Thermal shutdown-overload on 7x12??

[maxboostbusa]

I have been having some issues lately with my lathe shutting down on me. For instance I was cutting a 1/8 wide slot in the inside of a piece of 2.5" round 360 Brass. Sharp carbide, slow cutter feed speed. Then click the lathe shuts off. Move the speed control back to off then restart everything works fine until a minute or so later then same thing all over. It done it a few times threading also. Could something be binding? I wasent using the carriage feed so it wasent that. I could attribute the threading to the carriage feed since I found it was binding when I was threading. 13 TPI and it would kick without making a cut just feeding by itself. Loosened the right side leadscrew mount up and let it center itself and no more binding with it. What do you all think? Thanks in advance.

[pastera]

I don't think there is a thermal cutout on the 7x12

Check all of the connections to see if you have anything loose or any foreign objects (swarf) around the controller.

If you don't find anything, contact Jim Rabidwolf (http://www.unclerabid.com/).

Aaron

[maxboostbusa]

Could be a 7x10, no tags and the bed measures with over 10" travel. I checked all the connections in the control box and going to the motor and everything is good. It clicks when it shuts down like a overload we have on stuff at work. I was just wondering if anybody else has even noticed this.

[Al_The_Man]

If it the same as the LatheMaster, there are a couple of interlocks, one on the swing guard and one on the cover, I do not believe there is an overload per se.
The start button is a bit 'Mickey Mouse' as what you actually do is push the armature of the start relay closed, which then latches itself in until a stop button is pushed.
The click you can hear is probabally the relay releasing, any of the above interlocks will cause it to drop out.
Al.

[maxboostbusa]

Interlock for the chuck guard is bypassed since its no on there. This particular machine doesent have an emergency stop button. Main power, 3-position for the forward, reverse, and a potentiometer for the speed control that also serves as an off switch. The lamp on the on-off switch stays illuminated when it trips, just hear a faint click and it stops. Reset the speed control knob to off and it will power back up every time. I was playing with it a little bit ago with a new carbide 60 degree cutter in 6061 and slowly fed the crossfeed in and it done fine great chips, then I really cranked the handle and fed probibly 50 thou in a few seconds and it never chattered or hummed like it was under a strain just click and everything stopped. I dont know I'm stumped.

[Cassini]

Did you ever find a solution to this problem?

I have something similar going on with an HF lathe I got in a trade (used). After everything gets warmed up, the motor will shut down if it has any significant load on it. All I have to do is turn the speed down, then cycle the illuminated on-off switch. Flipping the fwd-off-rev switch has no effect.

[Al_The_Man]

The motors on the Chinese imports are notoriously bad, Either start capacitors failing or the centrifugal switch not turning off, this causes overcurrent due to start windings always in circuit.
Al.

[Claven2]

Mine will sometimes cut like that if I feed too aggressively or remove too much material in one pass.

The solution is probably to re-fit it with a better quality american or european made motor, but I have not gotten that ambitious as it doesn't click off that often for me. Mostly just when I over-hog or cut threads with the cross-feed instead of angle-feeding with the compound.

[eddieprice]

Hi, I have just joined this group after seeing the queries regarding thermal shutdown. I have just taken delivery of a Sieg C2 mini lathe from Axminster in the UK and am having problems keeping the motor running. I am reluctant to return the complete lathe after spending a couple of hours removing the red gunk and generally tuning it up, and I wonder if there is a solution.
The motor cuts out after running for a short while. I have only been machining aluminium so there is no great mechanical load, and the yellow overload led does not come on. If I leave it a while to cool down then it will start again. Has anyone come up with a solution?

Eddie Price

[maxboostbusa]

One thing that I found to help alot is make sure the leadscrew isnt binding up. You may have to slot the holes in the mount on the right end of the machine. While I was messing with mine I also drilled oiling holes in both of the blocks. Mine very rarely does it anymore since I installed the 5" chuck. It gives it enough flywheel effect to take some load off of the board.

[RTP_Burnsville]

I have a similar problem with my HF 7x10. My guess is that it's an over current limit as it will only do it it I push the lathe (like trying to drill a fairly large hole in stainless.) I don't think it's a temperature cut-out as that would require a cool down time and not just cycling the speed control pot.

[dvbrownell]

I have a 7x8 Craftex from Busy Bee tools. If the controller on yours is similar to mine then there is a high current cut-out when the motor is under too high a load. I managed to increase the cut-off current by adjusting the trimpots inside the controller. My controller has three trimpots, one sets the low speed limit, one the high speed and the third the current limit. They are not marked with their function. There seems to be are fair amount of interaction betwwen the trim pots. If you plan on trying to adjust them there are a couple of things to remember. They are multiturn devices, only turn one at a time and keep track on the number of turns you move it. There is no hard stop on the adjustment when it reaches the end of it's travel the adjustment screw will still turn and you will hear a small click with every turn. If you reach this point and continue to count these turns it will be impossible to return the trimpot to it's original location. Check the operation of the controller after every adjustment you should be able to determine the function of each trimpot with a few adjustments of each. Return each trimpot to it's original setting before you go on to the next one. The high and low trim pot should be fairly easy to identify. The one that sets the current limit can cause the controller to do some strange things. At one setting the motor would only run at full speed independant of the speed setting. The way I set the current limit was to run the spindle at low speed and brake the chuck with my fingers until it stopped, adjusted the limit and rechecked how much effort it took to stop the chuck. I found that the limit trimpot also affected how well the controller regulated the motor speed. At some settings of the trimpot the motor would acellerate considerable when placed under load. With some time I was able to get a fair comprimise between over current cut off and speed regulation. I wasn't able to fully eliminate the high current cut off as I would have liked. I should mention that I had to also adjust the high and low speed trimpots as I adjusted the current limit to maintain proper controller operation. I'll let you guys know if I do figure out how to eliminate the high current cut out completely