I should know better

[canuck750]

I sure hope I never do this again! I have spent over six hours to get the remains of the rotor bolt out of the crank. I was lucky (I guess) that the bolt snapped off at the outer edge of the crank. Unfortunately the spinning of the crank combined with the rotor retained by the outer cover wore the head of the snapped bolt into the outer surfaces of the female threaded recess, in short the stainless steel raw edge of the bolt was practically welded to the crank. No tapping or striking resulted in any ability to thread the bolt out.



I used a 90 degree air drill and a very sharp titanium drill bit, left hand no less, just a tiny one at first, 1mm diameter, and worked up to a couple mm, Drilling stainless centered through the bolt is a very slow process. Eventually I could get an easy out into the center of the bolt but again no movement at all.

I found a special drill bit that is an 8mm tap / drill and in a hand held tap holder cut through the outer edges until the remains of the bolt broke free.



I made a thread chaser by cutting some deep cuts into a bolt and then very slowly cleaned the threads. I have a few mm of less than perfect threads but the remainder is all good threads.

Harper's are sending me some NOS rotor bolts, the correct high strength steel type.

[Chuck in Indiana]

Good save on a tough job.. Stainless is no fun to drill by hand.

[Dave Swanson]

How do you spell relief!!  Nice save!

[canuck750]

Curtis mailed me a nice used alternator cover, typical wear and tear. I no longer send out my aluminum polishing, It's pretty easy to do, just take time. I have learned a few short cuts, first I use a foam pad palm air sander and a 320 grit sanding disc. I sanded one half of the cover, takes about 5 minutes to get the scrapes and pits out,





Then I use sizol wheel, it has a burlap rope wound into the wheel and cuts very fast,



A rouge polishing paste and frequent dressing of the wheel makes the 1st cut quick



Then the fine wheel and a white paste (white is rougher than red but I want a satin finish)



and another couple minutes and it finishes like this





ten minutes later the other half is done



Polishing is messy business but the results are worth it



Harbour Freight sells a reasonable priced long shaft bench top polisher and they carry the polishing bricks and various polishing wheels. For under $150 bucks you can get everything you need. My cheap polisher has lasted over five years and done at least 10 Borrani wheels and many other alloy parts.

[Muzz]

Try to find an original bolt if you can, even if used. I think they are class 10.9 in the harness scale (don't quote me), but should be at least 8.8. I personally wouldn't use Loctite in that spot and I would also not use an SS bolt if you can't find the original and have to make one out of something out there.

Good luck.

10.9 would bolt in. I would have thought 8.8 would do as well. SS is not a high strength bolt, stick with high tensile steel. You can get a low grip Loctite that will cause the bolt to resist vibration and not much else if you are worried about it coming undone again.

[canuck750]

Thanks Muzz,

I am going to fit a shnor washer and be done with it!

[Antietam Classic Cycle]

Thanks Muzz,

I am going to fit a shnor washer and be done with it!

Wasn't the original washer a "split lock" type?

[canuck750]

Wasn't the original washer a "split lock" type?

yeah probably but I trust the shnorr more than the split lock type, originality be damned.

[lucky phil]

yeah probably but I trust the shnorr more than the split lock type, originality be damned.

Nice rescue on the crank nose. Why the hell is everyone so convinced these schoon washers or whatever they are called are of any use, same goes for these split spring washers. If you need to use these then its an admission that you are either using an inferior bolt/material (like Stainless Steel, why the heck you would use SS on anything other than a boat I don't know as its a totally useless bolt material) or there is a design issue in the first place. Over 40 years working on aircraft and I've never seen these used in aviation and I've never reinstalled/installed them on motorcycles and engines.
These things are an admission there is an engineering issue, so fix the issue.

Ciao

[Muzz]

The schnorr washer will cope with vibration.

They really do work if you don't want a (usually) nut or bolt to vibrate loose.

Had a case where a farmer who was a customer of ours had a nut on a valve that kept shaking loose. Sold her a schnorr washer and she bet me $20 that it wouldn't work. A month later she came in and handed me $20. (I didn't take it) but I can tell you she was real happy to have found a solution.

[keener]

 just to be clear....Schnorr/bellevue ... washers are not effective in aluminum  they need a hard substraight  as in steel to be effective , a wave washer is best in aluminum ....
correct ?

[Muzz]

just to be clear....Schnorr/bellevue ... washers are not effective in aluminum  they need a hard substraight  as in steel to be effective , a wave washer is best in aluminum ....
correct ?

Ya got me there. The "ratchet" action on the washer would be the same; whether the gripping surface on the two faces of the washer need a hard substrate to be effective I don't know. I would have thought that it would still grip on alloy. Must do some research....

[canuck750]

Greg Bender's site has some pictures of Schnoor washers cutting into alloy bearings and rear drive covers, not the best I would think for Aluminum, the old lock tabs seem to work just fine for those applications, but the crank nose and rotor are pretty tough steel.

I had the V7 Sport out the other night for a ride after replacing the rotor bolt and cover, no issues runs like a top, I just love thrashing that 750!

[Muzz]

Good explanation on the use and applications for Belleville washers.

Looks as though aluminium is on the list.

http://ecmweb.com/content/how-use-belleville-washers-correctly