If you use tools frequently you may get frustrated with the safety switches, particularly those that you have to activate before you can pull the trigger of the tool. I know that they are well intentioned, but the fact is that I often feel less safe having to try and twist and cock my hand a certain way to be able to hold the safety switch and pull the trigger of the tool. I have several Ryobi cordless tools, and they use a similar safety switch among them which is thankfully easy to defeat without changing the switch operation of the tool at all aside from removing the (un)safety switch. You could simply remove it, but it helps keep out dust and grime from the tool, so I trimmed it and put it back in. It is not a terribly involved process, and as long as you understand that your tool, like all those before tools had safety switches, will come on when you pull the trigger (isn't that the way they were meant to work after all?) then this instructable is for you.
Step 1: Disassembling the Jigsaw
For this particular instructable, I am showing a Ryobi cordless jigsaw, but I defeated the safety switch on my cordless sawzall (reciprocating saw), too, and they are nearly identical procedurally, so this will cover both of those and maybe more.
First, you need to remove the front cover on the jigsaw by prying it off one side and unwrapping it. There is just a post on each side that goes into the body of the saw to hold it on. Hopefully it goes without saying that you need to remove the battery from the tool before proceeding any further- if this is a revelation, you may really want to reconsider this instructable. Then all you need to do is unscrew the two halves of the saw case with a Phillips head screwdriver. Carefully pull the halves apart and make sure to keep track of all the screws- I'm pretty sure all of mine stayed in the body when I lifted it out. On the jigsaw the door for the blade store will come out and has to be put back in when you put the saw body halves together again as it is only held in place by the two halves being mounted together.
You will see the safety switch resting above the tool trigger switch, and it will simply lift out of the tool. If you look at the back of the switch you will see that it has a ridge in the middle that is right in front of a ridge on the safety switch, and that to each side of that on the switch there are pockets. The pockets let you move the safety switch to either side, depress the trigger and the ridge on the safety switch will go into the pocket. Without the ridge on the safety switch in place, the trigger can be pulled at any time with no interference, and since the safety switch is very simply removed we will remove it, and then remove the ridge from it. Also note what part of the switch would need to be removed to gain clearance above the trigger.
Step 2: Modifying the Safety Switch
With the safety switch out of the tool, you can use a rotary tool like a Dremel (I like the Black and Decker MTX because it works with all of Dremels tools and has a lot of torque) or if you wanted to use a coping saw or other tool of your choice the sky is the limit- you just need something that will cut through the plastic switch. I used my Dremel copy with a grinding stone because it was handy. A sanding drum or other grinding type wheel should work just fine. in a perfect world I probably would have used a vice to hold the switch, but since were talking about removing a safety switch I dont feel badly telling you that I hand-held it while using my Dremel copy. You can see the shape that resulted- I took a tiny bit more off than absolutely necessary because I wanted to give it a pleasing curve, but that is just anal retentive, especially since that part of the switch will no longer be seen once the tool is reassembled.
Step 3: Reassembly
Once the material has been removed from the safety switch, it can go back in the tool. Just set it back in the tool body. You need to reinstall the jigsaw storage blade door also, which should be the only point of possible difficulty since it has to line up with both halves of the body. Otherwise, once the two halves of the body are lined up, tighten all of the screws back down and the tool is ready to try out. You can see in the picture that there is now clearance between the trigger switch and the safety switch. It maintains the original look of the saw, but the function, in my opinion anyway, is vastly improved and safer than it was with the (un)safety switch intact.