MK4 Bed Cable Strain Relief for MK3S+

This will add heater bed cable strain relief to your MK3S+.  The only thing you need to do is to get a small strand of a string trimmer nylon cord and drill a small hole into your Einsy case. There is no difference between these two heater bed cover top and bottom parts and the official parts R2 parts, I just included them for your convenience. 

Additional Hardware needed

• 2.5mm nylon string trimmer cord from hardware store

Print Instuctions

• PETG
• 20% infill
• .2 layer height as usual per official parts

Instructions:

1. Go to your hardware store and get a roughly 2.5mm thick nylon string trimmer piece of cord. Get one as stiff as you can find. Cut it much longer than you will need.

1. Print out the two heater bed plastic MK4 official parts here and get the same M3 hardware the instructions use for that part of the install on the MK4 instructions
2. Make one end of the cord small enough to fit into the small hole on the lower heater bed attachment. I found when I assembled my MK4 that the nylon cord they included was really stiff for its smaller diameter.  With my Home Depot cord 2.41mm diameter string trimmer cord, I had to slight shave off a side of my cord end to fit into the hole on the lower bed heater attachment
3. Bend the end of the cord so it stays in place when it goes through the heater bed cover hole. similar to the shape of the cord that comes with the MK4

1. Ideally, unplug all the electronics from the MK3 Einsy case and Remove the Einsy board from the Einsy case so you don't accidentally drill into it or any cables. Drill a small hole the same width as your string trimmer cord in the position I show in the pics. Now put all the electronics back into the case. (I guess you could skip removing everything and just drill into it but be super careful not to drill to far and damage anything.)
2. Now just follow the MK4 heaterbed cable attachment instructions for attaching to the heater bed
3. Include the nylon cord in the cable wrap
4. Follow the MK3S+ instructions for attaching to the Einsy case, but insert the nylon cord into its own separate hole you made in the Einsy case

1. Insert it far into the hole and place it inside the case between the edge of the Einy board and the Einsy case so it is wedged in place. It should be not pressing against any electonics components.  It should stick out one cm past the lower edge of the case
2. Trim off the end  below the edge Einsy case, leaving at least one cm visible 

Now enjoy the nice bends and supported arches of your heater bed cable bundle on your MK3S+! 

Note - the optional and unrelated mod you see in the pics, the Einsy frame brace piece, can be found here : https://www.printables.com/model/83874-prusa-mk3s-frame-brace-replaces-einsy-door