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Old 02-02-2016, 09:48 PM   #2041
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Default Re: Cutting a motor commutator & motor tweaks

Where the hell did everybody go? Had to take a break from crawling for bit. Mostly just for lack of time. Getting ready for spring though. I have done a few motors in the last few days. Had to get some P94 brushes and a couple other things from Eddie.

I have a Hudy tech and a Cobra. I think the Cobra needs some adjusting since it likes to take a little off as you bring the bit back. Hudy cuts great after I put a new carbide bit in it. Going to have to head to Ace tomorrow as long as this blizzard is over to hunt down some drive belts.

Learned a lot from this thread and still think it's the best one on this site. Just read the whole damn thing again because, old man memory. Thanks to all that have contributed.
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Old 02-04-2016, 05:56 AM   #2042
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Default Re: Cutting a motor commutator & motor tweaks

Everybody is around, but there aren't a lot of folks indulging in brushed motor maintenance on the regular. Not many worm axles eating up motors, and the middle price rebuildable motors are losing favor. Between sealed can motors being "enough" at cheap prices, brushless closing the gap on startup, and brushless wheelspeed being the #1 request, the rebuildables aren't getting rebuilt as often. I think we only refurbish 3 to 5 a week for customers on average.

Pure comp crawlers still favor brushed, but they go a year or two between rebuilds. And then they send email in and don't post here, lol. I wouldn't doubt we see some revitalizing this year though. Comp crawling seems to be growing again.

Last edited by JohnRobHolmes; 02-04-2016 at 06:00 AM.
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Old 10-22-2016, 08:42 AM   #2043
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Default Re: Cutting a motor commutator & motor tweaks

So how many people still run brushed motors? I know i still do and alot of the local guys like them.
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Old 10-22-2016, 10:03 AM   #2044
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Default Re: Cutting a motor commutator & motor tweaks

Oh yeah..........always brushed. I run a 27T HH TM pro... I love being able to rebuild my own.
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Old 10-22-2016, 10:24 AM   #2045
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Default Re: Cutting a motor commutator & motor tweaks

I'm running brushed. I've been using disposable sealed cans till now. I just picked up my first lathe motor, an integy 35T. Looking forward to tuning it some, I always enjoy developing new skills and learning new things.
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Old 10-22-2016, 11:02 AM   #2046
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Default Re: Cutting a motor commutator & motor tweaks

Yes it is. I like seeing the gains with advanced timing vs truing up the brushes with the comm.
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Old 12-10-2016, 03:31 PM   #2047
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Default Re: Cutting a motor commutator & motor tweaks

I picked up a Cobra pro com 2000 lathe. I'm going to try and rebuild a few motors. So do I need a left or right cutting tool?

There's an extra cutting tool that came with the lathe part # AL4- C2 is this cutting tool a correct bit for the cobra 2000?


If I wanted same style cutting tool as above.. I think I need a AR4-C2 bit...

I have a gut feeling AL4- C2 is not the correct cutting tool.

If both bits are wrong? Can someone give me a part # for carbide cutting tool and a Diamond cutting tool.

Is the cobra 2000 right or left handed?

Thanks.

Last edited by tapped-out; 12-13-2016 at 09:41 PM.
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Old 12-13-2016, 08:36 PM   #2048
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Default Re: Cutting a motor commutator & motor tweaks

AL4 is what you need, my cobra and Hudy take the same bits. Stay away from diamond bits until you're more experienced, they're pretty fragile.
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Old 12-13-2016, 08:54 PM   #2049
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Default Re: Cutting a motor commutator & motor tweaks

Thank you.
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Old 12-14-2016, 06:12 AM   #2050
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Default Re: Cutting a motor commutator & motor tweaks

I wouldn't recommend the carbide, although it will last a few cuts. I haven't found one that is sharp enough as bought. Shim it up just a hair if it rubs. There is generally a bit of radius to the cutting edge, and when installed on center it rubs more than cuts. We tried carbide at the shop and everything needed honing before use.

My recommendation would be HSS tool blanks, learn to grind your own. They stay sharp longer than factory carbide and can be resharpened easily.
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Old 12-14-2016, 09:02 AM   #2051
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Default Re: Cutting a motor commutator & motor tweaks

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I wouldn't recommend the carbide, although it will last a few cuts. I haven't found one that is sharp enough as bought. Shim it up just a hair if it rubs. There is generally a bit of radius to the cutting edge, and when installed on center it rubs more than cuts. We tried carbide at the shop and everything needed honing before use.

My recommendation would be HSS tool blanks, learn to grind your own. They stay sharp longer than factory carbide and can be resharpened easily.
Thanks John, "honing before use" what do you use to hone a comm?
And which Diamond blade cutting tool would I buy for my lady cobra Pro 2000 lathe.
I've bounced around through this thread for the last few days or so going to officially start reading from page one through today. Maybe some of the answers to my questions are in here.

Last edited by tapped-out; 12-14-2016 at 10:04 AM.
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Old 12-14-2016, 09:35 AM   #2052
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Thanks John, "honing before use" what do you use to hone a comm?


A stone on the tool edge.....


