How about a poor man’s sine vise? I had an unused cheap bench vise, so I clamped a 123 block in my mill vise, and then clamped the bench vise onto that. I took a skim cut over the entire base of the bench vise to ensure all square.
Then made the round pieces...make sure the diameter is the same. Doesn’t matter at all what the diameter actually is. I milled a small flat on each for the base contact.
Then drilled and countersunk the mounting holes on the rods, at that center to center spacing of the vise rails.
I used the mill DRO to space the rods exactly 5” apart, and of course exactly parallel and square to the vise jaws ( still clamped onto the 123 block). Drill, tap and attach, done.
If you have not used a sine vise or sine bar before, it is a very clever application of trigonometry. If you want a particular and very precise angle, this is the tool. It works because of the exact and known 5” between rollers, in that the hypotenuse (long side) of the triangle is always that, 5”, no matter the angle the vise is at. If one roller is raised by say 1” exactly, then the angle of the vise is now the arcsin (angle whose sin is) 1”/5”, or arcsin (0.2) or 11 degrees, 32 minutes, 13 seconds.
The other way, more generally useful, is to figure the height needed for a given desired angle. Say you wanted a 15 degree angle. The sin of 15 degrees is 0.2588. Multiply by 5”, to get 1.2941. Now make a block 1.2941 high, stick under one rod, done.
Of course make the rod spacing whatever fits your vise, just make it exact and change 5” to your new number.
Keep the rods shorter than the width of the bench vise so you can clamp the whole assembly, vise plus height reference, sideways in your mill vise.
View attachment 272852View attachment 272853
