How to Tram A Milling Machine 

I was taught to have the quill extended for greater accuracy and finer adjustment. Also not to have too much travel on the indicator as it can damage the stylus / plunger when sweeping out of the the tee slots. Here is a quick release indicator holder ideal for general use on a Bridgeport. - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-_djgGUKpULs.html or for use in a chuck or collet - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-3r9xVYoTK38.html

1) understand your place as a learner and don’t try to act like you know everything already. Show that you want to learn from others. 2) have a rigid setup. Always shorten any kind of stick out 3) understand everything about the machine. Know when you can change settings (running/not running) 4) understand speeds and feeds 5) understand what climb milling is and when it is and isn’t appropriate I have all my lecture notes and videos organized in one place here: engineeringtechnology.org/et-curriculum-and-lecture-notes/

Just to add, if college is an option have a look at engineering technology. Less theory than engineering, more career options than trade skills alone, but high value on trade skills. If you have questions, just let me know: engineeringtechnology.org/about/contact/

I'm not a machinist, but in the past they had machinist (very precise bubble) levels. Level table means level vice and you can level a part with a machinist level. Now we have digital smart levels. You can zero the smart level to the table and then your part. I would do my best to level the machine though. It really doesn't take very long.

So let's say a block is messed up and is 6/8 instead of 5/8, you can put a facemill in and easily chop off .125 quickly, let's say it needs to be a perfect 90 or a squared block, so you need the side and top to be perpendicular, but let's say you didn't tram or indicate and you cut it. Now it will be slightly off whether that be by 1 degree or many, you messed up the block and have to completely restart or if you put in a drill instead of using a drill press cause you were pressed for time (hah comedy) as you drill the hole will be at a slight angle instead of perfectly down. Basically if you are using the machine at all that isn't trammed it's not a smart idea

@Thedudeabides803 You are right, a machine does not really have to be leveled. The first problem is that some folks don't understand the difference between "leveled" and "trammed". The former means "the XY plane is perpendicular to the direction of gravity", whereas the latter means "the XY plane is perpendicular to the Z axis". This video is about the latter, a prerequisite to precise machining. The second problem is that without mentioning numbers (accuracy) "perpendicular" has no meaning. Practically speaking, it turns out that you can measure (as has been shown in the video) the deviation from perpendicularity of the Z axis (tram) and you can actually see the results when machining. Measuring "levelness" is not as precise, so you don't really know how far off things are, and I would challenge anyone who would want to claim that a machine that is not leveled will produce something visibly different or bad. That said, leveling is likely a good practice -- folks may assume the table is leveled and use a level when fixing a part. It may be that the coolant system (or tray) assumes a reasonably leveled machine. Lastly, as a stretch, the geometry of an unleveled machine would be exposed to ever so slightly different gravity-induced force vectors, but I'd offer that practically such changes would be infinitesimal and insignificant. However, the gravity-induced forces can distort (e.g., twist) a machine (to the point of detectable problems) if the supporting feet are not equally pressurized, so adequate support and floor is important on large highly precise machines. But this has nothing to do with leveling.

As a toolmaker I can safely say it matters, this is not a scientific explanation but has happened to myself during my work. A machine I was using was on a slight slope about 5° to the right, no big deal until the machine to the left had parts on it, so I hung the part off the back right side of the bed with the head about 85° in C and started drilling some deep holes. Well, the Inertia of me pulling the handle down helped tip the machine right over, I didn't know my own strength as this milling machine came crashing to the floor. No injuries just a snapped drill and a huge hole in the ground. Every machine was bolted down afterwards.

The head and table need to be perpendicular with each other for accurate machining. The machine itself doesn't need to be level. Check out Mr. Pete's tramming video #662.