FP2 Y-axis vertical power feed shaft repair
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    Default FP2 Y-axis vertical power feed shaft repair

    I got my Deckel FP2 about seven years ago. It's second generation, built in 1964.

    When I got it there were some serious problems that needed attention. There were also some "little things" that I noticed but they didn't keep me from using the machine and didn't appear to be doing any damage, so I left them for "later".

    One of those was a rumbling noise when the motor was running. I figured it was probably the motor bearings or the bearing on the upper motor pulley input shaft, which Peter and others here have said is usually damaged.

    One of the other forum members here (Karl, Charly_DE) has been working on this part of his own FP2, and on the feed/speed boxes, and offered to help me with mine. He came over this past weekend with some bearings and seals that he had purchased alongside those for his own machine, and some extra gaskets that he had cut. Since he's just done this to his own machine, and knew exactly what was needed, it was very fast. We cleaned out the speed gearbox (which was not particularly dirty and and looked good inside):



    which now also has a proper gasket instead of glue under the cover:



    The more interesting part was around the rear power input shaft bearing, which in this photo is hidden behind the chain gear and lower circular flange/cover:



    Removal of the rear bearing is straightforward if the vertical shaft which feeds power to the Y-axis feed can be disconnected. For example see the following post Deckel FP2 OIL LEAK and posts 5, 10 and 17 in that same thread. Post 13 in that thread has good photos of this feed.

    I have never before removed the rear cover from my machine, but through the gaps I remember seeing an odd-looking "overlong" taper pin on the cylindrical piece that connects the lower feed shaft to the Y-axis drive at the top (the little stub sticking down at the top right of this photo):



    The shaft (not shown, coming up from the bottom) is connected to this by a hollow cylinder attached top and bottom with taper pins. See the photos here: Deckel FP2 OIL LEAK . The idea is that to remove the input power feed shaft bearing, you drive out those taper pins and slide the hollow cylinder down. This provides enough clearance to lift and remove the lower shaft. Then you can access the bearing. (Alternatively you can grind off part of the flange, as described by Peter in the post linked above.)

    Here you can see what was needed to remove that cylinder on my machine. The "odd looking taper pin" turned out to be a piece of a 4.2mm drill bit, crudely ground and hammered into place. But when Karl looked at the cylinder, he noticed a bulge near the taper pin hole, visible here:



    In this photo you can see the source of that bulge, which is the remains of a taper pin, friction welded to the inside of the tube by a crash:



    I think this is similar to what Dennis found inside the gearbox to his machine, where a taper pin had been sheared. Fortunately the access that we have here is better. For anyone who needs to remove this, a good method is to slit it lengthwise with a fine abrasive cutting wheel on a Dremel, going almost to the top. Then spread it with a nut splitter:



    When I am done making it, I'll post a photo of the replacement for this part, which will be the same on the bottom as the normal cylinder but on the top will be secured with a split clamp and pin.

    By the way, as Peter had predicted, the rear input bearing was worn/noisy. It's now been replaced with a new FAG 2RS bearing from which the inner seal (and grease) have been removed. Outer seal is intact.

    The other source of noise is the motor pulley, which has a 24mm keyed shaft. The grub screw holding down the key was loose, and the pulley has wobbled enough to wear the shaft and key slot. I've got the motor apart now to replace the bearings. I will probably grind the shaft between centers down to 23.8mm and bush the pulley for an interference fit on that shaft.

    An interesting question is, how did the power mechanism create enough torque to do the damage shown above? We checked and the shear pin mechanism is working as it should. A 2mm soft steel pin can not transmit enough power to do such violence. My theory is that the Y axis was crashed during a rapid move where the Z axis was moving downwards. The energy source for the damage was NOT the normal feed mechanism, but rather the kinetic energy of the mill table and support moving downwards. These can transmit that energy to the feed shaft that runs from front to back through the bottom of the machine, and via that path to the Y-axis feed shaft.

    Moral of the story: make sure Y is stopped when doing X or Z moves!

    Karl, thanks again for your help!

    After I am done with the motor and the new shaft coupling, now that the machine is apart, I guess it's finally time to paint the side and back covers...


