Harold Hall

Workshop Projects


Body. (5)

First, relating to a Myford lathe only, I will comment on the diameter shown as “X” on the drawing. This in theory needs to be a close fit within the bore through the lathe's mandrel but I found on my lathe that the bore reduced over a short distance being larger at the entrance and further into the bore passed the reduced diameter. The body could be pushed passed this as the slits would allow it to reduce to enable this but this would then necessitate the Stop Bar Holder being pushed in from the chuck end, not really practical.  There was therefore no option other than to make the end a diameter that would go through the reduced portion. I have recollections of having read that the split ring that secures the head adjustment can result in the bore reducing.  Whilst the outer end was made to a reduced diameter the short length (4mm) next to 20mm diameter was made to fit the outer end of the bore.


Cut a piece of 20mm diameter just over 85mm in length and place in the chuck, face end and turn the 16mm diameter by 15mm long section. Remove and return to the chuck this time holding it on the diameter just turned leaving a gap of around 1mm between the end of the jaws and the 20mm diameter, centre drill the end. Support with the tailstock centre and turn diameter “X” over the 40mm length, smaller at the end if required, see above. Reduce the central part of this to 12mm diameter as per the drawing.


Now skim the 20mm diameter just sufficient to ensure that it is concentric with the other diameters turned and support this using the fixed steady. Remove the tailstock centre and drill though about 9mm diameter followed by producing the tapered mouth, Photograph 3, you can now return the top slide to its normal position.


With the deepest available boring tool produce the 10mm diameter, hopefully at least 50mm deep, at this point then there are now two options. The 10mm diameter can be extended by drilling through with a 10mm drill, as I did, with the bored hole as guidance or reversing in the chuck and opening up the bore from the other end, a little over 10mm in diameter as concentric bores will of course not be possible.


As stated above I went down the 10mm drill route but this drilled marginally under size and the Stop Bar Holder would not pass through. I then took a length of wooden dowel  sawed down this a short way and inserted a length of emery paper wrapping this around it. This makeshift lap was then placed into the bore with the other end in the drill chuck and the lathe started up and run for about ten seconds moving the lap backward and forwards.  After doing this a couple of times the Stop Bar Holder entered with ease.

Using a Fixed Steady