Ed

Is the prop bolt for a U.S. - 41 a metric size ? And could you please tell me the correct length that it should be for attaching a spinner backplate. And if at all possible, tell me how to accurately drill the spinner hole in the middle of the bolt ?

Thank you.

Ed

w8ye

My Feedback: (16)

Take the engine into the hardware store and see what size bolt it takes? I think they are 5/16-24 but it has been 6 years since I've seen a US 41.

I ream the back plates out with a prop reamer.

ahicks

My Feedback: (2)

B&B Specialties (http://bennettbuilt.com/index.html) will have your prop bolt, pre drilled and tapped for a spinner bolt. Buy a couple of them. They're not expensive and bend easily with prop strikes.

Antique

My Feedback: (4)

I gotta see a 5/16-24 bolt that was bent by a prop strike

Tired Old Man

My Feedback: (1)

Bolt length is determined by the thickness of the parts stack the bolt is supposed to retain plus the required thread engagement depth. There's is no "one size fits all" bolt length.

Ed

Hey Ralph; do you have any of these drilled for a spinner up in your neck of the woods ? They need to be 1 3/4 to 2" long to allow for the thick prop washer, and spinner backplate. I can always cut to proper size depending on parts stack. If yes ..... I'll call you soon.

I'm now off to ACE hardware to size the friggin thing.

Ed

ahicks

My Feedback: (2)

I don't know who you think you are some days. Why would I waste my time writing that if it had not happened? Bent bolts are not the kind of thing I save for people in doubt of that possibility. The incident was fairly well documented right here a couple of years ago.... look it up if you like. I had a vibration I had at first attributed to a bent crank, prior to finding the bent bolt... and I did it again afterward. Really don't care much if you believe that or not.

Antique

My Feedback: (4)

Didn't say I ddn't believe it..I know I'm a 76 year old fart that has been working on Quadras and US 41s since they were Quadra 35s and 40s...It would take a sledge hammer, not a prop strike, to bend a 5/16 grade 8 bolt that only sticks out of a prop hub the width of a prop...There were some US41s that were made with crooked hubs drilled off center...If a US 41 is crooked its likely a bent crank, not a bolt..Us 41 cranks are hard and will usually break if straightened...Been there...

ahicks

My Feedback: (2)

I could be wrong, but I think the Bennett supplied bolts are grade 5? Whatever...

Antique

My Feedback: (4)

Mine are grade 8 Lake Erie brand...Almost unbreakable...