Bridgeport Mill head rebuild?

[nvreloader]

Guys

I am in need of some info on who/where to send a "J" head Bridgeport mill head for rebuild.

I think one or more bearing went "Kaput" on the mill,
it was a used mill when I bought it in "86".
as the saying goes,
"It was rode hard and put away wet".

Any suggestions on where to send this head for a check up and rebuild,
in the Western half of the US?

I am looking at the Grizzly Model 0755,
as a back up till I get the Bridgeport back up running.

Tia,
Don

[M-Tecs]

Bearing replacement is easy on Bridgeport's. If it's the variable speed you want to replace the sleeves in the pulleys also. If you are an average mechanic you can do it yourself.

[oldred]

I rebuilt the head on my Bridgeport J clone and it was easy as has been said. In my case I used genuine Bridgeport parts and they did indeed fit as I had been told they would but that's not a problem for you anyway since you have an actual Bridgeport and not a copy, the point is except for having to handle a bunch of heavy greasy parts the rebuild itself is quite easy and parts are not at all hard to find, not cheap but not hard to find.

I think there are even outfits that will exchange your old head for a rebuilt unit, can't remember a name right now but I'm sure I saw a couple of places that does that back when I was working on mine. You can even find complete rebuilt heads on Ebay for decent prices.

[akajun]

I am about to tackle this as well on an old series 1 step pully head I just picked up. . WIll be purchasing bearings from H &W who made the above video, and will then be sending the spindle off to be re ground to either Wells Index or SGS (spindle grinding services).
Both of those companies also allow you to send them your bad spindle and they will re bearing it and grind it as well.

[country gent]

What machine repair did at work when they changed out a bad head ( usually to much end play in spindle bearings) and it was exchanged for a refurbished head direct from bridgeport. The Index mills we had they rebuilt in house. The factory recomended way of removing the head is to un wire it, roll it 180* so flat top is down spindle nose is up. a wood cushion is nice here. Bring table up so wieght of head is supported by table. Un bolt at heads swivel joint. You can then use the table to gain clearence to lift up and off mill.

[Buckshot]

..............If I'm not mistaken Lagun (www.lagun.com) has a facility in Long Beach, CA that will rebuild milling machine heads. It's been several years ago but a friend mentioned his dad had them rebuild the head on his dad's mill, and re-grind the spindle to accept R-8 collets from some size of Morse taper.

...............Buckshot

[jmorris]

I have some pretty good books on the subject, nothing to it really but it was nice to see everything before I went in.

[Clark]

These books on rebuilding Bridgeports are shockingly good.
http://www.amazon.com/Guide-Renovati.../dp/1482368005
http://www.amazon.com/Renovating-Bri.../dp/1482367912

I buy them and give them away just as examples of well written books.

When I rebuild my Rockwell 21-100 head, I made a drawing so I could understand it.

[W.R.Buchanan]

I have rebuilt no less that 15 BP mills from minor take apart, clean and reassemble to full on regrinds with new paint. It ain't that hard and if you are mechanically inclined enough to use the thing in the first place, you are probably good enough to take it apart and put it back together as well.

Most, (99%)of these machines respond really well to just being taken apart and cleaned and reassembled.

My old mill has the same spindle bearings it came with and they have been apart with the balls picked up off the floor and reassembled 3 separate times. The drive support bearings in the head are cheap $15-30 each, and simply push into place. The hardest thing about the whole job is getting the balance spring for the quill actually hooked to the opinion shaft and wound up so that it works right.

Turn the head sideways to take the quill out. Remove the motor (2 bolts,) and the rest is self explanatory. These are not complicated machines, and are designed to be worked on in the field.

If you go on line you can find any parts needed from 15 different sources but getting a real live Bridgeport Parts list will help you out.

When you send the head out for rebuild you are putting it in the hands of someone who probably isn't any better than you are, and you will be paying for parts you didn't need and workmanship that you can see. You are infinitely better off doing the work yourself, then you know exactly what you've got. You are also going to pay way too much for the service which is probably guaranteed but you'll have to return it to the shop to get them to fix it. This is a PITA!

Take my word for it, You can handle it. I tore my first one apart with nothing but a parts blow up and it went back together just fine with no new parts and ran in their shop for 20 years. Now a friend of mine still has that mill, now in his garage shop and believe me he hasn't lifted a finger to clean it in 25 years, and he ran the shop it was in to begin with.

Randy

[seagiant]

These books on rebuilding Bridgeports are shockingly good.
http://www.amazon.com/Guide-Renovati.../dp/1482368005
http://www.amazon.com/Renovating-Bri.../dp/1482367912

I buy them and give them away just as examples of well written books.

When I rebuild my Rockwell 21-100 head, I made a drawing so I could understand it.

Hi,
These books are EXCELLENT and EVERY BP Owner should have the one to match their mill!!!!

I have a 1965 Series I J Head and they can bury me with it!

Still waiting on your book Randy, but fear it got pushed Way Back, because of your Excellent Hand Loader!!!

[BwBrown]

I have rebuilt the heads on both my Bridgeports - a J head and a step pulley head. Different heads, but both went well with good results.

What I now need to tackle are the feed screws on both mills' tables - the X feed. One has over 270 degrees of play - if it weren't for the DRO it would be otherwise unusable.

