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  1. #61
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    J&H -

    the red circled item is part of the dog ring and there is only the 1. I have no idea what it does but my thought is that the rounded nose on it helps the dogs to align properly. In my pictures neither of the dogs are engaged - the red arm that they are both attached to is vertical whereas in an engaged position it will lean to one side or the other.

    I think you keep referring to the 74T gear but mean the 72T?

    The 1:1 4:1 16:1 lever is part of the speed change mechanism. There is a rotary lever (not shown in any picture - sorry ) that in each position gives a choice of three speeds dependant upon whether the level is in 1:1 4:1 or 16:1 (slowest to fastest).

    The W/M lever only chooses between the 2 dogs and nothing else. I cannot see that it can move the whole shaft in any way. Even if it did, there is absolutely nothing for the 63T gear to mesh to UNLESS the whole back gear area has been put together wrong. Currently the 74T and the 63T back gears do NOTHING meaning they feel like spares for swapping out.

    Hopefully Stefan G can help find some paperwork for the lathe!!!!

    EDIT: - and I a agree that the back gears is the only place that could be providing any Whitworth to Metric conversion

  2. #62
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    Quote Originally Posted by Mk1_Oz View Post
    J&H -

    the red circled item is part of the dog ring and there is only the 1. I have no idea what it does but my thought is that the rounded nose on it helps the dogs to align properly. In my pictures neither of the dogs are engaged - the red arm that they are both attached to is vertical whereas in an engaged position it will lean to one side or the other.

    I think you keep referring to the 74T gear but mean the 72T?

    The 1:1 4:1 16:1 lever is part of the speed change mechanism. There is a rotary lever (not shown in any picture - sorry ) that in each position gives a choice of three speeds dependant upon whether the level is in 1:1 4:1 or 16:1 (slowest to fastest).

    The W/M lever only chooses between the 2 dogs and nothing else. I cannot see that it can move the whole shaft in any way. Even if it did, there is absolutely nothing for the 63T gear to mesh to UNLESS the whole back gear area has been put together wrong. Currently the 74T and the 63T back gears do NOTHING meaning they feel like spares for swapping out.

    Hopefully Stefan G can help find some paperwork for the lathe!!!!

    EDIT: - and I a agree that the back gears is the only place that could be providing any Whitworth to Metric conversion
    Too many numbers.... Lol. Yes, I keep mixing up the 72 and 74.

    When you say the circled bit is part of the dog ring, does it move with the dog ring, or is it stationary and the dog ring slides over it?

    And bugger on the W/M lever, I was really hoping we'd find some at least kind of sleeve or something attached to engage or disengage the 'christmas tree' as Stu calls it.

    Back to my scribbling, I'm trying to figure out Stus layout, but had to work out some usable gear numbers first, lol.

    It's getting incredibly more likely though that there's supposed to be another plate inside the rear change gear cover to cover setting that part up, and you're just supposed to KNOW that you need to do that in addition to following the threading chart. Probably assume you read the instruction manual or something silly like that.

    *EDIT* Goddamnit, he's right again. *Deleted, might start fresh. Thinking*

  3. #63
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    I'd say the red circled thing is just the end of the key the gear is on.

    Been trying to brute force the maths of the gears teeth numbers and just seen a mistake that means I've been wasting my time. lol

    Tomorrow

  4. #64
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    Quote Originally Posted by Jekyll and Hyde View Post
    ...When you say the circled bit is part of the dog ring, does it move with the dog ring, or is it stationary and the dog ring slides over it?...
    It is part of the dog ring. It is the first part of the dog ring to touch the shaft/gear. That is why I believe it is there to line up the dogs (similar to synchro hubs in a car gearbox).

    I will sleep on it all......

    Thank you everybody for your input so far.....

  5. #65
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    So, I proved Stu right (GRRR! lol). I was thinking that pretty much proved the need for changing the external gearing, but now I'm not so sure again...

    I buggered around with different teeth counts to get the correct 2:1 ratio between each metric position, and ended up settling on 90/60 for the gears on shaft A, and 75/100 on shaft B. This gives a reduction of 2 each letter step.

    So in metric configuration, A is 1:1 to the bottom shaft - but in imperial configuration, A would be 0.83333(recurring) times the speed of the upper shaft. But what I can't work out is whether that's useful as a conversion factor or not, but I've seen that bloody number somewhere before with respect to threading, I'm sure. Of course there are probably other teeth counts that would work that give a different ratio here.

