Hull / Keel / Rudder / Tiller

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Author Keel bolt hole resize question
Frank
Atlanta, GA

Boat Name:

Model/Year:

Hull No.

Hailing Port: 		05/18/2005 2:56 PM Pacific Time
I have a keel bolt sheared off right at the hull. With a long 3/16 bit and an ez out I will attempt to extract this and retap using a 5/16 SS bolt I cut down and drilled in a press for alignment(a very slow job with SS). If things don't work out with that idea, I plan to drill it out to 1/4 using the 3/16 hole as a pilot and chase the threads with a tap. If none of that works, is there any issue with drilling to 3/8 and tapping?
Thanks,
Frank
Michael Smalter
Webster, NY

Boat Name: Marrakesh

Model/Year: 1986

Hull No. 13645

Hailing Port: Rochester, NY		 05/18/2005 3:48 PM Pacific Time
The keel bolts go into what is called a weldment. There isn't enough steel to retap a larger thread. If there is anything you can do to get the old thread out without damaging the thread in the boat, it will be worth it.
Frank
Atlanta, GA

Boat Name:

Model/Year:

Hull No.

Hailing Port: 		05/19/2005 1:12 PM Pacific Time
Thanks Michael, I will do my best to get it out with the current threads intact. Catalina really cut it close if there is not .032 to a side in the weldment.
Frank
Atlanta, GA

Boat Name:

Model/Year:

Hull No.

Hailing Port: 		05/27/2005 12:12 PM Pacific Time
The sheared keel bolt fix. 1st - I drilled it through with a 7/64" bit as close to center as possible. Tried a #2 spiral extractor. Never could get it to bite. 2nd - Drilled it out to 3/16" now that a nice pilot hole exists. Tried the #3 extractor but no luck. 3rd - drilled it out to 1/4". Ran a 5/16" maintenance tap in it to clean the old bolt threads. Followed it with a bottom tap. I am using a 1" bolt which should be fine since it is well over the 5/16 dia. shear strength. Moral of the story is: if you can center the bit and drill out to 1/4, you can clean up the existing threads and remove the old bolt threads(be sure to drill all the way through the bolt, but not any further). Thanks to Michael for his info or I would have probably opted for the easy way out and tried to go to 3/8".
 
 
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