Hi all. I just finished installing a laminate floor in a kitchen. The rest of the house is hardwood floors. With the underlayment, pad, and the thickness of the laminate, I have a 3/4" difference in height. One 32" cased opening (no door) and one 9' stretch where we removed a wall.
All the pre-made threshold/transitions I could find will allow a 1/2" difference. I've bought a piece of 5/4" oak and am going to make what I need on the table saw. It'll look and work great. But, I have to wonder how a professional installer would solve it.
Andersen makes a thick transition piece that you use on their patio doors. If that doesn't work, make one.
Take a 3/4 piece of stock and cut a 12 degree bevel on one face. Leave 1/4" on the low side so it doesn't split or crack.
I did it for a ceramic to hardwood floor transition with 4/4 oak. It was 82" long. Had to sand off some burn marks due to the length, but worked out fine.
If this isn't what you can do, try a woodworking shop.
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."
B. Franklin 1759