bought used machine - needle broke - diagnosis needed

cross-posted from: https://slrpnk.net/post/3317096

I bought this machine from the 1960s (cost: 12 Big Macs). I did not clean it or oil it as I wanted to just see if it works.

It made a straight line without issue. Then on the 2nd straight line the top thread got bundled below the plate. I cleared that & started over. Then went to the narrowest zig-zag setting and the needle broke.

I’m just starting to learn. I know from videos that pushing the fabric while the needle is down can bend the needle and put it in harms way. I don’t think I was pushing or pulling the fabric when the needle broke. So I wonder what would cause this-- does this mean the timing is off and needs adjustment?

I’m not enthusiastic about doing much experimentation at this point because needles seem pricey enough that I don’t want to break many (1¼ the cost of a Big Mac in my area buys 5 needles). But I just removed the top thread and bobbin and installed the empty bobbin case. When I manually spin the wheel with no thread at various zig-zig widths, there is no apparent contact with the needle. So perhaps the thread occasionally bundling up under the plate is part of the issue.

update: if I load thread and manually crank for the zig-zag patterns, most stitches are missed. The thread is plunged in from the top but does not get grabbed from the bottom most of the time.