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Belt keeps falling off

Posted: Sat Jan 13, 2018 10:00 pm
by Douglas1968
Hey guys, just fired my Heavy Ten up for the first time and the leather serpentine belt keeps falling off. I just wanted a thumbs up before I attempt to move this bottom pully in line. Looks like two screws need to be loosened and a slight push forward, right?

Re: Belt keeps falling off

Posted: Sat Jan 13, 2018 10:25 pm
by Douglas1968
Lathe has been leveled

Re: Belt keeps falling off

Posted: Sat Jan 13, 2018 10:56 pm
by spro
Sure that is it ! The 9A has similar cabinet drive. There are quite a few adjustments to the elements. We have to look at twist and under tension the actual alignments. It is a devil sometimes. Depending upon shipping and jarring, a heavy motor or co-shaft may have shifted away from its familiar position. Since you have already leveled the bed, the drive must come together to that. You will see there are many lock rings to position and eccentric ones. The first thing I would try to check is the back side of the head pulley to cone. Twist is a thing sometimes to be correct for the certain surface or level where it was.

Re: Belt keeps falling off

Posted: Sat Jan 13, 2018 11:02 pm
by SteveM
Thru that hole in the cone pulley, there is an allen screw. There should be two of them.

Those screws need to go into countersinks in the shaft - that's your confirmation that the cone pulley is in the correct place on the shaft.

Not sure if the drive mechanism has an alignment adjustment.

Also, run a straightedge along the large v-belt pulley next to the cone pulley to be sure it is aligned with the motor pulley.

Just a word of caution:
For lining up the belts, that level is OK, but when you get to the point where you REALLY need to level the lathe, you will need a machinist level that can measure 0.005" per foot, like a Starrett 98 (not a 97).
The lines on that level are 1/8" per foot, which is the slope you need to make a gutter drain.

Steve

Re: Belt keeps falling off

Posted: Sat Jan 13, 2018 11:38 pm
by spro
Well, I don't expect any twist of the bed at this basic drive alignment. Just saying there are many points which could require adjustment. We will agree that those motors are Heavy( relatively) . Jostling them and heavy co-shaft means that ... well it means that a look at where the motor is mounted and work the way up to where it goes wrong. There are at least two planes which have to be in sync for the belt to run And they have to be easily adjusted. That's a tall order and does depend upon gravity to some extent. That does mean it has to be level

Re: Belt keeps falling off

Posted: Sun Jan 14, 2018 12:13 am
by Patio
The headstock does not have a lot of room to move, so I would guess, that the misalignment is in the bottom pulley set up. There should be a method of aligning it to the head stock pulleys.
I suggest you get a manual for your lathe. I had one when I had my SB10L lathe. In it is had all the information I needed to adjust the lathe. The back gear must be adjusted really well to keep it from popping out of gear and still have clearance between the gears.
The spindle pulley, also has a grub screw in the middle of it, for inserting a special grease.

Re: Belt keeps falling off

Posted: Mon Jan 15, 2018 1:52 pm
by Douglas1968
Okay guys, I was able to locate the parts breakdown CE 3458 on pdf that’s been recommended for my particular lathe. I’m now attempting to remove the shaft to loosen a stuck Step Cone. These two pictures are contradicting when you look at the bearings. The manual shows it’s remove outward. The picture of the guy shows that it’s inward. And btw, why is he cutting into the shaft? Please help.

Re: Belt keeps falling off

Posted: Mon Jan 15, 2018 2:24 pm
by Douglas1968
UPDATE! I just found a video on YouTube called
South Bend Restoration Part 31. What do you guys think?

Re: Belt keeps falling off

Posted: Mon Jan 15, 2018 4:46 pm
by wlw-19958
Hi There,
Douglas1968 wrote:
Mon Jan 15, 2018 2:24 pm
UPDATE! I just found a video on YouTube called
South Bend Restoration Part 31. What do you guys think?
I 'skimmed' the video and it is a more-or-less straight forward approach
to the disassembly of the underdrive on the cabinet model. Personally,
I have only worked on the cast iron pedestal underdrive units on the
Heavy Ten (I have taken apart the cabinet underdrives on the 9 inch and
10K cabinet models which are similar). He is a little 'ham-fisted' at times
but he doesn't seem to be too barbaric in his approach. I would recommend
using a dead-blow hammer instead of brass. I don't know why the stepped
cone pulley was so difficult to remove from its shaft (unless rust had developed
where the shaft and cone come together). Usually, these come apart with
little persuasion. It isn't strictly necessary to remove the large diameter
2-stepped drive pulley to replace the bearings.

The exploded diagrams in the parts manual are a reference to the relative
position of parts and not strictly a disassembly manual. I have no idea as
to why the gentleman is grinding on the shaft in your earlier post.

Good Luck!
-Blue Chips-
Webb

Re: Belt keeps falling off

Posted: Mon Jan 15, 2018 5:07 pm
by SteveHGraham
I saw the title of the thread and immediately thought of the wonderful results I've had since my recent decision to switch to suspenders.

Re: Belt keeps falling off

Posted: Mon Jan 15, 2018 7:48 pm
by Douglas1968
Tonight, I am King Of The Hill! So, looks like I destroyed two barrings and one Allen Screw was missing from the Cone. So my next question is where is the most reasonable place on the web to replace these items? I’ve been reading everything you guys are messsaging. Thanks for your help, support and advise. Now, I think I’m gonna let the shaft/Cone sit in WD40 until tomorrow. 😊

Re: Belt keeps falling off

Posted: Mon Jan 15, 2018 8:31 pm
by SteveM
Those aren't any particularly precision bearings.

Any industrial supply house can probably get them for you.

There are probably numbers engraved on the sides of the races.

Steve