Joe, I wonder if this is like the 99 that I have on my bench right now. It's been trying to tell me knock knock jokes, but never gets to the punchline. Worse still, the noise seems to rocket around the machine - sometimes it seems like it's by the needlebar, sometimes by the vertical shaft, sometimes even by the hook. As with your machine too,.. if the stop motion knob is in bobbin winding position, no more knocking.

I finally narrowed it down to the whole horizontal shaft. It was moving left to right, there's a tiny bit of play in it, and when you get it up and running, all heck breaks loose. The faster you go, the worse it gets.

Might not be the same problem, but maybe a direction to troubleshoot in?

The 413 might have a couple of nylon washers to take up "lash" (I think that's the word) and quiet them down. That 758 I was working on? I was oiling near the cams, when out of the corner of my eye I saw something roll casually toward the back of the machine.... it was one of those washers, broken in half.

Since you have two of them there, maybe you can compare the two to see if there are washers in one and not the other, or something else that's obvious, or not so obviously different?

Tammi,

Looks like great minds think alike. About the second thing I did to this machine was replace the nylon thrust washer and set the lash. So I'm pretty sure it's not horizontal movement of the main shaft.

I've had both of them stripped to their bare undies so to speak sitting side by side and there is nothing that visually stands out. Other than one is a noisy thing. I even took the noisy one to my LSMG and he said there was too much clearance on the vertical shaft. But when I reduced it the motor could hardly turn the machine, and the noise was still there. So I loosened it just till there's enough to run free.

I've got a manual for the 538 and it's series of machines. Step by step diagnosis and adjustments for everything that moves. I need one for the 413 cos I sure can't sell it like this.

I'm about to tell my wife we're gonna run the noisy one till what ever is making the noise breaks. Run it till it blows up.
It probably won't though.

Joe

Terry's site for slant-o-matics and such has info on the 400's. I've just about wrapped up the 416, and it's pretty quiet, so I have nothing to suggest. I'm sure you have already oiled everything that could take oil.
This is far fetched....could the feed dogs be banging into the needle plate?

Does it make the noise with and without the bobbin case?

The 416 I worked on had a nylon or plastic bobbin case. I think some came with metal. If it's the case, maybe a switch?

The noise is there with the bobbin case in or out, the needle plate on or off. This 413 has the metal bobbin case, the other one the Apollo case. They don't interchange, I tried.

Joe