I love Sawyer Cobra oarlocks, but they're so-o-o heavy. So I jumped on a pair of Sawyer Mini-Cobra locks that weigh half as much (NOTE: they fit 1-3/4" oarshafts max). One problem: the shanks are 1/2" diameter instead of the whitewater 5/8" standard.
I'd already drilled out my oarstands to 5/8. So, instead of driving around to several machine shops and pissing them off for a couple $1.58 parts, I went to ACE hardware and started poking in the bins.
Found a brass thingie the right length with a great-fitting 1/2" bore, but the outside was too big. So I set it up on a carriage bolt (above) and put it in the drillpress (on the slowest speed).
A coarse file took the barbs off in a couple minutes— it fits snug in the oarstand.
Here 'tis with the stands and a Mini-Cobra lock. Feels good without grease. Next time I go to town I'll get better fitting springs & washers. The spring shown is way too stiff.
The lightweight frame is half-done. I decided to use some different fittings and had to re-order. Should have photos next week.