Is there such a thing as an ‘external reamer’?

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Is there such a thing as an ‘external reamer’?

Home Forums Beginners questions Is there such a thing as an ‘external reamer’?

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  • #559043
    John Reese
    Participant
      @johnreese12848

      There are also adjustable hollow mills like these:

      **LINK**

      There are also solid hollow mills with some degree of adjustment. The OD has a slight taper. A ring is pressed on the OD to provide adjustment.

      **LINK**

      Brown & Sharpe made hollow mills for use on screw machines.

      **LINK**

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      #559162
      Tim Stevens
      Participant
        @timstevens64731

        There is a hidden problem with the Paul Lousick method using a boring head of the type shown (at 01:50:36 above). To cut the inner edge with the standard tools, the head needs to revolve backwards. This doesn't seem like a problem until you remember that the head itself (the black bit) is carried on a large thread on the taper fitting (the shiny steel bit). When this unscrews part way through the job, it is not just the newly-formed part that gets mangled.

        Sorry – bin there, done that…

        Cheers, Tim

        #559166
        JasonB
        Moderator
          @jasonb

          Easy enough to grind up a tool for the boring head so it can be used to do outside diameters while still rotating the same way, done it plenty of times.

          #559196
          Robin Graham
          Participant
            @robingraham42208

            Thanks for further replies. I have 12 to do, so just into double figures, hence the desire to look for a 'mass production' method. I was hoping that there was a (modestly priced!) off-the-shelf tool which would do what I want. It looks like the tools John Reese linked to are what I had mind but, as Emgee points out, not modestly priced! I guess I could make something similar out of silver steel but after reading replies and fiddling about a bit with a boring head I've come to the conclusion that for a dozen pieces, to get the sort of tolerance I want, I'm best off just turning the the spigots normally. It takes me maybe half an hour per piece, but I'm time-rich.

            Thanks again for suggestions and apologies if this has been a time-wasting thread – but sometimes one has to travel down dead ends in the learning process.

            Robin.

            #559470
            John Reese
            Participant
              @johnreese12848
              Posted by Emgee on 18/08/2021 23:46:45:

              Posted by John Reese on 18/08/2021 22:32:18:

              Hollow mills are available. Here s an example:

              **LINK**

              Mouth watering price £100 + shipping from USA and then Duty + VAT

              The problem using a die head would be cutting to the disc face, usually the dies are inset slightly.

              Emgee

              Hollow mills are made in the UK. About 52 Pounds for 8mm.

              Projection type chasers would allow the die head to cut up to a face.

              #559471
              John Reese
              Participant
                @johnreese12848

                For a dozen parts special tooling cannot be justified.

                #559482
                pgk pgk
                Participant
                  @pgkpgk17461

                  Could one get away with finagling a fitting to use rotabroach cutters…not that expensive if one can find a size to leave the correct spigot?

                  pgk

                  #559485
                  Nick Wheeler
                  Participant
                    @nickwheeler
                    Posted by John Reese on 23/08/2021 00:42:22:

                    For a dozen parts special tooling cannot be justified.

                    When they each take 30 minutes to make? I'd spend the £50 in a heartbeat to get that done to a few minutes per part. Getting them all the same without any extra measurement and faffing about just adds to the value.

                    #559489
                    jann west
                    Participant
                      @jannwest71382

                      ebay is currently offering a job lot of capstan tooling, with what looks (??) like an appropriately sized box tool in the top left of the 1st photo: ebay item: 393514125752

                      https://www.ebay.co.uk/itm/393514125752?hash=item5b9f4509b8:g:i0wAAOSwOIFhG83l

                      Although for 12 items it'll probably be more effort to "make work" than just making the parts by hand.

                      Seems like the better answer to making 12 items is getting a DRO.

                      #559496
                      Anonymous
                        Posted by John Reese on 23/08/2021 00:42:22:

                        For a dozen parts special tooling cannot be justified.

                        Oh dear, I've been making special tooling for onesies and twosies:

                        cutting tools.jpg

                        embarrassed

                        Andrew

                        #559500
                        JasonB
                        Moderator
                          @jasonb

                          But unlike Robin's parts you could not have easily done them without the special tooling.

                          As his problem was just an involuntary movement of the handwheel then a bit more time spent making sure it is rotated to the right dial or DRO reading is all that is really required having made a not of the reading from the first one that fitted.

