Harold Hall

Workshop Projects


Body S2 This is the only other item that needs special attention, Cut a piece of steel 92 mm long mount in the four jaw chuck and set to run true. Drill and tap M8, remove reverse and centre drill the second end. Fit a hex head screw gripping this in the three jaw chuck and supporting the other end with the tailstock centre. Turn the outer diameter to 44 mm.


Once more, accurately mount in the four jaw chuck and support the outer end with a fixed steady. Turn the internal diameters and thread in the first end, turn end on end and repeat for the second end and through bore 26 mm diameter.  The book mentioned earlier details this sequence in more detail.


The remaining items for this are S3 to S7 and S9 and S10, all being relatively simple with only the collet (S7) worthy of some comment.


Place a piece of 16 mm steel in the three jaw and with about 30 mm projecting. Face the end and turn the 6 mm bore by 17 mm deep. As concentricity is vital bore this hole rather than using a 6 mm drill. Next turn the taper, ideally using the top slide still set at 12 ° from making the collet chuck body (S8).  Drill and tap the M4 hole and part off. Make the four slits in the collet using a similar system to that detail below for the larger collets.


Large Collet Chuck Assembly (AS 5)

Adapter L1 With a piece of 25 mm in the three jaw chuck, face end and drill through 10 mm diameter. To minimise the amount of machining required when eventually mounted on the threaded stub mandrel later, pre bore the 17 mm bore at 16 mm, also a little short on depth, say 27 mm. Similarly machine the 22 mm outer diameter oversize at 23 mm.


Remove from the chuck, turn end on end and replace holding it on the 23 mm diameter just turned. Bore through at 10.5 mm a close sliding fit on the end of the spindle. Similarly, bore for the 1/2" x 20 TPI thread, also the 1/2" x 2 mm deep bore, Photograph 21. This bore replicates the locating bore in the drill chuck that can also be fitted. Make the 20 TPI thread.


Turn the 22 mm diameter and skim the 25 mm outer diameter to ensure that it is running true. Do take the absolute minimum off else it will reduce the thread outer diameter beyond what is acceptable. If your three jaw is not reasonably accurate then use the four jaw so that the 25 mm diameter can be set to run true. Make the 25 x 1 mm thread, Photograph 22.

Screw Cutting on the lathe