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  1. #1
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    Default Overhauling a Wohlhaupter UPA-4

    G'day All,
    I've just finished modifying a Wohlhaupter UPA-4 boring and facing head for use in a Thiel Duplex 158 mill.
    While doing the modifications I stripped the head down so I could both clean and machine it as required.
    I decided to document the stripping and reassembly process and post it up here on the off chance it may be useful to anyone who might be considering doing something similar.
    Cheers,
    Greg.
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  2. #2
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    Nice job Greg, I like the fish tank idea! I don't recall seeing that before.

    Taking the time to photograph and document everything is well worth the effort.. good stuff.

    Ray

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    Very nice Greg.

    I pulled my 5-s6 apart a while ago, and was left with a spring and brass slug left over. In none of the photo's i took could i find where it came from! Looking at yours though it may well be what you are calling the regulator/ brake. Hmmm, now where did i put them....

    Ew
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

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    Excellent! Thanks very much for going to the trouble if documenting this so well Greg.

    You mentioned you needed to modify the head to suit your mill and wonder what modifications you needed to make and how you went about making them?

  5. #5
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    Greg,
    Thats's a great write-up!
    I have an old UPA-3, and while the internals are very different and much simpler than your model, your doc is useful as well as being interesting.

    I notice that you modified the shank from 40 taper to parallel, and I am facing the same task because my UPA-3 has an integral Moore jig bore shank, but the mill is a Deckel with 40 taper spindles. The UPA-3 shank seems to be very hard, but I don't have any suitable grinding equipment or a lathe that's really good for a solid cut with carbide. How did you modify the shank?

    Cheers,
    Bill

  6. #6
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    What a fantastic resource you have created for all the Wohlhaupter owners Greg. Well done.

    Whilst I don't own a UPA-.. I am also keen to hear about your arbor modifications.

    Bob.

  7. #7
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    Default Modifying the shank

    G'day Fellas, and thanks for the kind comments.
    Regarding the shank modifications, the taper of the late 1950's Thiel 158 is fairly unique and more like that usually found on a lathe rather than a mill.
    I initially considered just running the head in a 1" collet but it's fairly heavy and I didn't want it to slip in the middle of a cut so decided to make the correct shank.

    First step was to machine the Deckel 40 taper down to 1" parallel (sacrilege I know).
    Photo 1 shows the head mounted between centres in my Hercus 260 ready to begin machining.
    Everything that could be was removed and critical areas protected with a few layers of masking tape.
    The skin on the taper is very hard and about 0.5mm deep but cuts are much easier when you get through it.
    I used a Sandvik TCMT090908 tip running around 250 rpm with a 0.7mm DOC and 0.1mm/rev feed which ran with very little chatter.

    Photo 2 shows a cut where you can see the hard skin (shiny bands) and the softer material below it (dull areas).

    I wanted to use the dog slots in the head but as the existing shank had a S20x2 thread this meant I had to make the shank sleeve in two pieces.
    The first part including the drive dogs and the 20 degree taper was made to be a shrink fit from 4140.
    The second part including the internal s20x2 buttress thread, external 18TPI Acme thread and two locking grub screws to prevent it from loosening was made from EN36a which is much nicer to thread than 4140.
    The taper and shank diameter were left oversize on the diameter so they could be finish machined after final fitting.
    Photo 3 shows the head and two sleeve components prior to assembly.

    Photo 4 shows the first sleeve shrunk on.

    Photo 5 shows the second sleeve fitted.
    Locktite 243 was used on the thread and two M5 grub screws (with brass pads) are positioned such that they fit in the flat section at the end of the thread so it shouldn't come off in a hurry.
    The larger holes closer to the end are for a 6mm allen key to pass through when tightening the sleeve on.

    Photo 6 shows the shank machined to size and ready for the 18TPI Acme thread used by the Thiel drawbar.
    The finishing cuts were made using Korloy TCTG090204 tips running at around 30RPM and 0.1mm/rev feed so as to eliminate chatter.
    Each pass took around 25 minutes but the finish was very smooth and needed only the barest touch with emery to polish.

    Photo 7 shows the Acme thread being turned. I ground a parting blade to cut the thread.
    Photo 8 shows the finished shank against a Thiel collet. The collet looks a bit smaller because the shank is closer to the camera.
    Does anyone know why that keyway is always machined through the threads on these collet types?

    Photo 9 shows a view looking down the new shank where the end of the original shank can be seen.
    Photo 10 shows the finished item.
    All the work was done on the Hercus 260 working between centers and when mounted in the mill, the TIR just tickles the needle on a 0.01mm indicator.
    All in all I'm pretty happy with how it all turned out, no pun intended.
    Cheers,
    Greg.
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    Very nice work Greg.
    Mine was an MT5 and i simply machined the shank down to fit in a sidelock holder. It takes up a hell of a lot of Z though, so something like what you have done is on the cards but i need to make an NT40 shank.

    Ew
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

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    Greg,
    Thanks for that write-up, which gives me some extra ideas as well as specific cutting tool recommendations.
    Not an easy job to adapt it to the Thiel, but the result is impressive.
    For holding the boring head between centres I was expecting that you might have found (and used) a centre drilling under the cross slide of the boring head, and I will certainly be looking for one in the UPA-3 if I try to modify the Moore jigbore shank, but making an adapter to 40 taper may be a better idea.
    Cheers,
    Bill

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    Quote Originally Posted by kwijibo99 View Post
    ...............

