Is it safe to drink iced drinks in thailand? As in iced coffee and stuff like that where they use alot of crushed ice?

I have never been sick from drinks with ice in them. The ice pieces shaped like cylinders with a hole in it are supposed to be safe. I don't buy drinks with ice in it from any street venders. Even if they buy good ice they sometimes are careless with handling it.

I don't think you will have any problems with ice at McDonalds or bigger restaurants popular with tourists. I have a habit of even having some ice in a beer glass in Asia, an old habit from when I lived in Vietnam when most of the beer available was sold warm.
When in doubt leave it out!

Generally, ice is safe. Most is made at same plants.

Where problems arise is with the handling. Contamination, after the manufacture, is the concern. If it appears to be stored in its own, clean container, not with meat or other products, it should be OK.

The "hole in the middle" connotes that it is made with a restaurant's own machine. Why this would make it more safe eludes me. Most restaurants will use a very simple filtration system.

x3, generally you should be OK with ice in Thailand, but use your common sense - established restaurants aimed at tourists are more likely (though not always!) to have better hygiene standards and filtration systems. I had drinks with ice all over SE Asia and was only properly ill once, and I'm pretty sure that was from ingesting river water in Laos. I was taking doxycycline though (going back to that!) which as an antibiotic is sometimes prescribed for stomach upsets, so it's possible that it helped me fight off any nasty blighters.

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Owner, travelforum.org
My latest travels: Shikoku Pilgrimage

We drank iced coffee from street traders in Bangkok and had no problems.

I travel with the view that traveller's diarrhoea is probably going to happen sometime, so I carry the treatment and get on with enjoying one of the best (for me) parts of travelling - the street food!

Yep, good advice - I always travel with a few rehydration sachets in a small first aid kit... take up no room at all and much needed for when you get a case of the squits. Of course they sell that kind of stuff in the Land of Smiles too, but sometimes you are unable to leave the room. A few tablets of Imodium or other anti-diarrheals are also handy for emergencies when you absolutely HAVE to travel. They are not advised as treatment for a dodgy stomach as if you have a bacterial infection all you are doing is "bottling it up".

I've never had any problems in Thailand with illness, not even stomach bugs. In India, on the other hand, I was sick as a dog

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Owner, travelforum.org
My latest travels: Shikoku Pilgrimage

Cylinder shaped ice with hole in it.

I have heard that this is safe ice for over a decade. So far it has not made me sick. I even see some of the ice shaped like these cylinders for sale in Seven Eleven stores.

Here is a post from another forum. See item number 11.
Phuket - drinking tap water

And number 9 on this post.
Ice in my drink or not - Lonely Planet travel forum

I have never been in a bar that made enough money to have their own ice machine! Guess I got to win a big lottery to check one out!

Yes, all perfectly safe.

Having said that: too much cold in your stomach is not good for you, and the cause of many stomach problems attributed to contaminated ice.

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Diving Phuket and Similans

Well, if "factory made", I would assume it to be a small factory. The "extruding" machines are generally for small operations.