    Cheers,
    Bruce

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    I like to replace those pulleys with a serax taper bushing pulley
    These are really cheap at Hug technik shop (Germany)

    These clamp even on a somewhat worn shaft
    If the shaft is too worn I grind the keyway out so no sharp corners
    Then weld up the shaft
    Turn it to size by holding the rotor in a steady rest Then also turn the centre in possition again
    I never had a electrical motor yet that had steel for the shaft that hardened So easy to weld
    Then a new keyway again All original now

    PS Also see if the bore and shaft and particuly the keyway and key of the top pulley are not worn
    I find that very often To prevent that keep the bolt that holds everything ,also the handwheel, tightened
    Or a serax taper bushing off coarse

    Peter

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    Hi Peter,

    Thanks for contributing!

    Quote Originally Posted by Peter from Holland View Post
    I like to replace those pulleys with a serax taper bushing pulley. These are really cheap at Hug technik shop (Germany).
    I looked at Hug Technik. That seems like a really good and easy solution. The 2 belts on my FP2 are profile A78, 13 (mm wide) x 1980 Li (mm internal length). Do SPA pulleys fit OK? Do you use their Taperlock Keilriemenscheibe SPA 2-rillig? Prices are reasonable, 10-20 Euro for the pulley, plus another 10 for the taper lock bushing. Or do you have a part number for the pulley (Generation 2 FP2, 1400 rpm motor)?

    (By the way I searched Hug Technik and Google for "Serax" but did not find anything.)

    Also see if the bore and shaft and particularly the keyway and key of the top pulley are not worn. I find that very often.
    They are in good shape on mine. The pulley is some kind of plastic or bakelite, with a steel bushing for the shaft pressed in. Is that usual?

    Cheers,
    Bruce

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    SPA belt is higher So a A belt will fit
    Also if the top pulley has more as 2mm clearance at the bottem a SPA belt will fit also

    And yes the pulley is some kind of bakelite often
    Check if its not worn in that the belt bottems out

    Peter

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    Hi Peter,

    I just ordered a double row SPA/A13 pulley (95mm working diameter, 101mm actual diameter) with a 1610 24mm taper bushing. Total cost including shipping is 22.90 Euro from the Ebay seller "intest-shop". I suspect that will work well because the wear on the shaft is in some spots but much of the shaft is still intact. If so, it's a great solution, thanks for suggesting it!

    Cheers, Bruce

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    Taper lock drives are good enough to be effective even without a keyway....its a good solution to a damaged shaft....
    Can even purchase for a shaft that is for a smaller standard size and bore the bushing to accept a non standard "trued" shaft.

    Cheers Ross

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    Hi Ross,

    Quote Originally Posted by AlfaGTA View Post
    Taper lock drives are good enough to be effective even without a keyway.
    I had a look, and you are correct. Here are the numbers.

    If the motor (2.2kW, 1400 rpm) is running flat out, at maximum output it will be providing about 15Nm of torque.

    There is a table of "average slip torques" for taper lock bushing connections on page 152 of this Farnell catalog:
    http://www.farnell.com/datasheets/17471.pdf
    It gives the average slip torque for a 1610 taper lock bushing on a 24mm shaft as 135 Nm, which is nine times the motor-generated torque. It's about the tightening torque of a good quality (class 12.9) metric M12 bolt.

    Can even purchase for a shaft that is for a smaller standard size and bore the bushing to accept a non standard "trued" shaft.
    If I'm not happy with the fit/runout, then my plan is to get a taper bushing for a 15/16" shaft (23.81mm) and then turn or grind down the motor shaft to that size. The only modification I will have to make to the bushing is to widen the key slot from 1/4" (6.35mm) to 8mm, or to make a custom key.

    Ross, what do you make of my idea about how that cylindrical coupling got a piece of taper pin welded inside?

    Cheers,
    Bruce
    Last edited by ballen; 06-30-2020 at 01:19 PM.

