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  1. #1
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    Default Step collet chuck

    I finally got started on the step collet chuck for my 10ee. Ordered Dura-bar for the stock material, I though of making patterns but since it's a one-off it didn't see to be worthwhile. I might have saved something on the cast iron but lost it on the time taken to make the patterns; besides, Dura-bar is sorta fun to machine, like hard butter.

    Started with a chunk 3.75" dia by 3" long, faced and cleaned up one end then chucked that up. Setup the compound for the taper by indicating on the spindle face. Remounted work, faced and cleaned up the other end, then drilled through and bored to about 1.200. Bored the start of the recess for the D1-3 spindle face 1/2" deep and 2" diameter. Used the compound to turn the taper, checking it by bluing it against another D1-3 spindle face I have. Blued up well so I finished boring until the spindle would seat. Did the finish face, taking a light cut with a nice fresh tool.

    Considered the work for the pins and SHCS locks. Measured up a couple of D1-3 plates and made a few guesses, found the BC for the pins but not the SHCS locks (they're on different BCs). Asked and John Oder told me the BC and angular displacement - with the measurements that was enough to calculate the positions. After quite a bit of work on the mill I have this:



    It mounted up nicely:



    It fits well, you have to bump it with your hand to pop it loose, but it's in contact with the whole spindle face. Perfect.

    More work next week - got to bore the 1.250 through (in place it'll end up dead on) and turn the outside to diameter. The I'll put on a 2 3/16 x 10tpi nose (same as Hardinge uses) for mounting the 5C step collets. I'll have to make the 2" step chuck as I've never found one on eBay (not one in my price range, anyway).

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  3. #2
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    Fine work Russ.

    Great work in progress photos, keep them coming.

    Hal

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    "The I'll put on a 2 3/16 x 10tpi nose (same as Hardinge uses) for mounting the 5C step collets."

    If made the same length from the D1-3" gage plane to the end of the 5C taper, thereby duplicating the major dimensions of the 10EE's 5C nosepiece, and then the exterior is made the same as from the end of a threaded TL's or HLV-H's 5C taper back to the 2-3/16"-10 register and shoulder, then all the Hardinge tooling should work, and so also should the 10EE drawtube/closer.

    Hardinge-Sjogren "Speed-Chucks" were available in 5C with both 4º and 2-3/16"-10 noses for use with Hardinge step collets, as well as conventional noses, of course.

    A challenge will be the 5C indexing pin, and for that purpose, I would recommend the Monarch way, coming in at 90 degrees to the axis, and not the Hardinge way which is a common setscrew, especially ground, coming in at an oblique angle to the axis, and retained by a jambed setscrew.

    An interesting project, Russ.

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  6. #4
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    Took a little time today and did the register and threads, matching the Hardinge dividing head as planned. Here's the finished result:




    And here it is with a 3" step closer mounted:




    I still need to stamp the pin numbers, put a transition between the body and the collet base, and make and install a collet stop pin - a step collet doesn't really want to tighten up and needs the pin for that as well as for repeating location.

    There's quite the pile of cast iron swarf in the bed.

  7. #5
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    Russ,

    Assuming the O/A length of the piece is the same as the Monarch 5C nosepiece, you could make a 2-3/16"-10 internally threaded, externally tapered nose protector and use that combination in place of the standard 5C nosepiece.

    My Monarch 5C nosepiece is 3-1/4" long, so perhaps your drawtube is a little longer or shorter than mine.

  8. #6
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    Hi Russ,
    Now that is really pretty! If I could just squeeze loose a weekend without other jobs to do, I think I'd sincerely flatter you by making a copy! The other adaptor I want is similar, a D1-3 to Hardinge taper (I've got a few chucks that fit that taper). Oh well, maybe next summer. BTW, do you have a favorite supplier for dura-bar?
    By the way, thanks for the CD, lots of nice stuff to look at right up till BOTH(!!) CD drives on my desktop failed!
    Cheers,
    Steve

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    "BTW, do you have a favorite supplier for dura-bar?"

    Logan Actuator is a good source.

    Shipped by USPS flat rate, so the shipping is inexpensive for what is a rather dense, heavy product.

    I've purchased 6" dia sections from Logan, for making special adjust-true backs for conventional scroll chucks, but 5" and other diameters are available, too.

    I try to get my Dura-Bar locally, if possible, as Logan can be a little touchy with complicated orders for this material.

  10. #8
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    The OAL is a little different from the standard nose, but likely not enough to make any difference. I have to relieve the inside somewhat from the 1.250+ that's there now and may well "relieve" with a 5C taper. The 2" step collets are a bit odd in that they have both the large diameter taper and the standard 5C taper, I was planning on making this for 3+ and using the regular chuck for 2-. That's probably the best way to go as the regular one is hardened and this puppy is just cast iron.

