.9° extruder motor mod

DRV8825+E3D Hobb Goblin+.9° stepper motor="The Poor Man's Bulldog XL".
Or, as I would like to call it, the next mod that should be done!

I recently purchased 2 motors off of OMC-stepperonline.com for some testing.
A 17HM08-1204S "half-stacked" motor would be ideal, since it would weigh less than the stock Solidoodle extruder motor 
SM42HT33-1334A. In comparison:
OMC Motor | SD Motor
-----------------------------
150g          | 220g
That's quite a load off! However, it only had enough torque to load the filament, and
could not actually print a skirt! That's out the window. After installation, I compared
specs and here's how it breaks down:
OMC Motor  | SD Motor
------------------------------
11Ncm        | 22Ncm
Screw that. At least I have a motor for testing or small projects

Then it was time for the 17HM15-0904S which is about 3mm deeper than the stock SD motor if I recall correctly. Due to the added weight by comparison, I was not as keen on it and wish the half-stacked pulled its weight....or anything.
OMC Motor    | SD Motor
--------------------------------
280g              | 220g
An added 27~% weight isn't as bad as it could be, but I was still trying to shave off mass to avoid speed limitations. Then again, the torque was very appealing:
OMC Motor    | SD Motor
--------------------------------
36Ncm          | 22Ncm
This thing is phenominal! I get prints that rival my Bulldog at a drastically reduced cost!
DRV8825 (not applicable for some boards like Smoothieboard or Printrboard)- $10~
E3D Hobb Goblin- $15
OMC 17HM15-0904S- $12
So for less than $40 (before shipping), I have a high performing extruder setup that performs as well as my $150 Bulldog XL. The differences between the two machines actually build more support for this approach:
#1            | Spookidoodle (thanks again for the name, jagowilson)
----------------------------
Bulldog XL | OMC .9° motor, Hobb Goblin
RUMBA      | Sanguinololu
E3D v5      | E3D v6, Volcano
.4 nozzle    | .6 nozzle

On my #1 I usually use .2963 layer height due to the outdated v5 heating block and .4 nozzle size. On the Spookidoodle I usually use .3951 layer height which would show more flaws if anything. But one other factor I should mention in the defense of the still-great Bulldog is that while both beds are aluminum, the Spookidoodle has a bed stabilizer I recently installed which works pretty well.

Pros:
*Spectacular resolution.
*Added weight does not seem to hinder performance. This weighs far less than the Bulldog which comes in at a whopping 495g!
*Height and width are the same as your stock motor. So cable chains and mounts do not need to be modified.
*It's black, so it matches my frame

Cons:
*It gets hot. VERY hot. With an IR I measured around 208f.
*The wires are short. Very short. Like 8" short. So be sure to have some extra wires around and either solder (what I did) or crimp some extensions on. Alternatively, you can splice into your old wires and save the plug, but the approach I took allows for painless reversion in case I wanted to go back for some bizarre reason. Pololu has these plugs which are my personal favorites. If you go this route, you will also need to get female crimp pins and some practice crimps...it can be tricky at first.
*The motor has an added 3mm depth and comes 5mm away from hitting the Z rods. With the added heat it builds in comparison, I've considered using a 20mm fan, but that would sacrifice another 15mm~ in build space.
*Once again. Heat. I used some Arctic Silver 5 for thermal compound, between that, a heatsink, and a 10mm fan, it still gets very very hot. I ran it with caution for some small prints to start as I calibrated, but once I hit the 20 hour mark, I went back to my 1+ hour prints and I am very happy.

As usual, you would have to adjust your EEPROM settings. This would double your original number....roughly. I went from 285 steps per/mm to 565. Just double it to start then dial it in from there.

Pics will be added ASAP.....hectic schedule. Took me over a week to type this.