Prop Hub Bolt: How to hold crank while tightening?
Posted: Thu Oct 15, 2015 7:06 pm
by Gunther
Hello to all. I’m ready to assemble my AeroVee with the factory-installed hub. Step 10 in the manual calls for torquing the bolt to 80 ft-lbs. How does one hold the crank while torquing? I’m tempted to try clamping the crank to a table but there must be a better way. I doubt if even my mother-in-law could hold it.
I’m looking forward to assembling this engine. The packaging, labelling, instructions and support are all first class.
Thanks,
Gunther
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Thu Oct 15, 2015 7:15 pm
by SonexN76ET
Hi Gunther,
If you purchased the option of the pre-assembled crankshaft and hub, the factory has already torqued it to the proper torque.
Please check your Aerovee manual, I believe it says to skip that step if you have the preassembled crankshaft and hub. However, DO NOT TAKE MY WORD FOR IT. Check your manual!
This came up for discussion awhile back as well and I believe that was the concensus. I will look up the previous posts.
Jake
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Thu Oct 15, 2015 7:27 pm
by Bryan Cotton
What I have done on other motors for a similar situation is to turn back from TDC and feed a length of closeline in through a spark plug hole. It does not compress and you can tighten or loosen the nut. Not sure if this will work here as I have not built my aerovee yet.
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Thu Oct 15, 2015 7:34 pm
by mike.smith
Bryan Cotton wrote:What I have done on other motors for a similar situation is to turn back from TDC and feed a length of closeline in through a spark plug hole. It does not compress and you can tighten or loosen the nut. Not sure if this will work here as I have not built my aerovee yet.
The step he is talking about is the bare crank, before being assembled in the engine. I just rebuilt my engine last week and I have to admit I couldn’t come up with a good way to hold the crank without damaging any metal (I originally bought the pre-assembled prop hub). So I just tightened it down with my air-powered impact driver. No torque value; just whatever the driver gave me. The bolt is important insurance, but I’m pretty sure the shrink fit and woodruff key are going to keep it from going anywhere.
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Fri Oct 16, 2015 8:46 am
by vwglenn
I’d get an old VW flywheel (easy for me I have a couple in the garage) secure the crank to the flywheel and temporarily screw/bolt the flywheel to a bench and apply my torque.
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Sun Oct 18, 2015 8:47 pm
by Arjay
Can’t you just put the crank in a vise to hold it while you tighten down the bolt?
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Sun Oct 18, 2015 10:21 pm
by mike.smith
Arjay wrote:Can’t you just put the crank in a vise to hold it while you tighten down the bolt?
Most surfaces of the crank are critical wearing surfaces. Would not be a good idea to use a vice. Besides, half the weight of the engine is in the crank. It’s heavy! Tough to hold such an animal in the average work bench vice.
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Sun Oct 18, 2015 10:21 pm
by Gripdana
I did mine when the flywheel was installed and secured the flywheel.
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Sun Oct 18, 2015 10:55 pm
by mike.smith
Gripdana wrote:I did mine when the flywheel was installed and secured the flywheel.
That has to fall into the “why didn’t I think of that” category! No reason the bolt has to be set before installing the crank. It can be done after the engine is built. 
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Mon Oct 19, 2015 9:16 am
by Rynoth
mike.smith wrote:
Arjay wrote:Can’t you just put the crank in a vise to hold it while you tighten down the bolt?
Most surfaces of the crank are critical wearing surfaces. Would not be a good idea to use a vice. Besides, half the weight of the engine is in the crank. It’s heavy! Tough to hold such an animal in the average work bench vice.
With a big enough vice you could do this with blocks of wood to protect the crank. This is how I did it, but my vice was barely big enough and the crank still wanted to twist as I approached proper torque, had to be careful.
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Sat Oct 24, 2015 9:53 am
by PeterNYNJ
Hi Gunther,
I’m building the Aerovee mostly by myself now too. I was able to tighten the crankshaft bolt by myself with the wood vise in a Black and Decker Workmate (model 125) that Jeremy recommended on one of his videos. I carefully supported the crank diagonally by the closest part to the hub bolt to minimize torsional stress and bending.
The Workmate was great for bending the control fairings too.
Good luck!
Peter
Re: Prop Hub Bolt: How to hold crank while tightening?
Posted: Sun Oct 25, 2015 4:03 am
by SNX1508
SonexN76ET wrote:Hi Gunther,
If you purchased the option of the pre-assembled crankshaft and hub, the factory has already torqued it to the proper torque.
Please check your Aerovee manual, I believe it says to skip that step if you have the preassembled crankshaft and hub. However, DO NOT TAKE MY WORD FOR IT. Check your manual!
This came up for discussion awhile back as well and I believe that was the concensus. I will look up the previous posts.
Jake
I had a question concerning Loctite on the crank bolt for Sonex Tech Support back on 10/9/2014, which I have copied here (see below). As for skipping to step #10 in the assembly manual, in REV Z of the assembly manual this step says after the crank is assembled and cooled to room temperature to remove the crank bolt, apply Loctite and then torque the bolt. So it does not appear that this step can be skipped if you purchased the pre-assemble hub/crank kit.
Terry
Hello Sonex Tech Support,
I purchased the preassemble crankshaft & prop hub with my AeroVee engine S/N
0736. Could anyone tell me with any certainty whether or not Loctite was
applied to the prop hub bolt when it was assembled? The AeroVee assembly
manual says I should remove the bolt and apply Loctite. I do not want to put
the engine into service without Loctite here, but then I do not want to
disassemble it to apply Loctite if it was already applied.
Thank you,
Terry L. Cooper
Sonex #1508
Hi Terry,
It will be necessary for you to remove the bolt and re-install it with
Locktite.
Sonex Aircraft Tech Support