Harold Hall

Workshop Projects


The Lathe

Having stated that this is aimed at the lathe only workshop, by which I mean no milling machine, I do anticipate there will be a small drilling machine available. Obviously, there is a minimum size lathe that can accommodate the project but with the Hobbymat I am using, having a centre height of just 65mm, it should be a possibility for all but the smallest lathes. Only the Box Bed (29) and the Soleplate (11) of the 10H were on the borderline.


Of course, the methods suggested will be equally at home on larger machines but working with a small lathe does place extra complications on some tasks so the methods used will be taking account of this fact. Typically, the use of a few very simple fixtures for mounting some of the parts onto the small size faceplate that the smaller lathe has. I do though consider that in most cases the methods will be the best approach even on a larger lathe.


Manufacturing Basics.

As this is primarily aimed at those with limited experience I have gone into rather more detail than would normally be the case in the Model Engineer magazine. More experienced workshop owners will I think find some of the methods used of interest but can bypass the basics should they wish.


The Drawings

The first task, and a vitally important one, is to study the drawings carefully, both the exploded assembly and  individual part drawings, ensuring that they are fully understood. This is  important as whilst the drawings are very clearly drawn some aspects for a particular part have to be established by reference to another. To help understand the content of these pages take a print of the 10V exploded assembly drawing


The kit comes complete with all the materials including hardware items, but it is likely that there will be thread sizes for which you do not have the required taps and or dies so make a list of the tools required and take this to the workshop and check if you need to purchase any. This includes checking that you have the tapping drill sizes. There are three sizes 8BA (1.9mm) 7BA (2.1mm) and 5BA (2.7mm), the sizes in brackets being the tapping drill sizes that I used. If you want  guidance on the drill sizes to use in other cases this can be found elsewhere  on my website.

Also needed will be some spanners, flat, and ideally box. These are for the 7BA screw heads and nuts which are nominally 0.172” AF.


Lathe tools

In the case of lathe tools some carbide tipped tools are to be preferred in view of there being iron castings to machine. The newcomer may be unaware that cast iron can have hard spots that may play havoc with your HSS cutters. Even carbide tipped tools may struggle unless the machining can get below the hard area which, if present, is almost always on the surface.


With the part projecting appreciably from the faceplate in some cases only very light cuts are acceptable, and as a result, in just two cases, I found even the carbide tipped tool could not remove a hard spot present. This may not be immediately apparent whilst machining is taking place but can very easily be spotted afterwards by the offending area having taken on a glazed look and being above the level of the surrounding surface due to the tool springing.


If this happens you will need to remove the part and grind away the effected area. However, do take care not to remove too much as you may end up below the level that the part has to be machined to. On the other hand, you will not want to remove a very small amount only to find that there is still a problem when returned to the lathe. The easy way to avoid this is to test the ground area using a scriber, if the scriber skids over the surface more needs removing.


As HSS cutters will be sharpened in the workshop I will not comment on them here other than to say that their general shape should follow those of the carbide tipped tools that I am suggesting. With regard to these the following would be ideal. If you are apprehensive about forming and sharpening HSS lathe tools, my book, “Tool and Cutter Sharpening”, number 38 from the Workshop Practice Series may be of help


ISO5 Right Hand, for machining right facing surfaces.

ISO5 Left Hand, for machining left facing surfaces.   

ISO3 Outside diameter turning.

ISO8 Through hole boring tool.


If needed, details of these tool shapes can be found in my book “Metalworkers Data Book” number 42 in the Workshop Practice Series.





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