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Harold Hall

Workshop Processes

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Photograph 7 shows the mounting method clearly with the vice at right angles to the length of the cross slide table. From this it can be seen that the vice can be moved into any position whilst still leaving the fixings in the same place. In this photograph one of the small castings is having its edges machined, taking a cut 0.050" wide by 0.2" deep using the side of the end mill, a cut that was well within the head's capability, machining gun metal in this case. Note also that it is being machined in the direction that the head is less rigid, more about that shortly. The upper surface had also been machined with the same set up.

 

If you purchase a toolmaker's vice it will not be supplied with the required table clamps so you will have to make these yourself. These are simple items but do attempt to chose dimensions that will enable the vice to be mounted both in line and at right angles with the cross slide without having to make a second set. Maybe including slots rather than a single hole for the fixing. Photograph 8 shows the vice mounted in line with the cross slide. In this the ends of the mild steel connecting rod are being reduced from 1/2" to 1/4" thick.

 

The engine has few steel parts that require milling and this item proved the head's ability to cope with machining this material. As I explained in the head's construction pages, it is more rigid when milling towards or away from the head using the saddle than across the head using the cross slide. I think most readers will understand the mechanics of why this is. For this operation I used a 10 mm cutter running at about 400 rpm and taking a cut of 0.060" deep and 0.120" wide with no noticeable stress when traversing the saddle. Incidentally, the saddle was fed under power at a rate of 0.002", when machining gun metal this was increased to 0.0029" and I am sure these values could have been increased without any problem

 

The limited throat in this direction may cause a problem in some cases, but using the cross slide for larger components would still be possible, it only being necessary to be a little more patient by taking lighter cuts.

 

Photograph 9 shows one of the main bearings having its side machined and is another typical example of the machining tasks presented by this engine.

 

The vice in the above photographs is quite large and a smaller one may also be useful especially if required to be fitted to another accessory, the rotary table for example. In this case a smaller vice may be required not only to fit the table but also the available headroom may not be sufficient to accept a larger vice. The thickness of the eccentric outer bearing is seen being machined to size in Photograph 10 using a smaller vice.

 Milling Head, Lathe mounted, using. Parts for horizontal steam engine "Tina"
 Milling Head, Lathe mounted, using. Parts for horizontal steam engine "Tina"
 Milling Head, Lathe mounted, using. Parts for horizontal steam engine "Tina"
 Milling Head, Lathe mounted, using. Parts for horizontal steam engine "Tina"
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 7

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 8

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10

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 9