I appreciate the tip. The shank was ½ a bicycle axle bolt with non-standard threading. I could not have switched to a standard bolt because the nuts that interface to ball bearings needed to be on the bolt.

Good to hear your anchors held up over 10 years. Someone else just mentioned they’ve not bee so lucky: lemmy.dbzer0.com/comment/5372639 I suppose it’s important that they be used in a dry climate.