It would work, but it would be a waste of a K1000 as you are only going to need "B" mode. Mounting the Pentax frame to the lensboard will be more complicated than the rest of the camera. A cheap leaf shutter from an old folder would make things much easier for you. Shutters on pinhole are a bit of an extravagance anyway. I've glued steel washers around my pinholes and used refrigerator magnets for the shutter. Works great.