    Does anyone know why that keyway is always machined through the threads on these collet types?

    Cheers,
    Greg.
    Hi Greg,

    The 3C collets I use in my little Hercus and the W20s in the mill's dividing head are a similar configuration to your collet. I reckon the keyway being cut through the drawbar thread is for maximisation of the collet bore diameter and for ease of alignment with the spindle drive pin. The thread being a slightly smaller diameter than that of the collet's shank aids in that alignment.

    Bob.

    ps. Any chance of letting me know the grade of the Sandvik and Korloy inserts you are using? I'm keen to find some alternatives to the fragile Kennametal inserts I've been using.

  11. #11
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    Very classy work Greg. Well done indeed.

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    G'day Ewan,
    I just went back and re-read your original post, you were actually part of the inspiration to document the whole pull-down process in the first place.
    I don't know if you have replaced the index spring in the coarse feed lead screw but I lost mine too and used a spring from a cigarette lighter which works pretty well.
    You mentioned that you cut your shank down, do you reckon it might be possible to drill and thread it again?
    If so, you could probably shrink on a sleeve similar to how I did then machine it down to NT40 and let the drawbar screw into the original shank.
    Rather than relying completely on the shrink fit to stop the head from spinning in the sleeve you could use a grub screw similar to a side locker.

    G'day Bill,
    Unfortunately the centre, if there ever was one has been bored out to make the pocket for the feed drive the UPA-3 may be different though.
    The boring bars have centres at each end so I just went with the shortest bar and adjusted the fine feed screw until everything ran true and tightened the locking screw.
    This seemed to do the trick as I checked it a couple of times along the way and it didn't seem to move at all.
    I just had to google a More shank and that thread on the end looks like a tricky thing to deal with, I'm not sure what would be the best way to go with that one.

    G'day Bob,
    The Sandvik TCMT090208-UM tips are a H13A (HW) K20 uncoated tip which is a cast iron machining grade.
    The Korloy TCGT090204-AK tips are a H01 grade uncoated tip which is an aluminium machining grade.

    I purchaced these tips on ebay and it was a case of suck it and see.
    All I knew was that they were the correct size for my holders and that I wanted to try a couple of different grades and nose/edge geometries.

    The Sandvik tips have a larger nose radius and have very good durability and hold up well taking heavy or interrupted cuts.
    They give a fairly good finish as long as you keep the cut above 0.5mm and use an aggressive feed.
    Take lighter cuts or use a slow feed and they will chatter or rub on a light machine like my Hercus.
    They work pretty good with brass and of course are great on cast iron.

    The Korloy tips have a fine nose radius and sharp edge. They are fairly fragile and will not do interrupted cuts.
    They can take fairly heavy cuts but tend to loose their edge fairly quickly when doing so.
    They are however excellent for light finishing cuts and leave a really nice finish when they're sharp.
    This of course applies when using them on steel or stainless, they work ok on brass but the sharp edge tends to dig in.
    I haven't used them on aluminium but I can only guess they are good being as that's what they are designed for.

    The Sandvik tips were a one off from a seller in Germany while the Korloy ones were from onlineseller68 who still sells them.
    http://cgi.ebay.com.au/ws/eBayISAPI....E:L:OC:US:3160

    G'day Pete,
    Thanks once again.

    Cheers fellas,
    Greg.

  13. #13
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    Thank you Greg for the thorough reply to my query.

    I often encounter inserts on eBay that visually look similar to the high positive rake Kennametal inserts I've been using but they are described as being suited for turning aluminium. Here's an example http://www.ebay.com/itm/10-x-Inserts...item232b5ec900. I seldom turn aluminium but the German seller's inserts are less than half the price of Kennametal HPs on eBay and a quarter of the price for the same inserts bought locally. Might be worth a punt???

    Bob

  14. #14
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    Hi Bob,
    What size inserts are you using? (CCMT right?)
    I would really recomend the Kyocera cermets on ebay, like this http://www.ebay.com.au/itm/221176050...84.m1497.l2649

    Hi Greg,
    I don't think i would have a hope in hell of drilling and tapping into the end of the shank. I think a shrunk on sleeve and if i can a cross drilled pin. I may need a carbide drill to get through it though!

    Ew
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  15. #15
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    Quote Originally Posted by Ueee View Post
    Hi Bob,
    What size inserts are you using? (CCMT right?)
    I would really recomend the Kyocera cermets on ebay, like this http://www.ebay.com.au/itm/221176050...84.m1497.l2649

    Hi Greg,
    I don't think i would have a hope in hell of drilling and tapping into the end of the shank. I think a shrunk on sleeve and if i can a cross drilled pin. I may need a carbide drill to get through it though!

    Ew
    Those cermets are my size Ew but my Hercus isn't some beefy, big horsepower beast. Do you reckon ..... xxxx it !, I just watched Ray's clip http://www.woodworkforums.com/showth...27#post1744627 . Hit the go button on a box of ten.

    If the little Hercus hasn't enough puff and rigidity, the 13 has, so it won't be 44 bucks wasted.

    BT

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