Pratt & Whitney milling machine identification, information, and advise
Close
Login to Your Account
Results 1 to 20 of 20
  1. #1
    Join Date
    Nov 2019
    Country
    UNITED STATES
    State/Province
    New Hampshire
    Posts
    5
    Post Thanks / Like
    Likes (Given)
    14
    Likes (Received)
    1

    Default Pratt & Whitney milling machine identification, information, and advise

    I recently acquired a Pratt & Whitney #3 Bench Milling Machine. I'm not a machinist but it's something I've always been interested in and wanted to learn. I was smart enough not to try and fire it up, it's sat for at least 10 years. Everything seems to move and turn smoothly but it's tight as in needs to be cleaned and lubed. I don't even know the proper terms for for most of the parts so don't slap me too hard. In order to move it I had to partially disassemble it. I was able to remove the table? from the column? without too much problem, unbolt everything from the bench and move it. It was raining so it also got a bit wet. From what I could see there was a putty type substance around the gears that I'm sure was grease many years ago. I could figure out how to remove the spindle? and further disassembly of the table didn't seem like a good idea without some guidance. It's missing some things, there's only 3/8 and 1/2 collets?, a few arbors and some cutters but it dose have a dividing head? and some other parts. Any advise (other than offers to take it off my hands )?
    Attached Thumbnails Attached Thumbnails mill-5.jpg   mill-4.jpg   mill-3.jpg   mill-2.jpg   mill-1.jpg  


  2. Likes Giglio_A liked this post
  3. #2
    Join Date
    Jul 2002
    Country
    UNITED STATES
    State/Province
    Maryland
    Posts
    4,426
    Post Thanks / Like
    Likes (Given)
    740
    Likes (Received)
    625

    Default

    Any advice you ask... take a class in machining at the local comm college if you can, and if it is available. Learn the basics on someone else's machine. Otherwise seek out someone who has some experience to give you some pointers and at least keep you headed in the right direction. Be careful w/ scotch-brite. A thorough cleaning, lube, & repair of broken parts, is generally preferable to repainting and polishing if you are intent on taking it apart.

    Here is a link to some info about your machine if you don't already know about it.

    Pratt & Whitney Precision Bench Millers

    There are a few of us who have the 3C model that was the next generation after yours. I believe yours is somewhere earlier than 1920/1930-ish - but just hazarding a guess as to its age. I saw your SN info in your prior post. I looked to see if your model # was in the SN books, but there is no listing. SN info is scarce on the these small millers.

  4. Likes Lysdexic liked this post
  5. #3
    Join Date
    Oct 2018
    Country
    UNITED STATES
    State/Province
    Maryland
    Posts
    76
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    12

    Default

    I volunteer at the Tuckahoe Steam and Gas Association machine shop museum. Just last week we picked up a donated 3C the same vintage as yours. It has the vertical head and dividing head and the right angle table.

    If you only have a few collets they are 3PN and come up on eBay somewhat regularly. But other parts are pretty scarce. Like morsetaper2, I have the newer, larger, 3C.

  6. Likes Lysdexic liked this post
  7. #4
    Join Date
    Feb 2004
    Location
    peekskill, NY
    Posts
    24,453
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4563

    Default

    Removing the spindle:

    1) do you really need to, is there something wrong with it? If not probably best to leave it alone. Otherwise:

    2) It probably is similar to the lathe spindle of the similar vintage lathes. If so then the rear bearing is a cylindrical
    bearing into a tapered bore in the main casting, and is given crush to reduce the clearance by snugging the cap
    on the back end of the spindle. So first off, get a suitable pin wrench and slack that cap nut off a bit.

    Next be sure the cone pulley is free to float on the center portion of the spindle. There will be at least one setscrew
    (possibly two) that secure the cone pulley. They may have lock screws on top of them. So loosen all the setscrews
    you can find so the cone pulley can rotate and hopefully float side to side. A bit of heat and some oil may be needed.

