Best way to make this cut.

[finsruskw]

At a loss here as to the best way to make this cut.
Close as I can tell it is a 2.125" radius.
Mat'l is 3/8 x 2 bar stock.
I'm thinking rotary table of mill vise using a boring bar?
Securement in a mill vise will be an issue though as I have already cut the long angle after a rough freehand cut on the band saw.
Maybe I should have cut the arc 1st.
These are guides for the vertical arms on a Cat 0 three point for a Cub super.

 

[ErichKeane]

How accurate does that need to be? If it is just a relief cut, I'd consider just doing it with a belt grinder, and cut to the line.

A rotary table would work here too. BUT another one to consider is a boring head if you have one capable of the offset. Set the head to the proper diameter/radius, and you can cut to your position that way. Both cases, clamping to a fixture plate is probably your best bet.

 

[Just for fun]

Plasma cutter and an angle grinder to clean it up.

 

[C-Bag]

I’ve done similar cut just using the rotary table with an endmill. Worked great. I used clamps set off the table so I didn‘t foul the RT.

I had to do different radii and needed to be able to do concave/convex mating to form metal with. So it had to be able to be adjustable because I couldn’t figure springback. I used 80/20 to make a double arm setup so I could do up to 24” concave/convex radii. Done mostly UHMW, nylon and hard rock maple. But I feel I could do steel plate if it’s not too big a radii.

 

[Jimsehr]

Use a fly cutter like a boring head. Take a few smaller cuts And cut to size.

 

[Flyinfool]

If it does not need to be super accurate, a 4.25 dia bi-metal hole saw used on the mill will make short work of it. I use hole saws all the time for non critical radii. A mill is rigid enough that you do not need the pilot to guide the saw, just chuck it up clamp down the part and go. Lots of cutting oil.

 

[Flyinfool]

Forgot to mention, if it is a critical radii then I use the hole saw to rough it close and finish with the boring head. Using the hole saw with no pilot drill also leave a nice chunk of stock to put back in the stock rack instead of turning it all into chips.

 

[finsruskw]

Got em done this afternoon.
Used the fly cutter and snuck up on the size.
Worked pretty good.
Just have to blend in the taper on both sides of the arc.

 

[Just for fun]

Good Job! They look nice.

 

[finsruskw]

Blended the short angle into the arcs I cut the other day.
4 or 5 short passes and done!!
I'm sure glad I sprung the $100 for that RT!!
Sure a slick way to do some of this stuff!!
Now they have to get 2 slight bends and a hole on each end to fit the plate they bolt to.
Trick will be to get the bends in all 6 parts the same.