76 KZ 900 -530 Chain conversion

Doing the 630 to 530 chain and sprocket conversion. The original front sprocket has a small hole that captures a tang off of the folding lock washer.
My new JT front sprocket has no hole to capture the tang so if the nut came loose the lock washer would just turn with the bolt . Anyone run into this and what was your solution ? I'm guessing the sprocket is hardened so not sure about drilling a hole. Thought about a Nylock 20 mm nut but not sure I have enough thread.
Thanks

What about fabricating a new washer out of sheet stock that engages with the small threaded holes to hold it in place?

Answered my own question.

Carry on.

Ed,
Great idea!! Should be an easy fix,,,,,, thanks for the suggestion.

You've heard of Loc-tite. Blue, Red. OK,
This is the stuff! I started using it over 30 years ago.
"VIBRA-TITE" Does not harden, Been in major Industrial Factories forever.
But! Real Stuff Costs Real Money! Not Cheap. The small bottle with a brush top is about $25 bucks.
This is the GooG for it.

Vibra-Tite VC-3 Threadmate
Vibra-Tite VC-3 Threadmate is one of the most versatile threadlockers available on the market. An alternative to traditional liquid lockers which cure to form a hard bond, VC-3 is a blend of resins designed to remain flexible and absorb vibration. This unique difference makes VC-3 coated fasteners truly adjustable, removable, and reusable.

A decent machinist should be able to put a lock tab hole in your new sprocket in short order with the proper endmill.

Rick H.

I think Rick H is on the right track. But even simpler couldn’t you clamp the sprockets together, properly aligned of course and use the old sprocket as a template to drill your our hole?

Normal drilling is not an option, front sprockets are made out of tempered steel. You will need a carbide drill bit!!!

Special bits might be required, but possible. I once had to buy a special bit to drill a missed hole from the factory on a bulletproof door for a gun range. It was $90 but it completeld the project.

Grinding the hole/depression for the tab with a small dremel stone would work.

I would probably use a coated plunge cutting endmill, or carbide, of as close a size as I could get to the real hole. Don't overheat the hole and make sure the hole is in the correct relation to the spline. I don't think the new hole size has to match the OEM sprocket exactly. You just need a hole in the right spot to catch the tab. You could check the sprocket for hardness. I don't think I would use a drill bit for this unless I had a very good drill bit specific for the task. Not a hand drill job in my book. There are a couple of rudimentary ways of checking the surface of the sprocket for hardness. If it's hardened in a typical fashion the hardness will be relatively thin. You wouldn't even have to go all the way through the sprocket, just enough to seat the locking tab. If sprockets were super hard they would never wear out.
Rick H.

M20 axle nut.