Improvements to Bed Attachment

#1
I found it a nuisance to have to hold the bed screw with a wrench or fingertip to stop it spinning when adjusting the bed levelers. I also found the wingnuts not very convenient to turn, and disliked the way the screws fall out of the holes every time you remove the bed. To solve all these problems, I designed a screw head lock, a thumbscrew, and a rubber spring/retainer.

The screw heads are heat-staked into the (printed ABS) head lock pieces by heating them with a soldering gun until the plastic melts enough to push them in. Don't apply too much pressure or the soldering gun tip will bend; just be patient until they get hot enough to melt the plastic and slide right in.

The rubber springs were printed in Ninjaflex at 0.25mm layer thickness and no support. The hole is undersized to grab the screw and prevent it from falling out. The rubber springs also add some stiffness to the metal springs supplied with the printer, and the metal springs help keep the marginally-successful bellows design of the rubber from buckling. They make it look nicer, too :)

The thumbscrews were printed in ABS and an M4 nut slides right in. Reducing the hole size and tapping the ABS itself might work OK, but the nut provides insurance.

The parts were all created in Tinkercad and can be customized if you like:

https://tinkercad.com/things/396cj2kSQla-gmax-bed-screw-lock
https://tinkercad.com/things/iOMAYjM3eth-gmax-bed-spring
https://tinkercad.com/things/a5YsX03mZ3Y-m4-thumbscrew
 

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GORDON.LAPLANTE

Administrator
Staff member
#2
Thats a great solution Julia. On our end we have been experimenting with dual extrusion and the required dual fan shroud. I bring this up because we have found the new fan shroud hits the existing wing nut/bolt combo causing some very unpleasant stepper motor grinding.

Our solution has been to ditch the original M4x40mm bolts/wing nuts in favor of a new low profile M5x25mm and low profile M5 nut combo. This new setup has the M5 bolt on top and the M5 nut on the bottom with a very similar printed lock bracket to hold the nut in place while turning. It does require a hex wrench to adjust but it also has a much lower profile than the original bolt/nut combo. More info to come.

Keep up the great work.