Derek, as a follow up to your earlier question on the handrail subject, danish oil along with all the others of that type such as teak oil, okene, tung oil finish are all a form of varnish, soft and fairly easily damaged varnishes, but varnishes all the same. Put enough coats on and you'll get reasonable protection.
As before I'd recommend using regular interior varnish, either oil or water based, but you should note the reservations I mentioned previously about the performance of water based polishing products. Slainte.
I have used oil-based interior varnish on hardwood handrails. I applied several very thin coats, flattening with 0000grade wire wool then clean-up with tack cloth between coats. Excellent result - five years on and still as good as new. (But don't use wire wool on oak - use a fine abrasive pad instead).