Prop size

[RobertDoak]

Ok...question...does anyone else measure a brand new prop before any work is done to it to make sure its starting at the proper size....
So here is the situation...I just recieved 3 new Octura props....x438..x440..x638
The x438 and the x637 measure what octura specs call for....the x440 measures actual size...1.52 or 38.72mm
Do I have a defected prop....?
Shouldn't it measure 40mm

 

[the german]

Robert
I usually check my props on a lathe with a digital measuring system .
For example my X440 is 37.75mm or my 1440 is 38.95mm .
It's very rarely to find an Octura prop who's bigger than the nominal diameter (my1950 is 50.19mm)
Hope this helps.

Alex

 

[RobertDoak]

Hello Alex and thanks for responding..this is what I have...
So a x438 is almost the same as a x440..
Looks like there may be a quality control issue...

 

[Terry Keeley]

They'll vary from the actual posted numbers, that's normal. Wait until you start putting a pitch gauge on them!

 

[shoboat]

Robert,

Octura x-440’s have been around 38 mm for many years. The pitch gauge will tell
more of the story for your application though. The X-438 is a Very Good 21-tunnel boat propeller. Just a little help here
from a guy that does quite a few propellers. If you want a more consistent diameter propeller try the Octura M-440
or switch over to an ABC Propeller like a
1514-17*-45%, 1515-19*-38%, or if you need more diameter go up to the 1614,
1615, or 1616. You will find the newer ABC Propellers will be much closer to what is on the charts than Octura Propellers. If you need any help give me a call 231-590-3023.

Thanks,

Mark Sholund

 

[RobertDoak]

Thank you Mark for the info..
I have saved your info...I never looked into any other prop...my lack of growth I guess...I started with Octura back in the late 70's/80's and never changed...
But i did make a call to Trudy @ Octura and had a long talk...she did some checking and responded back..saying yes x440 is a smaller prop than spec'd
and she dont know why..so I ordered A x442 and will adjust the size to a x440...perhaps a education into the ABC Props is in order....ABC has all the #'s for prop size...time to expand the knowledge base...