So today I finished my joiners mallet and I had a question about chiselling. When I was chopping out the moritise a couple days ago I had trouble with shallow humps along the slope on each side. I'm wondering if people have advice for avoiding that. In this first picture you can see the angles that I was following from top to bottom, and it was about half way or two thirds down that I seemed to have the hump/rounding. I was chopping from both top and bottom, and I first cleared out a channel from both sides with brace/bit. It was a very slight hump, but it just seemed to take forever to get it to go away so the handle would seat all the way, as it was so shallow so that I had a hard time getting purchase on the chisel business end. The mortise is 3/4" wide and I was using a 3/4" chisel. Thanks for any advice.
20220327_104103.jpg
Here's the finished product. I bought a hard maple "bowl blank" that I cut in half for the head, and the handle is ash from a tree that came down in my in-laws' yard. When it's had time to acclimate itself after a few weeks, I'll shave down the handle a bit so it seats lower, i.e. not sticking out much above the top. This is a Paul Sellers youtube project.
20220402_140235.jpg
After a coat of boiled linseed oil.
20220402_141458.jpg