What type of grass are you mowing? If you want to scalp your yard just take the wheels off.

Unless you are trimming a putting green why do you want to cut to one inch. Cutting it to 1.5 inches would be quite a slice below the normal growing height. From what I've read scalping does nothing to promote a healthy lawn and has a good chance of damaging it. If you want to remove thatch then rent or buy a de-thatcher.

It doesn't go lower because it's not needed. I don't know what you're doing/cutting, but you need a reel mower for 1" or less. Particularly if you're in zone 7 you wouldn't normally have any grass that can stand to be cut that low. With fescue and Bermuda, I might cut it down to 2" before overseeding in the fall but right now I'm up to 3.5" for the summer heat.

Seriously -- my typicaly complaint is that mowers don't cut high enough. +1 on the reel mower comment for 1" or less. I keep my grass at 3" or more most of the time, and it's the envy of the neighborhood.

The people who never have good grass spend a fortune on aerating, seeding, fertilizer and irrigation. Yet, they let the grass get too high, then they cut it too short, basically killing it. My neighbor does this EVERY TIME. He must be cutting 4" of grass down to about 1.5". The mower bogs down and gets hot, the deck gets clogged with grass and he leaves windrows of clippings on the lawn. Then, they gripe about how crummy the yard looks after spending all that money. I don't know what it is about maintaining a proper grass height, but people are not listening.

The Oregon 96-607 blade will lower it a half inch...

If the OP has hybrid bermuda, the norm is to cut 1" or lower, but should always use the 1/3 rule. It is better to use a reel, unless you have very bumpy terrain like I do. Mine has a severe slope also. I tried using a Tru-Cut, but was killing my back. So I have to be satisfied to use my Honda at its lowest setting and cut 2-3 times a week.

MY FRIEND RETURNED TORO MOWER TO BUNNINGS WITH SAME PROBLEM. BUNNINGS HAVE HAD SEVERAL COMPLAINTS RE THE MOWER NOT CUTTING LOW ENOUGH

in the USA lawns are cut higher than in Australia for example. Toro don't mow low enough for tough suburban buffalo grass say 309mm

1" much too low for healthy grass . Also 1.5" to 4 .5 " is the industry standard for mowers