Here is my version of a NEMA 17 motor mount. That is the size of the stepper motors used on a MakerBot. There are several other motor mounts on Thingiverse, but none of them would work for what I had in mind. This one is designed to fit the stepper motor onto 1" X 1" (25mm X 25mm) 80/20 series 10 aluminum T-slot framing. The mounting holes will accept 1/4" (M6) size bolts - which is the size the 80/20 uses for its T-bolts.
A note about 80/20 Aluminum ( http://www.8020.net - I have no affiliation):
If you crossed a Gilbert Erector Set with dimensional lumber (2x4, 1x6, etc.), you'd get 80/20 extruded aluminum. I'd never heard of it until I started playing with 3D printing and looked over several DIY websites which featured projects using it. Neat stuff. The 80/20 company has stocking distributors across the USA, but I'm guessing they are only interested in large orders and could care less about the DIY market. There are several web based vendors of the 80/20 parts. For me it was WAY easier to order through Amazon rather then try to figure out how to buy from any of the large raw material websites. I also see there are 1,000s of 80/20 parts being auctioned on eBay.
Printing takes about an hour and because of this item's size, using an HBP is a requirement to avoid curl. Be sure to center up your XY platform good as the mount is 83mm wide.
I printed the mount with a raft which was left on to add a little more strength to the face of the mount - uh, plus it was fused too good and did not cause any harm. To print this raftless, your HBP has to be leveled real good. Something just beyond what I could get mine to handle lately.
INFILL DENSITY in FILL was set to .2 which looks like it prints almost 100% for most of the object due to the narrow geometry of the 3 main surfaces. Your results are sure to be different, but I suggest trying .2 or even .1 INFILL DENSITY on your 1st printing attempt.
Little post-printing work is needed. Remove the excess plastic with an X-acto knife and clean out the 4 motor mount holes with an 1/8" (M3) drill bit. The 2 1/4" (M6) holes that hold the mount to the frame you are using can also be cleaned out with an X-acto knife.