unclesyd,
Unfortunatly I don't have all the answers to tour questions, but here are some.
The radius of SHCS's is approximatly 1.5 X the diameter of the bolt.
The surface of the crank and flywheel have been blued and found to be perfect.
I don't have the exact hole clearance but I imagine it...
unclesyd,
That is another very good approach which would no doubt help.
BillPSU,
Counter boring the holes also increases the effective bolt length which is also a good thing, using the dowels above would also do that. One of the repairs includes counter boring with far side tapped holes.
I...
dimjim,
I think you need to watch the video in full. Nord lock seemed to have the last say on the other thread mentioned. I have a sample of a Nord Lock washer, even finger tight it works incredibly well, with 45Nm I would be more than confident.
As for the dowels, they have been added after the...
I have been consulting with my preferred bolt supplier today and he showed me a lock washer I had not seen before. They are called "Nord-Lock" http://www.nord-lock.com
They are a two piece hardened washer which require the preload to increase before they can back off, which clearly would prevent...
unclesyd,
Sorry I meant fatigue do to cyclic loading in the shear plane, other wise you are correct in the mode of failure.
As I understand it the precision of the mating components is perfect although this was given as a problem further checks have shown the fit to be as good as possible...
Dimjim,
As I am trying to resolve a problem which is not directly related to my own equipment I have to make certain assumptions.
1. As the manufacture specifies a torque all be it too low I can only assume turn of the nut has never been applied. Certainly it would overcome lube uncertainty.
2...
More torque is clearly something I have proposed. Are you suggesting I treat the machined surfaces with loctite 635.
I had looked at this idea but couldn't find a product I thought was suitable, also if the product degraded it could lead to decompression of the parts which would get me back to...
I think it is cyclic movement which is causing the bolts to break. I know there is movement due to the fretting on the flywheel part. Any change in the type of bolt will only alter the time before failure.
Anton
You can download a demo or full bolt tightening software called TORKSense from http://www.boltscience.com/ I use it to check my own calcs. Doing a quick check it comes up with 48Nmm for the 1mm screw. I think this is definitely one for experiment.
Regards
Anton
As a mater of interest I have done the calcs with no grease or loctite and come up with figure of 56Nm and that would no doubt put extra torsional loading on the bolt as if it wasn't under enough strain already. So for me lubrication does several things. 1. It helps to give greater consistency...
Thank you all for your input, I didn't quite get to the bottom of loctite friction but did none the less confirm my conclusions regarding the joint.
Regards
Anton
OK so heres the story.
The engine in question has been built especially for the ultralight/microlight/Light sport aircraft category.
The flywheel has come loose on several aircraft cause instant engine failure as the magneto magnets are also attached to the back of the flywheel. The manufacture...
Now we are getting to the guts of the original question, may be I should reword it.
How does loctite affect repetitive torquing of multiple bolts.
I'm not sure the answer is going to come that easily.
The method of product application above would seem appropriate, using an ultrasonic extension...
