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Discussion in 'A BEGINNER'S FORUM (Learn How To Machine Here!)' started by Desolus, Apr 29, 2017.
Be sure if you can to actually see and hopefully use a little any machine you are considering.
I had thought of that, my approach was to make a expanding mandrel on a large arbor grabbed from the inside by a chuck, kind-of a reverse collet, and drill an off center index hole that indexes to a hole in a jaw of the chuck. because the first ops in the lathe have no index, and that's where I bore the surface the mandrel will be grabbing. although, After further thought, i can just leave the part in the chuck and install the chuck to the rotary table, index it once, and go to work. the expanding mandrel is still an excellent option to hold the work in the chuck though.
The ops I'm thinking about are as follows:
Cut blank with plasma/water jet/saw etc.
Clamp blank from outside with 4 jaw chuck in the lathe, turn the profile of the z axis(bottom of the watch) and bore the inside diameters to final tolerance, run a tap through the first ID (i love standard sizes)
Install the expanding mandrel in the back of the watch, grabbing the ID above the threading and clamp the mandrel in the chuck, turn the profile for the top of the watch.
Move the chuck, the mandrel, and the part to the rotary table and mill the x/y profiles
Elevate the rotary table to 45 degrees and mill the OD chamfer.
Take the rotary table to 90 degrees and mill out the recess for the crown to rest in, drill and tap all the holes for the crown and pusher case tubes.
I finally got the book in, looking over it now.
I own the book and think it is an excellent introduction to machining and the Sherline lineup of tools.
Are you looking for 4th a axis trunnion? This will allow work on three or four sides of a part in one setup, as seen here.
I realize that you you are not looking for such a machine but is this what you have in mind for a manual machine? If you have a rotary table stand it up vertically then either buy or make a table to fit your parts, the other end is simply a support much like the tailstock on a lathe, index and mill away.
Not exactly what I'm looking for, it's impossible to make the case I'm making without re clamping at least once, there are some stepped radius' on the back side that you simply can not get too from any other angle. while I can do do that on the fixed 4th axis like you show, then I would have to re clamp twice, to get the holes in the side of the case that are not 90 degrees perpendicular to the a axis. So a tilting rotary where the a axis and z axis are not fixed at 90 from each-other like the machine in the video.
edit: I take that back, If there was a very accurate tilting spindle, or tilting Z axis on a CNC setup with that table it would be possible to make any case by casually tossing in a plate and pressing the go button...
Well, I'm committed now, I bought a Sherline CNC lathe and mill. The way I see it, I still have access to a 36,000 pound Hurco on every other weekend so any heavy lifting can be done on that, or I can hire it done with what has been so far an average $120 per part.
Now I need to order some sapphire bearings... <.< >.>
Well I got my lathe and mill today, some M42 hss stock, and a ton of accessories.
Ground some cutters with the assistance of temporary handles (vise grips) And the lathe is removing a suprising ammount of 316 with ease both close and far from the spindle. Tolerance 6 inches from the spindle is 5 ten thousands of an inch.
I am a very happy camper.
Thankyou to everyone who offered their suggestions. And special thanks to mikey; you get an E-cookie.
If you want to see what you can do with a sherline check out clickspring on YouTube. I'm impressed with his work.
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Yeah I saw it, was one of the deciding factors.