Milling vice angle using DRO ?

I am making an indexable dovetail cutter similar to Randy Richards **LINK**

I want to set my vice up at 30 degrees to the x axis to mill the seat for the insert. I don't have a sine bar or gauge blocks. I have this DRO **LINK**

I have read the manual several times and it doesn't seem to have an angle setting function. Is there a way to do it using the DRO ?.

Should be able to use the linear pattern (bottom left of the 9 button group) to set two "holes" on a 30deg line, put your dti into the spindle and adjust vice until it reads zero on two "holes" placed a couple of inches apart.

Could also use trig to work out the X&Y for a given length of line at 30deg.

Edited By JasonB on 15/01/2017 16:34:33

You could use a draughtsman's 30° 60° 90° set-square ... probably quicker.

MichaelG.

Only if you happen to have one

As Michael says a set-square is quick and usually accurate enough, easy if you have a dovetail column mill to hold one side agaist that and the othe against the fixed vice jaw or a flat bar held in the vice

I see there is also an incline function, this can be used in a similar way as the linear pattern, just enter a large value for the step say 2" or 50mm and angle of 30deg.

Another option if you have a rotary table is to mount the vice onto that and clock it in true then rotate table 30deg.

Here is an excellent way for establishing precise angles on the mill.

It is easy to check the angle, if not set it. Reading x and y at two points will give you the tangent of the angles by dividing one into the other.

.

... or, if you can contrive to make them represent Sin instead of Tan, it's neater:

Sin 30° = 0.5

MichaelG.

To follow MichaelG's observation that sin 30 is 0.5 the easiest way to apply this is to measure the length of your vice jaws and offset one end half this length off the other along the X axis. For example if you have 4" vice jaws the Y axis value of one end should be 2" different from the other end.

Martin

Rough and ready. Far better to grip a couple of drill bit shanks (or similar) and measure distance changes from those.

I would not be surprised if there were a function, amongst the many in those instructions, which would calculate the angle on demand!