My FIL and I have bonded in the past over projects--my MIL told me he was really into the idea of helping me spray-paint something in his garage (and he put in a lot of effort setting up a spray booth using plastic sheeting, etc.
He's been working in copper since his retirement, and he made me (at my request, and following part of my dimensions and tastes) a stand for my plant. In the course of that, I was reminded again that when someone puts their creativity into something, they often don't want to follow your directions quite the way that someone making it "for hire" does. They invest themselves and their tastes.
So when FIL decided he wanted to make us a chandelier for our DR table, I decided that I'd just not get too emotionally involved in what it looks like. He was making it, it was his gift, and I'd go along with what he did--it would be much more pleasant.
So now to the situation w/ the question: I want to build something for my DD's dorm room; I've drawn it out, researched hardware, etc.; but I don't have a saw. FIL has a table saw, and I've thought maybe he'd help me cut the lumber.
So I showed him my diagram, etc., and when we were talking about the bookcase, he said, "You could put copper pipes for the sides." And I said, "I don't want books to fall out." And he said, "No, I would space them very tight." But I don't really want his design; I want my own. (My design would be calmer and more uniform--plus it's intended to pack w/ books or stuff, and it would be visually loud. And, I've just now realized, my design would let us put adjustable shelf standards; his wouldn't necessarily. But mostly, it's my bookshelf, my gift, and I want to do it my way.)
Then a little later we were talking about attaching the two parts, and he said, "when i make it, it will be like a tray." and I said, "No, wait, I am making this--you are helping me. This is my plan--don't try to take it over."
He got quiet--I was afraid I'd hurt his feelings. The convo in the room moved on, and we both sort of dropped it (though he took the diagram with him).
So now I don't know what to do--I don't want this to be a truly "joint" project--I really am not interested in having him change my design. Part of why I want to make this is for the fun of seeing if my ideas work out. Do I just get my lumber cut somewhere else? Do I wait and see if he brings it up? Do I ask him if he'd be willing to help me with cutting the lumber, and gently say, "I'm excited about doing this using my plans. Would you be willing to follow them, and not change them"?
(I have another project I'd love to have his help with, and I don't care much about anything except having it not waste space.)
My FIL has occasionally done the "Grandma, it's her plans, don't push your ideas or plans on them" thing--but not always.
Any wisdom and advice?