines with dovetail rams (J heads, most common). Up to their heaviest Series II head machines.

 

[HammerMechanic]

For home use, unless you have a definite need for it, I would stay away from Series II.
Way overkill for most.

 

[kazlx]

You will see far more J-heads than anything else. Basic step pulley is an easy, reliable way to go.

Read: http://www.lathes.co.uk/bridgeport/

 

[404]

Variable speed has lots of parts that wear out. There are many old Heavy American Iron mills that will outshine a Bridgeport style if you have the room and can manage the weight. Van Norman, Kearney and Trecker,

Abene

There is a whole galaxy of beautiful accurate machines beyond the BP.

Take some time to read Practicalmachinist.com to get a feel of what is out there.

DO NOT get some horrid china mini mill for 1000 dollars. There is much more machine for the money available.

 

[A_Pmech]

Hi Leaky,

First of all, don't worry about whether the machine has a DRO or not. They're easy to install and run about $1,000 +- new.

The ubiquitous Bridgeport is the Series I J-head. These came in various horsepower ratings over the years and both fixed and variable speed. Any of these machines would be a good home shop machine.

The M-head machines were the first Bridgeports. While they helped win WWII, they're not capable of as much as a J-head machine but they'll run a 3/8" end mill all day long.

The Series II machines came as either the Series II Special, which used an adapter to adapt a J-type milling head or the Series II Standard, which used the 4J head. These are relatively rare machines although they do come up at a good price on occasion. They're substantially larger than the Series I machines.

Condition trumps age, so look for a machine in good condition.

 

[mikegt4]

Bridgeports are like Chevy small blocks, there are millions of them out there, parts are relatively cheap and readily available. On the flip side, it's the most well known name so everyone new to the game wants one and the prices reflect that. The same with South Bend for the lathe side of the shop.

Don't restrict yourself to only a BP, there are plenty of other brand machines that are as good if not better than the typical BP. Condition and tooling are the top things to look for.

 

[Doug Arthurs]

I have a Bridgeport. If I buy another mill it will be one of the heavier clones for sure. Although if mine had less wear it would probably be fine.

 

[astroracer]

I picked up a small M headed FrankenMill last year. It is old but it is in good shape, the ways are tight and there was only 0.020 deviation over 20.5 inches of travel on the X axis table so the lead screw is also in good shape.
I just put a Tpac Tools DRO on the machine last week. Check them out.
http://www.tpactools.com/
$365 for a 2 axis, $455 for a 3 axis. They get good reviews on the machining sites and I am very pleased with mine.
Mark

 

[dr_clyde]

To elaborate on the J-head a bit, the regular J head is the one with the step pulleys, whereas a 2J head is a variable speed. Not to be confused with a series II.

Series typically refers to the body and table size, and the letters refer to the head. M, J, 2J, and 4J.

You could get a series 1 with M, J, and 2J

Series II was available with 2J and 4J.

There was also a slotting head available, but I forget what it was called. It fits on the opposite end of the ram, then you swivel the turret to get the head you want.

Bridgeport also made things like rotary tables and dividing heads, not just milling machines. Once Hardinge bought them they put their name on engine lathes too.

Not sure of the timeline, but Bridgeport also had a line of CNC machinery.

 

[Kevin54]

One thing when shopping for a mill, you don't want one with slop or excessive backlash. Look at the ways on the knee. If they are extremely wore, steer away from it. If it has excessive backlash it CAN be adjusted some, but that is up to you whether you can live with it or want to repair it. Run the table out to one end then move it front to back. If there is excessive slop steer clear as the mill is worn out. Listen to the head. If you hear a lot of noise, there is wear in the pulleys if variable speed, the bearings can be going out. All parts are readily available, or were for Bridgeports,, but parts for the older ones if you can source them are becoming more expensive. IIRC, it is about $1000 in parts to rebuild a head. That is about half the cost of a real decent used Bridgeport.

For an example, I bought a Lagun (Almost same as a BP) It has ball screws, 2 horse, 220v, step pulleys, and a readout. Super clean, and I paid $2300 for it, and the guy let me use his trailer to get it home.

He had a sweet BP round ram with a readout. No slop anywhere on it but need paint. $1300.

So make sure you shop around and not jump on the first one you find unless it is a killer deal.

 

[Kevin54]

I picked up a small M headed FrankenMill last year. It is old but it is in good shape, the ways are tight and there was only 0.020 deviation over 20.5 inches of travel on the X axis table so the lead screw is also in good shape. I just put a Tpac Tools DRO on the machine last week. Check them out.
http://www.tpactools.com/
$365 for a 2 axis, $455 for a 3 axis. They get good reviews on the machining sites and I am very pleased with mine.
Mark

For home use, .020 in 20" may not seem like a lot, but to a machinist, that may as well be 1" in 20". So it all depends on what a person intends to use the mill for. I couldn't live with that, but that is me. Being a Toolmaker all my life, when you pin two parts together like for a precision die, that may not make a good part.

