commit now before branching

README.md

@@ -48,21 +48,51 @@ This is ready to be applied in the [Little Rascal](http://gitlab.cba.mit.edu/jak
 - could abandond servo-belt type, not enough motor torque to overcome friction at this size. re-up on that for N23, with steel belts, for milling and other higher force applications.
 - in abandoning this, belt tensioning becomes easy: make simple, small stops and apply tension at the motor. become smaller. 
 - I would be interested in a motor-hanging-from-end-of-plate flying belt type at this size, for very fast applications (lasers). 
+- motor plate could come inside, to bring pulley closer to motor bearings ... take freedom to push tensioning screw against motor cage, not screws. 
+- while heat-setting M4 inserts in for the rollers, (1) there isn't *really* enough space to get the soldering iron in (without melting the adjacent pla) and (2) it's difficult to guarantee these go in straight. maybe use a press-in insert? / a hex nut ? 
+- pulley version needs lots of revisions
+ - motor mount should have flush-type inset like pinion motor mount
+ - upside-down pulley mount ... and tack-on belt clamp, need formalization and improvement. to keep the minimum width where it is, you can mount 'down the middle' and use the space on the sides for the plastic thread-forming screw 
 
 ### BOM for N17 
 
 Type | Size | QTY | Where Used | Vendor | PN
 --- | --- | --- | --- | --- | --- 
-Flat Head Thread-Forming | No. 6, 1/2" | 20 | - | McMaster | 95893A255
-Bearing Shims | 5x10x0.5mm | 22 | - | McMaster | 98089A375
+Flat Head Thread-Forming | No. 6, 1/2" | 12 | - | McMaster | 95893A255
+Flat Head Thread-Forming | No. 6, 3/4" | 8 | - | McMaster | 95893A258
+Bearing Shims | 5x10x0.5mm | 22 | - | McMaster | 98089A331
 Shoulder Bolts | 5x10xM4 | 2 | Pulleys | McMaster | 92981A030 
 Shoulder Bolts | 5x6xM4 | 8 | Rollers | McMaster | 92981A146
 Heat-Set M4 Tapered Inserts | M4 | 10 | - | McMaster | 94180A351
-Heat-Set M3 Tapered Insert | M3 | 1 | - | McMaster | 94180A331
-Various M3 SHCS | - | 5 | - | - | - 
-625ZZ Bearings | 5x16x5mm | 12 | - | VXB | [link](https://www.vxb.com/20-625ZZ-5x16x5-Metal-5mm-Bore-Miniature-p/kit250.htm) or McMaster 6153K113
+Heat-Set M3 Tapered Insert | M3 | 5 | - | McMaster | 94180A331
+M3 SHCS | 10mm Long | 4 | Motor Mounting | McMaster | 91292A113
+M3 SHCS | 14mm Long | 5 | Tensioning and Tuning | McMaster | 91292A027
+M3 Washers | - | 9 | Screws without Washers are Sad Screws | McMaster | 93475A210
+M4 SHCS | 20mm Long | 4 | Belt Mounting | McMaster | 91292A121
+M4 Washers | - | 4 | ibid | McMaster | 93475A230 
+625ZZ Bearings | 5x16x5mm | 12 | - | VXB | [link](https://www.vxb.com/20-625ZZ-Shielded-5mm-Bore-Diameter-Miniature-p/625zz20.htm) or McMaster 6153K113
 20T or 16T GT2 Pulley | 10mm or Wider, 5mm Bore | 1 | - | Amazon or SDP/SI | [Amazon Link](https://www.amazon.com/uxcell-Aluminum-Timing-Synchronous-Printer/dp/B072M2CM1W/)
-10mm (or 9mm) Wide GT2 Belt | Find Steel-Core for Stiffness! | 1 | - | Amazon or SDP/SI | [Amazon Link](https://www.amazon.com/BALITENSEN-Black-Timing-Printer-Machine/dp/B07F2X236H/)
+10mm (or 9mm) Wide GT2 Belt | Find Steel-Core for Stiffness! | 1 | - | Amazon or SDP/SI | [Amazon Link](https://www.amazon.com/BALITENSEN-Black-Timing-Printer-Machine/dp/B07F2X236H/)	
+
+### Materials for N17
+
+1/4" Acrylic from McMaster, for 12x24" for small lasers pick 8505K755 
+
+## HQ Wire Bundling
+
+Trying this with Heat Shrinks
+ - -> 1" 3M161381-ND
+ - -> 0.75" 3M161354-ND 
+ - -> 0.5" A100C-4-ND
+ - -> 0.375" A034C-4-ND 
+
+ - -> 3/8" ID Sleeve 2837K13
+ - -> 1/2" 2837K32
+ - -> 3/4" 2837K33
+ - -> 1"  2837K34
+
+ - Stanley Model 33-116, 6802A36 (3/4" width)
+ - Stanley Model 33-716, 6817A1 (1 1/4" width) 
 
 ## Gantry for NEMA23 Motor, 0.375" HDPE
 
@@ -99,6 +129,11 @@ Less Expensive Bearing Shim | 5/16" Screw Oversize Washer | 38 | Roller Separati
 
 ![RCTN23-025ALU](images/RCTN23-alu-dwg.png)
 
+### Going Notes
+
+ - aluminum flexures are no good, plastically deform over time
+ - look for a solution using spring steel, with known preload ahead of time... i.e. no adjustment, just good steel fixturing 
+
 #### [RCTN23-025ALU Fusion CAD File](cad/RCTN23-025ALU_v51.f3d)
 
 #### BOM N23 025ALU