Announcement

Collapse
No announcement yet.

Help with P&W 10" engine lathe

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Help with P&W 10" engine lathe

    Hello,
    I'm new to this forum, but not forums in general. About a year ago I purchased a Pratt and Whitney 10" engine lathe for 200 bucks. When I went to look at it, it was in pieces in a trailer inside the guys shop. Originally he was asking around 800, and I looked it over, everything felt tight and it came with a bunch of extra goodies. I told him I couldn't realistically give him his asking price without seeing it running. He responded with "make me an offer". I asked him to not be offended, and said I could do 200. He immediately said sold! And we loaded it up.
    Anyways, the lathe uses 5p collets, which I can't find anywhere (currently there's a 4 pack on eBay, other then these I haven't seen anything in the last year). I have the draw bar, and one 1/2" collet. Should I just keep waiting and looking? Or is it possible to convert to a different collet?
    The other thing is the spindle threads. They are 2.75"X8tpi! I've never seen a backing plate in this size, and I only have 1, which is on my 4 jaw. But I purchased a 3 jaw, and would prefer to not have to swap plates Everytime. Has anybody seen these or have a lead? I know I can turn one on the lathe, which brings us to my next question....
    My experience has been on Southend's with quick change boxes. My lathe did luckily come with all of the change gears, but without a threading dial, I am completely clueless as to how to cut threads on this thing? Any pointers?
    It also came with some tooling that I'm unfamiliar with, but I believe some is unusable with my lathe. I'll try to post some more pictures later and see if y'all can identify them.

    Thanks for any help,
    Jake

  • #2
    Good looker....

    Comment


    • #3
      With no threading dial I would say that you would engage the threading half nuts and leave them engaged until the entire threading job is done. Sort of like how we have to cut metric threads on a lathe with an imperial gear box. So you advance into the threading cut and once into the relief cut or at the end of where you want the thread to be you retract the cross slide to pull out of the cut then shut off the lathe. You then start it up in reverse and when the carriage is back at the beginning point you stop it again and set the cutter for the next pass. Repeat until the thread is done.

      Which means threading up to a shoulder would be avoided or need to be done with extremely slow speed and shutting off the motor or throwing out the spindle clutch if the power set has such a thing to stop the machine. A clutch would be nice but otherwise you will find that using back gear would be OK. Just make the end relief wide enough to give you the room and time you need.

      Is there anything on the end of the bed to indicate that there might have been a threading dial at some point? The idea and ratio in them are rather generic if you can find one from some other machine that has the same diameter and pitch you could use that.

      Where do the collets fit? I would imagine there's a morse taper adapter that goes into the nose? Or some other taper like a B&S? I cannot imagine a machine that size having as small a bore as the size I found for a 5P collet suggests.

      The back plates will be some work but will be far from impossible to manage once you do get set up for cutting your own threading. Grizzly has 6 and 8 inch cast iron blanks in a few different configurations. And a double check with Shars shows they have just about any size you could ask for up to 12". These are all threaded with too small a size. But you'll be cutting them away anyhow. I'm thinking that if you don't have a face plate that the 12" blank would be dandy for that. BUT you need to get the threading working. Assuming an 8TPI lead screw for the threading that's as simple as it gets since you then only need a 1:1 ratio of gears.

      Hey, when you take on a project like this you KNOW you're in for a ride. But in the end it looks like you'll have an interesting conversation piece that can make parts for you.
      Chilliwack BC, Canada

      Comment


      • #4
        No experience with P&W, but some quick googling suggests its 5P collet may be a rare bird.

        Collet dimensions here.

        Does the collet go in the headstock? If so, perhaps make an adaptor to hold an ER chuck, cuz I think you may be out of luck on the 5P's. That said, I did stumble upon this 5p set, but I dunno if they're the same as your P&W 5p.

        Comment


        • #5
          [QUOTE=BCRider;1103165]With no threading dial I would say that you would engage the threading half nuts and leave them engaged until the entire threading job is done. Sort of like how we have to cut metric threads on a lathe with an imperial gear box. So you advance into the threading cut and once into the relief cut or at the end of where you want the thread to be you retract the cross slide to pull out of the cut then shut off the lathe. You then start it up in reverse and when the carriage is back at the beginning point you stop it again and set the cutter for the next pass. Repeat until the thread is done.

          Which means threading up to a shoulder would be avoided or need to be done with extremely slow speed and shutting off the motor or throwing out the spindle clutch if the power set has such a thing to stop the machine. A clutch would be nice but otherwise you will find that using back gear would be OK. Just make the end relief wide enough to give you the room and time you need.

