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  1. #61
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    Quote Originally Posted by TNB View Post
    As for the tool, why bother ? A simplistic single lip tool ground with proper angle will do the trick easily !
    I can try this. I am making the adapter out of 42CrMo4+Qt. For a cutting tool, is it OK for me to use silver steel 1.2210 which I can harden and temper? If I understand right, I turn a cone of the right shape, then cut a slot in that to form the cutting edge, then relieve by grinding in front of the cutting edge (and also behind?). Is that right?

    (I could also drill parallel 6mm holes in the flange on the mill, then mount the flange on a faceplate on the lathe and taper the holes with a small boring bar. Setup is fussy and I would need to do it four times, but might be faster than making a tool.)

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    Some interesting reading...
    And guess what ? I found it on that forum !

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    3rd choice...they make tapered end mills.....If you don't wish to grind a tool.


    4th choice to be really "Cool" you need to look for one of these:
    Angle boring head......




    Has two slides. One that is driven by holding the knurled ring at the top of the head...makes that slide advance ,same as a facing head....
    However that slide can be angled so that the tool advances at an angle relative to the rotational axis...

    2and slide (top) provides diameter control over the angled slide.



    Believe "Wally" also made an angle boring head as did "Tree"

    This one is made by or for Maho.....Not seen another....





    Cheers Ross

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    Quote Originally Posted by TNB View Post
    Some interesting reading...
    And guess what ? I found it on that forum !
    Is this what you mean? D-bit geometry?

    So split on center then relieve the part behind the cutting edge?

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    Quote Originally Posted by AlfaGTA View Post
    4th choice to be really "Cool" you need to look for one of these:
    Angle boring head......
    That is cool! -- have not quite wrapped my head around how it works -- if I see one on Ebay I will try to add it to my collection.

    In the meantime, I think the tapered/relieved D bit sounds pretty good...

  8. #66
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    Look for a Wohlhaupter UK4 then, Bruce !



    As for the D-Bit tool, yes, that's the thread I post a link to. Didn't you see it ?
    If you decide to give it a try, you'll see that a D-bit is very easy to grind.

    Now just a thought for the kind of tool required to enlarge a pre-drilled hole to a tapered one :
    A single-lip grinder will only allow you to grind a purely radial relief behind the cutting edge.
    That may not be the best geometry for a plunging cutting action (i.e. with an axial feed).
    For that reason, typical three flutes chamfer cutters are ground with a combination of radial/axial relief.
    So if you don't get the results you want with your d-Bit by plunging, you may want to try to feed it radially with the UPA3.

    I don't think it will be necessary since the taper of the holes on the Deckel dividing spindle nose is relatively shallow, but anyway....

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    Hi Tien,

    Quote Originally Posted by TNB View Post
    As for the D-Bit tool, yes, that's the thread I post a link to. Didn't you see it? If you decide to give it a try, you'll see that a D-bit is very easy to grind.
    The thread is 40 posts long, and the first posts include links to websites that have changed in the past decade. There are also many solutions proposed and I have the impression that photos are silently missing from many of the posts. That's why I focused on a particular specific post which had a photo, to ask if that's what you had intended.

    Now just a thought for the kind of tool required to enlarge a pre-drilled hole to a tapered one: a single-lip grinder will only allow you to grind a purely radial relief behind the cutting edge. That may not be the best geometry for a plunging cutting action (i.e. with an axial feed).
    This was what I had in mind.

    For that reason, typical three flutes chamfer cutters are ground with a combination of radial/axial relief.
    So if you don't get the results you want with your d-Bit by plunging, you may want to try to feed it radially with the UPA3.
    I had planned to make the bit the same size as the tapered hole, with a bit of radial relief. So apart from the radial relief, it has the same cross section as the hole. Doesn't that rule out a radial feed?

    I don't think it will be necessary since the taper of the holes on the Deckel dividing spindle nose is relatively shallow, but anyway....
    I'm definitely going to try the D-bit first. Meaning create a cone with the correct cross-section, split it down the middle, and relieve the radius behind the cutting edge. Is that right? Should I use HSS, steel that I harden, or a bit of carbide?

    Cheers,
    Bruce
    Last edited by ballen; 03-03-2021 at 05:25 AM.

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    Quote Originally Posted by TNB View Post
    Look for a Wohlhaupter UK4 then, Bruce !
    I had no idea that such a thing even existed until Ross posted about it earlier in this thread. I did a little bit of reading about the Wohlhaupter UK4 head. The initials "UK" stand for "Universal Taper" in German (Universal Kegel) in the same way that "UPA" stands for "Universal Facing & Boring" (Universal Plan und Ausdrehkopf).

