My El Dorado lathe has been making quite a racket lately, so I (for the first time) removed the motor and removed the gearbox cover. After cleaning the internals out (I had hardly and trash in mine), I reassembled everything with fresh oil and took time to readjust the lathe drive. With the door opened to observe a few test runs, I managed to trace a lot of the operating noise to the single-shear-mounted adjustable idler roller on the bottom near the motor pulley.

I realized it performed such a minor deflection job that I could operate the lathe properly with it removed, after a few adjustments of course. A few minutes adjusting the motor bracket and the high/low tie rod gave me clockwork hi/neutral/lo operation with much less noise.

Hey Jason,

Maybe this is where my noise is coming from. I'm going to check it out today. Anyone else look into this? See any obvious reason why you wouldn't want to do it?

The only possible problem that I see may come from interference between the motor and the lathe drive housing. I have no interference on my machine there, and my lathe motor mount has plenty of adjustment travel to accomodate adjustment after removing the idler. YMMV.

The small idler adjusts both belts at the same time, which is redundant to me since the motor does the same. I assume the idler may prevent slippage by wrapping the belts around the pully more, but it seems unnecessary in this application.

Since the both the hi/lo lever and the motor adjust, I was able to adjust both of the belts on the motor to operate properly at hi/lo speed.

After first seeing that idler in position in the bottom of the case, it has always bugged me. I was unhappy with the way it was mounted, and I didn't like the loosen-and-slide method of adjustment. Its small diameter also makes it run very fast, creating excess noise.

Well, I pulled the little idler off and it didn't seem to make much difference on my machine. I checked the bearings and they are nice and silky so I just put it back on. Most of the racket I get seems to be coming from that chain.

I think mine was worse off, thus making a better improvement. My chain idler is now the noisiest part of my system as well. Servicing the sprocket bearing and tensiong it properly made little improvement. I think a direct drive with a variable-speed control is going to be the only solution...

I just took all that stuff off. Now they don't make any noise now. VFD baby!!

With a ACTech SMvector 230 1ph in, 230 3ph out VFD drive, 1 HP 3 Phase motor3, I've got 4 belt settings left and usable RPM from about 100-3000 on the Lathe now, and very little noise too. About the only noise I'm getting is from the gears inside the spindle housing, thought about removing them, but they carry oil up to the spindle bearings. I did think about direct drive via step pully on the motor to the main spindle pully, but I wanted to retain the spindle brake. Modified the brake lever stops inside the lever head to allow for only two position, Run and Brake.

On the Spindle pully, you can see the Beer can Aluminum reflector that i used for spindle speed via reflective optical sensor mounted on the door to the cnc software. Inside of the control box painted black to reduce any light flash that may effect speed sensor. Chips inside the case was from a mill job where they came thru the spindle bore, forgot to close the chuck. <Again>

Do you cut a lot of threads with this configuration?

I was under the impression that the chain and the gears that interconnect the spindle to the feed screw.

It seems to me that if you gut the drive train you would need to rig a sensor on your spindle and allow the computer to control the spindle speed through your VSD. Mach3 would then be able to cut threads under CNC control.

Are you doing this?
How well does it work?
Have you used it for both fine (~40 tpi) and coarse (~4 tpi) threads?

Do you miss the manual threading capability?

Bob

The threading is controlled by the gear train (threading gears), not the belt/chain drive train. You can remove all of the drive equipment and still run the threading gears.

I see this machine is set up for CNC and I'm not sure how threading would work in this case. If you wanted to thread manual you could just pull off the timing belt that drives the X axis screw. I think to thread with CNC you would need some way to accurately encode the spindle position.