    Then you need to understand the front bearing which is a hardened conical portion on the spindle, that seats into a hardened
    steel cone in the front portion of the front support. The clearance on this is set by another steel nut that is behind the
    upright, just in front of the cone pulley. Slack that off and if all is well, it can be undone completely and the spindle should
    slide out the front.

    Keep all the bits in order don't mix them up on re-assembly.

    The oil cups should have oil wicks in them to feed the bearings, these often get worn out/missing so you need to
    source some pipe cleaner like wicks that wrap around the inside of the reservoirs and go through the side hole in the
    vertical pipe, to feed into the bearing.

  8. Likes Paolo_MD, Lysdexic liked this post
  9. #5
    Join Date
    Nov 2019
    Country
    UNITED STATES
    State/Province
    New Hampshire
    Posts
    5
    Post Thanks / Like
    Likes (Given)
    14
    Likes (Received)
    1

    Default

    First, thank you all for taking the time to respond, I appreciate input from those who actually practice the art/craft.

    Sound advice morsetaper2, I probably wouldn't have considered that. I haven't noticed any machine shop courses offered but I wasn't really looking for them. I have known several machinists who moved on to other thing and there's a friend of a friend who runs a small shop. I should be able to at least find someone who will let me pester them a little. It never even occurred to me that my brother was a tool and die maker for forty-some years, but he's 1000 miles away.

    I prefer original and working properly over polish and new paint. If someone took enough pride in their work that it's still around almost 100 years later it's worth honoring them by passing it along some day still working and as close as it can be to the machine they shipped out. It must have been painted at some point because it's black and every other one I've seen in photos is grey.

    Scotch-brite? the green pads? The only thing I believe needs to be done right away is take care of surface rust on the table, pulleys, and end of the spindle. Just the pad? A rust inhibitor to protect it until I'm ready to clean it and lube it? It's too cold to try electrolysis until Spring.

    I did see the page you linked to. My belt isn't on correctly going by the picture, I wonder if the bench maker mounted the counter-shaft further from the mill than it's supposed to be. The angle from the mill to the top jockey wheel(?) isn't steep enough to fully clear the... arm that goes over the mill.

    I believe I stated the SN was 295, it was dark when I went out and looked. When I set it up on the bench I looked closer and it's 296.

    discodan I looked up the Tuckahoe Steam and Gas Association machine shop museum. I'd love to check it out some day. I was reading a number of the 3C threads. So it's basically a larger version of the 3? Are 3PN collets still in use on more modern day machines? or are these all survivors? Money is a bit of an issue. The only reason I got this machine is that it was offered along with a drill press and grinder for $200. The drill press had what looks to be a never used Westward cross slide vice worth almost that much.

    jim rozen at the moment I don't believe I need to remove the spindle, but I think I will when I'm ready to run the machine. I believe it's safe to leave it alone for right now. I will however take some time to look it over running through your instructions. It sounds like taking photos during disassembly and picking up one of those cabinets with the see through drawers might be a good idea for smaller parts, larger parts can just be marked with some masking tape. Dose the "tolerance" on the front bearing need to.. not sure how to say... be measured on reassembly?

    Right now it looks like some surface rust is all that requires attention.

    Thanks again for your time.

  10. #6
    Join Date
    Jul 2002
    Country
    UNITED STATES
    State/Province
    Maryland
    Posts
    4,426
    Post Thanks / Like
    Likes (Given)
    740
    Likes (Received)
    625

    Default

    The next generation Model M-1803 3C mill does have one date listed in the SN book, if those 3C owners might be interested...

    1947: 495

    Sorry Lysdexic, no serial info I can find for your earlier generation No 3 machine.

  11. Likes Lysdexic liked this post
  12. #7
    Join Date
    Oct 2002
    Location
    Kansas City, Mo.
    Posts
    6,450
    Post Thanks / Like
    Likes (Given)
    222
    Likes (Received)
    1899

    Default

    $200 is a great deal. The accessories you have are not often seen with the machine and the dividing head is fantastic. I have had one of these and the later model. Still have the dividing head and full set of collets and arbors. I suspect your machine takes 3PN collets. Did you get any?

