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mi7rennie
you won't get sharp with a pinhole. I can't remember the formula but the optimum sharpness is a balance between small (smaller=sharper in general, since light travels in straight lines) and not too small (you start to get diffraction since light is a wave). it's probably online somewhere, it's not too difficult to work out using a typical wavelength of visible light and the distance between pinhole and film.
what helps is having the pinhole as thin as possible, but you probably know that. are you using thin brass sheet? sand it down thinner where the pinhole is (so long as it doesn't become translucent) and take off any burrs from making the hole.
beyond that, the non-sharpness is one of the joys of pinholes - nothing is in 'focus' but everything is just as sharp, from foreground to distant.