# Part II Bridgeport head assembly



## modela (Sep 9, 2012)

*THIS IS THE BRIDGEPORT


*


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 When I fired up my Bridgeport for the first time I knew I was in trouble by the bearing noise everywhere.  So, thinking perhaps life could actually be simple, I pulled the motor off.  Obviously the first step was to take off the pulley.   I didn't have a pulley puller in that configuration and I anticipated  it would be a tough one so I soaked it for days in penetrating oil.   Today I decided to pull it off.  First, I took a brass hammer and drove  the pulledy on just a bit more to see that it was going to move.  It  moved about 1/16" inch rather reluctantly.  Regardless, I didn't want to  damage it.


*MOTOR AND PULLEY*



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 The two pictures above show how I got it off.  When I built my  welding bench I made a trap door in it for future uses unknown like this  one.  I put an old fixture on one side of the shaft under the pulley  and slid a 3/8" steel piece under the other side.  This meant I could  get a good flat surface under the pulley, better than a puller would,  anyway.  With a brass drift I drove the shaft steadily down until the  motor dropped on a block I had placed below.  I was so careful.

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 I looked closely at the pulley to see that someone had been there  before me and had tried to pry it off damaging the lowest step in the  pulley.  Another Problem/Challenge. They had damaged the pulley in two  places.  So, the only thing I could see to do was turn down the damaged  part and widen the pulley grooves to compensate.  This meant off to my  old Logan lathe.

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 There was enough material left that I could turn take out the broken  chunk and then turn and clean up both tapered sides so it would  function, even though I will have a somewhat lower gear ratio.

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 Here it is shown cleaned up  ready to be replaced.

The motor needed brushes so I farmed that out to a local motor rebuilder who got the brushes in wrong (no reverse) and a few other mistakes which meant I had two trips back.  That is another story.

*DOWN TO THE NITTY GRITTY*


Anyway, after looking at the machine I decided I needed help.  I bought the book listed below from the people at H&W machine. The Bridgeport is really a simple machine but this step by step  book will help you through a few spots that are a bit  counter-intuitive. Again, I have to recommend this book if you want to make your life  easier.


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I disassembled the upper part and ordered a rebuild kit from H&W Machine.



I then proceeded to tear it all down, cleaning parts as I went.



This casting is shown upside down. You can see how the clutch halves mate up.  The brake was basically okay.  I cleaned everything up and sanded the shoes lightly to remove any oils.  The upper belt housing was so filthy inside that I cleaned all out,  primed it and painted the inside.  In addition the casting was rough so  the additional coats of primer and paint will make it easier to keep  clean in the future.



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   This is the upper section where the motor with the step pulley  attach.  I cleaned up the step pulley somewhat on the lathe. The book was especially good here for things like oil level, sealing, etc.  The only tool I didn't have was a blind bearing puller which was necessary to pull the bearings out of the aluminum casings.  Some how I have done without this for years through improvising.   I cleaned up the  brake pads, sanding them lightly and replaced them.

All these assemblies I worked on were put together and set aside after cleaning, replacing bearings.   I want to give a  plug to the friendly H&W people who have provided me most of the  parts for this endeavor as well as the book and advice as I needed it.


*QUILL AND QUILL BODY*

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 Now I shift my focus to the quill body. I scrub it inside and out and  finally give it a bit of shower with this spray bottle.  I check the  mechanisms and they work smoothly.  The pull down gears above are in  good shape and so I decide to leave well enough alone.  I am convinced  that most of the problems with this mill were caused by the previous  rebuilding.


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 I pull out the clock spring mechanism which didn't seem to want to  withdraw the quill and to my surprise it is in pieces.  I order a new  one from my Iphone from H&W.

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 After looking at the cost of bearings for the spindle I decided to let the professionals do it.  I package up the spindle and send it off to C&M Precision Spindle.
 C&M Precision Spindle has it back in less than a week   (I built that bullet-proof box, by the way).  These guys do a  beautiful  job adding two bearings more to replace the spacers.  The  total cost  was not much more than buying the bearings.  They are nice  folks and  invited me to view their place next time I am in Portland.   Beautiful  job.

