Good call on going with the mill and lathe. I would estimate 90 percent of the parts a team would make can be made on a decent mill and lathe. If you are crunched on space on option is a mill/lathe combination device. There are pluses (one machine needed to complete many different tasks) and minuses ( only one type of machining operation can take place). One of the most important is making sure the machine is calibrated properly, both the manual dials on the axis hand controls and the digital readout. On Team 93 we have our own machine shop (it is the High School shop) which has several mills and lathes at our disposal. The biggest issues is maintaining them and losing calibration as these will see higher levels of abuse than normal; students learning new skills often make mistakes that result in damage or extra wear and tear. This is something to keep in mind when buying the equipment.
As for how we use them, our goal is for students to be making the majority of parts. When I was a student on the team I learned a lot and now as a mentor know these students gain a lot of skills by being in the shop making the parts they design. It gives you a sense of what can and can't be done. The machines are used to make everything from frame members in which we use the mills to precisely locate holes, to complex hubs and device parts. Also, the machine tools can be used to make some complex parts, with the right tooling. Be sure to have a good vice for your mill, along with dial indicator to check squareness. Also, a good 3 jaw self centering chuck can accomplish most things on a lathe. A typical process for us is to use a lathe to turn a drive shaft of some sort, then go to the mill, and cut a keyway in it. Most operations like that are done by students with mentors nearby.
As for the welding, its handy to be capable of it but I have had seasons in which we have built robots without any welding at all.
One thing to seriously consider when moving up in size/quantity of machine tools is trying to have access to experienced machinists and tradesmen. Often they have seen things go right and wrong and are invaluable resources to have working with students (and mentors). It is amazing what can be done on a manual mill with a quality Digital Readout Device and some knowledge about setting up the machines.
Sad to hear about the young lady, a harsh reminder that these tools are neat to use they need to be respected. I have been involved in my fair share of close calls, and always am sure to teach students the importance of respecting the tools we work with.
If you have any questions or want some additional information let me know! If I don't have the answer, I promise I know someone who does in the arena
