Drilling holes in shovel handle for rescue sled?

Does anyone have any experience drilling holes in shovel handles for the purposes of a rescue sled?  In making sure that I had all necessary equipment to fashion a rescue sled (a la www.skiingthebackcountry.com/ski-articles/emergency_rescue_sled ) I realized that my shovel handle does not actually have holes in it, which is sort of a necessary piece of the puzzle.   I mostly want to be sure I don't mess with the actual function of the shovel were I to go and drill holes.

If drilling holes in the handle is a bad idea, anyone know of what shovels out there already have holes in the handle? 

Thanks.

I drilled several holes in various shovel handles for the same purpose -- you can get away with a pretty small hole, big enough to the bolts you use to pass through. 1/4" or so. Lots of info in this thread , which also has a bunch of other good tips on stuff folks carry for emergencies.

.....anyone know of what shovels out there already have holes in the handle? 

Thanks.

k2skis.com/tools/rescue-shovel-plus

Another thing that works well for expedition use is drilling holes in pickets.

I drilled several holes in various shovel handles for the same purpose -- you can get away with a pretty small hole, big enough to the bolts you use to pass through.  1/4" or so.  Lots of info in this thread , which also has a bunch of other good tips on stuff folks carry for emergencies.

Excellent.  Thanks to you (and others) for the helpful information.

For the best results, drill the holes so that they are parallel to the blade. i.e. the same direction as the other expanding pins.