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*Bridgeport J & J2*

*Bridgeport Type Knee Mills*

 For Bridgeport type knee mills, C&M Precision Spindle’s special  rebuild can make your spindle run smoother and last longer. The key is  C&M's 5 pak precision bearings instead of the ordinary 3 that most  manufacturers do (as shown in the illustration).

 After the five bearings are installed, the spindle taper is R-8 precision ground in its own bearings .0002 concentric.

*Bridgeport Lubrication:*
I had been told by several rebuilders that the Bridgeport oiling system  left something to be desired so I decided to make some modifications  after receiving my rebuilt quill assembly with instructions to keep the  oil off the sealed bearings as it seeps into them and ruins them. In  addition, I was told that the lubrication system did not adequately  distribute the oil. So, I decided to make a few modifications. Here is  the before picture.



I modified the end of the quill to keep oil out of the sleeve and quill  bearings. I turned an old nylon gear (blue) down to fit and made am  insert (white) on my lathe and attached it to the end of the sleeve  sealing it with silicone.



It is shown here inserted into the quill body.



Finally, I shortened the tube on the lubrication cup.



The job was still not finished because oil could run down the splined shaft so I added an oil slinger (see black washer)



So, to this point I should have eliminated most of the oil going down  into the quill bearings. I wanted to provide some point lubrication for  the feed gears and bearings so I drilled and tapped a 1/8" NPT thread  where I could insert an oil tube to the right length (I recorded these  for the future).



I will write myself a letter of lubrication instructions since all of  this will be enclosed and hope I can keep everything well lubricated in  the future.

By the way, I posted my changes on another forum and created quite a controversy.  Some people loved it and some ardent Bridgeport loyalists disputed the claims that Bridgeport mills ever had any problems.

*COMPONENT REASSEMBLY*

After working on each of the components, cleaning, replacing parts, and painting as needed, I put the parts together.   It is finished.  At least the head.  It is amazing how smoothly the new bearings run in comparison the the old.

   There is a tremendous time gap from the last notification (except the  Bridgeport lubrication post). I had a few problems here and there from  abused parts but all and all the book walked me right through it.  Most  of the problem was in the bearings and some abuse from the person who  rebuilt it before me.
 There were quite a few delays here and there as I waited for parts  that I found needing replacing.  C&M precision rebuilt the spindle  in a timely fashion.
 I didn't do anything to the lower end, figuring I would see how  precise it ran in operations.  Notice below I picked up an 8" Phase II  rotary table.  I was amazed how precisely it moved.

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Totaling up everything goes as follows:
 Bridgeport mill including power feed, collets, Enco vise, a few tools                                          $1,000
 C&M Spindle  Rebuild                                                                                                           550
 motor rebuild including bearings and brushes                                                                           260
 Bearings set, drawbar, and other parts required                                                                       220
 Miscellaneous solvents, sealants, etc.                                                                                      18
 Shipping                                                                                                                             15
     Total                                                                                                                        $2,063

 Labor–lots, I should have kept track.
 Delays–quite a few waiting for parts.
 Was it worth it?  I think so.  Your observations?


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## Kennyd (Sep 9, 2012)

Superb writeup!:thumbsup:


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## Bill Gruby (Sep 10, 2012)

Awesome write up and rebuild. Great job.

 "Billy G"  )


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## nolo (Sep 10, 2012)

Really nice job.  Makes me want one even more


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## davidh (Sep 11, 2012)

next time your in my area, stop by and fix the auto down feed in mine. . .  i can;t lift that stuff anymore. . . 

oh, right next to lake superior, where it starts. . . . .


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## KBeitz (Jul 31, 2018)

Great job....


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## Kroll (Aug 3, 2018)

Well worth the effort and money.Its a good investment,increases the value of the mill and the joy of using it for next several,several yrs.I like your ideal of the oil seal which I will use your ideal on mine.Thanks for posting well done


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