How to mill a V in the center of something?

D

D.sebens

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I’m playing around making a bench block and want to add a Vee in the center. I have it mounted at 45* and a 5/8” end mill. I have indicated center line on it but after thinking I think my slot would be off center if I stayed there.

My current thought is that I made a line 5/16” lower measured on the face of the part and aligned the edge of the end mill with that. If it works how I think it “should” be in the center when the end mill reaches full depth on the end face of it? I think I would only be turning X axis for depth and Y for the slot. I would leave Z alone? Seems logical in my head but I’m not sure if I have the thought right, the 45* angle is really skewing my thoughts. Maybe I need to make a 45* box for me to stand on so I can see the big picture. Here’s some pictures of the setup. IMG_3091.jpegIMG_3092.jpeg
 
After more thinking I think I should set it 5/8” lower for my setup?
 
Clamp the mounting block and part flat on table. Cant the head to 45 degree, align edge of end mill with center and cut. Feed up table in Z.
 
OTmachine said:
Clamp the mounting block and part flat on table. Cant the head to 45 degree, align edge of end mill with center and cut. Feed up table in Z.
Click to expand...
That may be the easiest and I might. I was afraid I wouldn’t be able to move x far enough for the vise and didn’t want to go through tramming the vise for one operation. I didn’t think about bolting the fixture to the table.
 
or you could do the math.
do you know how deep you want the bottom of the V?
If you do, you can divide the 45 degree triangle in half, you now have the height, and the angle so you have a way to calculate


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oops, did that wrong The height is as such, and the 2 angles are still 45.
.675 is your height and your leg, so double it, and 2*.675 is your hypotenuse across the larger triangle .
Or .675 is your offset from center.

oh brother, did I botch that up.


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Last edited:
Too lazy for the basic math...

You are creating a triangle by cutting a 90 degree cut into an angled bit of material.

You could easily draw this in CAD or with a simple 45 degree triangle.

Do not have one?

Take a sheet of paper and fold the end over to the side.

Use this to first draw a line at 45 degrees.

Now place 2 lines crossing this at the width of your part.

Make a third cross in the center of the other 2.

Flip your triangle over so you get opposite angle from first, draw line through the center line.

Now with ruler or caliper at just under 5/8, holding it horizontal, place the points on the line from the center and the face of the part.

Draw horizontal line here, vertical where it crosses the center.

Measure these points from baseline and good to go.


Now you know where the depth of cut needs to be as well as how far to cut.

Or...

You could use the a-squared +b-squared =c-squared to get the lengths of the triangle, the sides of your V are 5/8 inch, square that, double it, then square root to get the width of the too of the V, divide by 2 to get distance from center.



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OTmachine said:
The pictured setup is not very solid.
Click to expand...
I dont disagree. I doing have a machinist background so sometimes I go a little sketchy to see if it works. I would like to know how sketchy I can get. I like your idea of just turning the head.


I appreciate the people that told me how to math it. It makes sense for people that do this or have done this. I couldn’t think of how to calculate it at the time.
 
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