This is a "Extreme Makeover 3D Printer Eddition". I bought my CTC Prusa I3 off craigslist in November 2017. This is the first printer that I purchased and my only intention was to print parts for a Hypercube Evolution. So now that the Hypercube Evolution is done, calibrated and has way better prints than the CTC Prusa, I figured I'd upgrade it so I can have it as a backup. At first I was only looking at doing a AM Prusa build, but then i thought better...ANOTHER HEVO.

The goal of the project is to use as many parts from the CTC as possible and print as many parts as possible:

CTC Parts re-use:

• GEETECH Board
• Power Supply
• Heatbed
• Steppers
• Rails
• Linear Bearings
• Screws
• Cables

Upgrades:

• Board bootloader and Marlin 1.1.8 (note I have detailed instructions on the upgrade HERE).
• Upgrade to optical endstops
• Upgrade the Min Endstop connectors on the board to 3 pin (+5V, Signal, Ground)
• Upgrade to Auto-leveling with proximity sensor
• J-Head style hotend
• Bowden drive
• Build volume: 200mm x 200mm x 180mm

BOM:

• 3 x optical endstops
• 2 x 12mm linear rails (400mm) need to cut it down
• 8 x 350mm 3030 extrusions (standard size you can buy already cut, but you could go shorter)
• 4 x 400mm 3030 extrusions (standard size you can buy already cut, but you could go shorter)
• 2 x 340mm 2020 extrusions (buy what you can and cut down. DON'T buy 2020 from 8020.net. You can't use hammer nuts on their 2020 extrusions)
• 2 x 140mm 2020 extrusions (buy what you can and cut down. DON'T buy 2020 from 8020.net. You can't use hammer nuts on their 2020 extrusions)
• 100 x M5 Buttonhead screws 10mm
• 100 x 3030 hammer nuts
• 50 x 2020 hammer nuts
• Teflon grill mat (smooth, not rippled)
• Galvanized metal sheet 26ga or 28ga
• Glass for the the heatbed with corners trimmed (from Hardware store)
• 3mm screws HEVO screw kit (cheaper than buying them individually)
• J-hotend $7
• Extruder or print one and purchase the connectors which saves about $4
• Nylon cable chain. I've printed several, the nylon just holds up better IMHO and is only $8
• 3mm Nut inserts (5mm x 5mm)
• Fiberglass reinforced T20 belt
• 6 x toothed idler pullies
• 2 x smooth idler pullies

Print list:

see files. Piece count is in the file name.
Many parts are directly from HEVO
Some have been modified e.g. extra long X end stop flag, Z top mount to provide clearance for drag chain, etc.
I used green PLA from ZYLtech. Printed nice, but go easy on the soldering iron temp when inserting the brass inserts.

GT2560 Board mod:

• Remove min connector housings from board
• desolder/remove the connector housing from the optical enstops
• Use one pin from the removed optical endstop and solder to the Arduino board +5v
• Place optical endstop connector over the 3 pins

HOT BED:

We will be mounting the hotbed inverted (heat element up)
Desolder the leads and remove all the solder you can
Solder the leads through the holes and make sure you keep the solder flush on the heat element side.Place a smooth Teflon Grill mat on the heatbed and cut to size This will make sure we don't short anything out
Cut a flat 26 or 28ga galvanized steel sheet to size of the heatbed, drill holes for the bed leveling screws.
Make sure the bed leveling screw heads are not higher than the glass you will be using. If you are using the CTC screws grind them down a little. you want the heads below the glass surface to protect your nozzle.
Screw everything together and clip on the glass with the trimmed corners.
Extras:
Enclosure:

Buy enough plexi glass to enclose the sides and top and bottom. I needed:

• 4 x 16.125" x 16" (0.125" thick)
• 2 x 16.125" x 16.125" (0.125" thick)
• 4 x 3" x 15.875" (0.250" thick for the top brim)Plastic Solvent Cement (fuses plexi glass... needed for the top)

Octopi:

• Octopi with Logitech 270 webcam
• Print the webcam holder
• watch YouTube video on how to adjust focus 

UPDATE 3/2/2018
I tried the Klipper firmware on the MINI and it looks promising. Lots of fun watching this thing crank away at 100mm/sec. Currently it's like a sports car that is meant to go fast, but has no comforts. I hope the auto bed leveling will be industrialized soon as that is the only thing I really miss. It has it somewhat enabled, but the intent seems to be to run the bed leveling and then use the values to update the config vs. it just running automatically before the print job. It also doesn't have the LCD working, but I can upgrade my RPi to a 3.5" LCD and that would handle my last requirement. I'll post the config file near the bottom of this summary just in case someone wants to try it...

