Small diameter turning tool with 360 degree travelling steady

[thehomeengineer]

Hi All
I made this tool several years ago for making BA threaded stock diameters for my modelling. It doesn't get used that often but I had to make some M1.4 x 0.3mm (0.055" diameter) aluminium studs for a job at work from 2.4mm TIG welding rod. So I thought I would share the tool with the community on HMT.

The tool fits a standard tool-post holder and has a micrometer barrel to finely adjust the HSS tool bit to the desired diameter. Under the tool bit is a grub screw to adjust the centre height of the tool relevant to the brass button. This is important as the brass button needs to be on centre and true so the HSS can be adjusted to lathe centre height. The brass button supports the shaft diameter while the lathe carriage travels along the bed. This brass button gives 360 degree support on the stock material outer diameter allowing the tool to maintain a constant turned diameter. The cutting tool is set to cut the required diameter in one pass to size.

There are commercial available tools which are very expensive without the fine adjustment of the micrometer barrel or the traditional roller box as used on capstan lathes.


Main body in standard tool holder


Selection of buttons with different hole diameters. The 5 buttons to the left are spares which can be drilled to suit the external stock diameter of the bar to be cut. The buttons can be made from other materials to suit the stock being cut.


Back view of tool without button in place


£/32" button in place ready to be set to cut the TIG welding rod


Short test cut to correctly adjust/set HSS tool bit to required finished diameter.


Cutting the Tig welding rod to 1.4mm diameter (0.055")


Checking finished diameter for size.

Thank you for taking the time to view and I hope you have found this of interest.

The Home Engineer