Gearbox for Battlebot or Sumobot motor RS755 and RS775

Reduce high speed from the motor (DC 24V: 34000 rpm).
Compatible Models: 755,775.
Reduction aprox.: 12,7:1
Torque With DC Motor 775: 20kg.cm
It will be use on Robot Sumo. Battlebot.
It was printed with ABS around 5 hours.
Test
https://youtu.be/E07UPMWj7z0
You need :
2 screws for attaching the engine
5 washers
1 motor model DC 755, 775
http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_775vcwc
4 screws for top 3mm
Two rods or axles 3mm diameter
Oil or grease for the axles and gears.
Print 2 "Main Reductor".

Tires are not here yet but with your help we will design a lot of robots and share them here.
If you want to donate a contribution for us :
https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=FC3EZSZD42LLJ&lc=US&item_name=ZayelMech¤cy_code=USD&bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted

You can buy the things here
Metal pinion: http://es.aliexpress.com/item/2pcs-Motor-Metal-Steel-Gear-Wheel-Top-Screws-15-Teeth-Tooth-5mm-Hole-Diameter/32279062245.html

Motor DC755
http://es.aliexpress.com/store/product/3V-24V-4700-39000rpm-the-length-of-shaft-24mm-bassinet-DC-geared-motor-Model-Aircraft-ship/133375_1682540199.html?spm=2114.04010208.3.123.PQKITu&ws_ab_test=searchweb201556_6,searchweb201644_4_10001_10002_10005_301_10006_10003_10004_62,searchweb201560_1,searchweb1451318400_6151,searchweb1451318411_6448&btsid=5bf490d1-491a-4f7b-8559-1b5ca0cb35e4