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View Full Version : Lathe pulley repair with pics



wierdscience
06-13-2012, 09:34 PM
At work the Boss has a HF 9x20 tucked back behind the counter to do quick and dirty jobs on small parts for customers.Awhile back it dropped the setscrew out of the motor pulley and spun the shaft in the pulley.Patched it temporarily when it happened with shim stock and a new setscrew,but it wasn't right.

After seeing this thread by Philbur I had the idea to fix it by channeling my inner German:)

http://bbs.homeshopmachinist.net/showthread.php?t=54552

Bored a 3/4"per foot taper in the pulley and machined up a collet of the same taper with a 14mm bore.Sawed the splits in the collet with a .035" Jewelers saw and drilled a 5mm hole for a pin to engage the motor shaft key slot.
http://img.photobucket.com/albums/0903/wierdscience/001-2.jpg

The collet is pulled up tight with the 1/2-20 nut and washer.It drew up tight,won't slip ever and the run out is less than .001"TIR.Only took me 1hr and 15 minutes not counting looking for a Jeweler's saw that wasn't dull or split:D
http://img.photobucket.com/albums/0903/wierdscience/005.jpg

wierdscience
06-13-2012, 09:44 PM
Another view of the collet showing the slits.They were done by holding the collet blank buy the threaded end in a 5-C hex block clamped in the mill vise.I ran the slots full through the wall of the collet and into the opposite side.

http://img.photobucket.com/albums/0903/wierdscience/003.jpg

darryl
06-13-2012, 10:18 PM
I like that method. I wish more pulleys were made to mount like that.

John Stevenson
06-14-2012, 04:10 AM
I like that method. I wish more pulleys were made to mount like that.

They will be now :D

wierdscience
06-14-2012, 08:48 AM
They will be now :D

Lets hope,between the chewing gum alloy in the pulley and the centerless ground concrete rebar motor shaft something has to change at the factory:D

Your Old Dog
06-14-2012, 09:41 AM
So what's the secret to cutting that distance with a jewelers saw and having it go where you want it to go? Mine always veer off course......way off course!

wierdscience
06-14-2012, 02:06 PM
So what's the secret to cutting that distance with a jewelers saw and having it go where you want it to go? Mine always veer off course......way off course!

The spindle has to be dialed into the table,the saw needs to be reasonably sharp and much care taken when starting the cut.Let the saw do the work and cut it's own path for the first 1/8" or so of depth,use plenty of cutting oil.

The single biggest thing is the arbor.I make my own and face them true in the mill.The commercial ones,the cheaper ones anyway put a cup in the blade when tightened.That tends to get them started off kilter and it goes down hill from there.

motorworks
06-14-2012, 06:22 PM
Very nice work two thumbs up :)
eddie