A better quality lamp holder

[Skyline]

Both of these cheap plastic things have broke now where they attach to a tripod for my 2 softboxes. One I screwed to tight, the other snapped when I angled the softbox.

What lamp holders do you recommend without braking the bank?

 

[Nionyn]

I'm guessing that's an ES (Edison Screw) lampholder?
What kind of lamps are you using in it? CFL or some flavour of incandescent (maybe TH?)?
I'm not personally familiar with these fittings but I'd imagine heat from tungsten lamps would weaken some, at least.

 

[Skyline]

Yes, es and daylight 5500k bulbs