More on compound angles

Sorry, something got screwed up in the formatting.

Here is the answer I was looking for some time back. It has been great revision for me and I have had considerable help from a mathematics forum.

The problem was to find the set-up angles required to make a skewed milling cut in a rectangular block following given angles on three of its surfaces.

Image here:

angles are A, B and C in planes YOZ, XOZ and XOYrespectively.This is a right handed coordinate system with angles X -> Y,Y -> Z and Z ->X being +ve.1. Align vice jaws // X.2. Set block in vice so that line at angle A is // to XOY3. Tilt vice by angle D to XOY. WhereD = atan(cosAtanB)4. Rotate vice by angle E from XOZ. WhereE = atan(cosAsinC/(cosCcosD-sinAsinCsinD))John.

Sorry I don't seem to be able to fix this.

"Machinist60" fired this volley in news:i3fr5f$tqm$ snipped-for-privacy@news.eternal-september.org:

It's a great revision for me, too, to need considerable help from a mathematics forum for something that has been tabulated for woodworkers for over a century.

LLoyd

What's that Lassie? You say that Machinist60 fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Thu, 5 Aug 2010 22:04:39 -0400:

Looks like you needed a space after your URL

Another attempt to get the formatting right on Dan's advice. I searched up and down and asked about this some time back. Nothing came to light, I guess because this use group was not around a century ago and nor was I.

Here is the answer I was looking for some time back. It has been great revision for me and I have had considerable help from a mathematics forum.

The problem was to find the set-up angles required to make a skewed milling cut in a rectangular block following given angles on three of its surfaces.

Image here:

angles are A, B and C in planes YOZ, XOZ and XOYrespectively.This is a right handed coordinate system with angles X -> Y,Y -> Z and Z ->Xbeing +ve.1. Align vice jaws // X.2. Set block in vice so that line at angle A is // to XOY3. Tilt vice by angle D to XOY. Where D = atan(cosAtanB)4. Rotate vice by angle E from XOZ. Where E = atan(cosAsinC/(cosCcosD-sinAsinCsinD))John.

I give up its not that important

Hmm, I seem to recall having learned this in high school; recently had occasion to look at that text Practical Shop Mathematics Volume II, by Wolfe & Phelps. Sure enough, compound angles are written up inside the front and rear covers.

Those old practical math texts from the early 1960's have come in very handy at times during my professional career... I still have All my math and science/physics text books from grade 10 on. They are a great help for a quick refresher on sometimes nebulous memories.

Wolfgang