Meddeling with Mendel

Its been nearly a year and a half since I last posted about my Reprap Mendel. ¬†I haven’t actually made any progress building it either! This is because I got side tracked with other things including developing RapCAD
Well recently I have taken interest again and started meddling with my Mendel. The first outstanding task was to solder the voltage reg and capacitor to the motherboard. I didn’t much like the official reprap solution of powering the motherboard entirely via the usb port! so rather than add a jump wire between the comms port and the 5v track I instead used a spare track to connect a power connector at J4. This still leaves J1 J2 and J3 to be used for additional¬†extruder’s.
The motherboard will be powered instead from my previously hacked ATX power supply which will provide 0v 5v and 12v via the XLR connections. For some reason the official reprap uses these 3 wire connectors as well but doesn’t utilise the third wire.


Neat hack to ATX power supply

I have been progressing slowly with my reprap build, spending a little time here and there modifying the electronics so that the wiring is neater. There are some details on the reprap wiki about how hack an ATX power supply to give you a universal power supply. This is my sightly neater solution which is specifically suited to reprap only.

With minimal filing the standard ATX power supply grommet hole can be opened out to fit a standard XLR socket. I used a female socket as opposed to the male socket mounted on the reprap. This is standard practice and ensures that the pins of the socket cannot be touched if the connector is removed. In general the live end is protected and the cold end is not.

Hobbed M4 Insert

After a few helpful comments I was pointed in the right direction for drilling a hole down the middle of my hobbed M4 insert. Unfortunately I didn’t have a drill vice, so I used my trusty Block’o’Wood and a fair amount of extra caution instead.

It really is amazing how well this technique works, the drill bit doesn’t have to be perfectly centered but because the work piece is spinning around a central axis its near impossible not to get the hole dead centre. I guess this is why a metal lathe has the drill bit set-up in the tail-stock.

Here is the hobbed insert with the central hole:

I am very pleased with the result, as it runs nice and true when rotated. All I have to do now is drill the M3 grub screw hole.