Making adjustable legs

I needed to make some legs for the benchwork in the middle of the train room. I wanted them to be adjustable. I decided to use 2x4 lumber and some 3/8" thread connectors that I have had laying around for decades.

I drilled a hole in the end of the lumber:

Here is an example of the 3/8" connector:

which I then hammer into the hole:

all the way in:

Then I thread in some 3/8" inch hooks left over from some turnbuckles. One could also use 3/8" bolts too.

The installed leg:

I expect the rubber mat to compress with time. I will then unthread the hook to take up the slack.