Milling a circle

It's the "stem" on the part that is the deal breaker. A plain circle can be cut several ways on the mill, but a circle with a stem would mean getting out the rotary table or going with @Latinrascalrg1 's suggestion.
 
How good are you at trig.
Calculate the location of the 2 corners between the dia and the stem, then do the math for each 1° and make a lot of small moves around the perimeter. It will be so close to round that I doubt you will see the facets. If you do some quick work with a file or sandpaper will clean it up.

I did this for a cam that I had to make, It was tedious but it worked great.
 
Much along the lines of Flyinfool's suggestion, you can calculate the coordinates of the perimeter. Here's a link to Tubalcain's approach to laying out the coordinates for making a spoked flywheel. He calls it the 'DRO method'. At about two minutes into the video, he tells you how to calculate or look up the coordinates.

By milling more holes, you can make very nearly a full circle and clean it up with a file/sandpaper/etc.

If the link doesn't work, just go to youtube and do a search on 'how to cut a circle on the milling machine'. His video is 'Machine Shop Tip #153...'.

Regards,
Terry

 
I think if I needed to make parts like that I would do as much as I could on the mill or shaper, and then freehand cut, file, and sand/grind the rounded lobe ends as required. Curved shapes like that can be pretty forgiving to the eye, and while a round shape may not end up being geometrically perfect it may be quite acceptable visually. Having said that though, if you’re looking to make a stack of them then it may be worth it to find a small rotary table.

That’d be a really cool model to see completed — good luck if you take it on.

-frank
 
Already into it. Currently working on some of the.more linear parts.
 
Finally broke down and ordered a rotary table.
Now just have to figure out how to use it!:rolleyes:
 
You must log in or register to reply here.
Back
Top