wp55b0dd48.png
wpd530b04e.png
wp91074f43.jpg
wpa4923fff.jpg
wp0fe7637b.jpg
wp54b53ef2.jpg

Harold Hall

Workshop Processes

wpff6a4396.png
wpff6a4396.png
wpff6a4396.png

Photograph 21 shows a typical task for the machine in which the bearing cap, having already been completed is being used to position the holes in the lower portion of the main bearings. This was followed by drilling the hole (prior to reaming) for the flywheel spindle, Photograph 22, and was the task where the problem surfaced. When using a standard drill there is a tendency for this is to be drawn in to the gun metal casting, because of this the chuck was pulled from the taper on the machine spindle. Fortunately, I had, as one should for a task such as this, clamped the vice to the machine table as can be seen in the photograph.

 

I should have removed the helix from the drill's cutting edge as is the norm for drilling brass and similar materials but as I normally work with mild steel was reluctant to modify my drill as I would then have to remove a fair amount of the drill to get back to a cutting edge suitable for my normal uses. With a lot of care and quit a few failures I eventually managed to complete the two holes, one should really use the appropriate drill. Even so, I had no problem drilling the large number of smaller holes in this material using standard drills.

 

Cylinder assembly

Finally, in terms of machining activity, I will comment on the cylinder assembly showing a few operations involved with this including two that show that the milling head set-up is more than a match for even quite complex tasks.

 

Whilst the cylinder block is quite large and certainly the most complex item that the engine requires, most of the activity is of a simple nature, as a result, they are tasks that I will not expand on.

 

Having accurately bored the cylinder block to the required diameter using the 1" diameter of the locator jig to act as a gauge, the jig was again used to position the drilling jig for drilling the six holes on a PCD as seen in Photograph 23. Using the tapped hole on the rear end of the jig, a bar was clamped onto the other side of the cylinder that was then held in a vice as the photograph shows. The process was repeated for drilling the holes on the second end

 

As the cylinder end flanges have a 1" spigot for locating them onto the end of the cylinder this could also be located in the drilling jig allowing the jig again to be used for placing the holes on a PCD, Photograph 24. The four sets of six holes were therefore made with ease, but far more important, with a degree of precision that would not be possible by any other method

Parts for horizontal steam engine "Tina"
Parts for horizontal steam engine "Tina"
Parts for horizontal steam engine "Tina"
wpe7285997.png

21

wpe7285997.png

22

wp5edc7c73.png

23

Parts for horizontal steam engine "Tina"
wp5edc7c73.png

24