[akajun]

Just thought I would post an update to this with some pricing as to what to expect when rebuilding a Bridgeport step pully head.
Spindle bearing kit, the 2 high precision and one top bearing, $325 from h&w, as well as $16 for a new quill felt. In addition my spindle may require a regrind of the taper but I won't know until I get the new bearings in and check for runout. Wells index quoted me $126 for a r-8 touch up .
Also gonna need new pulley housing bearings and belts, add another $100.
keep in mind you may find other problems once your into the head, for instance my splined gear hubs are severely worn due to lack of maintainence by the previous owner. These are not cheap about $300 each, I'm going to try to weld them up and re machine as others have done, what have I got to loose .

[seagiant]

Just thought I would post an update to this with some pricing as to what to expect when rebuilding a Bridgeport step pully head.
Spindle bearing kit, the 2 high precision and one top bearing, $325 from h&w, as well as $16 for a new quill felt. In addition my spindle may require a regrind of the taper but I won't know until I get the new bearings in and check for runout. Wells index quoted me $126 for a r-8 touch up .
Also gonna need new pulley housing bearings and belts, add another $100.
keep in mind you may find other problems once your into the head, for instance my splined gear hubs are severely worn due to lack of maintainence by the previous owner. These are not cheap about $300 each, I'm going to try to weld them up and re machine as others have done, what have I got to loose .

Hi,
I really don't see that as bad, if it gives you a nice running BP Mill?

I think you have to run a clone, to see how really nice the BP is!!!!

[akajun]

No I don't either , this rebuilt will last me the rest of my life with my hobby use hopefully. Besides I only paid $200 for this head and I knew it was going to take work. It's going on my lagun horizontal anyway, it's my secondary machine, but when I get it up and going I'll take my primary lagun head apart and re build/ regrind it . It also has a rattle in low gear, so I suspect it needs the gear hubs repaired too, but it's nowhere near as bad as this one .

[W.R.Buchanan]

Akajun: I would look around before I paid $325 for a set of Spindle Bearings. Unless they have had sand poured into them They can be cleaned and reused. Grade 5 Bearings are a lot cheaper. My 1956 mill has the originals in it and they were taken apart and the parts dropped on the floor three times and that mill has been in my shop running since 1991. It is currently setup up with a right angle head being used as a cutoff saw for my Hand Press Guide Rods. I touched up the collet seat by running the spindle as fast as it would go and using some wet or dry sand paper on a piece of wood dowel as a back up. You only need to knock off the high spots and leave everything else alone. This will cost you zero.

The big drive bearings are too cheap to clean and reuse but just by popping the Shields off you can rinse the goo out and blow them clean with air. You can feel when they run clean. You blow across reversing direction until they run clean,,, taking care to not wind them up to warp speed with no lube in them as if the seize they will break your fingers.

I have been salvaging small G7 to 9 Spindle bearing for many years. Very seldom does one go in the trash. Usually a victim of corrosion. You can't fix that.

As far as that $18 piece of felt? Get some material from the hardware store or McMaster Carr and cut it out. That felt acts as the spindle oil filter and there is no need to overthink it.

Neither of my mills have the key in the spindle either. Completely unnecessary and will ruin your collets and arbors.

As long as you are not going to be drilling .020 or smaller holes a few tenths of run out is not going to affect your work in any way.

One last point or tip. Use "Amsoil 20-50 Racing Oil" for lubricant. It is synthetic and is absolutely the best way oil and spindle oil and gear oil there is. I have been using it for 30 years and my machines all run smooth. If you run your compressor pump with this oil you will not get rust in the tank. If rust is already in the tank switching to the Amsoil 20-50 Racing Oil will coat the inside of the tank and all you get when you drain it looks like soapy water. Trust me on this, it works so good you'll be amazed.

If your screws are that loose and hour glassed then you'll have to buy new ones and nuts too. If you are going to put money into the machine that is the place to put it. Better yet a pair of rebuilt ball screws will make your machine an absolute joy to run and you will be able to do climb cutting which always leaves a superior finish on parts.

Randy

[akajun]

Too late W. R. the new bearings are already in the spindle and I am crating it up to send to Wells Index for the re grind.
THe Old bearings were unsalvageable, they were pitted from moisture, and the head looks like it was lubricated with Motor OIl over the years, which lead to the bearing failure and premature wear of the teeth. There was a black goo coating all throughout the head, which reminded me of the bottom of an engine with poor maintenance which is why I think it was lubed with motor oil. PRoper oil for a BP and clone is either Mobil DTE Medium or Velocite 10 in cold climates. Neither of these oils are expensive so that's what I always used on my good head.
The new bearings are lubricated with a tub of included Kluber permanent grease. Packing the bearing you can feel the difference in it an other greases I have used. The upper bearing is sealed so it requires no lube.

[Clark]

On my Rockwell 21-100 head the established procedure was to replace the two bottom bearings on the spindle a pair of ground to match bearings from England at high cost.
My mill had been working well for gunsmithing until the runout changed from .001 to .005".
I realized someone had replaced my bearings a long time ago with generic cheap bearings. Because the bearing thrust was only in one direction and so the wear was only on one side of the inner race and the opposite side on the outer race, I just flipped over the bearings and put them back in. That mill is still working today with .001" runout. I did replace the $5 bearing way up at the top of the spindle.

Half of what I do on a mill is make scope bases or drill and tap for scope bases. The runout plus side shake of .001 is no real handicap.

[W.R.Buchanan]

The runout plus side shake of .001 is no real handicap.

This is quite true.

Randy