Seeking knowledge at the well of Wisdom

[ltlvt]

Here I am humbly asking for guidance for re machining a VEE Way on my lathe saddle. I was busy studying girls in math class so here I am at age 72 and have forgotten what I learned from girls.

Okay nuff of the funny stuff. So imagine a VEE and you want to take .050 per side of the VEE off in multiple passes with a 70-degree end mill. (35 degrees per side of the end mill) Machining only one side first and then moving to the other side and repeating the same. I am seeking a formula to arrive at how many thou of down/ZEE travel and how many Y travel to achieve .010 depth of cut on each pass. So I am asking for a simple dumbed down explanation to do the math. Or even butter an online calculator that will do the math for me. Thanks in advance.

 

[woodchucker]

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[MyLilMule]

Assuming your V way is 90 degrees, the math is simple trigonometry. I'm curious, however, why not use a traditional endmill and nod the head to 45 degrees so you can cut both sides in one setup?

Regardless, assuming the cutting side of the endmill is in plane with the existing side of the V way, you would need to move the saddle .014" to take .010" off the V way surface. For a right triangle at 45 degrees, the length of the hypotenuse can be found by multiplying the length of either leg (they are equal) by the square root of 2 (1.4142...). In your case, one leg is going to be .010", so the hypotenuse is 0.014" - which will be how far to move the saddle. I included a cad drawing that proves the math.

 

[Martin W]

I only remember SOHCAHTOA and I think that’s for right angle triangles.
Darn girls were such a distraction
Martin

 

[MyLilMule]

I only remember SOHCAHTOA and I think that’s for right angle triangles.
Darn girls were such a distraction
Martin

It was the girls in history class that did it for me. I failed it and had to take it as a summer school course or I wasn't going to graduate the next year!

 

[ltlvt]

It was the girls in history class that did it for me. I failed it and had to take it as a summer school course or I wasn't going to graduate the next year!

Graduate? I was too busy working and supporting my new baby boy. He just turned 54 this week.

 

[extropic]

@ltlvt
Just to be clear, you want to take .050" off the face of each side of the V groove. Right?

Assuming the long aspect of the groove is aligned with the X axis, moving the cutter in the Y axis .0872", from the cutter tangent to the workpiece, will take .050" off the workpiece surface. That's equal to 5 passes at .0174" Y axis passes. Don't move Z (quill) depth. lock Z before you start the cut.

 

[extropic]

@ltlvt
I have edited the numbers above. Be sure you use the current (.0872").

 

[ltlvt]

Assuming your V way is 90 degrees, the math is simple trigonometry. I'm curious, however, why not use a traditional endmill and nod the head to 45 degrees so you can cut both sides in one setup?

Regardless, assuming the cutting side of the endmill is in plane with the existing side of the V way, you would need to move the saddle .014" to take .010" off the V way surface. For a right triangle at 45 degrees, the length of the hypotenuse can be found by multiplying the length of either leg (they are equal) by the square root of 2 (1.4142...). In your case, one leg is going to be .010", so the hypotenuse is 0.014" - which will be how far to move the saddle. I included a cad drawing that proves the math.

View attachment 488166

I had originally thought I would just tilt it on the bed or knod the head anc cut it with a regular end mill but when I started doing my homework, I discovered that the Clausing 5900 series lathes have 70-degree Vee ways. So the easiest way for me was just to buy a 35-degree end mill and cut one side at a time with the cross-slide flat on the table. You should try to find a 35-degree end mill. Only one place that I found, and it was recommended by a member of this group. No cheap end mills for the combined 70 degrees. I paid over $80 US dollars for this one. 60-degree and 90-degree Vee end mills are a dime a dozen and easy to find. I have several of them so I guess Clausing had their reason for making the Vee ways 70 degrees.

 

[ltlvt]

@ltlvt
I have edited the numbers above. Be sure you use the current (.0872").

I am a little confused now. You are correct the long aspect is aligned with the X axis and moving the y is what I will be doing with the Z locked but your edit comment confuses me as well you and MyLilMule have different numbers.