JitsuGuy

Any tips so I don't buy something that doesn't suck?

Thanks!
J

Hixsy

Make sure you get a CARBIDE BIT!

Diamond bits break to easily when your just learning how to
use it! my personal prefrence is ball bearings but V blocks are good to!

RCGaryK

iTrader: (3)

I couldn't more strongly disagree with the previous post. If you look in the pits at the guys who build motors for a living, they use diamond bits and v-grooves. The diamond bit will last a heck of a lot longer then a carbide bit, plus the diamond bit cuts cleaner and truer. A carbide bit will freshen the comm, but it doesn't get the surface quite as smooth. Those surface imperfections can speed up brush wear, which in ture can speed up comm wear, meaning you'll be cutting your motors a lot more frequently. The main thing to remember with whatever lathe you go with is you don't remove all the material in one deep cut; you make a number of small sweeping cuts to remove only as much material as you need to. Also, make sure you have the motor running in the correct direction. If you have the armature spinning backwards and you run the bit into it you could ruin the arm, the bit, and more. I've used the Hudy, Trinity, Reedy, and Cobra lathes, and they all work extremely well.

Hixsy

Rc Driver,

everything you've said is absolutely correct , only thing u forgot was that this is Jitsuguys first lathe and with no cutting experience he could easily chip the diamond bit.
like Rc driver gary said all of those lathes a good but if u got
the extra cash then go for the hudy, just makes the pit look better

RCGaryK

iTrader: (3)

No, I didn't forget. If you buy cheap, you buy twice and end up spending three times the money though. Lathes are not difficult to operate. Hell, "I" can do it! LOL

If it's something you're worried about, take a motor and your lathe to the LHS, ask them if they can help you set it up and show you how to do it.

fatdoggy

V-blocks, forget BB's they just clog up with shavings.

Daimond bit = $80 and are fragile

Carbite bit = $5

$80 + one screw-up = worthless bit. I use carbides and have great finishes, either replace when necessary or resharpen them. I seriously would not say go buy a daimond bit to a newbie lathe user. IMO A cut with a fresh carbide bit is just as good as a cut with a daimond bit. If your not a pro you really don't need to risk burning $80 for a super sick finish, a sick finish will surfice.

Just my take...

Rory

I heard that carbide bits actually give a better cut than diamond, although dimond cuts look better. is there any truth to this?

adrian

Rory, I wouldnt calll it a better cut, they can cut just as well as dimond, but this is only if they are sharp. For your first lathe i would recomend getting a carbide. If well maintained they cut very well, i have had my lathe for about 3-4 months and i cut quite often and i it has not needed to be sharpened. Dimonds are more fargile and i would only recoment it to a more expericend racer. Just make sure you practice on an old crap arm. Chances are you will stuff a cut up when you are new to cutting, so its better to do it on somthings thats not worth anything as opposed to a race motor.

Johnny J

I would also go with a Carbide bit. I use a Hudy lathe with a carbide tip and i can get finishes just as good as a diamond tip BUT, as Hixsy said, it must be sharp. I regulary have to sharpen my bit to get those results, so now I'm getting a diamond bit.


When i first started, I pulled apart and old 540 silver can motor and practiced a few times on that with an old carbide bit that was in the garage.

dimples

Carbide is one of the hardest surfaces known to man. In a machine shop you use diamond to cut carbide. Carbide is great but can be easily dulled. Also, carbide is much worse about holding heat. Heat gives you incorrect sizes because it causes the material being cut to expand. Diamond with a sharp point will cut through a comm smoothly without heat build up. The only problem like previously said is that diamond used for a coom lathe tool is small and easily chipped off. One carbide will last forever but will neeed to be resharpened to maintain good results. A beginner would be much better off with a carbide and some old handout silver can motors to practice on. When you can get consistent at cutting smooth clean comms then maybe think about switching to better motors and maybe a diamond bit.
As for lathes, I prefer the Cobra lathes. They are the best for the money in my opinion.
Thanks

TSR6

iTrader: (5)

Carbide v.s. Diamond

This is my personal spin on the bit issue.

If you have no lathe experiance at all, and have never watched someone cut your arms, and are afraid of wrecking a bit, go with the carbide.

If you have used a lathe before, or have watched someone cut your motors many times, then don't be afraid to go straight with the diamond bit. Just remember that until you get the hang of things, take your time! Make very small passes, and when closing the gap between the comm and the bit, go very slow.

The two major causes of bit breaking is going to fast. Either by going to fast when closing in on the comm that you end up hitting the comm, stopping the arm, or by going to fast, and going to far while making a cut, hitting the windings.

Be your own judge..

lazyboy

what kinda of laths do you guys use, and witch would you recommend to someone that has used a lath before but itsn't the best at cutting a com?

Grizzbob

iTrader: (2)

I agree, 100%, I think the best way to go today is go ahead & buy a lathe that includes a diamond bit(& I think Cobra's Pro Comm lathe is a good deal with the diamond bit at about $150 new) & then go to a local machine tooling shop to buy a couple of carbide bits as well(& for JitsuGuy, there's a good shop in Tulsa called Du-Mor on Sheridan near 11th street that should have any bit you'd need, I used to buy them form there before I got a diamond bit for mine. Just take the bit that comes with a lathe to them & they can match it, when I still used carbide, I was only paying about $1.50 apiece for them). Then go ahead & start using the lathe with the carbides until you get the hang of it, & when you feel ready(or when the carbide bits dull), it might be a good time to start using the diamond one. Once you do, it'll last a LONG time as long as you take proper care of it(I've had the diamond bit in my Cobra for about 4 years now, & it's still cutting as good as new)......

Omar

iTrader: (15)

i like The Hudy Comm Lathe