Quote Originally Posted by Doddy View Post
THIS!, eyeball the axis broken down as a sanity check!
Been having a good measure up. With the saddle all the way back to the column there is 5mm of existing leadscrew nut covered up, this being the backlash adjusting part of the nut. This could be removed in the quest for the greatest X travel if required. Even without removing that 5mm of metal I reckon I can get 200mm of X travel including a nut on the end of the screw to prevent accidental over-travel. So plenty of travel for the 160mm table with a safety margin.

I might put a couple of belville washers in to preload the nut to account for any backlash a la Jonathan's micro lathe job here. This is due to me using the 1204 and there not being a double nut option. The bonus is I can get the nuts in just without having to grind them - the 1204 ball nut height at the flat of the flange is 30mm with the leadscrew nut coming in at 35mm. Just enough meat...

Quote Originally Posted by Mat View Post

I'm currently modelling a homebrew double nut 1204 solution:

Click image for larger version. 

Name:	x-1.png 
Views:	3205 
Size:	217.6 KB 
ID:	29693
Click image for larger version. 

Name:	x-2.png 
Views:	3182 
Size:	209.0 KB 
ID:	29694

In theory the length will end up being 74-77mm so would need extra space on the Y.
Having said the all above and read your plan for the antibacklash double 1204 nut, an easy double nut solution would appear to be to bore out the existing leadscrew nut as planned anyway for the first ball nut and mount another back to back with belvilles between to preload and use a couple of the mounting holes on the ballnut flanges between with one flange threaded and the other opened out slightly to use bolts to apply the preload. Then the space created by all that can be used to mount the stepper with the shaft facing out and on the left hand side of the saddle. I plan off-stands made from aluminium block for the spacing for the mounting plate off the front of the saddle.