Spent the day practicing a through mortise before breaking actual pieces. Had a scrap cutoff of the maple to test on.
First attempt my layout was off by maybe 1/16" of an inch so when it broke through to the other side it caught the edge and blew out the backside.
Second one I paid a little closer attention and practiced using the mortise gauge a little more steady. It was going well until I chipped off the knife wall, wasn't paying attention and think I levered against it.
Third attempt went well and so moved on to the actual pieces and did all 4 of them.
Pretty happy with the results and they fit maybe a little too tight on the one test tenon I've cut. Would like to clean up the insides a bit and get better at not having them so rough. The last one was best, of course, since after 7 or 8 of the things my comfort level had grown. Went probably 3/4" of the way through the top so had less to punch through from the other side and that seemed to help the tear out going on in the mortise.
Tried to burnish the card scraper and just couldn't get it to scrape how I felt was right, not comparing it against YouTube instructions. Will try again but tomorrow is going to be mostly tenon cutting for these 4 mortise and seeing how the frame comes together. After all this work I am thinking of not doing the same joinery on the lower cross members and instead doing a bridal joint that I can pull off with a table saw, haha.
Moisture also slightly bowed my table top so would like to get it sealed up as well. But am kind of using it for my benchtop at the moment.