Lathe Belt Slipping

[crokett™]

My lathe is a late. 70s-early 80s Delta. I found it rusting away in a barn 8 or 9 years ago, the owner gave it to me for free. It has a variable speed which is done with a reeves pulley on the motor, the headstock spindle has a stepped pulley. When I got it, it needed a new belt. To install the belt you were supposed to drive the headstock spindle out of one side of the headstock, then put the belt on, then put it back. I couldn’t get the spindle to slide through the pulley so at the time i installed a link belt. The link belt is still there. Evidently it works with a Reeves. I didn’t know at the time If it would or not. However, the belt slips if I’m turning larger diameter things unless I go slow with the cutting.

Is a V belt going to have less slippage? I’ll probably have to take the spindle and pulley assembly to a machine shop. I got the spindle to move just enough to use the indexing pin a year or so ago but I’m thinking there might be an issue with the spindle that a machine shop can address, unless its just 40 or so years of dust and dirt and probably rust.

The advantage to the link belt is some built in catch protection.

[Timberwolf]

My lathe is a late. 70s-early 80s Delta.  I found it rusting away in a barn 8 or 9 years ago, the owner gave it to me for free.  It has a variable speed which is  done with a reeves pulley on the motor, the headstock spindle has a stepped pulley.  When I got it, it needed a new belt.  To install the belt you were supposed to drive the headstock spindle out of one side of the headstock, then put the belt on, then put it back.  I couldn’t get the spindle to slide through the pulley so at the time i installed a link belt.  The link belt is still there.  Evidently it works with a Reeves.  I didn’t know at the time If it would or not.  However, the belt slips if I’m turning larger diameter things unless I go slow with the cutting.

Is a V belt going to have less slippage?  I’ll probably have to take the spindle and pulley assembly to a machine shop.  I got the spindle to move just enough to use the indexing pin a year or so ago but I’m thinking there might be an issue with the spindle that a machine shop can address, unless its just 40 or so years of dust and dirt and probably rust.  

The advantage to the link belt is some built in catch protection.

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Dave, go to a music store and buy a small rosin block like they use on violin bows...while the shaft is turning, a hold the rosin block against both sides of the existing belt for a few seconds...It will stop the slipping..And on the plus side, there are plenty of other uses for the rosin......I have used it all my adult life and always have it on hand...old machinist trick....


Sometimes fiction is your friend...........

[KyleD]

If the belts are the same width and cross-section I can see the link belt working. For the drive to work right the two pulleys have to move together smoothly. When one gets pushed apart the other closes under spring tension. If the mechanism is not clean of rust and lightly lubed it will not move smoothly and you will get belt slippage. Sounds like time to at least partially disassemble and perform some maintenance on the mechanism. I do believe the link belt is directional as well.

[BloomingtonMike]

My lathe is a late. 70s-early 80s Delta.  I found it rusting away in a barn 8 or 9 years ago, the owner gave it to me for free.  It has a variable speed which is  done with a reeves pulley on the motor, the headstock spindle has a stepped pulley.  When I got it, it needed a new belt.  To install the belt you were supposed to drive the headstock spindle out of one side of the headstock, then put the belt on, then put it back.  I couldn’t get the spindle to slide through the pulley so at the time i installed a link belt.  The link belt is still there.  Evidently it works with a Reeves.  I didn’t know at the time If it would or not.  However, the belt slips if I’m turning larger diameter things unless I go slow with the cutting.

Is a V belt going to have less slippage?  I’ll probably have to take the spindle and pulley assembly to a machine shop.  I got the spindle to move just enough to use the indexing pin a year or so ago but I’m thinking there might be an issue with the spindle that a machine shop can address, unless its just 40 or so years of dust and dirt and probably rust.  

The advantage to the link belt is some built in catch protection.

Can you set proper belt tension when set to turn the slowest where it is currently slipping? I am also in favor of the suggestion of clean all parts up/restore the machine.

[crokett™]

I don’t know what proper belt tension is. The link belt is as short as I can make it and still am able to install it. If I could get the spindle out I could install the correct length belt.

I’ll also look at lubing that reeves. I did some of that a year ago when I took apart the adjustment mechanism

[MichaelMouse]

I don’t know what proper belt tension is.  The link belt is as short as I can make it and still am able to install it.  If I could get the spindle out I could install the correct length belt.  

I’ll also look at lubing that reeves.  I did some of that a year ago when I took apart the adjustment mechanism

Back when V-belts were the state of the art, many turners deliberately allowed the belts to slip to moderate the effect of a "catch."  Not only did it do that, but it encouraged them to slice rather than gouge, resulting in a finer surface as well.  Just sayin' it might not be all bad, depending,,,,

[KyleD]

If you adjust the speed so the spring pulley is as wide as it will go and then clamp it open. Then you adjust the mechanical pulley all the way open. You might gain enough slack to take some links out of the belt while in place on the pulleys. This may or may not be possible - I do not know how easy it is to add and remove links from your belt.