There are plenty of posts on snap picks, so I won't bore you with the construction details except to say that the angles I have used seem to work pretty well - but you'll have to experiment a bit to find something that feels comfortable in your hand.
The pick tip element is filed with an oblong cross-section to fit the keyway (and I heated the tip of mine and quenched it in oil to give it just a bit more strength).
I also put a small length of thickish heatshrink tubing on the 'trigger' for neatness (and to stop the oxide on the surface of the coat hanger rubbing off on my finger with repeated use). Vanity, vanity all is vanity...
The sequence of pictures ...not my best, but YOU try reaching for the button on your camera with your left hand forefinger over the top of the flash hood as you try and hold everything steady - it's like trying to juggle soot and plait fog at the same time... should show the basics of the operation.
One benefit for UK locks is that, providing you're right-handed, depending on how tightly you hold the shaft between your thumb and second finger, the snapping process will impart a controllable clockwise (desirable) twist to the snap pick which is transfered to the lock barrel; funnily enough, when I was filing and occasionally checking the size of the tip in a keyway, a few flicks would sometimes open the lock WITHOUT a tension wrench in play (but I would always recommend using a wrench).
The most critical part of using the snap pick comes in lifting the trigger part SMOOTHLY back towards yourself by sliding it up against the pick shaft - start with small increments - I found that I never had to pull the trigger up more than halfway before letting it slip off the pad of my right forefinger. The entry angle is also another variable - I found that angling the tip downwards towards the rear pin gave better success. It helps a LOT if you are able to pick manually, because you've then got a better idea in your mind's eye of what exactly it is that you're trying to achieve.
Obviously the coat-hanger metal I had to hand is not of high quality - however, an easy way to make tips interchangeable might be to use one half of an electrical 'choc-block' connector with two grub-screws in a brass connecting sleeve - one end attached to the shaft and the other to the pick-tip (this would also give the shaft more mass, which ought to be beneficial).
I used a no-name but heavy and solid five-pin motorcycle padlock to prove the point. By manual single pin picking I can (nowadays) open it in under a minute - with the snap pick it takes me between five and ten snaps to do the same thing.
All the best from sunny Cornwall
Gibson335
"Life is like a sewer; what you get out of it depends on what you put into it"
Picture 1 - Padlock and completed snap pick
Picture 2 - Snap-pick freestanding, showing the angles a little better
Picture 3 - Insert your grubby little hand
Picture 4 - Closing hand around the snap pick and locating 'trigger' with right forefinger
Picture 5 - Drawing back trigger smoothly, riding up the shaft of the snap pick
Picture 6 - Allowing the trigger to slide off the forefinger