    As for Durabar suppliers, the best is one local to you if you can find one. A 3" chunk of 3.75" comes out about 10 pounds and shipping is a killer. If Scott Logan has anything close to that size take it - fixed rate shipping wins over most anything else (and he's reasonable on metal prices, I've bought big 12L14 from him before). For this batch I used Speedy Metals for a 3" and 2" chunk and the total was almost $50.

  11. #9
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    The chuck itself is done, here's a pic with a 5" step chuck mounted:



    The indexing pin & retainer are in place as well. I thought that the OAL would work, but I neglected to take into account the longer step collet length, so I had to make a spacer for the drawbar. I made one, it worked OK, but it was difficult to tighten with the large taper area and so I decided to rework my drawbar.

    The drawbar that I have is an eBay purchase and all in all in pretty bad shape. the tube is in decent shape but was extended by welding more tubing on the end. The additional tubing was larger in diameter and was working against an inside shoulder on the spindle (my spindle has a 1.5" counterbore about 3/4" deep on the outboard end). While the new tube was fairly hard it did burr up some, and getting good tension on a collet could be difficult. So the rework was to include adding an on-hand thrust bearing.

    Turned down the hard area of the tube to 1.375 and then started turning on the hub on the back for the thrust bearing washer. About the time I was wondering just how the hub was on the tube I cut through the remainder of the weld and the hub went loose. I figured to glue or braze it on but it had too much clearance, so I made a new hub, and some bronze bits to center the tube in the spindle and such. Silver brazed the hub onto the tube this morning (added about 10 degF to the shop in the process, and the increase was appreciated) cleaned things up and mounted it.

    At that point I found that whoever had drilled the handwheel had drilled it off center, it's all wobbly. That's pretty much all she wrote, time to make a new tube. Anyone know of a decent handwheel that can be mounted and handle 4K rpm? I'm looking at a couple of options, thought I might check here as well.

  12. #10
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    Nice adapter! After much fiddling, I found the only way to get a true running handwheel, was to make the whole thing from scratch.

  13. #11
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    I took some time this weekend to make a new drawbar. I'd ordered some 4130 DOM tubing in 1.375 diameter and figured that I may as well go strong and went with a .188 wall since the 5C can't pass anything more than 1" stock anyway. Definite overkill, should have ordered .093 wall. Anyway, threaded for the 5C on one end, cut to length and threaded 1.250 20tpi on the other here:



    On the tube is a collar to center it in the spindle and give a good face for the thrust bearing on the end. I turned up an end with a 1.250 x 20 thread through and counterbored for the thrust bearing and collar, and mounted a Royal plastic handwheel. Here's the whole assy on the saddle:



    Likely I'll glue the end on the drawbar with some bearing retainer. Given the wall thickness I could pin it or even key it on, but a couple of drops of bearing retainer will hold it and it can still be removed with some heat.

    I had to take some pictures while it was still shiny. A couple of weeks in the shop and it'll look like it came with the lathe from Monarch.

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  15. #12
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    Nice looking job, but I think you should key or pin it. What's going to happen when you overtighten the collet, and the Loctite decides to let go? Sorry but I'm a pessimist when it comes to stuff like this.
    Harry

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    Russ,

    Thats a truly elegant bit of work, and exquisitely well done.....

    I'm quite impressed..... : )

    cheers

    Carla

  17. #14
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    Final update. After checking things on my Hardinge dividing head (it has the same spindle as I made here) I came up with what I think are the appropriate dimensions for the 2" step closer. It was bored, threaded, register bored and faced and stuck on the chuck. The outside was turned to the 3" diameter all the closers have and I bored the 'face' (same diameter as the register diameter, just at the inside thread depth). I then setup to bore the 10 degree taper on the body of the chuck and after that was complete bored the step closer.

    Here's the chuck with the 2" closer mounted:



    And here's the chuck with a Hardinge dead center mounted (best gage I had around):




    The depths and taper diameters are such that a step collet with both the 5C taper and the large diameter taper doesn't quite kiss the taper on the chuck when completely closed (overclosed, really) on the step closer. I confirmed these using the Hardinge closers and collets on the dividing head and replicated the dimensions for the spindle and closers here. I confirmed the gaps using plasti-gage on both, so I should be OK here.

    I did notice that many chucks for the 5C are counterbored in for some distance, only holding the 1.250" near the tail end of the collet. I'm not sure if this is for tolerancing in manufacturing (it's a lot easier to hold a bore diameter for a short way) or for clearance, if it ever becomes and issue I can always bore this out a bit. If the 5C taper looks a bit long that's likely the cause - there actually is more taper in there. (Hmm, I might need to take out some to make room for the transition on a collet between the taper and the shank....)

    While I don't expect to ever use this as a 5C chuck I think I'll make a little thread protector for the nose - just in case.

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