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    It was interesting to see, that there are many differences in details between Bruce's Deckel FP2 (2nd generation) and mine (1st generation, built in 1958).
    One explained example: In 4 different spare part lists, the bearing on the side of the input shaft (speed gear box) is noted as a both side sealed bearing (6305-2RS), but in forum threads in practice that bearing was open and sealed with a Nilos ring between the bearing and the sprocket. Nilos rings are specified for grease lubricated systems, not for oil lubrication.
    Manni's (banana_joe in the german forum "Zerspanungsbude") FP2 has the Nilosring. Bruce FP2 - same generation, built in the same year, but a little bit younger than Manni's - had no Nilosring and the bearing never had contact to a Nilosring. Both Machines have a groove in the flange, that drains some oil that goes through the bearing back to the inside of the speed gear box. If I remember right, mine had not that groove - and lost oil to the outside of the speed gear box even through the Nilosring.

    Because of Peter's hint, that unmounting the bearing on the rear side of the input shaft with the right tool is easy, I made such a tool before visiting Bruce - and unmounting was easy. Thanks, Peter.

    Many informations in this forum (especially thanks to Ross, and further members of course, too) and Manni's thread in a german forum with more than 630 photographs from disassembling a FP2 for cleaning (2nd generation, build in 1964) helped me to prepare, too:
    Meine "Werkstattgeschichten" - Seite 9 - Zerspanungsbude

    Both gear boxes of Bruce's FP2 must have been opened earlier (was sealed with some other material instead of an original gasket). Therefore the speed box was much more clean than expected. So we didn't open the feed gear box.

    Quote Originally Posted by ballen View Post
    By the way, as Peter had predicted, the rear input bearing was worn/noisy.
    Mine too.
    And: The bearing on the output shaft of the feed gear box, that drives the bevel gear pair at the front side of the machine (drives the grooved vertical shaft for x and z feed) was damaged much more - at Manni's FP2, too - due to chips that came in the groove of the shaft, passed the plastic bushing and came directly into that open bearing. I replaced it by a both side sealed bearing.

    Quote Originally Posted by ballen View Post
    An interesting question is, how did the power mechanism create enough torque to do the damage shown above?
    Yes, that's the question. I think, you're right, that automatic y and z feed were engaged while with automatic rapid move a crash occured; possibly with high weight on the table.

    I enjoyed working with Bruce a lot. Visiting Bruce results in big motivation on doing things I never tried before.

    Cheers,
    Karl

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    Hi Peter,

    Quote Originally Posted by Peter from Holland View Post
    And yes the pulley is some kind of bakelite often. Check if its not worn in that the belt bottoms out.
    The good news is that the pulley is not worn at all. The belts (I just bought two new ones) sit correctly at the top. The "bad news" is that the pulley is threaded for a puller, which suggests that it's supposed to be a snug fit on the steel shaft. On my machine it slides very easily onto the shaft. Also, the keyway is wide enough that I can "rock" the pulley back and forth a bit in the rotational direction.

    Since one of my goals is to quiet down the machine, that rocking can't be good. Do you know, is it intended that this Bakelite pulley is a snug fit on the shaft? Meaning that you need a puller to get it off? Maybe the pressure of the belts and the torque from the motor keep the pulley seated so it can't rattle. But I wonder....

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    Predicted you it could be like that (PS in post 2)
    Every pulley should be a snug fitt Otherwise it rocks and wears out the key/keyway
    That is the reasson I always put a set srew on top of the key To prevent rocking (somewhat)
    Perhaps that can solve your problen too Setscrew needs to be put in at a agle I suppose
    Or better yet Another taperlock pulley

    Peter

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    Cheapo solution would be a shim I guess? Brass maybe

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    When i rebuilt my FP3 (first gen) i wanted to have the higher spindle speed that came with the later machines (2500 rpm)
    Machine came to me with a 440v motor , believe it had been rewound as a single voltage, two speed motor by the former owner (Northrup Aviation) ,i had the motor rewound for 220v two speed. Anyhow using Vee belt pulleys
    did not give the output speed i wanted because the motor pulley needed to be smaller than was usable (too tight a radius for a Vee belt) I was limited in going larger on the driven pulley because of the enclosure.
    Long story short is i fitted "Polly Vee pulleys and belts that allowed the diameter of the motor pulley to be smaller....Has worked out well. Personally i prefer the polly Vee system. they run quieter and generate less heat.
    Pulleys at the motor and input are both taper lock hubs.
    Peter is correct. any clearance between the pulley hub and the shaft will allow the pulley to "wallow" on the shaft owing to the single sided pull from the belt.....Straight bore pulleys need to be a tight fit to the shaft.

