Plumbing – What accessories, aside from faucets, fit into sink faucet holes

Found a similar design at the Delta website. The round knurled piece should unscrew. The male threaded section should also unscrew. Apparently some have a hex shape to facilitate installation. Some have an internal female hex shape that is removed by an allen wrench. This allows the retaining plate to be removed. If there is enough room between the backsplash and the spout you could try holding the piece under the sink with a pipe-wrench, vise grips or large pliers and have someone spin the faucet.

The easiest option in my opinion is to get a sink with a 4th hole cutout for the soap dispenser if you want that. They are a fairly standard option when searching for sinks and I think the resulting look is the best.

It may be possible to drill another hole, but I wouldn't recommend it. If you attempt this, please use a center punch to make a dent to start the hole saw in, otherwise the bit will slide all over the sink and not where you want to drill. The reason I wouldn't consider it is the high risk of damaging the finish and possibly making the hole in the wrong place.

If you don't like the first two options, you can only use one hole in the sink for most modern faucets. They typically include an option to install a cover plate to hide the other two holes. If you don't use that plate, you have two holes to use for soap and lotion dispensers.