    Have fun and I like your attitude on preserving the age/character of the machine as opposed to making it look like a jewel. Don’t worry folks, I like the jewels too but as I get older and lazier the original aged finish looks good to me.

  13. Likes Lysdexic liked this post
  14. #8
    Join Date
    Feb 2004
    Location
    peekskill, NY
    Posts
    24,453
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4563

    Default

    If the bearing clearances are too tight it the fronts will warm up a lot. If too loose then you will go through a bit more oil than you
    might like. Keep the oil cups full, be sure the wick is in there. If there is no wick the oil will not go over the top of the pipe and
    get into the feed for the bearing. My preference is 0W30 mobil one engine oil.

    You could put a dial indicator on the front of the spindle (facing inwards towards the face of the spindle) and gently
    push and pull the spindle in the axial direction and see what kind of clearance you might find. I tend to keep mine
    somewhat below 0.001 inch I think. You cannot hurt anything by going a bit loose to start.

    The rear bearing is basically crushed down on the cylindrical surface of the spindle. I actually had to make a spanner
    wrench to get that clamp-down nut to move.

  15. Likes Paolo_MD, Lysdexic liked this post
  16. #9
    Join Date
    Oct 2018
    Country
    UNITED STATES
    State/Province
    Maryland
    Posts
    76
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    12

    Default

    The 3PN collets are proprietary to the P&W machines. They come up on eBay somewhat frequently. There are a few sets on there now. Here is one of them.

    TILTING COLLET FIXTURE + BLOCK W/ PRATT & WHITNEY 18 3PN COLLETS SOUTH BEND | eBay

  17. Likes Lysdexic liked this post
  18. #10
    Join Date
    Dec 2007
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    371
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    50

    Default

    I believe that 3PN and 3AM (as used on Ames lathes) are the same collet, with the mills having the threads on the inside of the collet and the lathes having the threads on the outside. I have some collets that have threads on both the inside and outside. Just something to keep in mind when you're shopping for tooling.

    It'd be nice to have some higher resolution photos.

  19. #11
    Join Date
    Oct 2018
    Country
    UNITED STATES
    State/Province
    Maryland
    Posts
    76
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    12

    Default

    Quote Originally Posted by tom_boctou View Post
    I believe that 3PN and 3AM (as used on Ames lathes) are the same collet, with the mills having the threads on the inside of the collet and the lathes having the threads on the outside. I have some collets that have threads on both the inside and outside. Just something to keep in mind when you're shopping for tooling.

    It'd be nice to have some higher resolution photos.
    Tom, 3AM and 3PN are different, with 3AM being larger. I did see some P&W collets on eBay that appear to be 3PN but the dimensions given are slightly smaller, so I am wondering if they are an earlier version. Next time I am at Tuckahoe I will have to measure the ones we got with our early 3C mill.

    Here is a good source for collet dimensions:

    Collet Dimensions - Transwiki

  20. #12
    Join Date
    Oct 2018
    Country
    UNITED STATES
    State/Province
    Maryland
    Posts
    76
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    12

    Default

    I decided to check my Machinery's Handbook from 1919 and there are in fact two collets that fit P&W of a very close size. Machinery's shows them as the No. 3 and the New Style No. 3. The New Style No. 3 is the same as the 3PN. The No. 3 has a smaller diameter body - 0.600 vs the New Style No. 3's 0.650 and the threaded end of No. 2 is 0.500-24 vs the New Style No 3's 0.645-24.

  21. #13
    Join Date
    Dec 2007
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    371
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    50

    Default

    Quote Originally Posted by discodan View Post
    Tom, 3AM and 3PN are different, with 3AM being larger. I did see some P&W collets on eBay that appear to be 3PN but the dimensions given are slightly smaller, so I am wondering if they are an earlier version. Next time I am at Tuckahoe I will have to measure the ones we got with our early 3C mill.