 

[Kevin54]

Leaky.....not knowing how far you want to drive, but here is one you may want to inquire about by phone. It is an XLO, but XLO were always great machines. It doesn't look bad for $1500, and it has a readout and a worklight (price some worklights sometime)

http://dayton.craigslist.org/tls/5022630678.html

Here is a plain Jane Bridgeport for the same price around Cleveland http://cleveland.craigslist.org/tls/5000127800.html for comparison

And a bunch of mills with prices all over the place http://dayton.craigslist.org/search/tla?query=bridgeport

 

[rsanter]

J head, step pully model
2j head, variable speed model
Round ram mill. First series they made, not as popular or rigid
Series1 , the basic Bport you always picture. Most common and likly what you want. The one that is the most copied
Series2, a bit of an upgrade from the series1, had the square ways verses the dovetail ways

 

[astroracer]

For home use, .020 in 20" may not seem like a lot, but to a machinist, that may as well be 1" in 20". So it all depends on what a person intends to use the mill for. I couldn't live with that, but that is me. Being a Toolmaker all my life, when you pin two parts together like for a precision die, that may not make a good part.

I said "only" in respect to the age of the machine. 20 thou is not bad as long as you keep it in mind. .020 divided by 20.0 is .001 per inch, well within most tolerancing schemes and I KNOW it's well within most of the stuff I do.
It's a moot point anyway because the installation of the DRO and the required calibration took it out of the picture.

Mark

 

[macgyver37]

It all depends on what a person wants to do with one, and I am guessing the OP doesn't yet know enough to determine what he wants to do.

I have a pair of non bridgeport mills, an Index Super 55 and a Tree Journeyman 200 (a cnc 2UVR). I have ran bridgeports alot and I appreciate them for what they are. The best thing about them has been mentioned, there are a ton of them out there and the aftermarket has made so many accessories for them that it makes it hard to not get one. From the R8 tools to the power feed assemblies and dro kits, they are all cheaper and easier to find for the bp.

I love my Index, it has some cool features and I use it most every day. It has brown and sharpe #9 spindle and it can be bothersome to find things for compared to the R8. I do believe it is a little better than the R8, but probably not enough to notice for many people, especially when considering the availability of the R8 stuff. I have a full set of collets for mine and I have not needed anything else. My Index will not spin or nod the spindle, only tilt side to side. So it makes it a little more rigid which makes it less flexible in some projects, like getting the head off the side of the table to drill a bolt pattern in a axle hanging off the side. This is partly why the Tree showed up, it has the same nod, tilt, in/out ram and spin as a bp.

The Tree uses a Z collet with their quick change system, these are even harder to find, but straightforward to make. It only goes up to 3/4", so the machine is capable of more than the tool in the spindle. This mill is comparable to the series II bp for size and weight, it puts the series I to shame, it has box ways, ball screws, bijur oiler, etc. Everyone I have talked to that has spent any time on a Tree prefers them over the bp, but they are not in business anymore and can be hard to find stuff for.

I also have a big horizontal as well and a shaper, so I don't have to do everything on these verticals like I used to.

If I were in the OP's shoes, I would find a series I J head (step pulley) in the best condition I could and add on power feeds and dro when I got the money later. The step pulley head is the simplest to fix if needed, the variable speed heads are just no fun to get into and fix. I also prefer the largest table and travel that I can get because most of my projects are not small, so the little table that can be found is not even desirable to me.
One thing to consider is the BP motor is a proprietary case and mount, so if you find one with a motor that you don't like for some reason, it will not be easy to swap with a common off the shelf one. Not sure how you plan to power it, but at 2hp or less, I'd pick a vfd.

 

[devonhubb]

Does anybody know anything about this mill? What is it?

http://tulsa.craigslist.org/hvo/5026507578.html

 

[Kevin54]

Does anybody know anything about this mill? What is it?

http://tulsa.craigslist.org/hvo/5026507578.html

It's a Bridgeport tracer missing a portion of it. There is supposed to be something similar to the head that is also mounted on the back plate. You can put a pattern of something on the table below, and use the one head to trace it while the other head cuts it. Not too many tracers around anymore, and with the coming of CNC mills, it all but did away with them. Personally, myself, I wouldn't want that beast in my garage. It larger than a standard knee mill and takes up a lot of room.

BTW Devon......Welcome to Garage Journal, and hope you hang around.

 

[Ign]

For home use, unless you have a definite need for it, I would stay away from Series II.
Way overkill for most.

This. I ran a Series II in school. It's so big it's impractical to run manually for quick jobs and one-off parts. You'll need a power drawbar or -more practical - a QC adapter in the the quill. CAT taper also means you'll likely be adapting BACK TO R8 (assuming lighter, hobby use here for the OP), negating much of the heavy-duty benefit of CAT40/50. Also would be a tight fit with an 8' ceiling.

However I'd reco the OP look for a 4" riser if he gets a typical Series I BP. A basic Series I is too squatty IMO. A nice Willis, Acer or Webb might also be a good alternative. Sharps are common around here but feel like cheap import to me.

 

[Leaky88]

All,
I really do appreciate all the feedback I'm receiving on this subject. It serves to make a better informed decision. Last thing I need is an 2000 # anchor in my shop that I cannot use. Many thanks. Leaky