Practice cutting comms, and stuff. Donations appreciated...

[redhatman]

Hey, I realize that I am going to have to cut open my motors every once in a while but I do not want to screw up on my good motors. I figured some of you guys have bad motors that I could use to cut open and practice on. LMK. Thanks
-Pat (redhatman)

 

[HeartBreak]

I personally don't have any, but what you could do is go to thrift stores, second hand shops, and the like, and get some old Radio Shack cars that have RS550 mabachi's in them, and crack them open... Slightly different comm diameter, but you should be able to get some practice in on them.

Overall cost, if you shop around, shouldn't be more than a quarter a pop.

 

[redhatman]

yea, I have this place in downtown MN that sells just micellaneous crap, and you can get some decent motors for 50cents, but I am 14 dont have a car and my parents dont like driving me everywhere after a long workday.

 

[HeartBreak]

I've been there, altho that was about 10 years ago... Other than that, All I can tell ya is set up your comm lathe carefully, and cut SLOWLY. Literally move the gibs slower than a millimeter an hour. As long as you're careful and deliberate, you literally can't mess up.

Oh, and set the stops so that the blade stops WELL before the tabs that capture the windings, or you'll shatter your bit.

The best thing I can tell ya is, talk to the local racers and ask if one will show you how to use your lathe. Odds on, you'll find that one of them might be more than willing to take time out to show you how to get perfect cuts every time. Seeing it done for the first time and paying strict attention literally takes all the fear out of it.

Lastly, safety glasses, and an area that you don't mind getting oil/copper splats all over is key. It is a VERY messy affair, second only by working with a dremel.

Also, get yourself a good pair of calipers - you will need them to tell you when you're getting too thin (you can only cut so many times, and so thin a comm diameter... .275 is the max. A new comm measures around .292). Each cut will take about .002, once you get the hang of it.

What model lathe do you have?

 

[FastEddy]

What model lathe do you have?

That was my question.
I just went through the learning curve a few weeks back. Its not as easy as it looks.

 

[Revo Rancher]

Phew! For a moment there I thought that this might be another "Will paint bodies for free" threads!

 

[HeartBreak]

That was my question.
I just went through the learning curve a few weeks back. Its not as easy as it looks.

Definately agreed, but seeing someone cut a comm takes a lot of the mystery out of it. It at least shows you the speed that you should cut at. And, if you have someone help you set the lathe up (bit depth, etc), it makes a TON of difference. I had to learn on my own, but thankfully, I had a bunch of old motors sitting around.

Phew! For a moment there I thought that this might be another "Will paint bodies for free" threads!

Naww, but I will cut comms for blonde women :idea: :smoke: :jk:

 

[Diver6127]

Redhatman probably needs to get the equipment first. I'd say get the HUDY comm lathe and power supply (they all require d/c via 4 cell pack or a power supply) since that's what we run.

IF your parents can get it for you, that's great otherwise start saving and get it done at the lhs till you get the funds needed. It'll cost a few hundered, to say the least.
[inwindow=300]http://www.hudy.net/xhudy/products/proddesc.php?prod_id=80&kategoria=0[/inwindow]

 

[nitrost]

mine lhs got a lathe for sale for 150 it one they used but they bought all new equipment so they sould alot of there stuff

 

[redhatman]

ok, i thought this was a simple cut open the motor, tear out some parts and replace them...

If this is so hard and costs so much money for all this equipment, why not just buy a whole new motor for $30??

 

[FastEddy]

For the most part you wont be rebuilding a $30 motor.
The motors that are used in racing go from 50.00 to 300.00
If you can rebuild a 50.00 motor for 10.00 4-5 times its worth it.
Do the math if your motor costs $150.00

Some races hand out a motor for you to use. If you tune it up you will have the advantage over those that don't.

 

[Plaidfish]

because you do this every 10-15 runs....is that worth 30 bucks every 10-15 runs???
when you can get over 100 per motor if you care for it....I don't race so I used my lathe to more or less clean the comm...they lasted a long time just doing that....every cut I made and the motors were screamers again

 

[redhatman]

so what all would I need to do a sucessful rebuild?