                          As I said earlier with any tailstock held tooling there is just as much chance of overfeeding that as the crossslide and marking the face of the part, probably more.

                          #559508
                          Nigel McBurney 1
                          Participant
                            @nigelmcburney1

                            bear in mind that end feeding tools such as hollow mills were mainly used on capstan and autos where the turret was far more rigid than a centre lathe tailstock,and by the time that a suitable tool is found ,bought at some cost,and set up and tried out ,it is far quicker to turn a dozen or so parts by the normal centre lathe practice,the one snag with short spigots turned from bar as in the photo is that when trying to use a mikcrometer is that the mike frame gets in the way,and a vernier has to be used,which is not as accurate as a mike. I have used hollow mills on a Ward 2a and never really liked them particularly when trying to hold fine limits on diameter over lots of components.

                            #559526
                            Neil Wyatt
                            Moderator
                              @neilwyatt
                              Posted by Andrew Johnston on 23/08/2021 10:12:00:

                              Posted by John Reese on 23/08/2021 00:42:22:

                              For a dozen parts special tooling cannot be justified.

                              Oh dear, I've been making special tooling for onesies and twosies:

                              cutting tools.jpg

                              embarrassed

                              Andrew

                              Isn't a Model Engineer's 'onesie' actually a boiler suit?

                              Neil

                              #559527
                              Neil Wyatt
                              Moderator
                                @neilwyatt
                                Posted by JasonB on 23/08/2021 10:21:35:

                                But unlike Robin's parts you could not have easily done them without the special tooling.

                                As his problem was just an involuntary movement of the handwheel then a bit more time spent making sure it is rotated to the right dial or DRO reading is all that is really required having made a not of the reading from the first one that fitted.

                                As I said earlier with any tailstock held tooling there is just as much chance of overfeeding that as the crossslide and marking the face of the part, probably more.

                                Perhaps it's time to make a bed stop for the lathe, which will continue to prove its worth on future jobs?

                                Neil.

                                #559528
                                JasonB
                                Moderator
                                  @jasonb

                                  I't's the cross slide he needs a stop for to give fixed diameter, suggested early on in thread.

                                  Edited By JasonB on 23/08/2021 14:16:34

                                  #559534
                                  Dave S
                                  Participant
                                    @daves59043

                                    In brass its a fair bet that for 12 an unhardened steel tool will last.

                                    This:

                                    797bdea1-1d3a-4655-92a1-7f0126ed0354.jpeg

                                    was made to produce a stem tube and crown guards in brass:

                                    a89e6cdc-81e1-4e0e-807a-9cfd309674c8.jpeg

                                    61470835-adf3-4acd-be70-2900a16ab105.jpeg

                                    Its much smaller, but its not really any different in process. Given the tool is still silver coloured I almost certainly didn't heat treat it.

                                    Make the hole the correct depth and it wont overfeed.

                                    I would bore a suitable hole in a piece of steel bar, ensuring it was the correct depth, then just use a hacksaw /files to gash the teeth. Being brass no rake is required. As its a spigot on a flat plane, rather than the tube feature I was making there shouldn't be a tendency for the chips to pack up – they can just fall off.

                                    To use turn the spigot to correct length and a small amount oversize in diameter, then run tool in in the tailstock.

                                    Dave

                                    #559854
                                    Robin Graham
                                    Participant
                                      @robingraham42208

                                      Apologies for not getting back to this and replying to further contributions sooner – I've been bad in health recently and unable to face going down to the dungeon (aka workshop), so I've been enjoying a pampered superterranean existence.

                                      I have digital scales on my lathe, so in principle I could use the cross slide scale to achieve the reproducible accuracy I'm aiming for. The reason that I was wondering about tailstock tooling is that I need either to (a) change tooling to part off each item, or (b) remove the stock from the lathe to saw Obviously (b) would lose reference, and I worried that (a) would do too. I normally use a Chinese QC toolpost:

                                      qctoolpost.jpg

                                      but I don't know how accurately it relocates the tool after a change. Perhaps I should measure, or maybe someone can tell me.

                                      I'm intrigued by the idea of a cross-slide stop, but at the moment I'm not sure how I could implement one on this machine. I have made a longitudinal stop, and, despite having scales, it's paid make the time of making many times over when doing repetitive work

                                      In the light of Dave S's post, I'll try a home-made tailstock cutter just to see.

