SINE PLATES (a question or two)

[ozzie34231]

I'm a hobby machinist and though I'm old, I haven't been at it long.
I recently acquired a couple sine plates, the price was right.
I know how to set an angle using gauge blocks.
Although the plates and their hinges are very heavy, the legs that hold the angle seem very light. I had been thinking that I could use them for milling but am wondering if that is their intended use? Or are they only for grinding?
Ozzie

[Glacern]

Are you referring to a sine vise as opposed to a sine bar? If you're doing some light milling or drilling, they should work fine.

For heavier machining, you can either use a sine bar to set the angle of the workpiece before clamping in a Kurt style vise (you may need to make some taller jaws), or you can get a hold of a tilting table as shown below.

[Konrad]

Gee..it's been a long time since I used something this heavy, it was in Switzerland in my apprentice time, [grinding room]. If it's a heavy beast like you mentioned, it might be OK for light machining?
If I machine something on a angle now, I rig up a bar, solid on the mill, into the vice, I then can clamp the piece good. Most sign bars I think cant' be locked, for grinding it's fine if you're going the right way, when used for milling you have to be extra careful.

Konrad

[ParkerMillguy]

As long as you have a support for your angle, you should be fine. I used to bolt a HAAS 5C indexer to a 10" Sine Plate and clamp it in a Kurt Vice. I would machine a support block the length of my Gauge Block Dimension and make some clamps out of flat stock (hole in one end and slot in the other) to bolt the Sine plate in place.
Just keep your toolpath in mind. It is pretty rare that you would have severe torque pulling away from your support block. Most of the stress is into the hinge. The only time I had a problem was when I tried to rapid into the side of my indexer....pulled the whole assembly out of the vice...Angle was still set on the plate