    Apparently Wohlhaupter made (in total) about one hundred UK4 heads between 1948 and 1968, and no longer has any parts or documentation, not even an instruction manual. They never took off in the market because they were too complicated to operate and the niche was too narrow. Of course I'm a sucker for these kinds of "orphan" tools, and it would be great to have a reliable way to make tapered holes. So if I see one for sale that appears to be complete, and the price is OK, I will probably buy it.

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    Quote Originally Posted by ballen View Post
    I had planned to make the bit the same size as the tapered hole, with a bit of radial relief. So apart from the radial relief, it has the same cross section as the hole. Doesn't that rule out a radial feed?
    Yes it does. To a certain extend.
    If you want it to work, your tool will never have the same exact full profile as the tapered hole, because that would mean there's no relief at all.
    So theoretically, you should be able to plunge, then feed the tool radially to finish the hole.
    Indeed, a radial feed may require more relief than on a "regular" D-bit.

    Quote Originally Posted by ballen View Post

    I'm definitely going to try the D-bit first. Meaning create a cone with the correct cross-section, split it down the middle, and relieve the radius behind the cutting edge. Is that right?
    Should I use HSS, steel that I harden, or a bit of carbide?

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    I got to spend the afternoon in the workshop today, so made the adapter plate which was sketched in an earlier post here: Hermle Universal index table.

    For scale this is about 89mm diameter, the screws are M12 with 20mm of thread and 18mm heads. These are not standard M12 which have a 10mm thick head that takes a 10mm hex key, but reduced-head-height screws that have a 7mm thick head that takes an 8mm hex key. Plenty strong enough for this.



    Making this was fussier and more time-consuming than I had expected, because the four mounting holes in the spindle are at slightly different radii from the axis of rotation and also from each other - the average separation is about 47.2mm. So I had to make careful measurements of each hole location, because I wanted an assembly with very little or no slop. Note also that I relieved the center to match the contact patch of the standard Deckel dividing-head spindle.



    There is 3mm of meat under the screw heads. It seems thin but since the countersunk hole is 18mm diameter, there is 169 square mm of cross section there, which more than twice the cross-sectional area of a screw at the root of the thread.

    Although I ground it parallel, when mounted the top of the plate was wavy by about 30 microns, so I fly cut it in place. Finish is terrible but it is level to a couple of microns.



    Here is a test-fit of one of the accessories on top of the adapter plate and Hermle spindle: it's as it should be.



    Last step is to locate the two holes for the mounting screws, grind a D-bit for cutting them, and make the holes. Hopefully sometime in the coming week.

    I've been using the mill with the Hermle table for making these parts, and so far I am liking it. The Hermle table surface is higher up than the stock fixed Deckel FP2 table that I was using previously, and I find that helpful, since I am often working on small parts and want to be near the vertical head.

    The extra weight is helpful when doing heavy cuts, as it add some additional stability and reduces vibration. I don't notice the weight when cranking Z, but do notice that it's harder to creep up on an X value precisely because of the extra friction. Maybe it's time to take up Franz on his offer to replace the taper gibs with Turcited ones.
    Last edited by ballen; 03-15-2021 at 03:45 AM.

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    Quote Originally Posted by ballen View Post
    The extra weight is helpful when doing heavy cuts, as it add some additional stability and reduces vibration. I don't notice the weight when cranking Z, but do notice that it's harder to creep up on an X value precisely because of the extra friction. Maybe it's time to take up Franz on his offer to replace the taper gibs with Turcited ones.
    This is not a difficult job and one i am sure you could easily do yourself....
    Might have a look at post #4 here......
    The FP3NC rebuild continues (large file, lots of photos)
    Cheers Ross

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    Hi Ross,

    Quote Originally Posted by AlfaGTA View Post
    This is not a difficult job and one i am sure you could easily do yourself....
    Not hard to do IF you have more than 1 mill

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    Quote Originally Posted by ballen View Post
    Hi Ross,



    Not hard to do IF you have more than 1 mill

    Obviously time to tool up....
    Cheers Ross

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    Ross, what sort of cutter should I use to take a few tens of microns off the top of the plate, to get a true surface and shiny finish? It's 42CrMo4+Qt, which I think translates to US/ANSI 4140 PH. Is single-point flycutting the right thing? Can I use my UPA3 or should I get a dedicated holder? HSS or carbide? Cheers, Bruce

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    Quote Originally Posted by ballen View Post
    Ross, what sort of cutter should I use to take a few tens of microns off the top of the plate, to get a true surface and shiny finish? It's 42CrMo4+Qt, which I think translates to US/ANSI 4140 PH. Is single-point flycutting the right thing? Can I use my UPA3 or should I get a dedicated holder? HSS or carbide? Cheers, Bruce
    I’m not Ross, but you could always use a cutter with a radiused tip. The lines in your cutting pattern are all left by the very tip of the cutter. Other options include using a high speed grinding attachment (like a Precise grinding head, or maybe an LK grinding head). Personally I like the cross hatch pattern you achieved. It shows that the head was very precisely aligned with the surface and it is quite pleasing to my eye. You could always stone it if the edges feel sharp.