Hang up and Drive
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Old 12-14-2016, 10:50 AM   #2053
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Default Re: Cutting a motor commutator & motor tweaks

carbide needs a "green" grinding wheel (silicon carbide) to be ground. It can also be honed with diamond coated tools. A diamond knife hone would probably work, never tried.
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Old 12-14-2016, 10:53 AM   #2054
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Default Re: Cutting a motor commutator & motor tweaks

Carbide work fine if you take the time to sharpen them correctly. A quick google search will probably find the old Big Jims instructions on how to sharpen them. ( The Late Big Jim's Benefits of Lathe Carbide Bits over Diamond Ones ) You need a diamond file/hone to do it by hand. I always found the Mcmaster carr bits plenty sharp out of the box, but they wear pretty quick. I have not bought them in years, as I bought a couple boxes of them way back when and never even used them all since we switched to diamond as we grew tired of sharpening them and I had a $1000 machine to do it on...

HSS works, but again you need to keep them sharp, but that's just a bench grinder with a white aluminum oxide wheel and a honing stone....a bit more skillful than a sharpening a carbide bit, since its with a power tool, but there are tons of videos to do it.

Integy was clearing out diamond bits a while back for dirt cheap, you may check there....

Your lathe uses an AL4 bit as others have said...

Later EddieO
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Old 12-14-2016, 11:15 AM   #2055
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Default Re: Cutting a motor commutator & motor tweaks

The carbide I've purchased from McMaster over the past 7 years has very poor edge quality, and gets worse every time I buy. A 40x scope shows the lack of edge. Occasional user, the carbide will work well enough. We have never gotten more than 10 cuts from the mcmaster bits before they dull though, typically it is 3 to 5 armatures before they get noisy.


I would pay $25 for the integy bits, but not the $70 they are asking. That much will buy a proper diamond tool from a reputable manufacturer.
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Old 12-15-2016, 11:03 AM   #2056
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Default Re: Cutting a motor commutator & motor tweaks

I've Been reading this thread for a couple days tons of great information...
Question on my lathe set-up I'm running a 55t Novak 540can wth a 5 volt (4 cell sub C) battery pack. Cutting tool is a AL4- C2. Seems to be cutting fine but I've read where some used 27t motors 3s lipo seems way to fast to me but what do I know...

So do you guys think my 55t Novak 540can on 5v nimh and AL4 - C2 cutting tool is a workable set-up?

I'll add picture later of comm.

Thanks guys for all the replies to my questions.

Thank you Eddie I did find that others had already mentioned al4-C2 over the last couple of days is that correct bit.
Thanks for taking the time answer already answered questions.

Last edited by tapped-out; 12-15-2016 at 11:17 AM.
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Old 12-15-2016, 11:55 AM   #2057
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Default Re: Cutting a motor commutator & motor tweaks

Some like to spin it faster with the 55t motors. The theory behind them was you could run them directly off a 12v power supply, but I always found it was still too fast along with not liking how motors run directly hooked to a power supply or a battery. With the 55t motors I use 5-6 volts depending on comm size. With a 27t motor, I use 3-4 depending on comm size...faster does not really hurt the comm per say, but I also found the faster its spinning stuff, when stuff goes wrong, its always worse

Later EddieO
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Old 12-15-2016, 07:52 PM   #2058
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Default Re: Cutting a motor commutator & motor tweaks

Couldn't agree more. 12v is what 55t motors "should" be run on in a lathe, but 5 or 6v is typically plenty for just servicing one motor. My setup is a 12v power supply with an esc to regulate the speed. One lathe with a 55t does require the full 12 though, it's a terrible quality motor. Everything else has 35t or 27t motors of nice quality, they run 3 to 4v depending on cutting tool and comm size.

The exact speed will quickly become intuition if you can regulate it. Anybody looking to service their own more than once will get best results by having speed control. A properly set up lathe with sharp tool should do the job in ten seconds, and emit little noise from the tool. Singing, screeching, or chatter is not normal noise.
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Old 12-19-2016, 03:27 PM   #2059
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Default Re: Cutting a motor commutator & motor tweaks

Quote:
Originally Posted by JohnRobHolmes View Post
Couldn't agree more. 12v is what 55t motors "should" be run on in a lathe, but 5 or 6v is typically plenty for just servicing one motor. My setup is a 12v power supply with an esc to regulate the speed. One lathe with a 55t does require the full 12 though, it's a terrible quality motor. Everything else has 35t or 27t motors of nice quality, they run 3 to 4v depending on cutting tool and comm size.

The exact speed will quickly become intuition if you can regulate it. Anybody looking to service their own more than once will get best results by having speed control. A properly set up lathe with sharp tool should do the job in ten seconds, and emit little noise from the tool. Singing, screeching, or chatter is not normal noise.
Yup it takes a lil feel.

My huddy comm lathe likes 5v with its 55t motor from a computer power supply. 12v was way too fast, and a 6 cell nimh pack (7.2v) was still a lil fast.

I actually broke out my comm lathe the other day and refurbished a 27t motor for my bomber... then quickly realized that a brushed 540 on 3s lipo wasnt gonna cut it and ordered up a brushless setup.
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