          Is there anything on the end of the bed to indicate that there might have been a threading dial at some point? The idea and ratio in them are rather generic if you can find one from some other machine that has the same diameter and pitch you could use that.

          Where do the collets fit? I would imagine there's a morse taper adapter that goes into the nose? Or some other taper like a B&S? I cannot imagine a machine that size having as small a bore as the size I found for a 5P collet suggests.

          The back plates will be some work but will be far from impossible to manage once you do get set up for cutting your own threading. Grizzly has 6 and 8 inch cast iron blanks in a few different configurations. And a double check with Shars shows they have just about any size you could ask for up to 12". These are all threaded with too small a size. But you'll be cutting them away anyhow. I'm thinking that if you don't have a face plate that the 12" blank would be dandy for that. BUT you need to get the threading working. Assuming an 8TPI lead screw for the threading that's as simple as it gets since you then only need a 1:1 ratio of gears.

          Hey, when you take on a project like this you KNOW you're in for a ride. But in the end it looks like you'll have an interesting conversation piece that can make parts for you.[/QUOT]

          That is a picture of when I first put it all together last year. I have used it many times since and it cuts very nice. The is no signs of having a threading dial previously anywhere, at least bit that I could see. I did measure the lead screw veggie and believe it is in fact 8tpi, I will have to double check though. But thanks for the tip on cutting without an indicator, I'll give it a shot.

          The collets slip right into the spindle nose, it has a taper to it but I'm unsure if it is in fact a MT, and the draw bar just sucks the collet in, closing the collet. It is in fact a 5p, or at least that's the one that came with it and was installed when I bought it. The bore is rather small in my opinion, but it is what it is.

          I'll have to check out the blanks and see what I can come up with.

          Thank you for your knowledge!

          Comment


          • #6
            Originally posted by MTNGUN View Post
            No experience with P&W, but some quick googling suggests its 5P collet may be a rare bird.

            Collet dimensions here.

            Does the collet go in the headstock? If so, perhaps make an adaptor to hold an ER chuck, cuz I think you may be out of luck on the 5P's. That said, I did stumble upon this 5p set, but I dunno if they're the same as your P&W 5p.
            I'm gonna see if a have any pictures of the head stock, if I don't, I'll try to grab some tomorrow.
            I will look into the ER Chuck conversion, and also check out the link you sent. Maybe an email to them will get me some dimensions to see if they are correct.

            Thank you

            Comment


            • #7



              Last one is fully assembled, didn't realize the motor/drive system wasnt on in the first picture..... Those are the best shots I have of the head stock/spindle right now. I'll get a better one tomorrow

              Comment


              • #8
                That's quite the overhead drive setup. Just be sure you don't lean forward to get a better look at something....

                The shot looking down the spindle nose shows a clear step in the taper. So I don't doubt that it's in fact a 5P and not that someone wedged a collet in there that isn't the proper item.

                That tapered nose isn't actually an insert is it? Like is the through hole on the nose for the collet the same size as the rest of the through hole in the spindle? Or is there a larger bore in the outboard end that runs up to within a few inches of the nose? If it is that sort of suggests that the collet nose can be bumped out of the spindle. No sign of a joint line on the nose between the threading and the tapered nose?

                If it is all one piece then there's still a chance of doing something different.

                One option would be to bore the 5P shape out to a MT3 or maybe MT4. Then you can use more of the standard morse taper tooling like centers and morse taper shank ER collet chuck. Another option is to bore out the 5P to take R8 collets. A quick check indicates that the R8 collets are a little larger in the important sizes for the straight bore and taper so you've got metal that could be shaved away to allow fitting R8's. What you would lose is any chance of any thru hole work with longer stock since R8's need a center draw bar. So work in the collets would be limited to the depth of the collets.

                Another option is to just ignore that it has a collet other than for turning down a 5P shape dead center to use for any turning between centers.

                I don't see a tail stock in any of the pictures. Did it come with one? If not I foresee a project for the near future. I can't imagine not having a tail stock to use for axial drilling or supporting longer pieces.

                I also see that it has a HIGHLY INTERESTING carriage setup. Very limited travel but with the ability to move the tool post along the carriage it's not so bad.

                What about some sort of compound slide? Angles are going to be a bugger without a compound slide of some form. That may become a further project.
                Chilliwack BC, Canada

                Comment


                • #9
                  Neat! Early P&W with the rise and fall cross slide. You should post some pics over at the antiques forum at practicalmachinist, there are a couple other owners of similar machines there.

