Square-to-round

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Jkassis

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I have a 3/4" thick, 6" X 6" aluminum plate. I need to make this plate into a 5" diameter round plate (still 3/4" thick). Can anyone tell me the easiest way to do this? I was thinking an 8" 4-jaw chuck in the lathe and plunge-cutting the plate to make my 5" round, but I can see possible disaster doing this. :thinking:
 
Are there going to be holes in the round disk . If so bolt it to somthing that you can chuck in the lathe or a face plate if you have one. If you cut the 4 corners off with a band saw it will help in turning.


Marty
 
The easiest ways are CNC and EDM. It usually meansd outsourcing for most home shops. To do it in the home shop a bandsaw will do to rough it out.

"Billy G"
 
This sounds like a neat little problem to solve. If you can't have a hole in the middle then I guess you could chuck it up in a 4-jaw and then make a plunge cut. If you don't go all the way through you could make it thin enough to take off and finish cutting by hand, and then re-mount the new circle on a 3-jaw with a spider behind it to make it stick out evenly so you can true up the last bit of the side.

Or if you can have a small hole in the middle you can mount in a 3-jaw and make the cut, maybe make some relief cuts in the sides first so when you cut through the excess just falls off instead of dropping like a captured ring and possibly grabbing something.

Or if you can just afford a small dimple you can make a dimple in the center of one side and use that to center it on your 4" rotary table and then you can clamp it down and make the cut on the mill. If you've got the dimple to help recenter it you'll be able to move the clamps as you go along so they don't get in the way of the bit.
 
Saw out the disk on the band saw, leaving stock for final machining. Grip an eighth inch or so in your 3-jaw and machine as much of the outer diameter as you can, using parallels or an indicator to make it run true (don't forget to take them out). Flip the disk around and finish what's left. DO NOT try to plunge cut it to size with a parting tool. Even if you don't go all the way through the chances for a wreck will be high.

Tom
 
Thanks for all of your replies! I do have a center hole, so maybe the rotary table on the milling machine would work the best?
 
You could saw it round,then super glue it to the faceplate or glue it onto another piece of metal in a chuck so you can completely turn the outside dia.. When done,heat up the aluminum to release the super glue.

I often glue down odd shaped pieces of metal that would be difficult to hold otherwise,or easily damaged by jaws.

Clean surfaces to glue with acetone thoroughly, and take reasonably light cuts.

Mitee Bite actually makes sheets of what look like some kind of waxed paper to melt beneath pieces to be machined. I prefer glue.
 
How big is your center hole? If it's big enough, I would get a bolt or all-thread to run through it. Then use a nut and washer on each end, tightning it up and put the bolt in your chuck butted up against the nut and turn it. 6"X6" is kinda big for this method but if your center hole is big enough it might be an option.
 
Jkassis,
I think you have the right idea. The rotary table and mill would probably be your safest method.

Randy
 
I machined the piece today and came out perfect. I decided to use the milling machine and a rotary table, as I felt it was the method I could relate to the best and also sounded like the safest bet for my experience level. After rough milling the circle, I chucked it up in the lathe, finished the OD and drilled the center hole to dimension. Thanks for all of your suggestions!:thumbsup:
 
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