MadModder

I was assuming that the motor shafts had been hardened, but I tried a file on one and it cut.  The hacksaw made fairly quick work of whacking 10mm off the end - so I guess I was wrong about the hardness.  I found that the Z carriage will flex.  If I can make it move by pushing on it - it'll move under load.

I'm in the process of redesigning both the slide and the carriage.  I'm going to bolt 1/8"x1-1/2" HRS on both sides of the carriage to keep it from flexing.  Since my carriage mounting plate is 84-ish mm wide, the spindle slide is 90mm wide, the carriage is 60mm wide, and I've only got 24mm from the carriage mounting plate to the back of the spindle slide when I need 40mm...  I need to play around with the numbers, get creative, and see how things look in the 3D model.

Mechanically, this is starting to come together.  I got the Z leadscrew cut to length, I installed the Z leadscrew, I disassembled the bed enough to remove the X leadnut block, I installed the X leadnut assembly in the leadnut block, and I reassembled the machine enough to measure the gap between the bed and the top of the leadnut block.  When I designed the leadnut block I wanted to be sure that my block wasn't too high, so I subtracted 3mm from what I had sketched out and printed the block.  I must have already subtracted that 3mm when I drew the sketch, because when I measured the gap it was 6.17mm.  It's no big deal, I'll just print a 6+ mm shim instead of a 3+ mm shim.  Here's a view of the gap from the motor end of the leadscrew.


This is a view from the other end of the leadscrew.


One thing I discovered when assembling the Z leadscrew is that the 84 oz-in stepper motor shafts are about 10-15mm longer than the original motor shafts were.  That gap you see between the blue coupler and the Z axis motor shouldn't be there.  I'm going to lose about 10-15mm of travel on all three axis when I install the larger motors.

I got my roll of Mango Yellow PETG today, so I can start reprinting the RT7R's yellow parts anytime.  It's a little darker than the Gold PLA I was using, and the Bruder Yellow - but I'll live with it. 

On the CNC front, I got the X axis leadnut plate drilled and tapped yesterday, today I got the X axis leadnut assembly assembled and adjusted.  I also got the Z axis put back together - mostly.  I still have to cut the spare leadscrew to length and get it installed.  If I take the lower leadscrew bearing out, I think I'll have enough room to be able to install the leadscrew that way.  If not, I'll be taking the spindle slide and rails out one more time.  Yesterday I also got the drag chain I'm going to use for the X axis.  My choices were: 10mmx15mm, 10mmx20mm, 15mmx30mm, or larger.  My cables are 7mm in diameter, I need 22AWG - 6 conductor shielded cable for the steppers.  I actually only need 4 conductors for the stepper - but I'll need 6 conductors to install the MKS42 stepper/servo conversion kit.  (I am NOT using that unshielded 28AWG ribbon cable!)  I've got 16AWG - 2 conductor shielded cable for the spindle motor.  I'll need a 3rd cable if I ever install homing and/or min/max travel limit switches.  The 10x15 drag chain would handle 1 cable with no problem, 2 would fit but it'd be tight, MAYBE 3 if you zig-zag stacked them, but it wouldn't be pretty.  The 15x30 chain is what I ordered.

Hi Ozzie,

It seems you're coming in on a IP address range which is, at least partly, assigned to North Korea 

Can you please use the "Contact" link at the top of the forum page, ping a message over (pretty much anything, just don't use "I ask about the prices for reseller" as your title - we get 2-3 of those per day, every day of every week, bloody spammers), and I can try to figure out WTF is going on with your IP address!

Cheers,
Ade.

OKAY.... The reprinted spindle slide is finally done, and this time it worked.  I modified the depth of the pocket for the leadnut assembly.  I had forgotten about the screws to hold the bearings in place on the first iteration and had manually drilled the screw holes.  I modeled those in, and I reduced the bore of the holes for the linear bearings from 15mm to 14.9mm.  It didn't work the first time I reprinted the spindle slide though, but that was operator error.  The first time I had started the print before I went to bed, when I got up the next l morning I ASSUMED the print was complete and popped the print off the build plate.  When I started examining the print I realized it was missing something, like the top 3mm of the print.  It was about this time that I realized the  print wasn't DONE, it had run out of filament and paused itself - waiting for me to add more filament.  Whoopsie, would have been nice if I had remembered the printer could do that BEFORE I ripped the print off the build plate.

OKEE-DOKEE, I aborted the paused print, added a fresh roll of filament, and started a new print.  I also ordered 2 more rolls of grey PETG filament, 'cause I'm really liking this stuff and I gonna reprint the RT7R in PETG.