I want to re-build my Printrbot Jr into a reprap, and while searching I've come across the tantillus, which would be buildable for under $100 with the parts I have right now.

Is it worth it? Currently my modded Printrbot can print 140mmx117mmx200mm, but the Tantillus can only print 100mmx100mmx100mm.

If not, what reprap do you recommend?

I expect the steppers and electronics would translate directly to the Tantillus. The z-axis screw looks like it might also work. Can't tell how big the rods are on the Printrbot. The Tantillus wants 4 lengths of 5/16" drill rod for the outside x-y rods. Two of them are 7 3/4"long and the other two are 8 1/2". You can use bronze bushings or printed PLA bushings on the outside carriages. The two middle x-y rods are 8mm hardened shaft, 6 3/4" long. These have linear ball beaings riding on them, two long ones and two short ones. I expect you could print all the Tantillus parts, including the case, on your Printerbot. Would take a lot of filament and a lot of time.

The strong points of the Tantillus, from what I've read, are its speed and it's quality of prints. I haven't printed anything on my Tantillus yet, but it seems like a solid little machine.

Chuck

First of all, I think you should point the reasons to change your machine. If it is working properly I see no reason to do it, but that's me.

One very valid reason would be to build it yourself and learn in the process, but to me, having a working printer gives you a lot of freedom to build other printers, so I'd rather keep the Printrbot and build a new one.

Worst case transforming the Printrbot to a Tantillus would be burning something out due to bad wiring, so you would be risking your actual machine.