I purchased 10 of these grip screws from SOLGW.
They are a 1/4 x 28x 1" screw made of 4140 steel. The head has a 3/16 hex plus its slotted and is finished in black oxide.
There is no visible thread locker on them that I could detect. The head of the screw is wide for a good clamping surface.
They are $2 each when bought in bulk.
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