I am in the mechanical section of my team, and I wanted to get some pre-season practice in on the machines before build season starts. Does anyone have ideas of something interesting or fun to make using the metal lathe and milling machine? It would be greatly appreciated.
Practice cutting diameters on a shaft with the lathe. Take a piece of aluminum bar stock and cut some standard diameters for a specific length. For example, on a 1" shaft, cut 3/4" diameter for 1", 5/8 for another inch, and 1/2" for the last inch. See how close you can come (at least within 0.001" at 68 F).
For the mill, cut a precise slot (say, 3/4" wide x 3/8" deep). Using a 3/4" mill won’t get you within 0.001 by the way…
Thank you very much for the suggestion. I will definitely use this to practice for the build season.
I think its ok for now if it don’t get to such a precise measurement, as long as I get the general idea of what I am creating and how I am doing it.
Again thanks, and good luck this year!
Trust me, it’s easier to do it right during build season if you practice doing it right during the preseason. I’d start with Don’s suggestion–but on your first one, try to hold a 0.010" tolerance. Then when you can hit .010 almost every time, 0.005". Repeat going down to 0.001".
If you can hold a 0.001" tolerance on a manual machine repeatably, you’ll be in good shape. It’s not exactly easy to do without practice.
For a bonus, you could try making a C-clamp. You’ll need both a lathe and a mill for this; the tricky part is the screw/C interface. It can take a while to do it right; get help from whoever’s advising you.
Ok Eric. Thank you very much for the advice.
I will definitely implement this into my pre-season practice.
The C-clamp sounds like an excellent idea.
Good luck to you too!
To expand upon Don’s suggestion:
Cut off the sections you turn on the lathe and see that they fit through slots or holes that you drill/mill into the plate. This will give you an idea of how tolerances and fits feel in real life, i.e. you will learn qualitatively the difference between 0.001" and 0.005" of clearance.
I would also try milling pockets in the plate of a specified depth, width, and length without going all the way through. This will teach you how to precisely control all 3 axis of the machine. I would also do the same pocket design in climb and regular cut directions to qualitatively learn the difference between the two.
A useful place to start is “Machine Shop Projects” published by South Bend Lathe Works in the mid 1950s. The original is obviously out of print, butLindsay Publications continues to reprint it. You can buy it direct from Lindsay (and if you get the catalog you’ll probably order a dozen extra interesting books), or you can also buy it on Amazon. All of the projects result in things you can actually use. Some of the more complicated projects require castings, which South Bend no longer sells, but the majority do not. (If you were super hardcore, you could even do the castings yourself ;))
Projectsinmetal.com is also a repository of lots of interesting basic projects for both the mill and lathe, that are also useful.
RPI has students build miniature cannons for the introduction to shop class. They are neat, but they really don’t require much precision. I’m sure you can find plans for a similar cannon without too much work.
If you want to move into some more advanced stuff, I have several books and websites for model engines too.
[EDIT] If you are going to get “Machine Shop Projects” you should also definitely get the companion book “How to Run a Lathe” by South Bend Lathe Works. Truly one of those oldy-but-goody books (Lindsay reprints the 1942 edition :yikes:)! [/EDIT]
You could design and build an ROV for the National Underwater Robotics Challenge. We used our old old South Bend lathe a lot to make our last ROV.
Learn how to read mechanical drawings and fabricate parts to the specified tolerances.
We design our robots in SolidWorks before any final parts are completed; at which point every part gets a part number and mechanical drawing. That way, it doesn’t matter if the parts are machined offsite by a sponsor or in our own shop by students or mentors, as long as they followed the drawing we just accumulate a giant pile of parts, and then over the course of about 7-10 days they all get assembled together.
For practice, try machining keyways into a shaft. For a greater challenge, machine stepped hex and/or keyed profiles into a shaft.
Though I have never done it, i have seen it done quite often: Create a full chess set. That will definitely take both the mill and the lathe. You will probably need a couple of curved lathe bits, but if you wanted to make a simple one, but you could just make angles rather than radii.
Something like this maybe:
I have an original 1932 edition and let me tell you, it’s one of the handiest books around. Lathes have not changed much in 80 years.
A chess set or a cannon is indeed a challenge, but for skills more relevant to a robot, think of things like what you’d need to make for a robot. I also agree with the advice to see if you can hold 0.010" tolerance for five diameters, then work your way to 0.001". You need to figure out what works and what doesn’t yourself.
Just turning stuff on the lathe without regard for tolerance won’t help you much.
And all this goes for the mill, too. Nothing beats experience, and you want to turn out 10 or 20 pounds of aluminum shavings from each machine before January 8th.
I’m a big fan of not wasting time, nearly all the parts that have been made during our fall training sessions have been for prototype items, upgrades for offseason events, or tools/jigs for machining (mandrels for the lathe, some setups for the mill to make certain repeated operations easier, etc…)
How about a prototype wheel for the robot?
On 33, we make a lot of wheels and rollers throughout the season. Often we do this using a holesaw for the rough cut, and then turn the rollers round on a lathe. This season, I had some of the kids make a “collet” to do this. The collet is essentially a piece of 3/8 or 1/2" hex stock faced, and the drilled and tapped to 1/4-20 (holsaws usually use a 1/4" drill bit). I am not sure about the fun part, but it is a realatively easy and useful project.
Thanks for the replies everyone.
They are all really helpful!
A “Turner’s Cube” is classic. For fun make one on a lathe and one on a mill.