War Depatment Bridgeport

[ogesII]

A neighbor of mine has an old M-head Bridgeport with USWD stamped on the table along with some numbers. He says it was a war dept machine. Anyhow it doesn't run due to a bad motor and he wants $200 for it with a SS phase converter.

The machine isn't rusty, scratched or dinged beyond what would look normal. And everything moves easily.

I'm sure the 1/2 hp m-head would be enough for me but the j series and R-8 sounds better. I don't need a $200 boat anchor but this sounds like an easy way to get a mill in my shop.

The only problem I see so far is that the collet won't release. Not sure if someone stuck the wrong one up there or what.

Is there anyway to put a J-head on this one or switch to an R-8?

And any ideas on the stuck collet?

TIA,

[jmelson]

A neighbor of mine has an old M-head Bridgeport with USWD stamped on the table along with some numbers. He says it was a war dept machine. Anyhow it doesn't run due to a bad motor and he wants $200 for it with a SS phase converter.

The machine isn't rusty, scratched or dinged beyond what would look normal. And everything moves easily.

I'm sure the 1/2 hp m-head would be enough for me but the j series and R-8 sounds better. I don't need a $200 boat anchor but this sounds like an easy way to get a mill in my shop.

The only problem I see so far is that the collet won't release. Not sure if someone stuck the wrong one up there or what.

Is there anyway to put a J-head on this one or switch to an R-8?

And any ideas on the stuck collet?

TIA,

Wow, sounds ALLLLL too familiar. I got a 1938 M-head Bridgeport (serial 1388) some years
ago. I can't recommend the M head, or maybe mine was shot after 40+ years of use (when I got it). The spindle was a bit too flexible for the stuff I was getting into. The worst, by far, was any attempt at boring left ripples in the surface. Part of that might have been the small shank I needed to use with the B&S #7 collets mine used.

So, I did put a wrecked J-head on it. It is MUCH too heavy, but Bridgeports are built tough, so nothing has snapped off from the weight, yet. My J head had a mounting plate like they use
to mount multiple heads on a T-ram machine. So, I machined a flat circle on the back of the casting so it could be bolted to the existing round-ram knuckle. When tramming the head you realize WHY later Bridgeports have worm screws on the tramming adjustments! It is REALLY hairy to do this all by yourself.

I had an end mill holder stuck in mine. I still don't know if it was the wrong taper or just got rusted in place. Massive hammering and prying didn't go anywhere. But, the machine was usable, as long as you wanted to use a 3/8" shank tool. So, I milled a pair of plates with C-shaped cuts in them, and drilled and tapped one to accept pusher bolts. I wedged those between the spindle nose and the flare on the end mill holder. I still had to ice the holder, heat the spindle with a torch, and beat on the drawbar to get it out. That isn't going to work for a collet, however. If some serious punding doesn't work, is there anything IN the collet right now? Depending on the size collet, you might be able to get a bolt up into the drawbar threads. If so, then a set of washers could be rigged to pull the collet while pushing against the spindle nose.

A couple other gotchas in a machine this old. The ways are not hardened. The original Bridgeport only had oil ports (Zerk fittings) on the right side of the X ways, so the far left end of the ways had to receive oil along almost 30" of oil groove. The oil never made it to the far end.
Also, some people greased these machines. Like ME! I had no idea you were supposed to oil a Zerk fitting. That probably didn't help the oil to get down there. I finally drilled into the saddle and installed a new set of fittings at the left end.

The leadscrew nuts are bronze, only slightly softer than steel. So, the leadscrews eventually get worn in the most-traveled regions, and the Y has to get what oil drips off the X screw. (The nuts are oiled through a little setscrew in the middle of the table. The table is put in the right place by aligning the "OIL" marks. Once the leadscrews are worn, you can't get screw holes to line up in mating parts, it is maddening, due to the differential wear in the screws. You can also get a concave wear pattern in the underside of the table, so the table can rock when you reverse X travel directions. You can also get looseness in the knee ways causing the knee to rock front/back when you raise/lower it.

