Jul 29, 2011

Can lefthanded threads be made on the SIEG C4?

My answer is yes.
The reasons to deal with this question here are:
1. Not explicitly mentioned in the manual.
2. I have read in reviews that the spindle and leadscrew relative rotation directions would be fixed.

Although there is no lever to change, but with proper placement of the change gears the leadscrew rotation can be changed relative to the main spindle.

Normal arrangement
Reverse arrangement for left threads


  1. Useful; thanks! Nice to see what a little thinking can do!

    By the way, thanks for the nice review on setting up your lathe. It was good to have confirmation of the cleaning issues Jaakko had mentioned and it was good to see your comments about little fixes you must do like the cross-slide screws, rounding the gib screws, etc. I am looking for a lathe and mill now and it is good to see real data from an actual SC4 user rather than just the many "expert opinions" out there. I am spending a lot of time deciding between a new SC4 or a used Atlas or South Bend (which will have their own problems).

    Now that a year has passed, are you still basically happy with the lathe? (I hope so.) It would be interesting to hear if the things you had to fix corrected the problems permanently. If so, then as you said, the time spent fixing those little flaws is an acceptable cost for getting a lot of good qualities like .005 runout for a very low price.

    Or is it an ongoing battle, so that you still lose time to keeping the lathe running accurately (but maybe still an acceptable amount)? Is the runout still that low or did they have some way to make it look good when you first buy it but that doesn't last.

    Anyway, hope your shop is going great. Thanks and goodbye from California.
    Happy trails!

    Ed Williams

    1. Ed,
      I'm awfully sorry for the delay, I did not notice your comment earlier.

      I do not heavily use the machine at all, and I still think that for eight-hours-a-day-use anyone would rather choose any of the more expensive professional machines available on the market. So after more than a year I can say that I am entirely happy with the machine. This lathe is precise enough to make the work enjoyable, resulting nice and usable end products for your household, hobbies, friends etc.

      The runout of the machine is exactly the same as it was out of the box.The cross slide is pretty stable, did not yet needed to be readjusted. Other than regular cleaning and lubricating of the lathe only the compound slide gib screws needed to be readjusted from time to time. As I do rarely effectively use the compound slide itself, I usually set it a bit tighter to reach better toolpost stability. I have changed the gib adjusting screws to hex headed ones of 8.8 strength grade for easier adjustment. I tried to form the tip of the screws to fit in the hollows on the gib and have as big contacting surface as possible.

      If I chose now, I would choose the same lathe.

      Again, sorry about the late reply: