Any suggestions on how to make the joint when you butt sheetrock to a timber frame post.
Yes, when making a butt joint to an exposed timber or to a window jamb,use a plastic J-mold for drywall. The J-mold is cut to length and slipped over the raw edge of the drywall. When installed it leaves a nice finished reveal which can be painted with the drywall. Wide side goes to the back.