                  You should be able to knock the 5P collet adapter out of the spindle from the other end, using a soft (brass, aluminum) bar. You could make another adapter and draw bar for a similar sized collet if you really need them.

                  As for threading, if it has an 8 tpi leadscrew, and you want to cut 8 tpi, you can engage the halfnut lever anywhere it will drop in, no thread dial needed.

                  Hopefully you have a tailstock somewhere?

                  allan
                  Last edited by kitno455; 03-03-2017, 08:03 AM.

                  Comment


                  • #10
                    Originally posted by BCRider View Post
                    That's quite the overhead drive setup. Just be sure you don't lean forward to get a better look at something....

                    The shot looking down the spindle nose shows a clear step in the taper. So I don't doubt that it's in fact a 5P and not that someone wedged a collet in there that isn't the proper item.

                    That tapered nose isn't actually an insert is it? Like is the through hole on the nose for the collet the same size as the rest of the through hole in the spindle? Or is there a larger bore in the outboard end that runs up to within a few inches of the nose? If it is that sort of suggests that the collet nose can be bumped out of the spindle. No sign of a joint line on the nose between the threading and the tapered nose?

                    If it is all one piece then there's still a chance of doing something different.

                    One option would be to bore the 5P shape out to a MT3 or maybe MT4. Then you can use more of the standard morse taper tooling like centers and morse taper shank ER collet chuck. Another option is to bore out the 5P to take R8 collets. A quick check indicates that the R8 collets are a little larger in the important sizes for the straight bore and taper so you've got metal that could be shaved away to allow fitting R8's. What you would lose is any chance of any thru hole work with longer stock since R8's need a center draw bar. So work in the collets would be limited to the depth of the collets.

                    Another option is to just ignore that it has a collet other than for turning down a 5P shape dead center to use for any turning between centers.

                    I don't see a tail stock in any of the pictures. Did it come with one? If not I foresee a project for the near future. I can't imagine not having a tail stock to use for axial drilling or supporting longer pieces.

                    I also see that it has a HIGHLY INTERESTING carriage setup. Very limited travel but with the ability to move the tool post along the carriage it's not so bad.

                    What about some sort of compound slide? Angles are going to be a bugger without a compound slide of some form. That may become a further project.
                    I don't believe it has a removable insert, but I've been wrong before. I'll have to take a closer look.
                    The carriage is neat, it's an old rise and fall setup. The wing screw on the back side tilts it up, and it also has a taper attachment (I'm missing 1 piece for that, but should be easy to make).

                    Tail stock, yes I have one. It has a mt2 tapper, and came with some nice Jacobs Chuck's of different sizes. I also have a steady rest for it as well. I should have just taken a new picture of the lathe before posting, then most everything would be in the picture!

                    A compound would be nice. But to much work and money I think. I did however upgrade to a quick change tool post, rather then the lantern style that it came with. I have been able to cut some pretty good free hand taper cuts (not completely accurate obviously).

                    Originally posted by kitno455 View Post
                    Neat! Early P&W with the rise and fall cross slide. You should post some pics over at the antiques forum at practicalmachinist, there are a couple other owners of similar machines there.

                    You should be able to knock the 5P collet adapter out of the spindle from the other end, using a soft (brass, aluminum) bar. You could make another adapter and draw bar for a similar sized collet if you really need them.

                    As for threading, if it has an 8 tpi leadscrew, and you want to cut 8 tpi, you can engage the halfnut lever anywhere it will drop in, no thread dial needed.

                    allan
                    Thanks! I've done some looking on practical machinist, seemed more "professional use", so I came here. But I'll have to check it out closer.

                    Again, I don't think it has a removable insert. But I will check again to be sure.

                    Comment


                    • #11
                      You should jump on those 4 collets....

                      Comment


                      • #12
                        One bit of good news, if in fact the leadscrew is 8 tpi, you won't need a thread dial to cut the threads for your 8 tpi backplates. Try it. Cutting threads that are the same pitch as the leadscrew, you can't get engaged in the wrong place, so no need for a thread dial.

                        I think this also works for any thread that is evenly divided by the leadscrew pitch.

                        Dave

                        Comment


                        • #13
                          I just figured the big thumbscrew was a lock for the cross slide. I had no idea it was to actually tilt the whole table! ! ! ! I'm not really into the vintage machine scene so I had to go read up on the concept. I think we know when Rube Goldberg was in his prime after seeing some pictures....

