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  • #324206
    martin107
    Participant
      @martin107

      Can anyone give a recommendation for a SPG 9512B milling machine with a R8 chuck please.

      cheers

      Martin

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      #8938
      martin107
      Participant
        @martin107
        #324222
        Oldiron
        Participant
          @oldiron

          Looks like a Sieg Clone. Most of these small mills in this range are OK for smaller work. Not as rigid as bigger machines so smaller cuts and a bit of care needed. I have a Chester Conquest which is similar. It is a good little machine. I have made many tools with it including a dividing head, several BXA tool holders and much more. Used with a good collett holder it should be OK.

          #324228
          JasonB
          Moderator
            @jasonb

            Probably a RealBull machine

            #324229
            mark smith 20
            Participant
              @marksmith20

              They arent bad but not very rigid ,a very solid bench will help alot.

              The gears would drive you mad ,hence buy or make your own belt drive and strip out the gears.

              The tilting column is a pain ,best to brace it somehow at the back where it joins to the base with a thick steel /aluminium plate.

              Possibly fit a gas strut of some kind to make the raising lowering of the head easier.

              Picture of mine below.

              I also replaced the cracked and torn rubber covers with homemade ones made out of  rubber coated kevlar material.

              I replaced the headstock bearings with taper roller bearings. (did the same with my chester conquest mini lathe that i used to own )

              The most annoying part is the fine feed,they may have improved but mines always been a pain. Has a habit of suddenly dropping and digging in to the work.

              All that said ive had my warco version for around 15 years or more and its been ok for small stuff .

              i have a bigger alexander gha mill now (still collecting tooling) so im using this less and less now.

              The mill is /was originally made by real bull and known under various guises such as xj12-300 .

              Some guy here has wrote a decent review and made similar alterations.

              **LINK**

              Edited By mark smith 20 on 29/10/2017 10:20:31

              p1350268.jpg

              Edited By mark smith 20 on 29/10/2017 10:30:12

              Edited By mark smith 20 on 29/10/2017 10:46:46

              #324318
              martin107
              Participant
                @martin107

                Many thanks to all, the review was quite interesting, the thing I like about it is that you can have a R8 chuck at no extra cost and as I am picking up by reading comments it is the way forward, as I am only thinking of doing small ali stuff for airguns it would seem sufficient for my needs and I also have a vertical slide on my ML7 as back up.

                Cheers

                Martin

                #324323
                JasonB
                Moderator
                  @jasonb

                  I think you will find the chuck is £60 and NO EXTRA POSTAGE when bought with a machine. Also be aware that those chucks are not ER chucks but a far eastern collet chuck which can be hard to find extra collets to fit.

                  Other suppliers will usually put any tooling purchased at the same time into the crate to save you postage.

                  #324334
                  martin107
                  Participant
                    @martin107

                    I ment that it has the R8 spindle fitted instead of a MT as most other small mills have and you have to buy the collet set extra from either them or any other supplier, I guess I should have said spindle not chuck in my post but I'm new to this game and sometimes use the wrong term.

                    Cheers

                    Martin

                    #324463
                    mark smith 20
                    Participant
                      @marksmith20

                      The fine feed on my warco xj12-300 has just decided to stop working 1/3 of the way through scribing graduations on a handwheel im making. Its just spinning around angry

                      #324467
                      mark smith 20
                      Participant
                        @marksmith20

                        Just removed the fine feed looks like the middle areas of the teeth on the worm gear are mangled .? Anyone know where i can get a replacement?

                        Thanks

                        p1350412.jpg

                        p1350410.jpg

                        #324596
                        mark smith 20
                        Participant
                          @marksmith20

                          If anyones interested one of the advertisers on here has them in stock at around £34 (with shipping and vat) , sounds a bit expensive to me compared to spares for the seig mills from arc.

                          The parts only 32mm diameter by 22mm long.Its not a proper worm gear either just probably a metric helical gear of some kind but i dont know anything about mod gears.

                          Does this sound expensive to anyone else??

