Compound angles


Been struggling with this for a while now.
Having a rectangular block I want to mill a groove whose bottom direction is
inclined to all sides at angles A, B & C (angles measured in the planes of
the sides of the block).
If I am correct the first two steps are:
With the sine vice jaws vertical clamp the block rotated in the vertical
plane of A such that top surface makes angle A with the vice base plane.
Tilt in the vertical plane the sine vice jaws to angle = atan (tanB x cosA)
Now comes the part I can't figure out. I need to set the vice base at some
angle in the X - Y plane (a function of C, A and B) to the X axis of the
mill. What is this function?
Help, corrections much appreciated.
John.

Reply to
Machinist60
Loading thread data ...
"Machinist60" fired this volley in news:hvnjc4$1ms$ snipped-for-privacy@news.eternal-september.org:
I believe you need compound miter settings, such as you will find for making depressed picture frames in carpentry.
Compound settings adjust both angles interactively to come up with a "corner angle", and a "slope angle".
For instance, if you wished to cut a frame for 45-degree sloping sides with 90-degree corners, you would NOT merely set the saw for 45-degree tilt and 45-degree angle, or the joint will not match up correctly.
See below, how that angle would actually require to be cut:
formatting link
LLoyd
Reply to
Lloyd E. Sponenburgh
formatting link

Reply to
Don Foreman

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.