Quieting a Noisey Bench Top Lathe. How ??

[L98fiero]

Randy, I never did wrap this thread up, so here we go. I installed the new *** 45x75x22mm class P5 unshielded bearings without too much trouble. The unintended press fit of the aluminum belt pulley was fixed so that everything was a "gage-fit" and the pre-load nuts worked like they were supposed to. Noise improvement was noticeable, but there are other sources of noise in the motor, in the toothed belt drive from the motor to the idler pulley, and in the v-belt in the final drive to the spindle. And in the straight cut threading feed gears, too. So I just decided that it was good-enough. BUT, I did find that paying special attention to the belt tensions, and keeping the threading gears free of debris and even using a little grease on the straight cut teeth helped just as much. I was unable to locate a magic bullet.
Lloyd

edit P.S. Almost forgot to mention that I found that with the opposed pair of tapered roller bearings, the preload ended up tighter than I expected, with no measurable axial movement. The bearing preload was established in a few different sessions over the period of a few weeks.

If the feed gear set doesn't have one, changing one of the higher speed gears to one with a fabric laminated phenolic, or possibly nylon, should cut down a lot of the noise from that source.

 

[Lloyd-ss]

If the feed gear set doesn't have one, changing one of the higher speed gears to one with a fabric laminated phenolic, or possibly nylon, should cut down a lot of the noise from that source.

I never seriously considered messing with the threading feed gears, but now that you mention it, I will take a look. The gear on the spindle and the first mating gear are both laminated phenolic/fabric. Wondering if a medium gauge toothed belt and gear combo might not work better for the rest of the train? The outboard threading gear train seems overly complicated for what it does.

@SmithDoor I have poly v belts on a few things but never converted anything to poly-v myself. Not sure how they compare with standard V-belt re: noise and load capability.

Considering both the poly-v and the toothed belts, and nylon gears, too.

Thanks for the suggestions.
Lloyd

 

[SmithDoor]

I never seriously considered messing with the threading feed gears, but now that you mention it, I will take a look. The gear on the spindle and the first mating gear are both laminated phenolic/fabric. Wondering if a medium gauge toothed belt and gear combo might not work better for the rest of the train? The outboard threading gear train seems overly complicated for what it does.

@SmithDoor I have poly v belts on a few things but never converted anything to poly-v myself. Not sure how they compare with standard V-belt re: noise and load capability.

Considering both the poly-v and the toothed belts, and nylon gears, too.

Thanks for the suggestions.
Lloyd

For quiet belts

1. cloth flat belt. BEST.
2. Flat belt leather
3. ploy-v
4. V-Belt
5. Timing Belit
6. Nylon gears
7. Metal gears
8. . Metal chain worst.

Dave

 

[SmithDoor]

ANOTHER QUESTION
I have stripped the lathe headstock end down by removing all external idler gears and pulleys.
The spindle has the chuck removed and all it is is basically the 2 bearings, the drive pulley, and the spanner lock nuts. Basically the spindle items 11-14 and 17-24 (less the belts) are still in the machine. The spindle turns freely with a kind of over-tight rubbing noise. It does not spin freely, not at all. You can see a small dot in the picture above the bearing pockets that are oiler balls. I do oil it, but the bearings do not put a smile on my face. I am thinking it is time to take the spindle out and inspect the bearings.
The spindle in the machine should turn freely and quietly, but not necessarily spin freely? Correct?
Anyone agree? Disagree?
Thank you.View attachment 148874

Look at your drawing on first page , it has timing belt running at high speed .
The is the spindle ball bearing close chuck #14 a chip can get ball bearing.
In photos look you took off the change gears.

If remove #14 replace with motor grade ball bearing class 3 or greater seal for life. . It will last over 20,000 hours

Dave