                          Edited By mark smith 20 on 31/10/2017 10:34:39

                          #324600
                          Anonymous

                            It sure isn't a worm wheel! I'm not even sure it is a helical gear. If it is helical the teeth ought to slope to one side, or t'other, at the helix angle of the worm. It's not easy to to tell from the picture if this is the case. If it's a straight spur gear then in theory it will only have point contact, which is probably why it is worn. For a spur gear to mate with a worm the axes need to be moved from a right angle by the helix angle of the worm. I wonder if even this was fudged, and the gears mated at 90°, as the gear only appears to be worn in the centre of the teeth?

                            The DP/Mod of the gear will be determined by that of the worm. Assuming that the pitch of the worm thread is rational, say 3mm, then the DP/Mod of the gear will be irrational as pi will be a factor. Or in other words the gear will not have a standard DP/Mod value.

                            Having said all that, the gear teeth don't look that bad. Are you sure the worm/gear is the issue?

                            Andrew

                            #324601
                            Michael Gilligan
                            Participant
                              @michaelgilligan61133

                              Mark,

                              Before spending £34 on a direct replacement, I would have a very close look at the design and execution of the gear pair. …. It appears, from your photograph, that the depthing is way too low: I can't see any other reason why [with no missing teeth] the mechanism should just spin freely.

                              Big Question: Is the depthing adjustable ?

                              MichaelG.

                              .

                              Edit: My post crossed with Andrew's … but I think we're on the same wavelength.

                              Edited By Michael Gilligan on 31/10/2017 10:55:16

                              #324602
                              mark smith 20
                              Participant
                                @marksmith20

                                Hi Andrew, the teeth are at an angle but only a few degrees. The worm shaft does only touch very slightly in the middle which is probably why they are such a pain to use and now it seems it is mangled in the middle and just totally slipping when turned as there is no contact.

                                I dont like the idea of buying another which will probably be just as bad after a few months of use.

                                I`ll take some measurements of the gear and teeth . The teeth maybe dont look too bad but if the worm shaft is only making contact at the very edge of the middle then its not really designed properly.

                                Thanks

                                #324622
                                mark smith 20
                                Participant
                                  @marksmith20

                                  Hi Andrew, yes the worm shaft and gear make very little contact , ive always had a problem of the fine feed suddenly tightening up then dropping too far. I just put it down to Chinese manufacture.

                                  When i push the worm shaft teeth into the gear in my hands ,there is around a 1mm gap at the bottom which doesnt sound ideal.

                                  The block at the handwheel end as a bit of wiggle room so that tightening the block pushed downwards has a tendency to push the gear end into the worm gear but not by much.Nothing is a tight remotely precision fit.

                                  here a few more pictures .

                                  The pitch of the gear is around 3mm as best as i can tell ,with 29 teeth and a outside diameter of 30.90mm.

                                  p1350421.jpg

                                  p1350428.jpg

                                  p1350434.jpg

                                  p1350436.jpg

                                  Edited By mark smith 20 on 31/10/2017 12:32:32

                                  #324634
                                  Michael Gilligan
                                  Participant
                                    @michaelgilligan61133

                                    Mark,

                                    Thanks for posting the photos.

                                    On that evidence, I would recommend that you buy a decent worm-wheel [to suit the available centre distance and the existing worm]: Then adapt it to suit.

                                    Note … If the worm is a difficult pitch it might be better to buy the pair.

                                    MichaelG.

                                    #324641
                                    Bazyle
                                    Participant
                                      @bazyle

                                      It looks like you have 'good' tooth still at the outer end away from the dog. You can prolong its use by

                                      A) machine off much of the dog teeth,
                                      B)recut the dog teeth deeper which is a low precision job possible even if you don't have a rotary table,
                                      C) turn off some of the gear teeth edge beside the dog
                                      D) make a thick washer to take up the slack for the bit you cut off

                                      A bit of measurement and good photos would make a good write up for MEW for other owners and earn you the cost of the cutter to make a replacement.

                                      I think the above is easier/cheaper for any beginners than making a new gear though the follow up article could be doing that.

