Thread: Using a dial indicator to set an angle?

Using a dial indicator to set an angle.

If one is using a metric indicator with graduations of 0.01mm and therefore 100 graduations per circumference, which means each 1 graduation is approximately 0.278 degrees (100/360). So to set say a tool post at a 5 degree angle, the indicator would have to move about 18 increments or 18 X 0.01mm (0.18mm).

Is this the approach a machinists would use setting angle with an indicator or is the method wrong?

Hope the question makes sense.

Thanks,
Tom

I'm not quite sure I follow you there Tom

I think your missing a key element of your equation and that would be the length of the part you are measuring.
From what I can gather you are effectively measuring a triangle, the indicator would give you the short side length, the length measured along your reference rod would be another important length

I have never done it before so not sure

If you have a reference piece with the correct angle you could look at mounting it in the chuck and using it to set your angle, I have done this before to make MT3 chucks for the tail stock

One would usually use a sine bar set to the correct angle and then indicated parallel with one of the machines axis.

Hey Topari,

I'd do the calculation the other way around.

ie if 100 divisions = 360 degrees

now divide both sides by 100

1 division = 3.6 degrees .......... this means that your dial has rotated 3.6 degrees every time one of the dial marks passes the index mark and your cutting tool has moved 0.01mm either towards or away from the dial knob.

If you could post a sketch or photo of what you are doing and give an indication of what sort of accuracy is required then you may get responses more relevant to what you want to achieve.

Some basic reading on trigonometry might be helpful ie things like this

https://www.mathsisfun.com/algebra/trigonometry.html

On metal lathes there is often a 360 degree protractor engraved on the cross slide around base of the compound slide that would allow rough as guts setting of a 5 degree angle see attached photo.


Bill

Originally Posted by Ueee

One would usually use a sine bar set to the correct angle and then indicated parallel with one of the machines axis.

Yea, I put a parallel on the cross slide, stick it down with magnets, set it running parallel with the ways.

Put a sine bar on that set to the angle and then set the top slide parallel with the sine bar.

Thanks for the replies. Opps yes 360/100. I will put sketch together. The general idea is to avoid trig and only use the indicator to set angles.

Originally Posted by topari

Thanks for the replies. Opps yes 360/100. I will put sketch together. The general idea is to avoid trig and only use the indicator to set angles.

Uh.. no, you seem to be suggesting using the dial itself as a protractor, that's not how to set up angles.... or how you use a dial gauge.. see the posts by RC and Ueee for how to use a sine bar.

You can also get digital angle gauges, but the sine bar method is more accurate.

Ray