One of the biggest problems with a lot of the home made tools I have seen is the extreme difficulty of setting up cuts. Many of them you can setup simply for one cut and then leave it there. But lets say you had some wood 1" thick you wanted to cut on your table saw. This is a matter of seconds to setup on a regular store bought saw. But if you try to do it on a home made saw where its not already setup you might need to loosen screws, move tops around, resquare a home made fence, etc etc. Then you need to cut a piece of wood 1.5 inches thick and few inches wider. Now you need to do it all again. Then you realize, you need to cut some more wood at the original size, now you have to put it all back again... and it has to be exact because this is very much a hobby where a millimeter can make a big difference. Bottom line is that while its possible to make a home made tool these are more curiosities in the hobby then practical machines. Then there is the issue of calibration. Like I said a millimeter can make a big difference. If your homemade tool relies on say wood as a construction material, and the wood you use expands, contracts, or warps with the changing seasons in any place that needs to remain dead flat.. well now all your cuts are off. And you might not even know it till you go to put things together and nothing quite fits right. And then there is issue of safety. Some tools really do need a motor that is attached by very strong bolts to a metal frame so that if something terrible happens (say someone knocks it over while in use, or something heavy falls into the belt and gets torqued around rapidly) your homemade tool does not literally kill or maim you or someone else. Obviously not all homemade tools would be in this category, but some I have seen frankly give me the heebie-jeebies with what-ifs. So as others have said, just buy used or new tools. You will be much happier in both the short and long run. That said, as someone who is constantly thinking first second and last about cost as a barrier of entry into this hobby my strong advice is not to buy a whole shop. But just the barest minimum of tools needed to get started. What is your first project? What tools do you need to complete it? Can you do it with less? Would powered hand tools work as well as the floor tools? Do you need a bandsaw, or would a jig saw be just as good? Do you need a table saw right away, or would a circular saw with a straight edge do for now? Etc etc.
there are things to make, (router table, sled, lifts and the like) and there are things to buy. In my mind things that can take off a finger you should probably buy unless you have already had some experience with them and with the engineering involved.
tthat action is called ballasting. Once done, I'll load it withe a spear and bands any any other hardware and take it into the water. Using 1/2oz fishing weights I'll add weight until two things happen. 1) the gun begins to very slowly sink and 2) move the weight front to back until it balances in hand. Once the weight and location are known, I'll drill out a trough with a first forstner bit, melt down the needed weight of lead in my crucible then pour it into the cavity. Epoxy will take up any more space and a mahogany cover should make it "dissapear" My brothers 62" FEQ teak gun took about 11 oz if I remember correctly.