How would you cut this radius?

[Winegrower]

How about: For balance, set up and make 4 pieces at once on your big faceplate, and sell three.

 

[Janderso]

On the lathe...
Make a sacrificial piece the same width and drill/ream a hole to where the center of the arc would be.
put them in a 4-jaw and use the center hole to properly align, keeping the edges flush.

Whew,
I’m not sure I follow.

 

[Janderso]

Once you set the head it doesn't need to be adjusted . Just move over and feed down .

Got it.
I modified my original design. I cut in .300”. That’s good enough.
David, your set up advice made this easy. Boring bar, feed in about .025” each pass using the auto feed on the mill.
Great finish. I’m using a Centurion bar. Should have had a shorter one but you do with what you have.
Thanks buddy

I should add, many of you suggested the same or other ways of cutting this radius.
All viable ideas. Thanks for your help!

 

[mmcmdl]

Got it.
I modified my original design. I cut in .300”. That’s good enough.
David, your set up advice made this easy. Boring bar, feed in about .025” each pass using the auto feed on the mill.
Great finish. I’m using a Centurion bar. Should have had a shorter one but you do with what you have.
Thanks buddy

I should add, many of you suggested the same or other ways of cutting this radius.
All viable ideas. Thanks for your help!

You are da man Jeff ! Looks great . Yep , then just flip it over and do the other side .

 

[Janderso]

You are da man Jeff ! Looks great . Yep , then just flip it over and do the other side .

I made sure to put a clamp on the vise jaw so I could just flip it and machine to the same depth on the dro.

 

[mmcmdl]

I made sure to put a clamp on the vise jaw so I could just flip it and machine to the same depth on the dro.

Very good my man . It was simple wasn't it ?

 

[Janderso]

Very good my man . It was simple wasn't it ?

Yep

 

[Janderso]

Made a little progress today.

I need to cut the radius on the front piece. Set up will be interesting.

I want to thank, 7milesup for the hardened and ground linear shaft.
I’ll probably cut it down a few inches. I’ll have to use a cut off wheel.

 

[Janderso]

I used my rotary table to cut the 2 1/2” radius. It came out perfect.
The more I use this RT the more I see what can be achieved.

The rough finish will be ground after heat treat.
I still have lots to do and this is a fun project.

 

[Toolmaker51]

Too late for the side cuts....
A) Hole saws don't appreciate unguided scallop cuts; this isn't a tube notcher.
B) I don't subject boring heads to such interrupted cuts.
C) Instead, a flycutter does far better. Set the shank in a V block.
Touch off shank with height gauge, subtract one half for centerline.
Add desired radius to centerline.
Raise height gauge to that and set tool tip.
Mount cutter and rough out until depth is reached with a finish pass.
Remainder of project:
I wouldn't radius the front for accuracy, just clearance. Locate exact center of indicator post, bore for a close fitting 1/2" or 5/8" bearing ball, set just deeper than half diameter and stake 3 points- that's the correct contact of a squareness gauge. It's a good plan drilling through for a pin punch to allow replacing the ball.