As you probably know, wise dwarf general must rely on altillery support to win a battle. Why? Well, dwarfs are slowest army in the old world. However, lack of mobility can be balanced by... That's right -altillery support (!) and carefull planing. Everything that looks dangerous on the other side of table should be blasted away before it can do harm to your troops. Sadly usually opponents try to get rid of Dwarfen altillery as soon as possible... How to protect them? There is couple of ways.

Try to deploy your machines not so close to each other (5-10" space) or the table edge. Now, when opponent will try to attack one of machines, other can shoot at him. Of course the crew of attacked machine should flee (there is very little chance that they would not rally in the next turn, on the other hand, if they would stay and fight, they would die for sure.) This tactic is practically universal and gives you some protection against any kind of troops.

Sometimes it pays to leave some strong character to protect your machines. Hero or higher rank runesmith with some magic items can stop enemy flyer, or small infiltration squard from wiping out week crew. Usually he would have to guard your precious altilery pieces 2 or 3 turns, and then can move where all the action is going on. After few turns opponent usually lose interest in destroying your war machines because they are temporarily useless (who want's to shoot to troops in HtH combat.

Gyrocopter or two is also good protection of your machines. Shoot from a steam cannon can easily destroy the small infiltration unit (especially if it's strength is enforced by some runes) or in the worst case make it flee. Sadly by leaving Gyrocopter behind the front lines you dont use his whole potential.

Finally there is the old good method of deploying small unit of troops to defend the war machines. The best position to place them is behind the war machines in charge range. In case of enemy attack on machines they can rush in and help the crew to fight.  Also a  strong character in this unit may be useful, because enemy monsters and finest men often try to destroy altilery single handed. Sadly such units are easily overruned by fast shock troops or skirmishers. They can wipe out the crew and run away in time which takes you to make a wheel to face enemy.

Sadly there is no 100% sure method to protect your machines. If you know one, send it to me, and I will place it here.

I discussed the problem of protecting your machines, but not many people know how to use them. Below I will try to present abilietes and ways to use them:

Bolt throwers: Leave such machines for elves. How do you want to hit something with BS:3 when you only have one shoot? Really, this machine will miss a lot during the battle, and if it finally hit the target, D3 wounds of damage just isn't enough.

Flame Cannons: Many people dont like to use it because of the "short range". Personally  think that it have range enough long to cause sirius damage to opponent even in the first turn. You can guess range up to 12", the fire template have 11" itself, and altillery dice roll can add up to 10" to the length of shoot. In total you have33" firing range. It also can hurt many troops at one time thanks to the large template! It's just really good, solid Dwarfen weapon. Recommended. Target on large units.

Organ Guns: The best piece of altilery you can get. It's equally strong to a cannon, much more cheaper, and shoots five times! Only disadvantages are short range (really it's enough to shoot enemy in the first or second turn unless you have really big table) and the reliability. Because you can roll altilery dice up to five times the chance for misfire are 5 times grater than in cannon. Still, that's one of best machnes available. Primary targets for this toy are large monsters, powerfull characters,  and large dangerous units!

Cannons: Standard weaponary. Relativelly long range, and strength. Quite universal, put not so destructive as Organ Cannon. It's just good piece of equipement you can relly on. It's most efective in combination with other war machines. As above, target it on monsters and characters, or units several ranks deep.

Stone throwers: Big and not so accurate. On the other hand if they hit the target they can do some sirious damage. For best results shoot with 2 stone throwers at the same target. Try to chose big units or other dangerous models in the midlle of enemy army. There ia always possibility that if your shoot miss it will scatter into other unit

Gyrocopters: Very nice machine. It combines speed with firepower. If you will not throw any bombs it's also very reliable. Sadlly, it can easily be shoot from the sky by enemy missle troops or war machines, as well as be beatten in HtH combat. The best option is to give it the rune of disguese, and untill it shoot use it to wipe out flaing enemy units. Also it can try to blow away enemy altillery crew with the steam cannon. Usefull, but not a must-have in your army.