upd8 N17

README.md

@@ -38,27 +38,40 @@ Make sure to change 'type' to .step, and check the 'save to my computer' box. No
 
 ~ ongoing ~
 
--42.3 mm - ( 6.5 * 2 ) * 1 mm
+- last rites before building a machine is to 3dp a new set of blocks and re-build that gantry on your desk. test it w/ new circuits and invent cable management that works real good. 
 
-https://www.vxb.com/20-625ZZ-5x16x5-Metal-5mm-Bore-Miniature-p/kit250.htm
+![n17sofar](images/n17-blocks.jpg)
 
-Flat Heads
- - 20mm for reach-thru on motor runner
- - ? there are more ?
+![n17sofar](images/n17-assem.jpg)
 
-- holes in plate
-- wj plate
-- wire organizer test, plate feet 
+### BOM for N17 
 
-- 3dpnext
-- wj
-- do we have belts, do we have pulleys, order bearings, last mcmaster, admirals, etc, close it out and next up we do software problems 
+625ZZ bearings are 5x16x5mm [VXB 20](https://www.vxb.com/20-625ZZ-5x16x5-Metal-5mm-Bore-Miniature-p/kit250.htm)
+Bearing Shims are 5x10x0.5mm (McMaster, 18-8)
+Shoulder Bolts are 5x6xM4 mostly and 5x10xM4 at the pulleys.
+Pulleys are 10mm GT2 (try to find steel-core GT2)
+Belt Pinion is 20T (speed!) or 12T (resolution!)
+Uses many Heat-Set Tapered Inserts, M3 (94180A331) and M4 (94180A351).
 
 ### Notes from the First Build 
 Increased preload from 0.2 to 0.4mm 
 A few fitting things ... motor mounts get lots more clearance
 Increased sizes for heat-set inserts to make overflow smaller. 
 
+Overall, pretty good. Could do with some more allowance around the 'reachover' ... recall the M4 Heat-Set Insert for the 'vertical' constraining bearing pushes PLA into the through-hole for its 'option-retaining' shcs.
+
+Might want to replace all M3 Heat-Set Inserts with Plastic Hardware.
+
+Mounting Blocks-Into-Plate wants a 3.5mm M3 through hole, and counter-sinks. Flat heads into countersunk holes helps overconstrain the finnicky plastic blocks. 10mm length black-oxide seems best.
+
+Plastic is heavy. 
+
+Added 1mm more space between the two blocks to try to eliminate the backlash I found in the planar direction. (i.e. in displacements not-normal to the rail). 
+
+It seems to run pretty well, wants to be pre-loaded into the 0.5mm range. 
+
+At the end of the day, they're not a *whole lot* smaller than the N23s.
+
 ## Gantry for NEMA23 Motor, 0.375" HDPE
 
 ![RCTN23-0375HDPE](images/RCTN23-hdpe-img.jpg)