# My Bridgeport Rebuilding with modfications



## modela (Sep 9, 2012)

*                     Part II Bridgeport head assembly                 *

*THIS IS THE BRIDGEPORT


* 










 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*
















 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.







 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.














 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.







 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.  










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.  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.













   This is the upper section where the motor with the step pulley   attach.  I cleaned up the step pulley somewhat on the lathe.   This is   pictured upside down as it mates to the part above.  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.


*QUILL AND QUILL BODY*






 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.








 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.







 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.







*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.






















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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## kvom (Sep 9, 2012)

Was that round ram original, or was the ram/turret replaced?

I have a pulley J-head and recommend using a VFD to run it.  Much nicer not to have to change pulley sheaves.


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## modela (Sep 9, 2012)

kvom said:


> Was that round ram original, or was the ram/turret replaced?
> 
> I have a pulley J-head and recommend using a VFD to run it.  Much nicer not to have to change pulley sheaves.



I believe it was original.  

I plans to use a variable speed, permanent magnet D.C. motor.  The old brush motor is quite noisy.  It is single phase as well.

I agree, controlling the speed with a VFD or D.C. motor is great.  I used a 3 phase motor with a VFD on my Logan lathe.

Jim


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## kngkong (Mar 31, 2013)

Hey Modela,

Nice work!
Do you have any idea how much your quill and spindle assembly weighed when you sent it off to C&M?

Cheers
John


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## modela (Apr 4, 2013)

I don't remember the weight.  I think shipping via FEDEX cost around $20.

Jim


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