Reducing Shaft Diameter Without a Lathe

admin

Starting to work out a plan to make the old bench grinder into a belt sander.  First hurdle - the motor shaft size.  Currently it is 0.98" diameter (with no keyway), and all the belt grinder pulleys have 7/8" a bore.  I want to bring the shaft down to 7/8" so any pulley will work rather than try to concentrically drill out a hub - that just won't happen.Since the motor will obviously spin the shaft, the question I have is what to use to grind the shaft down.A flat file on a restSquare edged grinding stone of some sort on a restAngle grinder/flap disk and a steady handAny other ideasThe pulleys all have set screws so a flat on the finished shaft should secure it well enough.

Yeswelder MIG-205DS(3) Angle Grinders at the ReadyJust a hobbyist trying to improve
Reply:Mill?Sent from my SM-G960U using TapatalkI haven't built anything I can't throw away.  Perfection is the journey.    Mac
Reply:Use flat coarse file with a light touch and a pair of dial calipers to measure progress. Use a sharpie marker to mark the high spots that need to be filed down. Not rocket science, just be patient and measure every so often as you remove metal. Unless you go for a long period of time without stopping or measuring I don't know how you could screw it up.When you get close to the measurement you need you could bust out some sanding paper and "shoe shine" it to the final dimension. AndyESAB 350 MPI ESAB 330I CVCCLincoln Idealarc 250Eastwood TIG 200Hobart Ironman 240Hobart Plasma CutterLincoln 110v MIGCH 110v MIGMK Industries Cobramatic with Prince XLMiller XR Wire Feeder
Reply:I believe you will not get a truly round shaft using your suggestions. I think drilling out a pulley hub would be the best method. The drill hole should be 1/64" small than 1" drill, as drills tend to drill over size. Then you could use an adjustable reamer to get to the .998" bore size.Last edited by milomilo; 3 Hours Ago at 11:57 PM.ChrisAuction Addict
Reply:Angle grinder to about 1/32 TIR then a file on a rest. If you can file up like a chainsaw gauge then you can tame the high spots by slowly lowering the rest.
Reply:

Originally Posted by Mac's Crew

Mill?
Reply:I was envisioning the motor running "as is" while reducing the shaft?If you take it apart, then have somebody else turn it to size.Last edited by tapwelder; 1 Hour Ago at 02:14 AM.
Reply:Problems you will have. Going to be about impossible to keep concentric. Keyway will be an issue as depth will not be deep enough. Boring and rebroaching the keway on the pulleys is a much better and easier option. Much cheaper to possibly ruin a pulley than most definitely ruin a motor shaft.