Est. 1998 — 27 years of woodworking knowledge
WHAM-O [na- ha missed me!]
Mark Mandell - Gone Round In New Jersey
Have a Makita LS 1211 slider.
Switch has gotten sticky so tapped lightly to get it to click off.
Apparently that light tap flexed the plastic safety shield just enough for the blade to grab it. Boom! Plastic shrapnel went flying across the shop.
Blade's OK as am I.
Order parts on line. I've blown out the switch several times so it's time for a new switch.
Yikes, I'll bet your nerves were on high twitch
Keith Newton
after that.
Re: WHAM-O [na- ha missed me!]
William Duffield
That sort of design failure just screams for a product safety recall.
The lesson for the users (all of them) is "There is no more important safety rule than to wear these…safety glasses!" I'm glad you weren't hurt.
Recall
Mark Mandell - Gone Round In New Jersey
I've removed the rest of the "guard" and inspected everything. All was tight so I'm mystified as to how that shield got tangled with the blade. The saw's nearly 20 years old and cuts fine. As I'm in the process of building and finishing out my new shop, I'm wonder if a new slider is in the near future. New ones have mush better dust collection designs.
Re: Recall
Garthinsandiego
Glad you are ok. Can't explain how blade contacted guard. However know that some plastics become brittle with age, especially PVC. May explain why the guard shattered rather than being cut or scraped. Don't think manufacturers design for longevity.
Re: WHAM-O [na- ha missed me!]
John in NM
I've had two different Delta miter saws do that, though without the sticky switch. Sure wakes ya up, doesn't it? 
Glad you can find parts
Kneale Brownson
I've been hunting for two years for a replacement for the dead switch in my PC SawBuck.
Re: Parts
Mark Mandell - Gone Round In New Jersey
Almost disappointed that I found them. A 10" would suit my shop just fine. A 12"miter is fine if you're doing crown molding or heavy landscape stuff where you need 4x cut capacity, but a 10" is, from my experience, better for what most of us here do as the 10" blades wiggle far less.
Guard
Mark Mandell - Gone Round In New Jersey
was clear plastic, not PVC.
Still finding pieces 
Re: Guard
Garthinsandiego
Don't know what material your guard was made from. However, PVC is often used in similar applications because it is inexpensive and relatively tough when new. Clear PVC is readily available from industrial suppliers. PVC becomes very brittle with age, especially if exposed to UV rays. Buried PVC irrigation pipe frequently shatters when I cut it with cutters made for the purpose requiring me to make a subsequent cleanup cut with a hacksaw. I also witnessed the energetic shattering of a spar buoy fabricated from a six foot piece of 12" PVC pipe when it was tipped over onto an asphalt driveway after sitting in storage a few
years in the sun. Pieces of plastic were thrown for several feet in all directions. I can understand why you are still finding pieces of your guard. I can only assume that other plastics may react to aging similarly.