                                      Robin

                                      #559877
                                      Howard Lewis
                                      Participant
                                        @howardlewis46836

                                        If the stock is large diameter, parting off in the lathe will save your muscles, although wastes more material.

                                        If it needs to be said, ensure that the Tailstock is properly aligned before using a cutter in the Tailstock, to minimise the risk of cutting oversize on OD, and undersize on ID..

                                        Howard

                                        #559885
                                        noel shelley
                                        Participant
                                          @noelshelley55608

                                          I did check new relavent rotabroaches and I found 9.6mm or 10.4 ID so no help ? Noel.

                                          #559897
                                          Michael Gilligan
                                          Participant
                                            @michaelgilligan61133

                                            Just a thought …

                                            For Robin’s application, the body of a ‘surplus’ drill-chuck could be modified to accept three cutters.

                                            [ no, I’m not suggesting using the jaws ]

                                            MichaelG.

                                            #559903
                                            ega
                                            Participant
                                              @ega

                                              Robin Graham:

                                              Cross slide stops: I have an album with a couple of photos which might help.

                                              #559912
                                              Dave S
                                              Participant
                                                @daves59043

                                                Just remembered seeing this:

                                                A rolling blog of everyday life on and around the workbench (shwoodwind.co.uk)

                                                where Stephen uses an ER collet as a cutter.

                                                Dave

                                                #559932
                                                Tony Pratt 1
                                                Participant
                                                  @tonypratt1

                                                  Cross slide stops, you don't need them you have a DRO on your by the looks of it decent lathe? The QC tool post you have has been tested on YouTube many times & will typically repeat within .0005", I may be proved wrong but your 'external reamer' will be a waste of time.

                                                  Tony

                                                  #560096
                                                  Robin Graham
                                                  Participant
                                                    @robingraham42208

                                                    Thanks for further replies. I realise that this is getting into 'by the time I'd written/read all these posts I could have made a hundred' territory, but for me the point of making stuff is not only the finished part, but also learning about tooling and techniques. When I started out I didn't even understand how metal could cut metal, but now I know about HSS and Carbide and Rockwell scales and all that stuff.

                                                    Pause to polish fingernails on lapel.

                                                    Howard – I once cut a 2" round steel bar with my muscles and a hacksaw. Never again. It looked like it had been chewed through by a mad beaver. I bought a bandsaw.

                                                    Noel – I looked at rotabroaches, but I think they are designed with the OD in mind, and anyway I I think the shank diameter is too big to mount in a tailstock chuck. Thank you for checking though.

                                                    Michael – food for thought perhaps. Though from your somewhat gnomic reply I'm not sure what exactly you have in mind.

                                                    ega – I had a look at your album. Nice work, but I'm not sure that in my case the effort of taking off the saddle to drill for the stop would be worth it as I have a digital scale.

                                                    Dave S – I've bookmarked that, An interesting 'DIY' approach.

                                                    Tony – half a thou repeatability for the QCTP would be fine – I'm astonished actually, I'd been thinking more like 5 thou, I'll have to measure.

                                                    Robin.

                                                     

                                                     

                                                    Edited By Robin Graham on 28/08/2021 03:08:50

                                                    Edited By Robin Graham on 28/08/2021 03:15:39

                                                    Edited By Robin Graham on 28/08/2021 03:17:22

                                                    #560100
                                                    Michael Gilligan
                                                    Participant
                                                      @michaelgilligan61133
                                                      Posted by Robin Graham on 28/08/2021 03:07:36:

                                                      Thanks for further replies. […]

                                                      Michael – food for thought perhaps. Though from your somewhat gnomic reply I'm not sure what exactly you have in mind.

                                                      .

                                                      I didn’t have anything exactly in mind, Robin

                                                      … it was just a fleeting thought perhaps [or perhaps not] worth sharing.

                                                      The empty shell of a 1/2” Jacobs tailstock Chuck [locked-up tight] could be adapted to accept a cutter or three … possibly saving a lot of tool-building time.

                                                      MichaelG.

                                                      .

                                                      33526553-0f4b-4214-b93c-d3cb4e95bc1c.jpeg

                                                      Credit: https://toolsmach.com/en/content/14-drill-chucks

                                                      Edited By Michael Gilligan on 28/08/2021 07:05:09

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