Sine Bar Holder for setting Compound Angle

hvontres

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I needed to cut a couple of precision tapers for another project, so I wanted to use a sine bar to be able to accurately set the angles.




This was just a piece of 2" aluminum flat bar I had in my junk pile. I milled a 5/8 slot down the center and then beveled the end to make it look nicer and to prevent the corners from interfering with the inidicator.
To use it, I clamp the bar under my BXA qctp and put the gage block stack between the compound and the bar. After that, just sweep and bump until the indicator stops moving (or until you think you are close enough and call it a day ) Using a 5" sinebar, a .001" difference over the length of the bar equals 0.0115 degrees or 0.6875 minutes of arc.
 
Hi Hvontres, I like your idea of using a sine bar to set the compound to a desired angle. It's an excellent idea. I have been trying to find a way of doing this. At the moment I use a combination square which is very "hit and miss" to get a reasonable accurate angle.
 
Thanks. I actually got the Idea from Tom Lipton (oxtool) over at youtube. His lathe has a nice flat cross slide and compound and he wound up using one of his hyper-accurate angle blocks to set up a taper in this video:
 
I couldnt get the pics to load. It said error. I have seen the tom lipton video on setting up a taper, great video
 
I had seen Ox Tool's video as well and was working on a similar approach. For a small lathe, a 3" sine bar works a little better. I hadn't worked out how to conveniently fix the sine bar in place and it looks like you have come up with a good solution.

One thing to check: The side of the compound on my Grizzly G0602 is not parallel to the compound ways. It has a .001"/'" taper. Not a problem as long as you know how much to correct for when you set your angle but definitely a consideration if you are trying to set precise taper angles.

Thanks for sharing.
 
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