New pin for the rear flywheel

[BigBill]

I think we nailed it. In sheer strength it’s very strong.

[BigBill]

The 8 mm Thompson shaft is perfect but needs to be threaded on both ends of the pin.

We must be able to tighten the pin on the flywheel so it compresses on the outside of the shaft. Otherwise we will have that flywheel rattle.

My son found a 8 mm shoulder bolt that’s 30 mm long, and is already threaded to 8 mm 1.25 on the end, I just ordered some. I want to see the fit in the 8 mm hole.

https://www.mcmaster.com/90782a125

One day shipping from my boys in jersey. Then we need to decide on Thompson shaft or the shoulder screw. Which fits better. My number 1 int154 has that flywheel rattle. I’m sure it has a bolt installed without looking at it.

Ok this shoulder screw arrived from McMaster it’s perfect no cutting or threading. It will work, might need a thin washer under the head but it will work.

[wagonmaster]

Having dealt with this problem several times before, 2 broken split hubs, I am confident that you have the best solution. A spiral pin through the center is not enough. The hub still will have a little wobble in it. It needs the split halfs drawn tight. Did you get it together yet?

[BigBill]

It’s sitting here waiting for warm weather. It’s going to work. The brake puck bracket may need more of a radious to clear the bolt head and nut but I’m sure it will work. Everybody seems to put in a screw and nut and it wears on the threads. That’s not a forever fix. I don’t fix things twice. The 8 mm shoulder bolt in shear is very strong. The orginal spiral pin seems like a spring. I think it flexes till it wears. The 8 mm Thompson shaft is a tad tighter fit. But both ends need to be threaded. Thompson shaft is surface hardened. I don’t think the shoulder bolt will fail.

[BigBill]

Another way is a metric Allen cap screw cut the threaded the same way so the threads are out of the hole.

The shoulder bolt fits tighter.