My waffle iron has a flip side that is also a sandwich grill....and a stepped hinge. and my previous waffle iron that only made waffled also had a stepped hinge to allow for thicker waffles.
back in the day before I was rich enough for a sandwich grill, I would heat 2 enameled cast iron fry pans....but my sammi , buttered on both sides in one pan and set the other on top.

Any frying pan, one size smaller than the bottom one, with a brick or two in will work.

While it isn't a necessary item, I find that I reach for my panini press time and time again. I also have a waffle iron, and the old-fashioned waffles/griddle from my mom. I also have a bunch of cast-iron pans and a hamburger press. Technically, I could have a DIY Panini press.But the designated One I have is just the right size and the lid is hinged, so even bigger sandwiches cook evenly without one end being squished. I got it several years ago when our local grocery store gave away small appliances with the accumulation of points. It is from Breville.

I use my George Foreman to make paninis .. that is about all I use it for.

We love grilled vegetable sandwiches, with eggplant, grilled peppers, onions, cheese, etc etc. We don't have a panini press nor would I buy one.

We plop them on the little indoor/outdoor reversible grill and put a weighted cast iron skillet on top of the sandwich. It works perfectly.

The grill

Thanks everyone! Lots of helpful information.

Pillog: I never thought about the lines adding crunch. I could certainly make the double skillet thing work.

Lindac: I think my waffle iron (older model) might be like you described-will have to check.

Pkramer: So simple-why didn't i think of that?

Jojoco: If I really get into these, I may need to look at a panini grill.

Tackykat: I don't own a George Foreman-does it work well for paninis?

Jasdip: Your panini looks delicious. Is your grill electric or is it a griddle that you put on stove or outdoor grill? Is it non-stick or cast iron? What else do you use it for? I'm asking all these questions because it looks like something I've been looking at for cooking bigger batches of pancakes,etc.when the grands are here.

Lizbeth, it's an electric indoor griddle/grill. The top flips and it's a solid cooking surface for pancakes, french toast, etc etc. It makes wonderful pancakes, and it's nice to make them all at once instead of 3 at a time in a skillet.

We like using it out on the balcony, and hubby will sit there with his music on in his ears grilling whatever I want to make.

It's a Salton non-stick griddle.

Here is a stock picture of it.

The main difference you'll get with a panini press is smaller, closer together grill lines. My small grill plate does that too, whereas the press and larger grill plate have the taller, wider ridges. BTW, they also make "sandwich irons" that are meant to be used over an open fire, with long handles. Those usually want sliced bread rather than rolls--they don't allow for very thick sandwiches.

Jasdip: thanks for the info and picture; that looks like a great size for cooking pancakes, eggs, bacon, etc. and having the flip grill side would be a real bonus.

Pillog: thanks for sharing that info; as you can tell I'm kind of behind the times on sandwich grills!

I just use a normal frying pan and turn the sandwich. You don't need a griddle to get a crispy sandwich and I prefer the lighter, toasty texture that you get if you don't press it.