Announcement

Collapse
No announcement yet.

A puzzle collet holder.

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

  • A puzzle collet holder.

    I just bought a small, apparently quite elderly, ( Square nuts, no makers name,but proper castings, good design, both drives by vee belt, strongly built), possibly locally made, horizontal/ vertical mill. The vertical head came without collet nut and any collets.
    To my astonishment the nut from my ER series of collets fits perfectly on the 32 mm dia thread on the vertical head, But my ER collets stick out about an inch too far from the tapered inner part of the spindle if I just try them in the taper and the taper inside the spindle does not seem quite the same as the ER collets anyway( thats just by eye at the moment)
    The taper in the spindle is 0.625 deep , 0.850 dia at the mouth and 0.660 at the bottom of the tapered hole ( These are caliper dimensions,hopefully within 5 thous).
    I will investigate the actual taper in the spindle this afternoon.
    In the meantime I wonder , have any of you any idea of what collets might fit??
    Regards David Powell.

  • #2
    That's the nose taper. But I bet there's a parallel portion deeper up in the spindle. The sort of taper you're describing makes me think that it uses collets that are shaped similarly to an R8 but which are smaller. And instead of a drawbar it uses the nose nut. So something like the small one in THIS PICTURE . And the pressure face on the inside of the nut rides against the shoulder on this style of shape. If you can reach up into the spindle and find a measurement for the parallel section that would help too.

    Oops, I also found THIS OTHER PICTURE where up in the top right there's a "tailless" capstan collet with the short and less steep taper similar to what you've described.

    Some time back I had found a big reference chart online which showed about two dozen different styles of collets along with good measurements for sizing them. Can't find it now though. But I found the pictures in the links to hopefully get you going in the right direction.

    Last ditch try... I found the image below for a type F collet as used on Schaublin and likely other smaller lathes and mills. The numbers look like they are not far off what you've measured. Perhaps make up a 40° testing pointer from thin sheet metal and check the taper. And check for the 16mm Click image for larger version

Name:	Schaublin type F collet.jpg
Views:	436
Size:	62.3 KB
ID:	1971945 back register parallel portion deeper up in the spindle.
    Chilliwack BC, Canada

    Comment


    • #3
      Thankyou for your reply. The Horizontal spindle does have an F type collet nose, indeed with an F type collet in it when I got the machine.
      However,in the vertical spindle the tapered portion is only about 0.625 deep, there is no parallel section further up the spindle the recess ends with simply a 1/4 inch dia hole which runs ] through the whole spindle as if for a drawbar or knock out bar.
      From the second picture the shorter of the two capstan collets would seem to be the most likely candidate.
      Thankyou ever so much for taking an interest and your helpful reply.
      Regards David Powell.

      Comment


      • #4
        You're very welcome.

        What about the short "capstan" version shown in the second link in the upper right? Does that look like what you need?

        I also saw in my 8 minutes of searching a collet that looked a bit like the tailless "capstan" option in another forum where it was identified as the collet for a 1/2" shank wood router. But didn't say if it had a particular name for the collet. Of course that same router would have come with collets for the 1/2, 3/8 and 1/4 shank sizes for sure. It's not much of a help but it at least suggests that something of the sort is out there.

        Chilliwack BC, Canada

        Comment


        • #5
          Hi again. The angle in the holder is, as far as I can measure, is 10 degrees a side, perhaps a shade less., certainly no more. Regards David Powell.

          Comment


          • #6
            Hi, With my wife's help in doing some of the maths for me( A minor stroke in 2007 robbed me of some abilities and I have had to relearn some things, one of which, rather annoyingly, is my shop maths). I managed to make a collet to fit this strange spindle.
            I made this one for 1/2 in tooling.
            It seems to hold pretty well, and a 1/2in end mill spins within a couple of thous.
            Now I can move on to the rest of the mill in the knowledge that I will be able to give it a few trial cuts.
            Thankyou. David Powell

            Comment


            • #7
              Post a picture of your mill, and also try to identify it on the "lathes UK" website.

              Comment


              • #8
                Believe me, I have had a good look at lots of pictures of milling machines, and I am familiar with many of the better known makes,but I have seen none quite like this.
                Initially I thought her very old, but the vertical head has Timken taper roller bearings and spiral bevels which seems to indicate a post 1925 or so job.
                So far I have not found any identifying marks or numbers, The main casting is a very hefty job for the size of the table.
                Both the Horizontal and vertical spindles are belt driven, there is no backgear.
                In the area she came from( Hamilton Ontario to Toronto) there were until the 1970s or so a number of small foundries which could have poured the main casting. I have had a few model steam engines made from locally cast castings.
                At a guess, maybe she was built, as a " foreigner" or " government job" for war work in WW2, some brackets etc are fabrications made with brazing or arc welding.From the scars on the vertical head she has had a fairly busy and hard life, yet the bed is virtually pristine.
                I will get my wife to take some photos and we will try to post them here.
                Regards David Powell.

                Comment


                • #9
                  In that case all the more reason to take and post some pictures. I'm sure I'm not the only one here that enjoys machine tool porn. And a rare small hobby mill most certainly qualifies ! ! !
                  Chilliwack BC, Canada

                  Comment


                  • #10
                    Originally posted by David Powell View Post
                    I just bought a small, apparently quite elderly,

                    Like yourself, and I



                    I will investigate the actual taper in the spindle this afternoon.
                    In the meantime I wonder , have any of you any idea of what collets might fit??
                    Regards David Powell.
                    It sounds old. Did you look at the B&S taper chart? Its probably an English taper. JR

                    Comment


                    • #11
                      I have a copy of the Crawford Collet catalogue in pdf form which is 186 Mb total. It shows dimensions of a large range of collets, so if your internet connection is reasonably fast, I might be able to email it to you, otherwise you would need to get some accurate dimensions of your spindle.

                      Comment


                      • #12
                        Too bad Hardinge literature is so hard to come by now. Their collet book showed practically every know collet with all dimensions.

                        I noticed the collet picture BCRIDER linked to. Capstan collets....those are more commonly called B&S dead length collets in this country. Used in screw machines and turret lathes. I guess capstan is turret lathe in England.

                        Comment


                        • #13
                          In Blighty, we usually call them capstans, but turret also is used.

                          Comment


                          • #14
                            The sort of use that a nautical capstan is put to sort of describes how the tool head on a capstan or turrent lathe functions. Somewhat better perhaps than the term "turret". Mind you the tool holders sticking out do rather look like the barrels of multiple cannon... So turret fits too.....
                            Chilliwack BC, Canada

                            Comment


                            • #15
                              It all gets more strange----- I now have the spindle out of the machine cleaned and on my bench. There seems to be provision for two toolholding arrangements. There is a Morse taper 3 bore extending 2 5/8" deep of such a size that #3 tapers do not bottom out and then as well for a length of about 1/4 " at the mouth there is a steeper taper which matches the collet which was in it when I got it.
                              I am simply going to ignore the collet, make a drawbar for a 3/8 by 16 thread to use my #3 MT collets which have been asleep in a drawer for 10 yrs or so.
                              I am still investigating the vertical head and will report later.
                              Regards to all David Powell.

                              Comment

                              Working...
                              X