Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

The sink has one existing hole, and 3 knockouts which are cut about half way through the material.

What are the best tools, and techniques for removing fixture knockouts on a composite granite sink?

share|improve this question
up vote 2 down vote accepted

Well Tester, as brutal as it seems, the prescribed method by FRANKE is to use a blunt ended large punch and a hammer. Set the punch dead center in the cutout and strike it soundly. Don't be too tentative, give it a good shot!! When i first saw my plumber do this on a kitchen job, I cringed! but it worked well. Weren't there any instructions with your sink? i'm just relating the way FRANKE recommends, maybe your brand might have a different method.

share|improve this answer
So no use for a carbide hole saw? After forking over that kind of cash, I'm tentative to smash it with a hammer. – Tester101 Apr 1 '11 at 13:40
Do you place the punch on the top (where the sticker indicating there is a "hole" there), or the bottom (where the partial cutout is visible)? – Tester101 Apr 1 '11 at 13:57
the instructions say on the top. . If you already have the saw, then pilot a small hole dead center from the side already drilled then finish it off from the top, using the pilot hole. – shirlock homes Apr 1 '11 at 14:27
And let us know how it goes! – aphoria Apr 2 '11 at 11:02
Had my friend knock it out, before telling him how much I paid for it. It did indeed just knockout with a punch and a sharp whack. – Tester101 Apr 5 '11 at 11:58

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.