Just completed my version of the overarm dust collector. The commercial versions go for $300-500 depending on the manufacturer.
A few improvements over the typical commercial versions:
1) Gate built into the collector for easy adjustments. I happened to have an extra 4" gate.
2) Ported for 4" instead of the typical 3"
3) Counter weighted to be perfectly balanced. I think the SawStop version uses a spring, so this might be a wash.
IMG_20200210_172601.jpg
IMG_20200210_172606.jpg
When not in use, swings out of the way.
IMG_20200210_172539.jpg
Comparison for 5 cuts of a pine board, with an open ended cut, since open ended is virtually guaranteed to throw out dust.
Without the dust collector, just in cabinet collection.
IMG_20200210_172521.jpg
With over arm dust collector working:
IMG_20200210_172333.jpg