 

[HeartBreak]

For the most part you wont be rebuilding a $30 motor.
The motors that are used in racing go from 50.00 to 300.00
If you can rebuild a 50.00 motor for 10.00 4-5 times its worth it.
Do the math if your motor costs $150.00

Some races hand out a motor for you to use. If you tune it up you will have the advantage over those that don't.

Amen, Brother Eddy!

Definately get a Hudy, as Diver recommends. I personally have the Team Cobra Pro-Comm 2K. I love it, but it's a BEAR to use unless you check tensions between each pass. Hudy's, on the otherhand, excellent. Given the chance, I'd moon the Pope for one.

so what all would I need to do a sucessful rebuild?

Basically, you're going to need the following;
1. Lathe (obviously)
2. Comm Cutting Fluid (this is basically a light machine oil.. makes ALL the difference in the cuts)
3. Motor spray (any will work, so long as it's ELECTRIC motor cleaner. Anything else will eat the epoxy in the windings).
4. New brushes (possibly springs, if the tension seems to be fading).
5. Small screwdriver
6. Power supply for the lathe (4 cell pack works perfect, but I have a power supply that outs' 5v dc)
7. Bearing/bushing oil
8. Time and patience

It sounds really difficult, but it's not (at least, it's not to me...). The whole key is going slow and smooth.

If you can get someone to take you under their wing for the first couple cuts, you'll be amazed how easy it will be (once you learn).

And, as Eddy said; the cost vs performance benefit is amazing. I went from being lapped multiple times to hanging with a guy that was sponsored, and the biggest factor was the lathe, hands down.

 

[redhatman]

why not go brushless? They dont require anything like this do they?

 

[FastEddy]

I'm using the Trinity Tru-Lathe 3 Pro.
I don't have experience with any other lathes but from what I hear its a good one.
I trashed 2 motors and one bit before I got it setup properly. It would have been nice to have someone to show me but I didn't. Its child's play now.

I have a question about cutting oil.
I was told that using a magic marker to mark the com will not only help me see the cut but will also act as a cutting oil. This is the way I have been doing it. What do you think?

 

[FastEddy]

why not go brushless? They dont require anything like this do they?

You can.
When racing they set limits on what can and can't be used in each class. More and more tracks and clubs are introducing brushless classes.

 

[HeartBreak]

I'm using the Trinity Tru-Lathe 3 Pro.
I don't have experience with any other lathes but from what I hear its a good one.
I trashed 2 motors and one bit before I got it setup properly. It would have been nice to have someone to show me but I didn't. Its child's play now.

I have a question about cutting oil.
I was told that using a magic marker to mark the com will not only help me see the cut but will also act as a cutting oil. This is the way I have been doing it. What do you think?

I personally don't use the marker trick. I just put a coat of oil on the comm, and run a couple drops down the tip... Then I make a real light pass - you can tell when it's true'd up when it's a solid, consistant *zzzzzzttttt* all the way across the cut.

If you put a heavy enough coat of oil on the comm and use a bright lamp, you can see the oil get wiped off as you cut.

I didn't have anyone/thing to help me set my lathe except for some general instructions (read; no pictures!! :shrug: ), and some articles printed off trinity's board. My first cuts left a zigzag (or charlie browns) on the face of the comm, and I couldn't figure out why... Then the sponsored guy I raced with explained the bit was hanging out too far, causing it to "chatter". After that, it was gravy.

 

[FastEddy]

My bit was to high.
I now use a strip of lexon to make sure its proper.
I put the lexon strip between the com and the bit. When I tighten it up till the bit touches the lexon the strip will lean forward on the top side just a tid-bit. This shows me that the bit is just above TDC. If its leaning to much I drop the bit down, not enough, bring it up.

I will get some oil and try it your way. Any recommendations on oils to use?

 

[sl0eg1n]

i personally use the marker so i can see the high and low spots on the comm while truing it. i only use royal oil on the v-guides for lubrication.