What Size Tapered Spindle Fits My Grinder?

A tapered spindle is needed to fit a polishing buff to a bench grinder or polisher/sander.

Most newer grinders use a metric thread (12mm for 150mm grinders, 16mm for 200mm grinders).  Some of the cheaper brands (Ozito etc) use a 14mm thread.

Most of the older grinders use a BSW thread (1/2" for 6" grinders, 5/8" for 8" grinders).

There are some other older/imported brands that have UNF threads.

I have nine sizes available, a list of these is below (along with the thread dimensions):

  • 12mm Left Hand (suits most newer 150mm B/Grinders) ISO COARSE 12 x 1.75
  • 12mm Right Hand (suits most newer 150mm  B/Grinders) ISO COARSE 12 x 1.75
  • 16mm Left Hand (suits most newer 200mm B/Grinders) ISO COARSE 16 x 2
  • 16mm Right Hand (suits most newer 200mm B/Grinders) ISO COARSE 16 x 2
  • 1/2" BSW Left Hand (suits most older 6" B/Grinders) ISO COARSE 1/2 BSW 12TPI PITCH
  • 1/2" BSW Right Hand (suits most older 6" B/Grinders) ISO COARSE 1/2 BSW 12TPI PITCH
  • 5/8" BSW Left Hand (suits most older 8" B/Grinders) ISO COARSE 5/8 BSW 11TPI PITCH
  • 5/8" BSW Right Hand (suits most older 8" B/Grinders) ISO COARSE 5/8 BSW 11TPI PITCH
  • 14 x 2mm (suits most polisher/sander machines and some Ozito bench grinders) ISO COARSE 14X2

What if you're still unsure?  The best bet is to simply measure the thread with a vernier.  Or if don't have a vernier, then buy a few different nuts in the size you think it is and see if it screws on.  Failing that, simply email the manufacturer and ask them.

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