So, you should just be aware of some of the wear problem areas in a machine this old.

Jon

[ogesII]

Thanks jmelson,

Based on your comments and what I've been reading I think I will pass on it. $200 is just so tempting for getting into a mill but the J heads and R8s sound much better. It sounds like buying a machine that you can't hear run is risky. Especially if the M-heads are undersized.

I thought the USWD part gave it some nice character also. But I'd rather have a mill that will work and last than a mill with character.

[jmelson]

Thanks jmelson,

Based on your comments and what I've been reading I think I will pass on it. $200 is just so tempting for getting into a mill but the J heads and R8s sound much better. It sounds like buying a machine that you can't hear run is risky. Especially if the M-heads are undersized.

I thought the USWD part gave it some nice character also. But I'd rather have a mill that will work and last than a mill with character.

Well, it WILL last, as it has for 70 years already! But, yes, I found my M-head to be the worst part of the machine, and although the J-head conversion is a big kluge and was pretty hard to do it made quite an improvement. Also, R8 tooling is just so much more available than the tapers used on the M. God help you if you get an M head with the B taper, Bridgeport's proprietary one. MT3 (or was it 2) is not so bad, but still not as versatile as R8. The 1J head I got cost almost as much as the whole machine did originally. Also, my 1/2 Hp motor on the M head never worked right. I originally ran it off a phase converter, and it was so weak you could stall it with your hand. I later got an early VFD, and that worked quite a bit better. I have run my 1 Hp J-head motor on both VFD and phase converter, anf couldn't tell that much difference in torque.

Still, I've made a useful CNC machine out of it and have cranked out a lot of work.

Jon

[ogesII]

Is there an easy way to tell what quill it has? Is it stamped somewhere? Or is there a dim I can take?

I guess if I could pick up a J-head for $200 it would be worthwhile. I'm not seeing much for working mills in the classifieds for less than $1500. Of course I have no idea what a j-head would end up costing me either.

[jmelson]

Is there an easy way to tell what quill it has? Is it stamped somewhere? Or is there a dim I can take?

I guess if I could pick up a J-head for $200 it would be worthwhile. I'm not seeing much for working mills in the classifieds for less than $1500. Of course I have no idea what a j-head would end up costing me either.

You will NOT be likely to get a J-head machine that hasn't been through a fire for $200.
I think I paid $750 for a TOTALLY trashed 1J head ONLY that had been in a guy's garage for 20 years, and that was 10 years ago. Fortunately, the head was rebuildable, the motor worked, and the main spindle bearings had been replaced just before the head was stuffed into a crate.

The "quill" is mated to the bore in the casting, and is not considered to be interchangeable. What you mean is the spindle taper. M heads came with a choice of 3, and I suppose you can measure the very end of the opening. No, I am pretty sure they do NOT bear a label anywhere that tells what taper it has. The M had B&S #7, Morse #2 or Bridgeport B3.

1J (step pulley) and 2J (vari-speed) heads most often are R8, but they can also be had with NMTB #30 taper or several quick-switch systems.

Jon

[ogesII]

<snip>
The "quill" is mated to the bore in the casting, and is not considered to be interchangeable. What you mean is the spindle taper.
<snip>

Ok, so is the spindle taper interchangeable? Could I swap it to an R8 if it has something else?

Also, I'm not sure what will happen to it when I try an get the stuck collet out.

[jmelson]

Ok, so is the spindle taper interchangeable? Could I swap it to an R8 if it has something else?

Also, I'm not sure what will happen to it when I try an get the stuck collet out.

The spindles of the M heads are interchangeable with other M heads, but the likelihood of
getting a spindle for an M head today are as close to nil as getting NOS spare parts for your 1936 Bugatti car. There is no way the small bearing set, etc. of the M could ever take an
R8 taper. The quill is QUITE a bit smaller than the one on the J head. So, it is limited to
1/2" tool shanks.

Spindles for 1J head machines are interchangeable with other 1J, same with 2J swapping to other 2J (the difference is the "tail" is longer on the 2J due to the taller belt housing.)

