Introducing a horse to the clippers!?

When introducing the clippers to your horse, do so in an open space so your horse does not feel trapped. Stand by the horse's head and not at his side so he can see the clippers. Holding the clippers in the hand furthest away from the horse, turn them on, keep them still, don't wave your hand around and don't bring the closer to him for now. Let your horse get used to the noise. After 30 seconds, turn off the clippers and show them to the horse.

When your horse stands still and accepts the noise of the clippers without getting excited or nervous, and is standing still, you can start moving the clippers closer to him slowly. Finally with the hand holding the clippers, rub the back of the hand against his neck, so he can't feel the vibration, but gets used to the idea of the noisy clippers being close to his skin. A good place to do this is in front of the shoulders. When he accepts this, you can place the clipper machine on him, keeping the blade off him so he can get used to the vibrations, slowly move the clippers over his body, both sides so he gets used to the feel of them. When he stands still and accepts this, you can start clipping a small amount of hair from his body, to get him used to the feel.

Don't go straight for his head or legs though, make sure he is comfortable with the clippers touching his body first and slowly work your way down to the legs or up to his head, and if possible, use the clippers on their lowest speed to reduce the noise level. Cordless is best to avoid either you or the horse tripping on the cord.

Also best to use the clippers on a clean horse as dirt will blunt your clippers.

Good luck

Slowly, for safety. Could take minutes or days depending on the horse.

Tie him in a safe location. Personally, if the horse was a big reactor or prone to freaking out, I'd put him in a round pen. Then again, if you think he will react very badly, he probably isn't ready to be clipped. Needs more desensitization and trust building.

Let the horse know you are there, and that you have the clippers in your hand. Step away from the horse several feet, and turn the clippers on. Watch his reaction.

If he flips out just from the sound, keep calm, but DON'T turn the clippers off until he settles down a bit. Only when he calms down (even if it's a little) does the sound go away. Do this several times, and gradually move closer. This may take several sessions/days.

When/if he isn't bothered, slowly approach him. Praise him, scratch him, pet him, for being a good boy. When he is being particularly good and quiet, turn the clippers off every now and then so he knows it does stop! Bring it by his ears while it is off. Bring it away, turn it on, then bring it by his ears again. DON'T turn it on right by his ears though! If he is still calm, clip small areas at a time, always bringing the clippers away every now and then to give him a break from that sound.

Eventually, he should not react to the sound or presence of clippers at all.

ETA: Partly Cloudy has a point. If he is at all uncomfortable, do not start near the head.

really like mozzie's answer. Another Thing you can add to her comment is that you could leave the Clippers turned on near his stall, and do something in the mean time. Do These for couple of days, and slowly start to place the Clippers near the horse within the stall over a span of some days. that way he/she has at least gotten used to the Sound#

of course dont start of with 30 minutes of leaving it on. just start with 5 minutes for the first day, and then come back after a small break (the same day) and leave it on for another 5 minutes. then you can slowly increase the time

I liked Whims answer, except I would not be tying the horse any time soon with the clippers buzzing around. Also, I would not be bringing them around his head for quite a while... start at the shoulder and neck...and do this for brief periods, every few days. Since it's been 9 years it does not sound like you will be in a big hurry...which is good!