They are probably a standard diameter. You need to measure the shafts and see if they have a flat. In my experience, getting the length of the shaft on the knob is difficult. You might have to settle for something that does not look quite right, but gain function and keep looking for the perfect-looking knob. If you really don't care how it looks, put some mini vise-grips on there :-)

You can go to hdwe. stores or spend some more time and less money looking at places like this.

Here is a link that might be useful: surplus

Thanks, just to update, I did a search and found an online place that sold replacement knobs for my Broan kitchen hood. Well, hopefully they will fit. Cost a dollar fifty, and like 12 bucks extra for shipping, what a jip, lol.

Will see what I can find for a dimmer knob replacement. May be just the same price to buy a whole new dimmer unit anyhow. I''ll make a trip to Lowes & Home Depot to see if anyone there has ideas.