When Plan A fails - - -

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monophoto

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So I was turning a spindle using a brand-X morse taper steb-style dead center in the headstock when the spindle came off the lathe.

Plan A says turning between centers is the safest way to turn because the workpiece is locked between centers. Perhaps, but not in this case. I suspect the live center wasn't properly seated in the dimple in the end of the turning - I had turned of the lathe to check the diameter of the spindle against the drilled mortise that it was meant to fit into, and when I turned it on again it made a rattling sound, but then flew off the lathe before I could react and turn the lathe off.

Plan B says that steb centers are generally foolproof - if something happens, the piece simply spins between centers with the teeth in the steb drive cutting a circular groove in the end of the piece. Perhaps, but not in this case.

Plan C says that the pin in the steb center is held in place with a grub screw. Perhaps, but not in this case - apparently, the screw was loose, and the spring forced the pin out of the drive and it disappeared into the shavings around my lathe.

Plan D says that if I lose something made of steel in those shavings, I simply reach over to grab the Harbor Freight cup magnet that is mounted on a handle and wrapped in a plastic bag - and just wave it over the shavings to find the lost item. Perhaps, but not in this case - I couldn't find the pin when I cleaned up under and around the lathe, but I didn't pull it away from the wall and filter through the shavings back there. I'm sure it will turn up someday - - -

So that brings us to Plan E - the pin measured just under 1/4" in diameter, so I cut off a length of 1/4" steel rod, mounted it in a collet chuck, and used a file to shape it into a new pin for the steb drive.

It's all part of the fun of turning!
 
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Plan C says that the pin in the steb center is held in place with a grub screw. Perhaps, but not in this case - apparently, the screw was loose, and the spring forced the pin out of the drive and it disappeared into the shavings around my lathe.

Plan D says that if I lose something made of steel in those shavings, I simply reach over to grab the Harbor Freight cup magnet that is mounted on a handle and wrapped in a plastic bag - and just wave it over the shavings to find the lost item. Perhaps, but not in this case - I couldn't find the pin when I cleaned up under and around the lathe, but I didn't pull it away from the wall and filter through the shavings back there. I'm sure it will turn up someday - - -

So that brings us to Plan E - the pin measured just under 1/4" in diameter, so I cut off a length of 1/4" steel rod, mounted it in a collet chuck, and used a file to shape it into a new pin for the steb drive.

It's all part of the fun of turning!


Don't you hate it when that happens... same thing happened to me.. lost the screw, but was being careful to not loose the center point, until one day forgot to catch it when I pulled the turning off the lathe... into the shavings heap and lost... I have a sweeper magnet from Lowe's, but no glory that day... the pin wound up in the burn pile along with all the shavings... oh well!


Don't know why I didn't think of plan E.... I still have the steb centerless, but what is the thread size on the screw... haven't found one in my shop that will fit the hole... do you think a grub screw will work... I've replaced the steb drive, but always nice to have a spare.

 

mark james

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I apologize for having to say that I... enjoyed the story. :redface:

Hope tomorrow is better.
 

Charlie_W

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On my drive centers with set screws...whether fixed point or spring loaded, I have blue tape around the center to prevent a loose screw from taking flight to never be seen again.
 

monophoto

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Don't you hate it when that happens... same thing happened to me.. lost the screw, but was being careful to not loose the center point, until one day forgot to catch it when I pulled the turning off the lathe... into the shavings heap and lost... I have a sweeper magnet from Lowe's, but no glory that day... the pin wound up in the burn pile along with all the shavings... oh well!

Don't know why I didn't think of plan E.... I still have the steb centerless, but what is the thread size on the screw... haven't found one in my shop that will fit the hole... do you think a grub screw will work... I've replaced the steb drive, but always nice to have a spare.

[/quote]


My first guess would be that these inexpensive Steb drives are made in China to metric specifications.


Mine came from PSI. I just measured the screw - it appears to have a major diameter of about 5.7mm and a pitch of about 1mm. Based on those measurements, I would guess that an M6-1 screw would work, but I would want to test it at the hardware store before buying something.
 
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Don't you hate it when that happens... same thing happened to me.. lost the screw, but was being careful to not loose the center point, until one day forgot to catch it when I pulled the turning off the lathe... into the shavings heap and lost... I have a sweeper magnet from Lowe's, but no glory that day... the pin wound up in the burn pile along with all the shavings... oh well!

Don't know why I didn't think of plan E.... I still have the steb centerless, but what is the thread size on the screw... haven't found one in my shop that will fit the hole... do you think a grub screw will work... I've replaced the steb drive, but always nice to have a spare.


My first guess would be that these inexpensive Steb drives are made in China to metric specifications.


Mine came from PSI. I just measured the screw - it appears to have a major diameter of about 5.7mm and a pitch of about 1mm. Based on those measurements, I would guess that an M6-1 screw would work, but I would want to test it at the hardware store before buying something.[/quote]


Mine that came apart also came from PSI... going to Lowe's today for some air fittings, will have to check out the screws as well.
 
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