    It would seem weird if you have an imperial leadscrew to not have the imperial threads 1:1, but there could be a couple of reasons - it might cancel out with the intended external change gear train. Or possibly you get a better selection of metric threads doing it that way.

    But still doesn't solve how to have both input (63 and seventy something ) gears driven at the same time without locking each other up, and if we can't do that I reckon we must be at the point where external change gears are required?

    If that's where we're at, I'd guess the 63 is in the right spot, being a semi-common alternative to the 127. We know that the output at 'A' is 1:1 with the output from the spring pin tumbler, and if we count the teeth on that tumbler and the correlating christmas tree gear at a given pitch (via the table), we can calculate what the train needs to be from there up to the spindle.

    But the imperial part is giving me a bit of a headache - unless we count the teeth on the gears in the box (on A and B), I don't think we can work it out? We could assume that .83333 (recurring) is correct, and try to get there with that, and it may or may not work out. Otherwise of course, it's the same as the metric, apart from the tumbler/christmas tree gearing going the opposite way...

    Stu, thoughts?

    *EDIT* Actually, I'm assuming we can reverse quackulate from the table this part, but maybe we also need the tooth count from the sliding A-D gear and one of its mates, in addition to the tooth count from the 'lead' gear of the lead/feed lever, and the gear that drives that? Thinking, thinking....

  6. #66
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    According to Lathes UK, this lathe can do 80 Imperial pitches. Given the 10 gear cluster and the 4 A,B,C,D there is a range of 80 pitches.
    My best guess of the 10 gear cluster is:
    posiion/teeth
    1/16
    2/18
    3/19
    4/20
    5/22
    6/23
    7/24
    8/26
    9/27
    10/28

    To get these pitches, and taking the lead screw pitch to be 0.5 inch (ie 12 threads in 6 inch) and not 6 threads in 12 inches, ie 2TPI.
    so to make a 16TPI thread, the chuck will rotate 16 times and the lead screw will rotate 2 times to make 1 inch of thread.

    Set the spring trigger to 1; this has to give 16 tpi provided the lever II is set to give a 4:1 reduction.


    This gear box arrangement is similar to the Southbend CQ box. Ie input goes through a double compound divide by 2 gear train then into the 8 cluster gears. The Eriksen has the drive into the 10 gear cluster then into a 3/4/metric? stage divide by 2 arrangement. What complicates the design is the ability to feed two different shafts and also apparently includes the Imperial/Metric selection.
    When this all works out OK then the starting point has been found.

    see lathes uk
    Eriksen "Emato" 180-NE, 200-NE & 50/200Rv Lathes

  7. #67
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    Quote Originally Posted by Mk1_Oz View Post
    It is part of the dog ring. It is the first part of the dog ring to touch the shaft/gear. That is why I believe it is there to line up the dogs (similar to synchro hubs in a car gearbox).

    I will sleep on it all......

    Thank you everybody for your input so far.....
    This confuses me. It shouldn't but it does. The one in dog ring B is in a different place relevant to the one in dog ring A (you can just see it poking out). Which makes sense if it's a fixed key on the shaft like Stu is saying (even though they appear to be a little different distance away from the dog on the main cluster), and what I would have thought, but you say it's definitely moving with the dog ring? That just doesn't quite seem right to me - especially since it would line it up exactly a tooth width out from where it should be, if that was its intended purpose? As in, the male teeth on one dog would directly line up with the male teeth on the other dog, but shouldn't the male teeth engage the female 'teeth'?

    Quote Originally Posted by rumpfy View Post
    To get these pitches, and taking the lead screw pitch to be 0.5 inch (ie 12 threads in 6 inch) and not 6 threads in 12 inches, ie 2TPI.
    so to make a 16TPI thread, the chuck will rotate 16 times and the lead screw will rotate 2 times to make 1 inch of thread.
    Saw this as I was previewing my post, I think you're missing a "1/"? I assume you meant to say:

    To get these pitches, and taking the lead screw pitch to be 0.5 inch (ie 12 threads in 6 inch) and not 6 threads in 12 inches, ie 1/2TPI.

    I hope so, cause that sentence burnt my brain for a minute! I'm guessing you were trying to clarify you were expressing an imperial thread in basically a metric fashion, as a distance between threads rather than the number of threads in a set distance?

