# Sieg SC4 cross slide



## 6061T6 (Oct 5, 2021)

Hello,
does anyone know the dimensions of the sieg SC4 cross slide screw? I thought it may be M10 1.25 but it doesn't seem to work with a nut of that size.
it IS metric, isn't it? is it a non-standard size?


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## catsparadise (Oct 6, 2021)

Just a thought - is it left hand thread? In the exploded diagram I've found, the cross slide nut is bolted to the cross slide, the screw mount is fixed to the saddle. If the handle rotates clockwise to drive the slide away from the operator (deeper cut depth) that makes sense.


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## homebrewed (Oct 6, 2021)

It probably is left handed.  The pitch depends on whether or not it is a metric or imperial machine.  20TPI if imperial.  If metric it won't be some odd pitch because it determines how much the cross slide advances per turn.  I wouldn't want one that advances 1.25mm/turn and you probably don't either .


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## 6061T6 (Oct 6, 2021)

catsparadise said:


> Just a thought - is it left hand thread? In the exploded diagram I've found, the cross slide nut is bolted to the cross slide, the screw mount is fixed to the saddle. If the handle rotates clockwise to drive the slide away from the operator (deeper cut depth) that makes sense.


That’s exactly correct! Thanks.


homebrewed said:


> It probably is left handed.  The pitch depends on whether or not it is a metric or imperial machine.  20TPI if imperial.  If metric it won't be some odd pitch because it determines how much the cross slide advances per turn.  I wouldn't want one that advances 1.25mm/turn and you probably don't either .



it is a Chinese machine so almost certainly metric. The hand dials are imperial to service the US market so it passes off as 20tpi. But I’d like to be sure of course. 

btw I am converting it to an electronic lead screw — Z axis is done. Was now in the process of doing the X axis so everything is automatic and I can cut tapers, curves etc.
It doesnt matter anymore if any measurement is imperial or metric. And no change gears of course.


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## homebrewed (Oct 6, 2021)

6061T6 said:


> That’s exactly correct! Thanks.
> 
> 
> it is a Chinese machine so almost certainly metric. The hand dials are imperial to service the US market so it passes off as 20tpi.


Do the dials indicate 0 to 50 or 0 to 40?  If the feed screw is 1mm the carriage will advance ***almost*** .040"/turn.....  I mean, who's going to quibble about being short by .0006299"/turn


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## 6061T6 (Oct 6, 2021)

homebrewed said:


> Do the dials indicate 0 to 50 or 0 to 40?  If the feed screw is 1mm the carriage will advance ***almost*** .040"/turn.....  I mean, who's going to quibble about being short by .0006299"/turn


0 to 50. 
I will be using the feed screw as a positioning indicator so the errors will add up over many rotations, say if I was turning down a large diameter.


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