Milling/drilling spindle

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Milling/drilling spindle

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  • #374026
    Steve Crow
    Participant
      @stevecrow46066

      I want to make a small belt driven milling/drilling spindle to accept 8mm watchmakers collets. I envisage making the body from 3/4" mild steel square stock.

      Has anyone out there made one of these or similar?

      I would welcome any advice regarding bearings etc and preventing any play along the spindle axis.

      Many thanks

      Steve

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      #9351
      Steve Crow
      Participant
        @stevecrow46066
        #374028
        JasonB
        Moderator
          @jasonb

          Given that you probably want at least a couple of mm of spindle around the collet body at a minimum then a 12mm spindle, more if the head is to fit without excess overhang. into a 3/4" housing does not leave much room for bearings, would probably have to be plain bronze to keep them thin enough.

          #374030
          Steve Crow
          Participant
            @stevecrow46066

            I was planning to use a 12mm spindle. The 3/4" dimension is not set in stone – I could go up to 1 inch square stock.

            I realise I won't have much space so I am thinking about oilite sleeves. What concerns me are the thrust bearings to prevent play.

            #374031
            Hopper
            Participant
              @hopper

              Have you considered the modern approach of buying a readymade milling spindle, with collets and motor with speed controller all in a package for under 50 quid? eg this one here **LINK**

              I don't think I could buy the material to make one myself for that. Not even for double that probably. Crazy world we live in.

              #374042
              Steve Crow
              Participant
                @stevecrow46066

                I have considered the ready made approach but the spindle you mentioned is a little large for my Sherline lathe.

                I'm also considering using 20mm round bar for the housing so it will fit in the clamp seen in this picture.

                mill_01.jpg

                #374049
                Ady1
                Participant
                  @ady1

                  There are also brushless spindles about nowadays

                  Even on cordless drills you notice the extra grunt with a brushless unit, especially under load, and a small milling unit needs to handle load to be successful

                  #374056
                  IanT
                  Participant
                    @iant

                    If you only need a vertical capability Steve – I'd consider using a Taig ER16 head. Mine (from Peatol) cost about £80 a few years back but it is a very solid piece of kit and works well. It will not fit within my EW's swing for end-milling/drilling though but works fine when set vertically – same as you have mounted your Proxxon.

                    For smaller DIY designs – Harpit's "Spindle" book in he Home Workshop series is about the best reference I think.

                    And for Brushless options – Steve Jordan (on YouTube) has been talking about various approaches with stuff he's purchased from BangGood & eBay. Maybe some useful ideas there too…

                    Below – My Taig head mounted on the EW…. a very useful vertical milling capability for smaller items

                    Regards,

                    IanT

                    EW with Taig - 101113.jpg

                    #374062
                    Steve Crow
                    Participant
                      @stevecrow46066

                      Thank you Ian, that looks to be a very useful setup. I would really like to use the spindle in positions other than vertical and to continue to use my watchmakers collets, hence my desire for a small compact spindle.

                      As for the book, I am intending to purchase it.

                      Regards

                      Steve

                      #374080
                      Trevor Drabble 1
                      Participant
                        @trevordrabble1

                        Steve , Bit of a long shot , but although he's now retired from the model engineering business , Mr Jackson of Arrand ( 01664 454566 ) MAY just have one of his excellent spindles available from his old stock . Trevor .

                        #374085
                        Steve Crow
                        Participant
                          @stevecrow46066

                          Thank you Trevor. I've googled them and seen area pictures. Have you any idea of the dimensions of the square housing?

                          Cheers

                          Steve

                          #374088
                          John Reese
                          Participant
                            @johnreese12848

                            If you are building the spindle from scratch consider a straight shank ER collet chuck. The ER collets are better suited to holding tools than lathe type collets.

                            #374092
                            Harry Wilkes
                            Participant
                              @harrywilkes58467

                              Hi Steve

                              This guy plays around quite a lot with various collet spindles etc maybe worth a watch https://www.youtube.com/watch?v=BuAp1VvOVrA&t=0s

                              H

                              #374115
                              Tim Stevens
                              Participant
                                @timstevens64731

                                May I suggest that the bearings could usefully be magneto bearings. That is a trade description so you don't have to buy one of Mr Bosch's masterpieces and strip it down. They are like small cup & cone bearings, and they work like small tapered roller bearings, so if you adjust the pre-load on assembly you can get a free running shaft with no end play and no side play. Here is a link to an example:

                                https://simplybearings.co.uk/shop/p42605/E7-Magneto-Bearing-7x22x7mm/product_info.html?backstep=1

                                Hope this is useful

                                Cheers, Tim

                                #374163
                                Steve Crow
                                Participant
                                  @stevecrow46066

                                  Thanks Tim, I've had a look at these and they seem ideal but the outer diameter is too large for the compact housing I'm trying to achieve. I'm looking at possibly a needle roller cage between spindle and housing but am still puzzled by how to eliminate endplay.

                                  I've ordered the Workshop Practice spindle book and hopefully this will shed some light on the problem.

