How do you Accurate Mill a Full Circle?

A rotary table (or a lathe compound, or other machine slides) feed can be operated quite smoothly and predictably using this relatively simple technique:
Starts at 6:15, money shot starts at 18:00
A drill with variable speed and an adjustable stop for the trigger is needed, along with a fabricated adapter to fit the handle. The end mill can be ramped down into the work as the rotary table rotates, and also ramped out at the end, leaving a nice smooth cut. This technique can be used with many machine tools to make an axis feed smoothly, a poor man's power feed and stepper motor. ;)
 
oskar said:
I want to cut 2 circles in 3/8” aluminum one 8” OD and the other 10” OD

Reading on various threads I gather a rotary table will be the only solution but my question is I don’t see how a rotary table will work unless this table is motorized?

Otherwise I will have to manually turn the table against a speeding end mill which I don’t think it’s safe to do

I don’t have a rotary table yet so I wonder how it works

Nicolas
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yeah hand crank for curved slot milling or as you say for cutting a circle. As has been mentioned the worm gear makes it very light work , only risk is backlash if you change direction mid cut.

Depending on the accuracy required you could use a router and a circle jig.

Stu
 
oskar said:
Hey Walker, the size of your shop and equipment are amazing!
Nicolas
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Start by drilling and tapping a hole in the OD for a lifting eye.
This is a drill press (-:
Ugly, smelly and LOUD. A very unpleasant machine in every way.
 
P. Waller said:
Manual rotary tables should be easy to find used, most job shops stopped using them 30 or more years ago, I suspect that many of them are entirely to large and heavy for hobby machines however.

For general hobby use a vertical/horizontal tool with a tail stock would be far more versatile.
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Yup. Exactly.

One thing to consider is size. I sometimes feel cramped on my 9" Troyke rotary table. Clamping stuff to the table takes room! I'd be hard pressed to clamp much onto a 4" rotary. But, if the stuff you're working on is small (yeah, I know, a relative term) then it might do the job..

OTOH, I have a 6" indexing head (Ellis) with a four jaw chuck on it -- love that thing!

I think the used market for these things has dried up a little. I don't see as many being advertised for sale as I did 20 years ago. But, if you aren't in a huge hurry you might start asking around, watching the auctions, etc. etc. You might turn up a bargain on a 6" horizontal / vertical..

MetaKey
 
Nice video and technique Bob, thanks

Walter that monster machine is a drill press? Never though they come in that size
 
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Hi Oskar, Guys,

If you are going to buy a rotary table, don't waste your money on one with a tilt facility. You will loose that all important rigidity. There are better and safer ways of milling at an angle.
 
P. Waller said:
. A very unpleasant machine in every way.
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Unpleasant to pay for and unpleasant to move I would agree with.
However I would love to own and operate
one.
-brino
 
brino said:
Unpleasant to pay for and unpleasant to move I would agree with.
However I would love to own and operate
one.
-brino
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If you ever have to use such a machine you will quickly change your mind (-:

I use this 40's-50's Warner and Swasey #5 turret lathe for drilling holes for boring operations finished in other lathes.
It is also big, ugly and smelly yet nearly silent when operating so go figure.
It will drill 3" holes through 8" of stainless without a spot or pilot drill all day long, a very powerful machine. 20" chuck and 5" through the spindle, turn it on and go and do something else until it is done drilling.

It will however explode a 2 1/2" High Speed Steel twist drill but you are better off not being there when that happens, it will not stop.
 
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BaronJ said:
Hi Oskar, Guys,
If you are going to buy a rotary table, don't waste your money on one with a tilt facility. You will loose that all important rigidity. There are better and safer ways of milling at an angle.
Click to expand...

Thanks for mention it but I thought about it and before I buy I will see the unit and check all details

Nicolas
 
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