R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 07-13-2004, 07:12 PM   #1
Tech Champion
 
JayBee's Avatar
 
Join Date: Mar 2004
Location: 12TH-MAN COUNTRY
Posts: 6,813
Trader Rating: 31 (100%+)
Post Comm Cutt'n 2

How important is it to CUT your comm, or better yet buy a comm cut'n machine? I mean, I took one of my motors apart last week and sprayed the inside of the can, bushings, armature, etc.., but when it came to my comm, I said "What the hell, I'm gonna try something...". So I grabbed a piece of scotch brite (very fine grit) pad and went to work. In about 5-10 secs, sprayed it off with motor spray and the comm looked as good as any machine job. So why is CUTTING the comm necessary?

Just a simple question, from a simple mind, wanting a simple answer

-JayBee
__________________
R C 3 G R A F I X _ F U S I O N . G R A P H I X _ S E A T T L E - R/C - R A C E R S _ E M E R A L D C I T Y R C . C O M

A E - 12R5.2 _ S M - REV8 PRO
JayBee is offline   Reply With Quote
Old 07-13-2004, 07:16 PM   #2
Tech Fanatic
 
Cardboard's Avatar
 
Join Date: Feb 2004
Location: Flushing,NYC
Posts: 843
Send a message via AIM to Cardboard
Default

The finish isn't important-it's the roundness that counts. A comm that has depressions in it is much harder on the brushes and they bounce.
Cardboard is offline   Reply With Quote
Old 07-13-2004, 07:18 PM   #3
Tech Elite
 
Join Date: Aug 2003
Location: Henderson, NV
Posts: 4,148
Trader Rating: 28 (100%+)
Send a message via AIM to Scott Fisher
Default

To answer your question: Not only does cutting the com "clean it" but it makes it round. You com will groove under the wear and pressure of the motor brushes as well as going out of round. A fresh cut restore the perfection that you will want out of your motor.
__________________
| Capricorn | Ybslow | Proline-Protoform | Johnny Bravo Racing | Desoto Racing | Murnan Modified | Matrix Tires | Powermaster Fuel |
Scott Fisher is offline   Reply With Quote
Old 07-14-2004, 12:59 AM   #4
Tech Master
 
Join Date: Nov 2003
Location: Florida
Posts: 1,154
Trader Rating: 1 (100%+)
Default

Like the others have mentioned.....the shine has nothing at all to do with the roundness of a comm or performance of a motor....a properly fresh cut comm will help give you optimum power as well as getting you the most time out of your brushes......it's a very important piece of equipment , even if your just semi-serious about racing......even at most club races a motor with just 3 or 4 runs on it will not be up to par for top competition......Inbetween runs you can use motor spray and a comm stick.....It will do effectivly what you accomplished with scotchbrite, but even better, because you can do it with the motor still assembled and also clean the inside of the brush hoods with it....
__________________
1/8 Scale: Tekno EB-48.2... Tekin RX-8 GEN-2 W/2050kv... Airtronix M11-X Radio... HiTec HS-7954SH Servo...

1/10 Scale: Associated B-5(rear motor)...Tekin RSX Gen-2 W/8.5t... Savox SC-1258-TG Servo
Joe B is offline   Reply With Quote
Old 07-14-2004, 01:21 AM   #5
Tech Regular
 
Join Date: Dec 2003
Location: Wichita, Kansas
Posts: 287
Trader Rating: 3 (100%+)
Default

Just tonight I cut the comm for one of the novice racers. His armature was a prime example of why you need to CUT it with a lathe. I had to do about 5 passes because he'd never had it done before, and what was interesting is after 2 passes 1/3 of his comm was perfectly shiney, while the other 2/3rds hadn't even been touched by the bit yet. Keeping it round is why you need to use a lathe and do it right.
psbarger is offline   Reply With Quote
Old 07-14-2004, 01:27 AM   #6
Tech Adept
 
Join Date: Oct 2003
Location: Melbourne, Aus
Posts: 167
Default

yeah, take a look at the comm of a newbie's motor that hasn't been cut for 50+ runs and where you can actually see the difference in diameter on different parts of the comm, then you will understand why you need to use a lathe
Rory is offline   Reply With Quote
Old 07-14-2004, 03:06 AM   #7
Tech Elite
 
Bugle's Avatar
 
Join Date: Sep 2003
Location: Sydney Australia
Posts: 2,082
Trader Rating: 1 (100%+)
Default

Also the more often you cut it the longer the comm will last. As they wear down more they also wear quicker. I do it before each race day.
Bugle is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Hudy comm lathe and Fantom comm lathe ACEDEAN R/C Items: For Sale/Trade 0 05-02-2007 11:27 AM
Comm Evilstealth Electric On-Road 3 04-29-2007 11:18 AM
Trade EXTREME COMM LATHE(Hudy)for MUCH MORE COMM LATHE JoeyE R/C Items: For Sale/Trade 0 05-07-2006 09:49 AM
just cut my first comm! kh15 Electric On-Road 8 01-23-2005 07:46 AM
What's a comm? yoshi Rookie Zone 3 02-25-2003 09:47 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 06:00 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net