Last I Checked a Square Is Not a Circle

One of our ongoing projects is replacing the mismatched doorknobs in our house.  At last count we still have at least four different mismatched brass doorknobs types. 

These, we believe, are original to the house.

standard 70s issue

At some point a couple of these were installed.

I do like the braid detail on this one

As were some of these.

Close match but no cigar

And finally, a few of these. This is one of the few I have managed to swap out.

Pretty blah, don't you think?

Aren't they all just lovely?

Slowly but surely all are being replaced by this style.

So much better looking, don't you think?  Current count:  3 replaced with 9 to go, not including the front and back doors to the house.  

But as I am replacing the knobs, I am finding that a quick swaparoo isn't always possible.  Not when you have holes like this

and this. 

Last I checked a square wasn't a circle and wasn't standard issue when installing a doorknob. 

Sigh!  So that means that I will be adding a hole saw like the one below to our inventory of "tools we didn't anticipate needing to buy to finish a project."