Sieg C6 Lathe new threading possibilities

[AlanWParticipant @alanw96569]

Thanks Graham, all very useful. I didn't notice at first that intermediate pitches are generated, thinking that they were just different combinations for the same result.

If you have read my previous replies, you will have gathered that I need to make some changes to the lathe for quite a few of the gear combinations to work, owing to the lack of distance between the second gear on the top spindle and the idler gear retainer. Having given it more thought and seen Andrew's modifications, I will probably make new, slightly longer, spindles and spacers of around 3mm thick so that the second gear clears the end of the idler spindle completely. That should allow quite large gears to fit.

Woodworkforums.com has now let me download the calculator posted there but I haven't had a chance to try it out yet. Then again, thanks to you, I have a comprehensive list so I may not need to.

Thank you.

Alan

[AlanWParticipant @alanw96569]

Further to my last post, I made a couple of extended length spindles and spacers to allow larger gears to clear the idler spindle. I haven't tried many of the combinations but the new arrangement worked fine for 26 and 27tpi and also for a 30.5tpi screw for a Victorian sewing machine. With some combinations, it puts the last but one in the train in half mesh with the leadscrew gear, so I need to lok into solving that issue.

Thanks for your input folks.

Alan

[Perko7Participant @perko7]

Hi all, as a newbie to this hobby, this site and this topic, and at the risk of slightly derailing the current thread, i have recently (as in Christmas 2015) bought a new C6 from Ausee and am now starting to use it for what it was intended. My previous lathe (a 1929 vintage light-duty machine which i have kept for sentimental reasons) has a handwheel on the leadscrew which i have found particularly useful in providing a finer feed than using the handwheel on the carriage, and i would like to provide a similar facility on the C6. Has anyone carried out this modification and if so could they provide some advice on the best way to approach it?

Thanks in anticipation, Geoff P.

[AlanWParticipant @alanw96569]

Hello Geoff,

It doesn't look as though many readers are monitoring this thread any longer. You may be better off creating a new thread specific to your question.

I'm not a C6 user but I don't think my Warco is so vastly different in general design. There is a powered leadscrew article coming up in the April edition of MEW; from the photo it looks as though the subject lathe is a Warco, so the method of attaching the pulley to the leadscrew will certainly interest me, for the same reason as your query re the C6.

[Neil WyattModerator @neilwyatt]

Posted by Geoff Perkins 1 on 04/03/2016 07:01:06:

Hi all, as a newbie to this hobby, this site and this topic, and at the risk of slightly derailing the current thread, i have recently (as in Christmas 2015) bought a new C6 from Ausee and am now starting to use it for what it was intended. My previous lathe (a 1929 vintage light-duty machine which i have kept for sentimental reasons) has a handwheel on the leadscrew which i have found particularly useful in providing a finer feed than using the handwheel on the carriage, and i would like to provide a similar facility on the C6. Has anyone carried out this modification and if so could they provide some advice on the best way to approach it?

The standard mod for a C3 is to drill and tap the end of the leadscrew M6 and add a stub extension, screwed and loctited in place.

Neil

[Tim StevensParticipant @timstevens64731]

When working out errors in pitch, remember that when a bolt is tightened, the bolt stretches and the nut is compressed. So, any errors could usefully be apportioned so that the error is reduced by tightening – bolts should have threads a bit close, and/or nuts a bit wide.

Just a thought

Tim

[Ron VOSParticipant @ronvos47704]

Hello everyone.

My name is Ron.

i have a sieg sc6 metal lathe and need to cut metric thread on shafts of an approx 30/35 mm diameter

I do have all the gears and downloaded screw cutting chart from this topic.

I never done threads before so would be very great full for any help please

thank you

ron

[Thor 🇳🇴Participant @thor]

Hi Ron,

Welcome to the forum. There are many books about the subject, like "Screwcutting in the Lathe (Workshop Practice series #3), and videos:

that may be of help.

Thor

Edited By Thor 🇳🇴 on 03/05/2023 07:26:01

[RobCoxParticipant @robcox]

Hi Ron,

The best advice I could give would be to start on some easy to cut scrap first, ally or delrin. Do lots of practice with a standard thread size (M12?) so you've got a nut to judge when the thread is deep enough.

If you're cutting a 30mm dia thread, what's the pitch? I did a M33 x 3.5 thread on a minilathe once but it's less straightforward than plunging straight in as the large thread depth and the low power of the lathe are somewhat at odds with each other.

You might consider some thread wires to check the thread, so you know when its right or how much needs to come off, once you're comfortable with the screwcutting process. Again, practice makes perfect here too, even though theyre fiddly to use at first.

Good luck with it, Rob

[Author]

Posts