    Here is a good source for collet dimensions:

    Collet Dimensions - Transwiki
    Huh. Maybe I never actually looked up the collet dimensions and just assumed that the ones I have for my P&W #00 mill are 3PN. They do match the 3AM on on the Ames lathe that came with the mill except for ID vs. OD threads. I've heard that it was possible to get some of these machines made with different collets etc. to match existing shop tooling, maybe this one was custom made for Ames collets, or maybe modified after the fact. The headstock is non-standard as well - it has a key that fits a slot in the top of the column, but is missing the slotted reverse dovetail that the lathes have.

  22. #14
    Join Date
    Dec 2007
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    371
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    50

    Default

    Quote Originally Posted by Lysdexic View Post
    Scotch-brite? the green pads? The only thing I believe needs to be done right away is take care of surface rust on the table, pulleys, and end of the spindle. Just the pad? A rust inhibitor to protect it until I'm ready to clean it and lube it? It's too cold to try electrolysis until Spring.
    Be careful with green Scotchbrites. They are great for cleaning up surface rust etc, but they are abrasive - there's abrasive grit mixed in with the plastic, so you have to be careful about where any runoff goes. The similar blue pads are just plastic, so are benign.

    One of the other problems with them is they'll dull any remaining scraping marks, making surfaces with remaining scraping look more worn.

    There are as many ways to do rust removal as there are people doing rust removal. My favorite for precision parts these days is Rust Dissolver (*not* the phosphoric acid based Rust Converter). I get it from Eastwood, but it's commonly available. It's not cheap, but it's reliable and the least risky chemical rust remove I've found, although I did discover recently that it will stain at least some stainless steel (such as my kitchen sink).

    If you've got the mill in an unheated space for the winter then you might want to invest in a can of Boeshield T9. It's a spray on wax that will keep the tools from rusting with the moisture that comes with temperature fluctuations.

  23. Likes jhruska, Lysdexic liked this post
  24. #15
    Join Date
    Feb 2004
    Location
    peekskill, NY
    Posts
    24,453
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4563

    Default

    I checked the clearance on the spindle like this, last night. I have it set at 0.0006 inch axial play. Takes
    a fair bit of force to overcome the oil film when checking this.

  25. Likes Lysdexic liked this post
  26. #16
    Join Date
    Aug 2010
    Location
    Medina OH
    Posts
    1,953
    Post Thanks / Like
    Likes (Given)
    175
    Likes (Received)
    896

    Default

    Scotch Brite comes in many colors. When working with historical artifacts, or anything “old” that I just want to clean, I use a white scotch brite. If I remember right they refer to this as a “cleansing pad”. It won’t remove material.

    If it has some corrosion that needs a little persuasion, I use an old rounded screw driver as a scraper to remove the rust. You’ll want to neutralize the rust to prevent further damage.

    Light grey and maroon will clean and are mild abrasives, however very fine, and with oil they will break up more reluctant corrosion.

    Very nice find, would love to have a little miller with the dividing head setup.

  27. Likes Lysdexic liked this post
  28. #17
    Join Date
    Jul 2007
    Location
    Stratham, Cow Hampshire
    Posts
    4,205
    Post Thanks / Like
    Likes (Given)
    404
    Likes (Received)
    1579

    Default

    I like the "early" Pratt & Whitney mills as they resemble the rest of the machine tool styling of that period.

    If memory serves someone in CT was selling one of these which he mistook as a P&W "Surface Grinder" - a use to which it might have been put to as it transitioned into a "that old machine" status.

    This one is a far better buy and far better shape - a win-win.

