Lowering the height of IMac screen

You could get one of those desks that has a keyboard tray that is lower than the main desk surface, then use the desk backwards putting the iMac foot on the tray and the keboard on the main desk surface. The others are correct, short of using a hack saw, the screen height is not adjustable.

Moving the screen any closer to the desk than what it is set at is a bad idea. The only cooling air intakes are on the bottom of the case:

and even reducing the distance between case edge and desk by 1/2 can cause excessive internal temperatures that can over time harm the computer. If it gets hot during a work session, the computer may do a safety shutdown. Then you will not be able to use the computer until it cools. Extended overheating episodes can cause internal components to fail.

I suggest looking for other methods, like a desk with adjustable work surface height, a different chair, or other means.

EDIT: Another thought: based on my computing travails, by chance do you wear bifocal glasses while computing Until I got dedicated computer glasses l alwasy had a sore neck and had gone youth all the permutations of stacking books, spacers, different chairs, etc. Computer glasses made setting up a comfortable work station much easier.

Get someone who is capable of working with wood. Some 2x4s, pine plywood. They should be able to design a desk with a drop-floor like WWII-era aircraft carriers. I am sure the drop-floor could have custom-height setting built in. Sounds far easier than balancing the writing surface and keyboard surface (that do apparently work) against a lower monitor height.

At least to me, who has built custom desk for my special need.

There is no method to change the height of the display. You can get a VESA mount for the computer and then wall mount it to the height you want but that is about it. Also, when posting we have no idea which iMac you have and they have been in production for over 20 years so you need to write a complete description. Please read Writing an effective Apple Support Question prior to posting so you get an idea of what we need to help you. It saves us from asking you 20 questions.

How about C-clamping the base of the stand to the bottom of a Desk/Table?

Yeah' I saw this blog by Adam Wolf a couple of months ago.

http://www.creativeadam.com/blog/8/61/How-to-lower-your-new-iMac-for-less-than-10

Although I'm wondering if the iMac is suffering from any overheating issues.

Since I don't have anyone handy to build a custom height desk, this works great - my chair is an $1,100 desk chair with about 75 adjustment settings (no kidding), so this winds up almost like leaning back comfortably and having the keyboard of a laptop on your lap.

I'm sorry you found my reply not helpful but it is correct and on target. I offered a solution and advice and if you don't find that helpful then you need to tell us what type of solution you are looking for. Insulting someone by writing "not helpful" will not help you out! Please search for a VESA mount for your year and size iMac!

Have you tried raising the height of the keyboard and your chair? You could build a custom desk that lowers the height of the iMac screen.

The screen height does not adjust. As rkaufmann87 suggests there are mounts to mount the iMac screen on a wall. This way you set the screen at exactly the height you need/want.

It is not possible to lower the screen - there are things to raise it, but not lower it.

I also prefer the screen being lower, so I simply got a cabinet/sheflves/table (or whatever will fit into your space) which is lower than the standard desk height. That is where the iMac sits and I have the keyboard and mouse on a small, leightweight laptop tray which I rest on my knees. Works well for me.

Hey ... whatever works. I had a huge basement to fill with as much desk as possible and did not want to spend thousands. But I tend to not follow the common path. I am actually intrigued by designing and building the drop-floor desktop design, but have no people I can think of to build it for.

I hope the OP finds the correct solution ... ill-fitting desks make working almost impossible.

No, there are no third party feet you can look at. A VESA mount is your best solution or like has been suggested to raise your keyboard height to match the display height.