    And I'm pretty sure that Mk1_OZ did mean 1/2 TPI, not 1/2" pitch as you're thinking of it, so I think you'll be out by a factor of 4.

    Now I'm going to have to do some reading on the correct use of 'pitch'. I've always just taken 'pitch' to mean TPI when speaking imperial (metric is pretty obvious). I wonder what's technically correct. Lathes.co.uk says the highspeed version of this lathe used a 1/2" leadscrew - I just automatically read that as TPI, and it matches what has been measured.

  8. #68
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    Quote Originally Posted by Jekyll and Hyde View Post
    Stu, thoughts?
    Apart from "this is doing my head in"?

    As it would appear that the lathe is currently setup to cut imp threads(or at least use that input shaft) I'd be testing some imp pitches, with any luck they will be correct. Once we have a correct pitch the change gears should be easy.(though maybe not, the different modules has me scratching my head again, but one step at the time)

    The closest my maths got was 0.18% but I was only using two gears that I think are in the ballpark(but gears are hard to count). 58 41. I doubt they were going for "close"

  9. #69
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    I have just re-read this thread from start to finish again and feel there might be a couple of misunderstandings creeping in that may be stopping us from getting the answer;


    • Are we all taking TPI as number of threads/number of inches? My lead screw has 6 threads in 12" = 0.5 TPI
    • Are we all talking 'Pitch' as meaning the measurement in mm between successive thread peaks?
    • The ratio between A, B, C & D is created by the large/small gear sets that are permanently meshed on Shafts A and B. On Shaft B the largest gear on left is A and turns the fastest with D being the far right and running slowest. (Compounding is occurring between large/small gears on Shafts A & B)
    • The lever that controls 1:1, 4:1 & 16:1 is all to do with controlling the spindle speed and is all in the head stock. This has nothing to do with ratios within the gearbox but only controls the spindle speed/speed of the 72T gear
    • If both the 72T and 63T back gears are powered, the spring lever & its tumbler gear will cause the gearbox to lock up
    • Whatever NML and CML means, it creates a ratio of 4 - this most likely relates to the Course Pitch/Normal Pitch lever but what the heck does the ML bit stand for?
    • I have played with the machine, spinning the gears manually, to test my power flow diagrams and feel they are correct
    • Pitch = Pi x Module so the ratio of 4 between the Pitch in mm and Module charts seems weird (I just learned that Module is a term to do with metric worm gear threads!)
    • On the Metric setting the change gears currently do nothing




    Quote Originally Posted by Jekyll and Hyde View Post
    ...If we (well, one of us!) counted the internal change gear teeth (and tumbler teeth) for whichever of the 1-10 pin position gives 1/2" pitch, we should be able to work out the required change gears on the back now, no? We know what reductions are created by any position of A-D, and the coarse/fine lever.

    So between that, and whatever the ratio is for the 1/2 pitch position, we should be able to figure out the combination of change gears required to give 1:1 rotation with the spindle?
    Sorry I missed this before (there was a period when we were all writing/replying out of sequence). I agree. We know the A-D ratios and the Course/Normal ratio.

    For Me To Do - hopefully tonight:


    1. check and double check that there is no way that the Whitworth/Metric lever can possibly to anything other than move the dogs (I am 99% certain at the moment)
    2. look in the headstock and see if the operation of the Course Pitch/Normal Pitch lever can be identified - this is in the headstock so any effect it has will be to change the spindle to gearbox input ratio
    3. count the teeth on the change gears (Xmas tree)
    4. put the thing back together and test Whitworth threading on the basis that CML/NML is Course/Normal - MAYBE (we know at this stage that the change gears do nothing on the Metric setting so nothing to be gained?)
    5. take another look at the tang on the dog to confirm its usage
    6. count the spring lever tumbler gears as this needs to be factored in (I think)


    Loving your help on this...
    Last edited by Mk1_Oz; 6th Oct 2020 at 11:45 AM. Reason: added point 5 & 6

  10. #70
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    Quote Originally Posted by Mk1_Oz View Post
    • The lever that controls 1:1, 4:1 & 16:1 is all to do with controlling the spindle speed and is all in the head stock. This has nothing to do with ratios within the gearbox but only controls the spindle speed/speed of the 72T gear
    Yes and No. (at least the way I am currently seeing it)
    I'm thinking the motor drives a gearbox(I assume there is some speed selection here?), the output shaft of that gearbox goes to the shaft the 48 tooth change gear is on. Between that output shaft and the spindle is another gearbox that gives you the 1:1, 4:1, 16:1.
    So 16:1 doesn't speed the leadscrew up in relation to the spindle, it slows the spindle down in relation to the leadscrew. Is this correct? (of course everyone else likely worked that out on page one lol)

    Quote Originally Posted by Mk1_Oz View Post
    If both the 72T and 63T back gears are powered, the spring lever & its tumbler gear will cause the gearbox to lock up
    It would seem that way at the minute. There are no other m=1.5 gears around?

