Damaged flywheel.

Hello everyone.

I’m almost finished putting together a 1913 new series c&p and in the process of getting the pin back into the flywheel, a large chip of the cast iron broke off where the outside set screw is. It’s a pretty big chip - about 1-2 inches but the hole where the drive shaft goes appears to be solid with no cracks. Can anyone tell me if this will be a safety hazard or if it can be repaired? The press is motor driven. I’m sure photos will help with the diagnosis so I will post some asap. Thanks in advance for your advice.


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It may or may not be a safety hazard, but if it were mine I’d have it fixed. The area around the shaft carries a bit of stress, and that metal was originally there for a purpose. Take it to a shop experienced in either brazing or welding cast iron, and have them fix it.

Thanks for your advice WCP. I’m in the process of finding someone who can weld the piece back on. I’m just hoping that it’s not too small to work with. Here are a couple photos of the wound.

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If I’m seeing the right it looks like it’s broke above a keyway. If that is the case absolutely get it fixed. There’s going to be a good bit of force applied to the key from the weight of the flywheel and the less material there is to spread that stress across the more likely even more of it is going to break.

I agree with Lammy that the part should be fixed. However, it’s not a terribly difficult repair. The broken part can easily be brazed back together.

I had a very similar break on a Kelsey Star once. I had it repaired by a company that fixes engine blocks, and it never gave me any trouble.

Yes - that’s right - it broke right where the key and set screw are. I was able to find a very experienced welder and metal worker who has said he can help. He said he’ll have to slowly heat the entire thing up before the repair and slowly cool it down afterwards to avoid the risk of cracking anything else. Now we just have to take it off again to bring it to him. I’ve been told to rent a wheel/gear puller to get it off. Is it true that if you heat it up it’s easier to remove? What’s the best way of going about that? Thanks so much for sharing your experience, I really appreciate it.

Here are a couple more photos.

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yes you’ll need a gear puller. You’ll need the kind with hooked arms and you’ll have to make sure it’s big/long enough to reach the thick shoulder on the back side of the wheel. The center bolt in the middle of the puller will go in the dimple on the end of the shaft.

So as it turned out, the fellow who had talked to me about hot welding the piece back on decided that the heating/cooling process would be too much of a risk for cracking. He’s now taken it to another fellow who uses a cold welding technique. He guarantees his work and has given an estimate of $50, which I’m very happy with. The repair will be done later next week so I’ll let you all know how it turns out.