I would recommend the save and quit method which makes them straight. To do this: 1. Prepare your merge as you would usually. 2. When you are ready to merge the object, grab it using a, but don't let it go. 3. Open the start menu and save and quit. 4. Restart the game and the object should be merged perfectly. Send me a FR if you need more help. GT: AmercanPsycho
Geomerging is an exploit, it wasn't meant to exist. It's a glitch and is therefore inconsistent. However, for better ways to geomerge, look here. Forging 101 has a lot of forge tips and tricks for forge. Trawl through it, there's a lot to be learned. they also have a YouTube series, check it.