I have a question about the frame support in some MV bulbs. I have two Philips bulbs and a Sylvania bulb. All these are 175 Watt.  When I touch the glass I can hear the frame rattling inside.  Is this ok?? I mean, I haven't tried these bulbs to see if they work, but I was just wondering if this affects their performance or life expectancy etc.

rattling is pretty much normal......so no worries.......

Most newer ED shaped lamps have the rattling problem due to the frame end being slightly bigger than the dimple.  With BT shaped lamps, rattle aint much of a problem, the frame on those has 2 springy pieces of metal that flex and fit into the cylindrical section of the lamp on the end of the lamp.

my 400 watt BT shaped merc from 1950s the oldest one I have has the "springy things" on top AND bottom of the cylindrical section

The frame can rattle due to 1) rough handling 2) poor construction, i.e. low-quality lamp 3) expansion due to heat, over time, changing the "fit" of the frame. Yes I find this more with ED-shaped lamps than BT's but I have an old, heavily used Westinghouse Lifeguard 700w BT-46 that rattles terribly when positioned vertically, not too bad when mounted horizontally.

I guess I'm just used to incandescents, I forget these lamps don't have a filiment that can break.  It usually happens that when an incandescent rattles it is finished, and I forget and apply the same concept to MV.

I don't even rely on shaking lamps, because I have had people shake it and say it's broken and I try it but the incandescent lamp actually works...

Plus depending on shaking lamps can make some people who knows nothing and not interested in lamps do dumb things, like actually shaking a 4 foot fluorescent, shaking an halogen, shaking a neon lamp, shaking a CFL!!!!!!!!!!!!!!

That drives me nuts!......in order to know if  the incandescent works or not.....look through it (even use a laser pointer to see shadows of the filament, I mean very often my mom shakes them and I tell her that it doesn't really help cuz even working ones can sometimes rattle like the tubular show light,  really big incandescent, junkie lamps, and of the sorts!

Yeah shaking is not a good indication the lamp is dead or spent, however sometimes you can get good deals if the other party thinks the lamp is dead