[How-To] How would you?

[finsruskw]

How would you create
this hole in a 1/4" plate?
It is 4.00" high by 2.735" wide.
Th biggest annular cutter I have is 2"

 

[mmcmdl]

Boring head or hole saw and then mill . I;m back in the tractor business fin , although green this time . Don't let that out over on OCC .

 

[finsruskw]

Thanks Dave, That's what I did but two 2" holes one lower and one upper leaves an interrupted cut and I am tearing up my boring bars!
They are just the cheap brazed insert sets from you know where, bought used w/unknown sharpness.

 

[mmcmdl]

Did you try a hole saw with pilot ?

 

[finsruskw]

I have a 2" annular cutter is all.

 

[talvare]

I'm assuming that you intend to cut the straight sides joining the two arcs with a milling cutter ? If so, maybe if you cut out that section before using the boring head to enlarge those 2" holes it would reduce the severity of the interrupted cut. Just a thought.
Ted

 

[finsruskw]

Yes, that's what I am going to try next.
film at eleven Ha Ha !

 

[OTmachine]

Use 1/4 drill bit to Incremental rough drill out inside. Then use boring head to machine radius at both ends. Then use the same setting boring head to flycut the radial tangent sides @ .025” d.o.c. per pass. Preferably using a boring bar that takes inserts.

 

[finsruskw]

OK, I have the flat sides milled to correct width, 2.375.
This still leaves .1875 on the upper and lower ends.
Should I set the bar for the full 2.375 width and advance it with the X axis?
Or, should I start at 2" at the correct X?Y axis and keep adjusting the bar outwards?

 

[OTmachine]

start at 2" at the correct X?Y axis and keep adjusting the bar outwards. This will reduce the interrupted cut gradually.