After watching Phil's short game DVD I googled Pelz' putting tutor, and after seeing the price I decided to make one on my own.
Here's a short howto:
Material: 1mm aluminum
Tools: hacksaw, drill, 5mm drillbit, countersink, file, sandpaper 80grit, marker pen
*) Just mark the outline of the tutor on a sheet of aluminum and cut it out with the hacksaw, see that the "bottom" end (where you put the ball later) is as straight as possible.
*) file the edges round and deburr all edges
*) mark the places for the marbles
*) drill the holes for the mables (5mm) and countersink them
*) sand the edges and the surface until it gets some satin finish (to make the ball slide less and have more "grip")
*) mark the ball place (40mm from the bottom edge) with the 5mm drill but don't drill through
*) draw the centerline square to the bottom edge
*) draw 2 lines parallel to the centerline, each one 25mm from the centerline
All in all, the whole tutor cost me nothing, zero, nada, 0,- because I had a sheet of aluminum in the workshop.
Ok, the marbles will be about 50cents...
Since I'm still waiting for my marbles to arrive, I don't know, if 10mm or 12mm will be best, but the calculated diameter could be 12mm.
Even without the marbles, just using the tutor on my indoor putting setup already helped me to work on my setup and get a good straight putting stroke.
With the 5mm holes you can even use 2 tees on the putting green to
a) fix the tutor so it doesn't move
b) use as gates instead of marbles
I looked at the pictures at the Pelz website and derived these measurements off of the size of the golfball (42-44mm diameter) showed there:
wide end: 135mm
short end: 80mm
marble diameter: 12mm
distance between marble centers:
normal setting: 62mm
pro setting: 56mm
super pro: 50mm
And that's how it looks:
Sadly I made an error measuring the holes for the pro-setting, but that doesn't matter to me, I will use the normal and super-pro settings...
Edit: _and_ I mis-measured the first line parallel to the centerline *g*
maybe this will give others some help making one...