    Quote Originally Posted by Mk1_Oz View Post

    1. check and double check that there is no way that the Whitworth/Metric lever can possibly to anything other than move the dogs (I am 99% certain at the moment)
    2. look in the headstock and see if the operation of the Course Pitch/Normal Pitch lever can be identified - this is in the headstock so any effect it has will be to change the spindle to gearbox input ratio
    3. count the teeth on the change gears (Xmas tree)
    4. put the thing back together and test Whitworth threading on the basis that CML/NML is Course/Normal - MAYBE (we know at this stage that the change gears do nothing on the Metric setting so nothing to be gained?)
    5. take another look at the tang on the dog to confirm its usage
    Sounds good to me.
    Also count the teeth on the gear on the splined shaft below the "xmas tree"(I'd normally call the the QCGB or maybe tumbler gears? used Xmas to separate from the rest of the QCGB. The change gears are the m=1.75 gears. At least as I see it, others may not agree) the intermediate gear doesn't matter.

  11. #71
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    Quote Originally Posted by Stustoys View Post
    Yes and No. (at least the way I am currently seeing it)
    I'm thinking the motor drives a gearbox(I assume there is some speed selection here?), the output shaft of that gearbox goes to the shaft the 48 tooth change gear is on. Between that output shaft and the spindle is another gearbox that gives you the 1:1, 4:1, 16:1.
    So 16:1 doesn't speed the leadscrew up in relation to the spindle, it slows the spindle down in relation to the leadscrew. Is this correct? (of course everyone else likely worked that out on page one lol)...
    Not sure you are correct there. I will try to measure spindle vs leadscrew speeds when I bolt the gearbox back together. The 1:1 4:1 16:1 lever to me is just a way to turn the 6(?) position rotary speed lever from 6 possible speeds up to 18. Will get back to you......

  12. #72
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    Quote Originally Posted by Mk1_Oz View Post
    I have just re-read this thread from start to finish again and feel there might be a couple of misunderstandings creeping in that may be stopping us from getting the answer;


    • The lever that controls 1:1, 4:1 & 16:1 is all to do with controlling the spindle speed and is all in the head stock. This has nothing to do with ratios within the gearbox but only controls the spindle speed/speed of the 72T gear
    • Whatever NML and CML means, it creates a ratio of 4 - this most likely relates to the Course Pitch/Normal Pitch lever but what the heck does the ML bit stand for?
    • Pitch = Pi x Module so the ratio of 4 between the Pitch in mm and Module charts seems weird (I just learned that Module is a term to do with metric worm gear threads!)
    I picked out the bits I'm not too sure about - Stus answered the first already.

    The other 2 - That module thread thing was bugging me last night, so I just tried (again) to figure out what it was, and found the same thing as you. The TOS I've been comparing against yours shows the exact same numbers (unlike yours, where the whole thing seems to shift over) in the metric and module chart, but the change gears on the back are different. For the metric leadscrew version of the TOS, there is a reduction through the change gears of 4:1, but for module the reduction through the change gears is 1.27:1. Thus, although the tables read the same, the actual produced thread in 'module' configuration will be much coarser.

    Quote Originally Posted by Stustoys View Post
    Yes and No. (at least the way I am currently seeing it)
    I'm thinking the motor drives a gearbox(I assume there is some speed selection here?), the output shaft of that gearbox goes to the shaft the 48 tooth change gear is on. Between that output shaft and the spindle is another gearbox that gives you the 1:1, 4:1, 16:1.
    So 16:1 doesn't speed the leadscrew up in relation to the spindle, it slows the spindle down in relation to the leadscrew. Is this correct? (of course everyone else likely worked that out on page one lol)
    That's the way I'm thinking about it, yes.

    So getting back to the NML/CML on the table (Back to Mk1_OZs point above) - we know that A and C are related by a ratio of 4, with C being finer. And we know that if we set the 4:1 ratio on the headstock, that the leadscrew now moves 4 times further for each spindle revolution, thus making any letter setting 4 times coarser a thread than it was at 1:1.

