Shaft runout question

[Rick486]

Now that we have the shaft out, the yard is measuring the runout at .003" at the center. The shaft is about 7 ft long. What do you guys think about the runout? Should I have it sent out to be straightened or is .003" at the center ok?
Thanks

 

[Maine Sail]

Now that we have the shaft out, the yard is measuring the runout at .003" at the center. The shaft is about 7 ft long. What do you guys think about the runout? Should I have it sent out to be straightened or is .003" at the center ok?
Thanks

Rick,

Where is it supported and how accurate are their roller bearings? The permissible tollerance from the ABYC standards and Table III ,for 1" shafts from 6-8 feet long, when supported at or near the ends, is .003". You are spot on provided it was measured using the right equipment.

A good test jig will allow measurement along the shafts entire length. This jig can be slid anywhere along the shaft to make sure it is within tolerance over the entire length. A one spot measurement is not generally how a professional shafting shop does it with a shaft that long. I just had one made for a customer that was about 6 feet long and it was measured every foot even when brand new. This particular one did not require any tweaking but many new shafts do..

 

[Rick486]

Thanks Maine. Yes they did measure the run out at points along the shaft with no measurable at the ends and .003" in the area of the middle. I did find your post on this subject a couple years back, highlighting the .003" number. So I think we're good to go. Going to replace the cutlass bearing as long as we have this all apart. My yard takes pictures and emails them to me on all the work they do. A nice touch.