AE Racer

My hudy tech lathe is driving me crazy. I cant even remember a time when it cut well. Im using the carbide bits sold by mcmaster.com that big jim reccomends. No matter what I do I end up with a bad cut. My biggest problem is ridges forming on the comm. Ive readjusted the v blocks many times and made sure that they are parallel to each other. Ive taken pretty much the whole thing apart and reassembled it, trying to find something wrong with it. I adjust the tension on the tracks so that it makes the knobs very firm, and there is no noticeable movement of the bit at all when I pull on it. Today I took a brand new bit, and experiented with different heights. It seemed to cut best with one .2 gold shim under the bit. It made very fine ridges that way. I tryed lowering the voltage from 4.8 volts to 3.5 and then 3.2. It seemed to cut alot better with the lower voltage, but its still not a perfectly smooth comm and theres a few faint lines here and there. And its also totally inconsistent itll cut pretty good like that then if I do another pass itll cut really bad again. It might cut good on one out of four passes. Sometimes it seems like the bit moves in the middle of a pass, messing up the cut, but theres no chance its moving, you pretty much could not have it set tighter and still be able to move the knobs well, and the bit is held in very tightly as well. I also tried a looser more normal tension setting thinking it might be getting hung up of something, but that didnt make much of a difference. I also slid the part that holds the bit off the track to see if anything was obstructing the track and it was fine. I really just cant figure it out. I think it's cut pretty good with these bits in the past. Mabey the bits are just no good? From what Ive read, other people have had very good luck with them. One thing I did notice, using a lower voltage, the motor is a bit inconsistant, I didnt notice it during a cut, but when I just turned it on, I could hear some some significant fluctuation in the sound of the motor. The voltage was constant on my charger so maybe the motor just doesnt run well at low voltages? Please help me before I chuck it at the wall!

Thanks

HVFracingwilly

iTrader: (17)

My first question would be what kind of guide bocks are you using if you are using the bearing supported blocks i would say small chips of copper are running on the bearings causing the arm to bounce as you make a cut across the com. thats my only thought. thanks willy

Exterminator

Also check your slave motor. Maybe the motor is loose. or the spindle, or the bearings in the slave are shot. I find that mine works good at 2 volts. Sounds like you slave motor needs a rebuild if it's not running correctly.

Also do you have the diamond files to keep the bit sharp?
Do you have in sharpened at the correct angles as recomended by Jim?

DerekEngland

Is the arm bouncing on the guides at all? If it is, try reversing the motor wires to see if that helps. I have a Fantom lathe and I only run it at 2v, but it is a different motor too. Other than that the only thing I can think of that could cause that is cutting too deep too fast..... I hope that helps.

corallyman

iTrader: (101)

Try raising the bit more, you said that after you raised it some it got better, but did you continue raising it until it started getting worse again. Keep going until you no longer see an improvement.

Steve

Anthony.L

iTrader: (41)

It's the bits, I had the exact same problem. I ordered two from mcaster and they are bad. Look a the cutting edge, it's a blunt edge instead of a sharp point. Switched to a different brand carbide bit and no more ridges in the cut.

baih

are you using any lubricant while cutting ? sharpie marker or WD40 ?
the carbide bit should have a pointed tip and not rounded.

asw7576

The tip ( even diamond tip ) is destroyed once you put wrong polarity to slave motor.

Before cutting make sure the tip angle / tip position followed the book manual.

AE Racer

My lathe has v blocks, and Im sure that the motor is running in the right direction. You really couldnt mess it up because of the colored wires and I checked regardless of that. I tried just about every spacer combination and it seemed to cut the best with one gold spacer (.2). I have not been sharpening the bits, but I started with a brand new bit yesterday, as in I took the wax off the tip and started using it. The hudy motor is meant to run of 4.8 volts so Im not sure what motor you guys are using on your lathes, but I dont think this motor could move uder the load of cutting a comm at 2 volts. I did notice the motor was loose which I hadnt noticed previously, but it didnt improv that cut at all when I tightened it up. If its the bits, if i get a diampond file and sharpen the bits to a point, would they cut correctly? I would have gotton a diamond file instead of new bits, but I couldnt find one anywhere and i have no idea what to order online.

AE Racer

Im using a sharpie for lubricant, and the bits do have rounded points, but according to big jim they should cut ok that way, they just wont last as long as a pointed tip.

Anthony.L

iTrader: (41)

Look at my post, above, it's the bits, they are bad.

AE Racer

What bits did you switch to to correct the problem?

Anthony.L

iTrader: (41)

https://www.ssl-stormerhobbies.com/c...ns&pn=COB2000C

redlinezak

i have the same problem with ridges and i am using a hudy diamond bit

TRF415boy

Ridges can be caused by two factors :

- If your lathe felt on the ground or something similar, there is a change that your screw is bent. To check that tighten the grub screws of the moving part of the lathe (the screws that hold on the delrin bit that goes on the guides) until you have to put some effort to get any movement (notice, you don't have to put a lot of effort, but you shouldn't be able to turn the screw with 1 finger). If there is a hard spot when you turn the screw, then it's bent and you should replace it.

- Otherwise, the grub screws that holds the delrin bit are too loose. As I said before, you shouldn't be able to turn the screw with one finger. If that is the case your lathe is set too loose and the guide isn't doing its job properly. Remember that with a lathe you're playing with microns, so a play that will end up with ridges is impossible to notice by just looking at it. You also have to do this for both directions (there are two screws and both need setting up). On my lathe (which is quite old now), the best setting I found is when I need to put one finger on the base to keep it steady whilst turning the screw. It's also a good idea to put a tiny bit of black grease on the guides.