                          Your P&W takes the concept a step farther though. I'm seeing dual short prismatic rails on the carriage for the arms of the "T" to ride on and what seems like a finely fitted slot at the rear to capture and confine the base of the "T" from side to side movement. Is that the case? The other machines with these rise and fall features seem to use a more or less normal full length dovetail. So the actual cross slide ends up running along a path which is slanted to

                          In your case it seems like the available cross slide travel is quite limited.

                          OK, found another thread that still has pictures that work. Looks like it might be the tarted up sister to your machine. And it sure does seem to confirm that there's a rather limited cross slide travel available. Not a great machine for facing off any bigger jobs as you'd have to move the tool post to finish the cut.

                          Most of the references to the use of the rising rest machines are focused on smaller sizes and secondary operations. And certainly the size of the work able to be held in the collets suggests that this is the case. Seems like a rather bulky machine for small finishing work though.

                          In that thread link note that a bit further down the picture of the accessories has a head stock center that has a 5P sized shank. That does suggest that the 5P taper is fixed. But I'd still look at it carefully to see if there's a line that suggests it's an insert. And perhaps a little more research into the old P&W's.
                          Chilliwack BC, Canada

                          Comment


                          • #14
                            Originally posted by BCRider View Post
                            I just figured the big thumbscrew was a lock for the cross slide. I had no idea it was to actually tilt the whole table! ! ! ! I'm not really into the vintage machine scene so I had to go read up on the concept. I think we know when Rube Goldberg was in his prime after seeing some pictures....

                            Your P&W takes the concept a step farther though. I'm seeing dual short prismatic rails on the carriage for the arms of the "T" to ride on and what seems like a finely fitted slot at the rear to capture and confine the base of the "T" from side to side movement. Is that the case? The other machines with these rise and fall features seem to use a more or less normal full length dovetail. So the actual cross slide ends up running along a path which is slanted to

                            In your case it seems like the available cross slide travel is quite limited.

                            OK, found another thread that still has pictures that work. Looks like it might be the tarted up sister to your machine. And it sure does seem to confirm that there's a rather limited cross slide travel available. Not a great machine for facing off any bigger jobs as you'd have to move the tool post to finish the cut.

                            Most of the references to the use of the rising rest machines are focused on smaller sizes and secondary operations. And certainly the size of the work able to be held in the collets suggests that this is the case. Seems like a rather bulky machine for small finishing work though.

                            In that thread link note that a bit further down the picture of the accessories has a head stock center that has a 5P sized shank. That does suggest that the 5P taper is fixed. But I'd still look at it carefully to see if there's a line that suggests it's an insert. And perhaps a little more research into the old P&W's.
                            There is limited cross feed movement, not as bad as you would think however. I'll see if I can get a travel measurement when I get home this evening. It also has adjustable stops, so you can set your max cut depth, which is nice. A compound setup would be awesome, and was available on the later versions, but as I said earlier...I don't think I could justify the cost, or if it would even be possible. However, if some of the tooling that I got with the lathe proves useless to me.... and I sell some of it.... Then maybe [emoji6] . I do believe that one of the attachments I have is a gear cutter of some sorts, but I can't see any way it would attach to my lathe. More pictures to come!

                            Comment


                            • #15
                              The sub thread "Old Metal Working Machines" of the " Old Wood Working Machines " web site :
                              http://www.owwm.org/viewforum.php?f=...bea3702da20fcc

                              might give more results than the Practical Machinist web site. I think this is a good link but if not Google should get you there.

                              Some thoughts on the possible collet adapter insert... I bought an Atlas mill with a 3/8" endmill holder in the spindle. That holder had been in there forever, and all the pounding on the drawbar I dared to do would not budge it. I finally removed the spindle from the machine, and with the help of a vise, sturdy drift & a 12 pound sledge I got the holder out of the spindle. And this was just a dinky 2MT arbor! So if that alleged collet adapter has been in the spindle over long it may take some effort to remove it. Like maybe arranging some sort of puller to put removal tension on the adapter plus a good thump from a big hammer.
                              Hopefully the old machinery site can tell you if that collet adapter is or is not part of the spindle.
                              I'm thinking it sure would be a waste of a big spindle & big machine to limit it to such a small holding fixture, but hey, what do I know? In a second operation machine, maybe it makes sense.

                              Anyway, I'm sure there are many people , including me, who are waiting to hear how this ends.
                              Best regards,
                              David

                              Comment

                              Working...
                              X