    Cheers Ross

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    Hi Ross,

    Thanks for confirming what Peter wrote.

    Quote Originally Posted by AlfaGTA View Post
    Long story short is I fitted "Polly Vee pulleys and belts that allowed the diameter of the motor pulley to be smaller....Has worked out well. Personally i prefer the polly Vee system. they run quieter and generate less heat. Pulleys at the motor and input are both taper lock hubs.
    If you are able to post a couple photos and a few details, it would be helpful. What are the pulley and belt sizes?

    Cheers,
    Bruce

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    Bruce:
    Sadly i don't think there are any photos. Detail;s of the belt and pulley sets will take some digging to unearth....its been maybe 10 years back soooooo.
    Cheers ross

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    Thanks Ross, no worries. It's always helpful to see how you do it, so if you come across those things, please post them.

    The top pulley on my FP2 runs on a 25mm shaft and has a 195mm OD, so an effective or working diameter of about 190mm. It's easy to get a taper lock replacement for that. On the machine side of the pulley is a sprocket/hub driving a chain which brings power to the feed box. Did you also replace that with a taperlock version? If I go this route I'll also need to figure out how to attach the hand "inching wheel" to the pulley. The end goal would be to have all of the components mounted to that 25mm shaft via taperlocks.

    PS: it's tempting to just add two or three grub screws to the large pulley and to the sprocket, to snug them to the key. If that doesn't work well, then I pull them off and replace with the taperlock types.
    Last edited by ballen; 07-02-2020 at 06:15 AM.

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    The sprocket wheel is hardened and cannot be had with a taperlock Also not enough meat for a taperlock
    It is some time ago already and my memory never has been that great but defenitly keep the bolt that tightens the handwheel As that also tightens the sprocket wheel
    So first tighten the bolt in the handwheel with the taper lock pulley loose but in place Then tighten the taperlock Then remove the handwheel again to place the cover/door
    Peter

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    Quote Originally Posted by Peter from Holland View Post
    The sprocket wheel is hardened and cannot be had with a taperlock.
    If I search ebay.de for "Kettenrad Taperbuchse" I see lots of them. Will they not fit into the space available?

    So first tighten the bolt in the handwheel with the taper lock pulley loose but in place Then tighten the taperlock.
    Thanks, that makes sense.

    When you replace the top pulley with a taperlock version, how do you attach the handwheel to the pulley?

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    Quote Originally Posted by ballen View Post
    When you replace the top pulley with a taperlock version, how do you attach the handwheel to the pulley?
    Simple
    Ad a spacer with a keyway and the 2 holes that grip the handwheel

    Look into this drawing and see "Kettenritzel'
    Peter
    Do you want to replace that with a taperlock????ritzel.jpg

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    Quote Originally Posted by Peter from Holland View Post
    Add a spacer with a keyway and the 2 holes that grip the handwheel.
    If the spacer has a keyway then it needs to be a tight fit to prevent rattling. Or is the idea that the handwheel is tight enough to prevent that rattling? Apparently it doesn't prevent it on the main pulley....

    Look into this drawing and see "Kettenritzel"
    Yes, that's what I am talking about

    Do you want to replace that with a taperlock?
    The chain gear is like the upper pulley: it is an easy slide fit onto the shaft, and can rotate a bit on the key. So if I want to eliminate the noise from the drive system, I thought that I also need to swap the chain gear for a locking/taper bushing version. Or have I misunderstood?

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    There is almost no torque on that spacer So no problem But ad a setscrew in the spacer on the key to be safe

    There is no space for a taperlock in the Kettenritsel So replacing it yes or no is a mood point
    So I would just replace the key. If you dare/must you could ad a little low strenght loctite Just on a few places Also the torque on that sprocket is not that big as on the pully So the clamping force resulting from the bolt in the handwheel will keep it in place

    Peter

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