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heavy 10 belt slipping

porthos

Aluminum
Joined
Sep 12, 2013
Location
western pennsylvania
OK; in the last couple months i've had a few issues with my heavy 10.. everything is well documented on the hobby machinist site. so. the latest issue (everything else has been resolved) is; the bottom step pully turns fine, coming off the motor. but i can stop the lathe chuck with my hand. the top step pully and the bottom are both turning. but, the belt is slipping on the upper step pully. the belt ( Al Bino synthetic belt). the belt seems very tight. when engaged i can "strum" the belt and it has a little vibration. i cleaned both pully's and the back (engaging side) of the belt. nothing has changed. i actually think the belt is too tight but that wouldn't cause the slipping. belt was installed 6 or 7 years ago. read something about polishing the step pully?? belt dressing?? thoughts??
 

packardbill

Cast Iron
Joined
Oct 10, 2012
Location
central Pa., U.S.A.
You can actually see the belt slipping on the cone pulley? In your post you say the top and bottom pulleys are turning but you can stop the chuck by hand. Have you checked the bull gear lock pin? Maybe disengaged or broken....Just a thought. PB
 

Peter.

Titanium
Joined
Mar 28, 2007
Location
England UK
Get a tin of spray glue and spray a light film on the pulley side of the belt whilst it's running. That's how I cured the flat belt from slipping on my hobber. That or cut and glue a poly-vee belt like I did on my own 10L.
 

porthos

Aluminum
Joined
Sep 12, 2013
Location
western pennsylvania
i've tried so many things that i have lost track of everything. so, i engaged the bull gear and it works fine. can't stop the chuck. at first i thought that it was the belt slipping. BUT, i can stop the upper cone pully???????
 

porthos

Aluminum
Joined
Sep 12, 2013
Location
western pennsylvania
tried again. pulled out the back gear pin and engaged the back gear lever. can't stop the chuck. dis engaged lever and pushed in the back gear pin. can now stop the chuck and spindle. i did " polish" the front cone pully with 400 and 600 grit. and put a little belt dressing on the belt. harder to stop chuck by a little bit , but still can stop both chuck and pully. this has to be a easy fix(I THINK) .......let me back up a but. i thought that the belt was slipping because i could see the belt not moving and the pully was. but the pully is the issue
 

TDegenhart

Diamond
Joined
Mar 26, 2011
Location
Geneva Illinois USA
Perhaps you should define what you mean by being able to stop the spindle. With back gear there is all kinds of torque. In direct drive the depth of cut is much smaller. What do you want to cut with it? You may be trying to push the machine beyond its capabilities.

Tom
 

porthos

Aluminum
Joined
Sep 12, 2013
Location
western pennsylvania
i can't stop the spindle/chuck when in back gear. i'm not pushing the machine. when this all started i was drilling a .375 hole in brass tubing .500 od .330 id. the chuck stopped moving. should have been a easy hole to drill. until this incident; i never tried to stop the chuck by hand. how about someone trying to do that and see if you can. just curious
 

MrWhoopee

Cast Iron
Joined
Nov 8, 2017
Sounds like the bull gear pin is not engaging. With tension on the belt, back gear disengaged and bull gear pin engaged, can you turn the chuck by hand and does the cone pulley turn with it? Do you have to rotate the cone pulley to find the right spot for the bull gear pin to drop in?
 

chipss

Aluminum
Joined
Jul 19, 2020
Ok, I don't want to turn this thread into one of those 'who brought the popcorn and let's watch it blow up for 30 pages'.

Engage the back gear.
Grab the belt tension handle and loosen the belt.
Open the top cover and try to turn the pulley. If the pulley turns freely it's not engaged to the bull gear via the pin.
If the pulley is locked up solid the pin is engaged and working.

If it passes the above tests, the belt is slipping, coated with oil, needs to be adjusted tighter, or the adjuster is stroked out of travel therefore the belt is too long. Or it's adjusted too tight and the tensioning linkage won't swing over centre and lock into position therefore it relaxes and the belt ain't tight. One more thing, is the belt from the motor to the jackshaft tight or is that one doing the slipping.

That is absolutely all it possibly could be.
 








 
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