Modelled this simple jig to align both the heater mat and the magnetic sheet perfectly central on the bed plate of my RatRig V-core4 500. I imagine the model can be used for the 300 and 400 versions as well, however I have only modeled it and used it on the 500. The STEP file has been uploaded for anyone that would like to remix it to suit the other versions.
You need two jigs, one for each side of your bed plate. You can just import the one model into your slicer, clone it, and mirror one of them.
The model is pre-orientated, and does not need supports.
The jig is designed to just slide into place, using the dog point screw and the other holes on the bed plate to align it. It is designed to be a fairly firm fit on the plate so that it is just held in place with friction, so you may or may not need to use a mallet to lightly tap it into place. Then when installing your heater mat and magnet, simply expose the adhesive at the back of the sheet, slide it into place so that it is firmly touching all edges of the alignment jigs, and press the adhesive onto the bed plate. Then you can use a squeegee or credit card to apply each sheet neatly from the back to the front, peeling off the paper cover as you go.
The jigs will align both the heater mat and the magnetic sheet, so just apply one, flip the plate over and apply the other in the same way. Once both sheets are installed, the jigs can be removed.
BE SURE YOUR BED PLATE IS CLEAN PRIOR TO APPLICATION
FOLLOW RR GUIDELINES FOR INSTALLATION
DO NOT ATTEMPT TO REMOVE YOUR HEATER MAT ONCE ANY PART OF IT HAS BEEN ADHERED TO THE PLATE
The author marked this model as their own original creation.