Sieg SX2 Plus build

[russell]

Still making some progress if a bit slow. I've now fettled the column dovetails (they weren't too bad really) and made the same mod to the gib screws as for the X and Y. It all works smoothly now.

Checked the alignment of the spindle to the column:

.. found the spindle is parallel to thee column within 2 thou over 8 in. However the head is skewed giving 20 thou variation in 8 in when measured as above. I'll have to separate the two head castings and re-align.

Russell.

[ian823478]

Checked the alignment of the spindle to the column:
. found the spindle is parallel to thee column within 2 thou over 8 in. However the head is skewed giving 20 thou variation in 8 in when measured as above. I'll have to separate the two head castings and re-align.

Russell.

Hi Russell
Thanks for sharing your build, I'm enjoying following it!
Have you had a chance to address the misalignment yet? I have the same problem but am living with it at the moment. Any experience you can pass on will be gratefully received!
For powering the z axis I'm a bit embarrassed to admit that so far I've just bunged the motor on instead of the handwheel, there's at least 1.5mm of backlash through the rack and pinion, but the repeatability is pretty good, I just have the clearance plane in cambam set to 3mm.
Looking forward to the next installment!
Ian

[russell]

Have you had a chance to address the misalignment yet? I have the same problem but am living with it at the moment. Any experience you can pass on will be gratefully received!

Yes, not a real problem. I took the head off the column, loosened the four bolts that hold the two parts together but kept them tight enough so that the friction was enough for them not to slip in handling, then put it back on the column. Then tap the head with a hide hammer until the test bar showed no (or little) dial movement when moving the head along the column. It took half a dozen taps and tests to get it right. Took the head off, tightened the bolts and tested again. The misalignment is now just under 2 thou along 8 inches of Z movement.

Russell.

[russell]

For powering the z axis I'm a bit embarrassed to admit that so far I've just bunged the motor on instead of the handwheel, there's at least 1.5mm of backlash through the rack and pinion, but the repeatability is pretty good, I just have the clearance plane in cambam set to 3mm.

Yes, I've seen that done. It depends what you're using the machine for but I would be worried about cutting forces moving the head up and down. How well do you find it works? What material are you cutting?

Russell.

[ian823478]

Yes, I've seen that done. It depends what you're using the machine for but I would be worried about cutting forces moving the head up and down. How well do you find it works? What material are you cutting?

Russell.

Hi Russell. It seems to be accurate to at least 0.1mm as far as I can tell, probably nearer 0.05mm. I have a counterweight on the head and the gib reasonably tight.
I mainly cut aluminium but had a play with some 304SS over the weekend. Here's a couple of pics (if I can work out how to upload them.......)

Cutting the stainless was painfully slow (10mm/min 1mm DOC with a 2.5mm slot drill) but that was to prevent heat buildup (no coolant and just HSS bits). I've definitely got a lot to learn and loads of tools etc to save up for!
I'm still on the original leadscrews/nuts and have the DIYCNC system 4 with 3.1Nm steppers driving direct. (I won't get the max from these motors cos the system4 only gives 3A while the motors can take 4A.) I'll probably change this to a 2:1 reduction even if I don't eventually move to ballscrews.
I'm trying to convince myself I can make a bit of pocket money from it before spending much more!
Cheers
Ian