                                      #324646
                                      Michael Gilligan
                                      Participant
                                        @michaelgilligan61133

                                        Interesting approach, Bazyle yes

                                        But, I think the underlying problem is simply that the mesh is too shallow; in which case [unless that is corrected], the repair would be 'Bad as New'.

                                        I do agree though that writing-up whatever Mark does to fix this should be of interest to many.

                                        MichaelG.

                                        #324647
                                        mark smith 20
                                        Participant
                                          @marksmith20

                                          Andrew ,i have thought of buying a helical gear but the angles of the the teeth are usually steeper on the common off the shelf ones such as from HP Gears (17 degrees or something) ,this one looks like only around 3 degrees.

                                          I could of just turn off the teeth part of the original and bored and glued on a rplacement bit.

                                          Bazyle , i did wonder about that you mentioned , problem is the teeth should ideally engage alot more than they do even if the part wasnt worn and it causes a lot of slack and backlash which id rather not have on the fine feed.

                                          #324651
                                          mark smith 20
                                          Participant
                                            @marksmith20

                                            When i look at the worm gear it probably is a mod 1 worm gear but without the hobbing just cut straight across. Also size seems to fit with the standard off the shelf versions but they have 30 teeth not the odd 29 teeth as this has.

                                            Such as this **LINK**

                                            the dimension seem about right apart from the tooth number.

                                            I was thinking it was a helical gear but the angles are too shallow.

                                            #324653
                                            Brian G
                                            Participant
                                              @briang

                                              Could you bore out the block and fit an eccentric insert to lower the worm onto the wheel?  Or perhaps more simply lower the entire block slightly by elongating the fixing holes?

                                              Brian

                                              Edited By Brian G on 31/10/2017 14:50:13

                                              #324655
                                              Anonymous

                                                Ok, it's definitely a helical gear, or at least masquerading as one. The helix angle will be small, as it should match the worm. Even if cut straight across at an angle, rather than the true helix, it should be ok.

                                                Ignoring the helix angle it seems to be a 1Mod gear, which gives a circular pitch of 3.14159 etc. The pitch of the worm should be the same, ie, irrational. I wonder if they've fudged it to mate with a worm with a 3mm pitch?

                                                The teeth are worn off centre and only on the tops of the teeth. So I agree with Michael that the meshing is wrong. Whether this is because the alignment of the gear housing is wrong, or gears with different circular pitches are being forced into mesh is a moot point. Either way it's a mess; where's Oliver Hardy when you need him?

                                                Andrew

                                                PS: Well I never, it seems I share a birthday with Oliver Hardy smile o

                                                #324658
                                                mark smith 20
                                                Participant
                                                  @marksmith20

                                                  I think the whole fine feed thing is a joke, i think the whole problem stems from a mixture of things starting with back lash on the rack and pinion on the main column. The fine feed when it does engage has to turn several times just to get the backlash out before it actually fine feeds in one direction and often the whole head drops around a mm or two and then you have to turn it multiple turns to get it back where you want it.

                                                  i`ll have to think what im going to do to fix it so it works a bit better.thinking

                                                  #324672
                                                  mark smith 20
                                                  Participant
                                                    @marksmith20

                                                    p1350412.jpgAlso i suspect that these mechanisms later were later changed somewhat as there are parts of the fine feed rod that appear on the parts diagram i got from a advertiser on here that certainly arent on mine such as the fine feed rod which on mine is just a plain rod but in the brochure it is different and more similar to the seig mini mill variation.Such as part 138 (adjustable union)

                                                    mill 1.jpg

                                                    mill2.jpg

                                                     

                                                    mill3.jpg

                                                    Edited By mark smith 20 on 31/10/2017 16:47:49

                                                    Edited By mark smith 20 on 31/10/2017 16:49:43

                                                    Edited By mark smith 20 on 31/10/2017 16:51:49

                                                    #324675
                                                    fishy-steve
                                                    Participant
                                                      @fishy-steve

                                                      Hi Mark,

                                                      Is your worm pinned to the shaft like the diagram? Have you checked that it hasn't sheared?

                                                      Steve.

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