I make books by hand for a hobby. They're not anything fancy, as I'm not able to afford equipment such as sewing frames, guillotine, book presses, etc. So I make do with small tools that pretty much everyone uses, such as exacto knives, binder clips, vices, etc. Even then though, when you use the right materials from places like https://www.hollanders.com/ or https://www.talasonline.com/ and follow traditional methods, the end results come out not only sturdy, but halfway good looking.
I've been thinking a while now about buying cheap paperbacks and re binding them using the double fan method and putting them in hard covers. Not only would the new binding be more sturdy than the standard perfect binding manufacturers use, but I'll have something new to figure out how to do and improve upon.
I haven't tried this yet, but I do have two things I'll need to figure out. In regards to removing the original glue, should I heat the spine up to take it apart or go to a print shop and have them cut the spine off. The heat method means I'll have to hassle with glue removal, but it'll preserve the margins of the pages. The cut method is easier, but it means I'm cutting into the margins. I also exclusively make flat back casings for my books and I'll have to figure out whether or not that pulls on the spine too much. If it does, I'll have to go with a more traditional casing, where there's not that extra bit of book board along the spine. Which might have its own unforseen problems.
Looks like I'll have to do some research this week.