Hunting around the workshop I found some 10mm Aluminium plate, I creates a model and machined it out on the CNC machine. 

Once this was done I hand filed the ends where the arms attach so as to ensure there would be enough clearance for the sides of the ball joints and then tapped them all with an M3 tap.
I really should check my taps as the one I grabbed from the M3 box was a UNF tap and as I started to tap out the hole in the first one I made it snapped off :( 

At this stage I was tempted to build a small spark eroder to remove the broken tap but the printer has been offline for way too long and machining a new plate effector was going to be a little faster.

Once the top plate was done I chucked it in the lathe to reduce the height a little more. Initially I was going to make the thing 10mm but the clamp that holds the J-Head in place was a little tight so bringing it down to 8mm allowed for a bit more clearance as well as reduced the weight a little.

Machined the top collet to hold the J-Head and inserted an M3 grubb screw just to make sure that the J-Head would not twist. The tolerance is prety tight so there is no wiggle but as with most things made from ali eventually over time things tend to get loose.

Then came the fan cover, this was machined from 50X50X4.5mm angle just because that is what I had in my bits box and a peice of aluminium tubing was cut bent and formed with a slot in it to match the seat cut in the top and bottom parts of the covers. 

Initially I was going to just bolt it together but received some aluminium brazing rod a few weeks back so brazed the parts together. Its not super pretty but seems to be strong.

There are 2 M3 rods that go from the base plate to secure the cover to the top of the effector. I could have used the J head to hold the cover in place but was a little worried that it may start to rattle over time and also did not want the thing to twist during use.

Next on the list of things to do is work out how and where I am going to put the optical bed sensor and machine up a nice little copper block for the nozzle/heater etc.. The original ones that came with the J-Head do not have a split in them and the grub screw that holds the element in place tends to wiggle loose causing some interesting problems with heat stability.