What's new
What's new
By:
Advanced search…

Bull gear/Cone pulley clatter

C

centsarg

Plastic
Joined
Apr 23, 2018
Hi, My South Bend 10L makes a clattering noise with every rotation of the spindle with the bull gear engaged. Unlocking the bull gear from the cone pulley to run in back gear results in very quiet operation. What is the solution to this noise? Pull the spindle and replace the bull gear to cone pulley pin that's driving it?
Thanks
centsarg
 
on mine it was play between the bull gear and the spindle, opened it up and jammed a shim in the keyway next to the key and it shut up, but it has started to act up, I've got to pull it apart again...bull gear and spindle must be tight or it does that.
 
Hi cyanidekid,
Thanks for your response. With the bull gear pin pulled out it spins dead quiet. Not sure what the pin looks like on the other side of the bull gear but it must fit into something to drive it.
I thought the bull gear was a press fit on the spindle.
 
The bull gear should be a tight fit to the spindle, as in light press fit. Check to se if there is too much clearance between the cone pulley and the bull gear allowing them to sorta tap together. Or the cone pulley with too much clearance on the spindle.
 
Does it actually chatter under power or just when you jiggle it?

You could make a new oversize pin and bore the bull gear and cone pulley to match.
 
Thanks for your reply, I tried cyanidekids solution with shim as an experiment. Instead of shimming the keyway I wedged .020 thick half inch steel banding between the cone pulley and bull gear to see what would happen. The clattering went away immediately. What does that indicate? The cone pulley out of location on the shaft or the cone pulley shaft dia. worn?
 
Have you checked the pre-load of the spindle nut. It is set to a slight pre-load and if too loose, it can allow too much clearance between the bull gear and the cone pulley as the spindle moves forward and back.
The cone pulley just rides on the spindle between the thrust bearing and the bull gear. Loosen the spindle nut off and feel for a loose fit of the cone pulley on spindle. It will most likely be okay unless it was run dry for some time. Check, at that time, the fit of the bull gear to the spindle. Does it feel like it is pressed on the spindle or is it loose.
 
Likely just normal wear...if so not worth fixing unless it impacts the work.

Check what Bobby said and maybe clean and lube the thrust bearing...make sure the bull gear is fully seated too.
 
Hi Bobby, I tried tightening the spindle nut but the whole spindle bound up with less than a quarter turn so I backed it off to where it was. Bull gear and cone pulley feel snug on shaft. Maybe I will just live with it for now and address it at some future point.
 
BobbyBailey said:
Have you checked the pre-load of the spindle nut. It is set to a slight pre-load and if too loose, it can allow too much clearance between the bull gear and the cone pulley as the spindle moves forward and back.
The cone pulley just rides on the spindle between the thrust bearing and the bull gear. Loosen the spindle nut off and feel for a loose fit of the cone pulley on spindle. It will most likely be okay unless it was run dry for some time. Check, at that time, the fit of the bull gear to the spindle. Does it feel like it is pressed on the spindle or is it loose.
Click to expand...

I was once mistaken on this matter myself.

The cone pulley on my lathe is ever so slightly shorter in length, than the distance from the step on the spindle (where the hardened thrust bearing washer sits) and the bull gear.

There is no adjustment. If your lathe is mismatched parts.. spindle, cone pulley, bull gear, then you can have axial slop in the cone pulley. If the cone pulley binds on the spindle when tightening the spindle nut then either the parts aren't original to the lathe or the bull gear isn't pressed all the way on the spindle.

If you never use the back gear then it doesn't matter if the cone pulley is axially too long, (any thrust on the spindle when in back gear will be transmitted through the spindle back gear to the cone pulley, then to the thrust bearing, which was never the intent). But if you do use the back gear a lot with heavy axial loads, then the bull gear and cone pulley will eventually wear down until the thrust bearing meets the step on the spindle and takes the axial load directly.
 
Hi all,
While goofing around on the lathe I remembered seeing a small Allen head bolt in the face of the bull gear about 180 degrees from the pull pin. I got wondering about it. It was a snug fit , but I turned it in a couple turns and the clatter noise went away. Does anybody know if this was a S.B. bull gear item or a previous owner add on? I'm thinking that I'm not the first to deal with the clatter on this machine. Runs quite nicely now! I just have to remember to screw it out when I pull the pin to run back gear speeds. Maybe I'll paint them both yellow or something. Sorry, won't let me attach my pic. will try again separately.
 
bull gear

hi, pic of bull gear pin and screw.
 
Can't see your pic, but if you have .020" clearance that is excessive.


The screw thing is a bad idea.

I would pull it apart and evaluate the surface of the bull gear and cone pulley where they nornmally rub against each other and possibly use a shim between the spindle shoulder and bull gear to tighten the gap shooting for about .004" clearance ( to give you ~.002 at each end in operation)
you can do it all one the bench to prove it out before reinstalling, just before you pull it apart turn and bore a spacer you can slide on the spindle end to tight the take up nut against in order to keep the thrust bearing up against the spindle shoulder.

Ain't no pro fix but would be easy enough and just might do the trick.
 
Thank you iwananew10k,
I can't figure out now why my pics. still wont upload. No problems with my original thread post.
 
You must log in or register to reply here.

Similar threads

B
Cone pulley runout causing vibration?
Replies
7
Views
595
BritWithSB's
B
S
Heavy 10 Bad squeal in back gear - cone pulley stuck to bull gear Please advise
Replies
8
Views
694
Siliconbronze
S
V
How to replace the back gear drive gear from the spindle?
Replies
1
Views
253
Ventport
V
R
South Bend Model 9A Quick Change Gear Box Shaft
Replies
4
Views
1K
Walther1522
W
J
Help needed in reassembling headstock of a SB 9B
Replies
2
Views
1K
JoeJoe62
J








 

ABOUT PRACTICAL MACHINIST

With more than 10.6 million unique visitors over the last year, Practical Machinist is the most visited site for metalworking professionals. Practical Machinist is the easiest way to learn new techniques, get answers quickly and discuss common challenges with your peers. Register for the world’s largest manufacturing technology forum for free today to stay in the know.

Learn more about us.

STAY CONNECTED

Facebook Instagram YouTube LinkedIn Pinterest Twitter Tiktok

Register Become a forum member. Register today.

Sign Up Sign up for our e-newsletter.

© 2024 Copyright Practicalmachinist.com. All Rights reserved.

Back
Top