    Joe in NH
    Attached Thumbnails Attached Thumbnails illo0531.jpg  

  29. Likes Lysdexic liked this post
  30. #18
    Join Date
    Nov 2019
    Country
    UNITED STATES
    State/Province
    New Hampshire
    Posts
    5
    Post Thanks / Like
    Likes (Given)
    14
    Likes (Received)
    1

    Default

    Thanks again. I've been checking in but haven't had a chance to reply. I've spent what time I've had tracking down the ton of old machinists e-books I downloaded years ago. I know I have some of the books suggested elsewhere on this site. I think I know what I'll be doing this winter.

    jim rozen forgive me for being a complete dub, I have no tools whatsoever except the machine. There's nothing that would indicate to me there's any problem "inside". The spindle turns without any perceptible play and feels very smooth but "tight like it probably only has residual oil left in it. I'm guessing the brass cups with a screw off top are the oil cups. There is a twisted wire attached to the one I took off but didn't know what I was looking at so I just put it back. It's starting to make sense. I'm not going to attempt to run it until I'm sure it's ready or use it until I'm ready. I'm going to take your first advice and not remove the spindle for the time being. I'll probably be asking questions about what to do where it's been sitting for years and I have no idea what was used for oil before I got it.

    discodan The collets were gone by the time I looked which is a good thing right now. Holiday expenses, I'd be the one sleeping in the crate and the new pup would be in my bed. At least I know what I'm looking for now.

    tom_boctouI think I'd better move the mill into the house. I don't think I'd get away with the dining room so it will have to be downstairs. I'm glad I looked before I leaped. I probably would have gone after it with PB Blaster and fine steel wool.I'll have to make sure to keep the rust dissolver away from the sink.

    Fal Grunt I haven't seen the white pads but I have seen the blue I'll have to look around.

  31. #19
    Join Date
    Apr 2013
    Location
    Damascus, MD
    Posts
    1,434
    Post Thanks / Like
    Likes (Given)
    4145
    Likes (Received)
    808

    Default

    If you suspect there is congealed oil in the spindle bearings, I'd suggest filling (and keep filling) the oilers with kerosene (which is a very light lubricant) and turn the spindle by hand from time to time.
    When the spindle starts spinning with much less resistance, you can switch to a proper spindle oil (e.g. Mobil Velocite No. 10) or, like Jim Rozen said, a high quality true synthetic motor oil, like Mobil 1 0W20, 0W30, or whatever (I don't want to start an argument here about using detergent motor oils in machinery, just noting that most of the issues are red herrings, there is much more study and development in motor oils than there is in traditional machinery oils, and the advantage of the lubricacy of synthetic oil outweighs all the possible negative issues of motor oils).

    When you put it under power, always monitor the bearing temperature: even at the highest speeds and loads you should always be able to rest your hand on the casting for more than half a minute.

    Paolo

  32. Likes Lysdexic liked this post
  33. #20
    Join Date
    Feb 2004
    Location
    peekskill, NY
    Posts
    24,453
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4563

    Default

    Those pratt whitney oilers should have a spring under the cap so you can lift the cap up without undoing the screw.
    There should be a bit of wick, which is basically a bit of pipe cleaner, that extends down into the reservior and goes up
    through the hole in the center post, which then communicates with the port on the machine. Pictures:

    Here it is, closed:



    Holding the spring-loaded cap open:



    The center post:



    The cap, showing the recess where the spring should live:



    The body:



    Here's another, home-made version where you can sort of see the pipe cleaner wick in there:



    This is a commercial one that sort of does the same thing, where the wick goes over the top
    of the tube, and not through a hole on the side. The general idea is to slow down the oil so it
    does not run out of the bearing instantly, but feeds slowly. You can get different wicks that have
    different capillary feed rates, but I typically just use a plain pipe cleaner. You know the thing is
    working if you need to periodically add oil in there. It really is a total loss mechanism. All the
    oil you put in there, will wind up on the floor. A side benefit of this system is the oil is filtered
    as it is drawn by capillary action in the wick. Eventually the wicks will clog up and get nasty, that's
    the time to change them.

    Oh, commercial version:


  34. Likes Paolo_MD, Joe in NH, Lysdexic, morsetaper2 liked this post

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •