Made to order, milled from a solid Aluminium 6082-T651 plate with 20mm thickness, high hardness (95 HB) better than 6061-T6. Or 3D printed of tough plastic.
This is one adapter (1 unit) plate to mount a Servo with 60mm frame on a previous made NEMA 23 holes.
Each ALU adapter is 20mm thick, if you require thicker, order x units you need up to your requirement and stack them.
On the plastic version we can do a single piece with your height requirement up to 20cm.

Custom plates can be made on request.

NOTE 1: There's no hole to access the coupler screw, you will have to mark and drill your own hole at the right position of your coupler screw.
NOTE 2: Also you will need to rework the adaptor hole size as required, see installation process below.

Standard installation process:
  1. Screw the adaptor to the old NEMA23 fixture 
  2. Use the adaptor as template to make the new drills in correct place in the machine plate, hole size and drill size should be 4.5mm to tap latter for M5 (See last photos of the drills)
  3. Remove the adaptor
  4. Check the holes you done
  5. Tap the holes with M5
  6. Relief the adaptor holes with 5mm or 5.5mm drill
  7. Position and screw the adaptor to the plate
  8. Mark the correct position of the coupler screw in a adaptor face
  9. Remove the adaptor and make the drill vertically
  10. Remount the adaptor
  11. Position and screw servo to the adaptor
  12. Done
As alternative to 2. and 5. you can also tap the last adaptor itself and use it to screw the Servo in, instead of drilling the machine plate. Plastic version will have a M5 hex nut slot for the servo as optional fixture.