    And the table bears that out:
    NML, A-1 equals 4mm pitch
    NML, C-1 equals 1mm pitch
    CML 4:1, C-1 equals 4mm pitch.

    I believe that 'CML' will just be some German abbreviation to do with using backgears, and that the Coarse/Normal lever helps create that table shift for the Module threads, probably at some odd ratio. I believe that you would change the backgears, and then flick the 'coarse/normal' lever in addition to create that shift.

    I do think it's likely that it works the other way round to what I said earlier though, I now think it should be set to 'normal' for metric/imperial, and 'coarse' for module.

    I've got the hat and tomato sauce on standby - and of course, both Stu and I are assuming that 4:1 and 16:1 are SLOWER spindle speed ranges than 1:1.



    Quote Originally Posted by Stustoys View Post
    Sounds good to me.
    Also count the teeth on the gear on the splined shaft below the "xmas tree"(I'd normally call the the QCGB or maybe tumbler gears? used Xmas to separate from the rest of the QCGB. The change gears are the m=1.75 gears. At least as I see it, others may not agree) the intermediate gear doesn't matter.
    Yep, I'd agree with that, the same occured to me last night - I'd forgotten about that little booger hiding in there.

    The other one that occurred to me is that although the headstock is marked 1:1 - is that 48 actually going 1:1 with the spindle at that setting, or is it possibly geared down some amount already, and does it matter? Just wondering if we might need to mark chuck and 48 tooth gear, and manually rotate (assuming you can do that with his clutch layout).

  13. #73
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    Yeah OK you may have convinced me a little about the 1:1 4:1 etc effecting the 48T (plus you 2 are ganging up on me lol). Will mark spindle/48T and count after work.

  14. #74
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    Quote Originally Posted by Mk1_Oz View Post
    I have just re-read this thread from start to finish again and feel there might be a couple of misunderstandings creeping in that may be stopping us from getting the answer;


    • Are we all taking TPI as number of threads/number of inches? My lead screw has 6 threads in 12" = 0.5 TPI
    • Are we all talking 'Pitch' as meaning the measurement in mm between successive thread peaks?
    • The ratio between A, B, C & D is created by the large/small gear sets that are permanently meshed on Shafts A and B. On Shaft B the largest gear on left is A and turns the fastest with D being the far right and running slowest. (Compounding is occurring between large/small gears on Shafts A & B)
    • The lever that controls 1:1, 4:1 & 16:1 is all to do with controlling the spindle speed and is all in the head stock. This has nothing to do with ratios within the gearbox but only controls the spindle speed/speed of the 72T gear
    • If both the 72T and 63T back gears are powered, the spring lever & its tumbler gear will cause the gearbox to lock up
    • Whatever NML and CML means, it creates a ratio of 4 - this most likely relates to the Course Pitch/Normal Pitch lever but what the heck does the ML bit stand for?
    • I have played with the machine, spinning the gears manually, to test my power flow diagrams and feel they are correct
    • Pitch = Pi x Module so the ratio of 4 between the Pitch in mm and Module charts seems weird (I just learned that Module is a term to do with metric worm gear threads!)
    • On the Metric setting the change gears currently do nothing





    Sorry I missed this before (there was a period when we were all writing/replying out of sequence). I agree. We know the A-D ratios and the Course/Normal ratio.

    For Me To Do - hopefully tonight:


    1. check and double check that there is no way that the Whitworth/Metric lever can possibly to anything other than move the dogs (I am 99% certain at the moment)
    2. look in the headstock and see if the operation of the Course Pitch/Normal Pitch lever can be identified - this is in the headstock so any effect it has will be to change the spindle to gearbox input ratio
    3. count the teeth on the change gears (Xmas tree)
    4. put the thing back together and test Whitworth threading on the basis that CML/NML is Course/Normal - MAYBE (we know at this stage that the change gears do nothing on the Metric setting so nothing to be gained?)
    5. take another look at the tang on the dog to confirm its usage
    6. count the spring lever tumbler gears as this needs to be factored in (I think)


    Loving your help on this...
    How about "CML" Coarse metric lead:
    "NML" Normal metric lead:
    Best Regards:
    Baron J.

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    I just realized the op is in Adelaide, depending what side of town i might be able to come round and have a look if it would help.

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