Small angle/sine plate

[olderdan]

I needed a small adjustable angle plate to fit on my lathe crosslide and vertical slide for a project that requires accurate angles. This is only 4 inches square and was made from the last pieces of steel plate from my scrap box, hence the extra filled holes which I can live with. There is some pitting in the working faces but they have been scraped flat to a surface plate.
Although I have a Moore & Wright vernier protractor which gives 5 mins of angle, just out of curiosity I thought I would provide a sine function to the plates by virtue of a dowel exactly 3.25 inches from the pivot point and of the same diameter which fortunately has turned out to be accurate from my checks with the protractor and a 30 deg angle gauge. This could be a way to make a sine table for those without access to a surface grinder.
As it is a small plate I opted for M5 clamp screws instead of my usual M6 and made some dedicated clamps. It pivots on hollow hardened pins and being a small surface I could not afford the support plates to be above the surface, so curved arms made from brass sufficed giving 0 to 45 deg. There is not enough room for a fence to be added so 2 location pins can be used to support a parallel when needed. This plate can also be used on the lathe faceplate for indexed milling using my live toolpost spindle, its not pretty but it will do the work I need it for.
In this size it is more suited to a model engineer but could be scaled up if one has the material available.


I even found an empty router bit box to keep it all in.