The Prop Shop - Propeller Shaft Diameter, Taper, and Prop Bore Size Chart
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Information and Chart to Determine Prop Bore Size, Shaft Diameter & Taper

 

 

If you are having trouble figuring out what diameter shaft, or prop bore you have, below you will find a handy chart with measurements for both propeller bores and shaft diameters.  In order to do these measurements, it is recommended you use calipers, as with a tape measure or ruler it is difficult to get a close enough measurement.  Even with calipers, your measurement may not be exactly what is on the chart, but they should get you very close.  ALL OF THESE MEASUREMENTS ARE ASSUMING AN SAE BORE AND STANDARD TAPER RATE OF 1:16.

  • First measure the full shaft diameter (not the taper) with calipers.  This will get you a good starting point.
  • When measuring the shaft taper diameter, get as close to the small end of the taper as possible.  This can be difficult since you are measuring a tapered surface. You do not want to measure the threaded area.
  • When measuring the propeller bore, you must measure the SMALL HOLE END. Also keep in mind that if the prop bore was deburred or chamfered, your measurements may be off by a bit.
  • If your measurements are not matching to the chart, give us a call and we can work through it with you.  800-634-8318. THIS CHART IS FOR REFERENCE ONLY, CONTACT US IF YOU NEED MACHINING DIMENSIONS FOR SHAFTS OR PROPS.

 

 

         
 

SHAFT

PROP

Shaft
Diameter (in)

Small end of
 taper on shaft (in)

Taper Length
(in)

Small End
of Bore
(in)

Key width
(in)

 3/4

0.625

2   

0.609

  3/16

 7/8

0.0727

2 3/8

0.711

  1/4

1   

0.0828

2 3/4

0.813

  1/4

1 1/8

0.093

3 1/8

0.914

  1/4

1 1/4

1.031

3 1/2

1.016

  5/16

1 3/8

1.133

3 7/8

1.117

  5/16

1 1/2

1.234

4 1/4

1.219

  3/8

1 3/4

1.428

5   

1.422

  7/16

2   

1.641

5 3/4

1.625

  1/2

2 1/4

1.844

6 1/2

1.828

  9/16

2 1/2

2.047

7 1/4

2.031

  5/8

2 3/4

2.258

7 7/8

2.234

  5/8

3   

2.461

8 5/8

2.438

  3/4

 

Tolerance

Taper rate 1:16

Tolerance

 

 

-.001, +.001

 

-.001, +.001

 

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