                                  Cheers

                                  Steve

                                  #374165
                                  geoff walker 1
                                  Participant
                                    @geoffwalker1

                                    Steve,

                                    I have a potts milling spindle which I use a lot.

                                    I had problems with spindle end play and solved it by removing one of the adjustment collars and replacing it with a slim thrust ball bearing (from simply bearings). The remaining collar is squeezed lightly on to the bearing ring and the end float is gone, completely. I locked the collar in place with small grub screws to retain the setting.

                                    My potts has plain parallel bronze bearings.

                                    Geoff

                                    #374167
                                    JasonB
                                    Moderator
                                      @jasonb

                                      Plenty of small lathes just use a pair of ballraces for the spindle and end play is dealt with by threading the end of the spindle so a nut/nuts can be used to take up the play.

                                      Assuming a 12mm dia spindle with a larger "head" to accomodate the collet taper then you can get thin ballraces 12mm ID and 18mm OD which you should be able to get into say a 20mm casing, could even narrow it down in the middle if you want to get it into a toolpost. This would mean a small amount of overhang due to the bearing not being around the widest point of the collet.

                                      If you wanted to have the whole of the spindle within the bearings then you would need say a 15ID x 24OD thin bearing at the tapered end but could still use the smaller 12mm ID at the far end. Body would need to be 26mm or 1" at a push but could still be thinned down for most of it's length to make it easier to clamp but I would think one flat face would be a good idea.

                                      The "head" would bear against the inside of one bearing and your fine threaded nut against the one at the opposite end. Spindle protrudes beyond the nut so your drawtube can bear on the end of the spindle

                                      #374169
                                      Michael Gilligan
                                      Participant
                                        @michaelgilligan61133
                                        Posted by Steve Crow on 01/10/2018 08:06:52:

                                        I want to make a small belt driven milling/drilling spindle to accept 8mm watchmakers collets.

                                        [ … ]

                                        I would welcome any advice regarding bearings etc and preventing any play along the spindle axis.

                                        .

                                        Steve,

                                        May I suggest that you have a look for a watchmaker's lathe headstock, and adapt that ?

                                        To the best of my knowledge there is no better compact bearing arrangement than the 'opposed double cones' which were common in those lathes.

                                        Here is a beautiful example of exactly what I think you need. **LINK**

                                        Much, much, easier than building something of similar performance from scratch !

                                        MichaelG.

                                        #374173
                                        Steve Crow
                                        Participant
                                          @stevecrow46066

                                          Hi Michael, that Lorch set up is gorgeous. I would give my right arm for a KD50 with all the bits. I might struggle to use it without a right arm though!

                                          I've got this headstock. Maybe I can adapt this.

                                          headstock.jpg

                                          #374183
                                          Ian S C
                                          Participant
                                            @iansc

                                            One way I got rid of end play in a shaft(plain bearings), I fitted the ball from a bearing, I think it was 1/8" in the centre hole in the end of a 1/4" shaft, this bared against a hardened disc in the outer end of the bearing bush, this could work with a ball race.

                                            Ian S C

                                            #374186
                                            JasonB
                                            Moderator
                                              @jasonb

                                              Just had a look at the spindles book an they are all more or less of the same design I described above, just a few variations on the nut arrangement.

                                              #374195
                                              Neil Wyatt
                                              Moderator
                                                @neilwyatt

                                                The WPS book 'Spindles' by Harprit Sandhu is full of practical designs.

                                                Neil

                                                #374196
                                                Michael Gilligan
                                                Participant
                                                  @michaelgilligan61133
                                                  Posted by Steve Crow on 02/10/2018 08:59:37:

                                                  I've got this headstock. Maybe I can adapt this.

                                                  .

                                                  That looks like a WW fitting headstock … If so, it should be a simple matter to make an interface plate.

                                                  It all looks very promising, to me. yes

                                                  MichaelG.

                                                  #374200
                                                  JasonB
                                                  Moderator
                                                    @jasonb

                                                    Had a quick sketch to illustrate what I suggested earlier using the thin bearings and along the lines of the 3/4" and 1" spindles in the book but with a hollow spindle to take WW collets and drawtube. I can't really see the point in having a round body and then a big clamp round it so you can hold it so went for 20×26 which allows for M4 fixings down the side though square would do if you wanted to keep it compact as per the opening post.

                                                    spindle1.jpg

                                                    spindle2.jpg

                                                    spindle3.jpg

                                                    I even did it with an Ali body so Neil can practice his anodisingwink 2

                                                    #374206
                                                    Neil Wyatt
                                                    Moderator
                                                      @neilwyatt
                                                      Posted by JasonB on 02/10/2018 11:40:40:

                                                      Had a quick sketch to illustrate what I suggested earlier using the thin bearings and along the lines of the 3/4" and 1" spindles in the book but with a hollow spindle to take WW collets and drawtube. I can't really see the point in having a round body and then a big clamp round it so you can hold it so went for 20×26 which allows for M4 fixings down the side though square would do if you wanted to keep it compact as per the opening post.

                                                      spindle1.jpg

                                                      Now we know how you 'make' all those stationary engines so quickly

                                                      Neil

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