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  23. #76
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    I would use a fly cutter....most of the ones i make (don't own any commercially built fly cutters) are discs with slot for a LH stick style lathe tool...offset to put the tool cutting edge on center. Relieved where the tool and clamp screws live to help with balance. For large cutters i mount the disc to a commercial shell mill holder....others i just turn down to 1" shank, hold in collet or Welden style end mill holder..
    I most often use high positive inserts for this.(CCGX)...Want low cutting forces here.

    Would not suggest the "Wally" as the interrupted cuts will not do well on the slide and screw....

    Of course, since its flat now.....dial it up on your grinder...best finish there...Or mount a cup grinding wheel on a mandrel running in the precision boring head (higher RPM than the milling spindle....Just be sure to cover
    all the sensitive moving surfaces....(poor mans Blanchard).

    Cheers Ross

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    Quote Originally Posted by ballen View Post
    ...
    Making this was fussier and more time-consuming than I had expected, because the four mounting holes in the spindle are at slightly different radii from the axis of rotation and also from each other - the average separation is about 47.2mm. So I had to make careful measurements of each hole location, because I wanted an assembly with very little or no slop. ...

    ...
    Hey Bruce,

    so you didn't use any part of the taper for centering your adapter I see. I assume that you have used the slot (on the table's spindle) and protrusion (on your part) to center along one axis, what about the other? Dialing it in?

    I assume you did not use SHCS heads for centering, though I find it strange that you went for minimal slop there.


    Quote Originally Posted by AlfaGTA View Post
    ....Or mount a cup grinding wheel on a mandrel running in the precision boring head (higher RPM than the milling spindle....Just be sure to cover
    all the sensitive moving surfaces....(poor mans Blanchard).

    Cheers Ross
    Well, how about that...I had used a cup wheel on the high speed head once, to true up a Jeep flywheel, but I thought, till now, that this was a crazy thing to do. Thanks for the tip Ross...

    BR,
    Thanos

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    Quote Originally Posted by thanvg View Post
    Hey Bruce,

    so you didn't use any part of the taper for centering your adapter I see. I assume that you have used the slot (on the table's spindle) and protrusion (on your part) to center along one axis, what about the other? Dialing it in?

    I assume you did not use SHCS heads for centering, though I find it strange that you went for minimal slop there.

    Thanos

    Think the upper plate is just there to give a spot for the holding screws from the accessory to engage, and to provide a flat surface for planer truth of the rotating accessory whden mounted...
    The radial truth is derived from the OD of the spindle fitting the mounting accessory....
    The bolted on plate i assume will have clearance so its run out (within reason) is not in play...
    Cheers Ross

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    Quote Originally Posted by AlfaGTA View Post
    Think the upper plate is just there to give a spot for the holding screws from the accessory to engage, and to provide a flat surface for planer truth of the rotating accessory whden mounted...
    The radial truth is derived from the OD of the spindle fitting the mounting accessory....
    The bolted on plate i assume will have clearance so its run out (within reason) is not in play...
    Cheers Ross
    Correct, understood

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    Hi Ross,

    Quote Originally Posted by AlfaGTA View Post
    Think the upper plate is just there to give a spot for the holding screws from the accessory to engage, and to provide a flat surface for planer truth of the rotating accessory whden mounted...
    The radial truth is derived from the OD of the spindle fitting the mounting accessory....
    The bolted on plate i assume will have clearance so its run out (within reason) is not in play...
    Yup, that's right. The bolted on plate is about 0.05mm (0.002") smaller in diameter than the accessory sockets. The Hermle spindle flange is also very slightly smaller than the accessory sockets. Until I have it all finished I won't know if that gives me enough play to clock in the accessories as suggested.

    The big question in my mind is whether 2 accessory screws in taper holes plus two with brass tips on the surface of the spindle are enough to lock the accessory sockets in place firmly. If not, this adapter plate goes in the trash and it's on to plan B.

    Cheers,
    Bruce
    Last edited by ballen; 03-18-2021 at 02:15 AM.

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