I'm thrilled to announce that I've reached a milestone of trivial importance

in my documentation of early Workmates!
We now know precisely when Black & Decker made one of the part changes.
On Monday, July 17, 1978 during the evening shift, while producing the 79-001 Type 4 at the Brockville factory, they changed the clip that holds the Workmate in its folded position. The original clip, used starting with the Type 1 in 1974, was made of two pieces riveted together and used a pair of hooks to engage with the lower frame. The revised clip, used for the next four years, is a single bent strip that forms into a hook at the end. See the two photos below.
This change illustrates B&D's efforts to simplify the Workmate and reduce costs. In my experience, the two different clips work pretty much equally well, so this seems like a mostly positive change.
My spreadsheet of Workmates with their production dates and components is now up to 217 entries, which is what made this possible. Unfortunately, because of the random nature of the data distribution, I still have some gaps that are larger than I would like. I have 7 weeks between the Type 1 and Type 2, and 17 weeks between the Type 7 and Type 8. Those are long enough that they could be a result of shutting down production for a while, or they might just be lack of data. I also have very sketchy data for late 1981 into 1982 that shows an odd situation regarding the Type 8 and Type 9.
So I'm going to continue data collection in hopes of filling those gaps. Will 300 entries be enough? We'll see...