If the collet is totally welded in there, your best bet is to fix a boring bar to the table and gently
bore out the ID until the collet is separated into 3 pieces. Then it will be easy to remove.
It is conceivable you could do this with a series of drill bits.

But, most likely, with generous applications of a good penetrating oil and gentle tapping, it will
eventually come out. It seems a collet could never get as stuck as the end mill holder in my
mill. I got that out with no damage to the machine.

Jon

[ogesII]

<snip>
But, most likely, with generous applications of a good penetrating oil and gentle tapping, it will
eventually come out. It seems a collet could never get as stuck as the end mill holder in my
mill. I got that out with no damage to the machine.
<snip>

Jon thanks a ton for all the info. After applying penetrating oil and letting it soak in, I should loosen the draw bar a turn or two then I am free to pound? Or do I risk damage if I give more than light taps on the draw bar?

In my mind if I have 3 or 4 turns of thread engagement, I should be able to hit it a little bit without damage. The threads are my biggest concern, right?

[jmelson]

Jon thanks a ton for all the info. After applying penetrating oil and letting it soak in, I should loosen the draw bar a turn or two then I am free to pound? Or do I risk damage if I give more than light taps on the draw bar?

In my mind if I have 3 or 4 turns of thread engagement, I should be able to hit it a little bit without damage. The threads are my biggest concern, right?

If you provide a support for the bearings, you are free to wail away at it. Make a wood piece
that fits around the spindle nose but leaves a clear space for the collet to move forward. You could also do this in metal, but make sure it has wide contact to the spindle nose. Don't get confused by my words here, you want to support the actual SPINDLE, not the quill, so any pounding doesn't apply force through the spindle bearings. The support block can be rested on the machine table.

As for the penetrating oil, I'd just dribble it down the drawbar hole, it should slide down around the inner walls of the spindle and get to the back of the collet.

What size collet is this, and is there something in it? (Yeah, I'm guessing there is a hard-as-hell tool shank still in the collet, otherwise you'd already have it out.) One other scheme I can think of is to make a bar that is small enough to slip through the drawbar threads in the back of the collet and rest on the tool shank. Then, try to tap the tool shank out of the collet. If the collet wasn't insanely tight, and the shank isn't also rusted in place, then you might be able to drive the shank out of the collet. Being hardened steel, it may be less likely to be rusted than the collet and spindle taper. Once the tool is out of the collet, it should be easy to get the collet out.

Anyway, I'd be pretty careful with this pounding stuff, as you definitely CAN damage the spindle bearings. Other than cutting the collet out of the spindle, I'm not sure there is any better method.
I guess pulling the spindle, or even the entire head, and making a support collar as mentioned above, and then putting the spindle in a really BIG arbor press would pop it out for sure.

Jon

[ogesII]

<snip>
Anyway, I'd be pretty careful with this pounding stuff, as you definitely CAN damage the spindle bearings. Other than cutting the collet out of the spindle, I'm not sure there is any better method.
I guess pulling the spindle, or even the entire head, and making a support collar as mentioned above, and then putting the spindle in a really BIG arbor press would pop it out for sure.

Jon

I'm not sure what size collet it is. I'll have to go over and look at it again. Of course now I am wondering how hard it has been pounded on by previous owners. For the most part is the worst case that I would have to replace spindle bearings?

Maybe I should rig up a method to spin the spindle at some speed before I dig into it. At least this way I would know if it makes an awful noise or anything already.

I wonder how fast I'd have to spin it to find out if there are any major problems in the head. I could probably v-belt an air compressor motor to it with a simple bracket to get it spinning...

[ogesII]

the collet nearest the spindle measures .703 dia. There is a chuck in the collet now.

The owner drives a hard bargain and will now give it to me free. So as long as I can reasonably find tooling for it, I will probably go through the hassle of moving it.

Eventually I would like a bigger machine when funds permit. So hopefully any tooling I buy can adapt to R8.

Any ideas on where can I find out what the .703 translates to?