You will need to print:
4 x Spacers
3 x Locks (for fixing the wing nuts in place after adjustment)
4 Clips (two of each type) - printed at 0.2 with no support
An adjustable heat bed support : http://www.thingiverse.com/thing:1689233
4 x Shims (if you want to use the original perf board)
Bolted Linear Rail Clips (Optional, but the clips are quite fragile and have a tendancy to break.): http://www.thingiverse.com/thing:1688852
The heat bed and frame need to be removed from the printer.
Remove the two screws in the top of the heat bed and slide it forward (or back) out of the frame to expose the ribbon cable connection underneath. Gently pull down on the retaining clip and carefully remove the ribbon cable.
Remove the two screws that attach the belt clamp to the underside of the frame.
Loosen and remove the two linear rail clips at the front and slide the entire frame out.
Remove the "L" support block from the centre of the frame.
Remove the four suspension clips and springs from the frame.
Cut two lengths of 12x3mm Aluminium Flat Bar at 140mm long.
Drill 4 holes in each, centrally and to suit M3 bolts aligned with the (spring) holes in the frame and the holes in the corners of the heat bed.
I used 25mm long bolts throughout and just cut them down to size as required.
Fit the flat bar to the frame using the printed spacers. The bolts should not protrude much past the nuts on the inside of the frame.
The left hand rear corner bolt head (when viewed from the front) needs to be countersunk to avoid clashing with the printers frame at that location.
The (spring) holes in the frame may need to be enlarged slightly too, to be able to fit the M3 bolts through easily - I used a 3.2mm drill bit for all the holes.
Fit the new heat bed support parts to the frame and heat bed.
Place a bolt in each clip, using the springs removed from the frame and positioned between the underside of the clip and the top of the flat bar.
Place a wing nut to the underside of the flat bar.
The bolts should not protrude below the underside of the wing nuts
Do this for 3 of the clips. For the left hand rear corner, countersink the flat bar from the underside and place a nut in the top of the clip - again to avoid a clash with the frame in that corner. The thread should not protrude above the nut on the top of this clip so as to not touch the underside of the heat bed.
This corner clip is designed to be fixed and not (easily) adjustable (it can be adjusted in place - with a screwdriver from underneath, but not as easily as with the other three corners).
Adjust it so that it is at an appropriate height relative to the frame.
Slide the frame back onto the rails and re-attach the belt clamp.
Secure the rails back into place with the linear clips.
Replace the heater bed ribbon cable back into the bottom of the heat bed.
Slide it up and back into place from the front through the clips until the heat bed support part slots down into its counterpart on the frame. The holes in the corners of the heat bed fit the dowels on the clips. Press them into place.
Slide the print bed into the clips (it's easiest at the outside corners as they taper inwards), and push it all the way back into position. I have found no need for any additional clips to hold the bed in place but YMMV.
You can use the original perf board by printing four of the shims to fit into the clips. The board then just slides over the top of them inside the clips.
Use the wing nuts to adjust the level of the bed on the 3 corners to match the height of the (fixed) back left hand corner.
Once aligned, push the locks over the flat bar with the wing nuts running parallel to lock them into place.
Adjust the nozzle height and enjoy raftless printing! :)
If you wish to return the printer to stock at any stage, simply remove the flat bar and refit the original suspension clips, springs and heat bed support.
You can see from the cross sections that using the glass+PEI bed (4mm) means that there is very little room for vertical adjustment, but in practice I had no issue in being able to level the bed.
The clips have been designed for my Glass+PEI print plate, but I have included a step file so that they can be modified if required.