Unsupported Countertop run?

[RyFitz13]

I'm in the late planning stages for some base cabinetry for my basement shop, and not sure if I'm on the right track.

I'm planning a pair of 30" wide cabinets, with a 24" gap between the two to allow a spot for me to sit down to work and/or eventually plug in another 24" cabinet if I find the need. I'd like to run an 8' countertop over the top of these - leaving a 6" overhang over each end.

So, assuming I go with any of the following materials, should I expect to see any problems with sagging countertops across the 24" gap or the 6" overhangs?
- Laminate Counter top (I'm assuming no here, but not sure I want to go to this expense)
- 2 layers of MDF with hardwood edging (probably a 1/4" hardboard insert, should I go with this method
- Some alternative you'd suggest?

[cabinetman]

- 2 layers of MDF with hardwood edging (probably a 1/4" hardboard insert, should I go with this method

Using this configuration with a 24" opening, and 6" overhangs you will likely not have any deflection. Screw it to both side cabinets from underneath.
.

[crokett]

You can have a 24" span with no problems. If you are worried, screw supports across the front and back of each opening through the frame of each cabinet. Then when you add the cabinet in the middle you can just remove the supports.