UPDATE 2/14/2018
I was able to sell my old CTC frame and other parts I didn't use for $20, so the cost is now down to $324 for the build!

UPDATE 2/10/2018
Just to note that this is a remix of the fabulous Hypercube Evolution by Scott_3d. This means that you can use the configuration XLS that is available @ https://www.thingiverse.com/thing:2254103to change the dimensions. However, you will be increasing the cost of this upgrade and may just consider buying it all and going to a 24V setup. Mini HEVO cost:

Extrusions: ~$80
10 x 3030 inside corners: $11
J-hotend $5
Screws ~$20
Optical endstops $3
Teflon tube $2
Nylon Cable chain $8
2x 12mm linear rails: $20
4x Linear 12mm bearings $6
100 x 3030 Hammer nuts: ~$12
50 x 2020 Hammer nuts: ~$6
Belt & pullys: $18
Galvanized Sheet Metal: $5
Glass: $3
Loom: $5 .
CTC printer: $140
Total: $344
A full build would be at least $500.

UPDATE 2/8/2018
I added some aluminum tape to the bottom (formerly the top) of the heatbed. It heats up to 65C in about 3 min. HERE is the kind of tape I used

UPDATE 2/3/2018
Added two 2020 brackets and two 2020 braces to the build. there just seems to be too much flex with the 2020 extrusions I bought, but of course they were super cheap! The ones I bought from 8020.net seem stronger, but I had to grind down all the hammer nuts to make them fit. I'll gladly print a couple of extra brackets to not do that again

Klipper printer.cfg file

This file contains common pin mappings for CTC Prusa i3 printer board in
COREXY configuration. To use this config, the firmware should be compiled for
the AVR atmega1280.
Note that the "make flash" command does not work with CTC boards -
the boards are typically flashed with this command:
avrdude -p atmega1280 -c arduino -b 57600 -P /dev/ttyUSB0 -U out/klipper.elf.hex
See the example.cfg file for a description of available parameters.
[stepper_x]
step_pin: ar25
dir_pin: !ar23
enable_pin: !ar27
step_distance: .0125
endstop_pin: ^ar22
position_endstop: 0
position_max: 200
position_min: 0
homing_speed: 50

[stepper_y]
step_pin: ar31
dir_pin: !ar33
enable_pin: !ar29
step_distance: .0125
endstop_pin: ^ar26
position_endstop: 0
position_min: 0
position_max: 200
homing_speed: 50

[stepper_z]
step_pin: ar37
dir_pin: !ar39
enable_pin: !ar35
step_distance: .0025
endstop_pin: probe:z_virtual_endstop

the higher the number the closer it gets to the bed.
position_endstop: 0.15
position_max: 180
homing_speed: 20

[extruder]
step_pin: ar43
dir_pin: !ar45
enable_pin: !ar41
step_distance: .0102

step distance started with .0105
nozzle_diameter: 0.400
filament_diameter: 1.750
heater_pin: ar2
sensor_type: EPCOS 100K B57560G104F
sensor_pin: analog8
control: pid
pid_Kp: 21.27
pid_Ki: 1.74
pid_Kd: 64.91
min_temp: 0
max_temp: 250

[heater_bed]
heater_pin: ar4
sensor_type: EPCOS 100K B57560G104F
sensor_pin: analog10
control: pid
pid_Kp: 175.55
pid_Ki: 16.11
pid_Kd: 478.17
min_temp: 0
max_temp: 130

[fan]
pin: ar7

[mcu]
pin_map: arduino
serial: /dev/ttyUSB0

[printer]
kinematics: corexy
max_velocity: 300
max_accel: 3000
max_z_velocity: 25
max_z_accel: 30

[probe]
pin: ^!ar30
speed: 5.0
z_position: 0.0

The Z position to command the head to move to during a PROBE
command. The default is 0.
activate_gcode:
A list of G-Code commands (one per line) to execute prior to each
probe attempt. This may be useful if the probe needs to be
activated in some way. The default is to not run any special
G-Code commands on activation.
deactivate_gcode:
A list of G-Code commands (one per line) to execute after each
probe attempt completes. The default is to not run any special
G-Code commands on deactivation.
[bed_tilt]
x_adjust: 0
y_adjust: 0
points:
100,100
10,10
10,100
10,180
100,10
100,180
180,10
180,100
180,180
speed: 50
horizontal_move_z: 5
probe_z_offset: 0.15