Help me identify whether I have a 1" or 1 and 1/8" shaft

[Rugglesworth]

I have a 93 350 mercruiser ski mag with 1:1 velvet drive in 93 ski ray tournament boat. I'm getting my prop swap on Monday and just realized after I bought a new prop, it's for a 1 and 1/8" prop shaft. I thought that was standard for ski boats but then realized that they used 1" shafts back then as well. So I measured the circumference and it came to 3 and 1/4 " approximately. From my calculations that means it's a 1" shaft and I need to run to the prop shop before it closes today and get a different prop. Can anyone here confirm the prop shaft size from my measurements?

Thanks in advance. we leave next week to the cabin for 3 weeks out of town so this needs to happen today.

 

[Mc Tool]

Can't you just measure the diameter of the shaft.

 

[airshot]

Depends being on how accurate your measuring is....3 1/4" equals a 1.034 dia. Shaft........you need a 3.125 circumference to get closer to a 1" dia.....

 

[nola mike]

Depends being on how accurate your measuring is....3 1/4" equals a 1.034 dia. Shaft........you need a 3.125 circumference to get closer to a 1" dia.....

And if my high school geometry is correct, closer still to 3.1416

 

[Mc Tool]

And if my high school geometry is correct, closer still to 3.1416

well that depends wether we are talkin metric or imperial Pi

 

[04fxdwgi25]

Instead of guessing, get a cheap vernier caliper. Available anywhere, such as True Value for under $20.

 

[Scott Danforth]

Open tool box

Grab 1" wrench..... Does it fit over shaft?

 

[Rugglesworth]

thanks y'all. I was right it is a 1" shaft. When I went to the marine shop yesterday asked for a 1" shaft and measured it and it was the same as mine. Glad I figured this out as I had to swap the new prop I just bought for the correct one. The swap is happening first thing tomorrow morning and then we head out to the cabin for 3 weeks shortly after.

 

[Rugglesworth]

Open tool box

Grab 1" wrench..... Does it fit over shaft?

Would have loved to do that but the prop is stuck on and therefore I couldn't get a wrench over it... For the future I'll get some calipers but my crude method worked