South Bend Swarf

Later G.H.T. suggested using a slightly finer angle ( 25 instead of 27.5 for W.W.). That has the advantage of giving a fine skimming cut to the trailing flank and a better finish.

Russell.

I remember an article in aeromodeller, many years ago. It described the evolution of glider design through about 20 stages, each step an improvement, until it got right back to the first design.

Likewise, I imagine you can keep 'improving' the angle until you end up plunging straight in again.

I prefer Tubal Cain's technique, plunge in but move sideways a little with each cut. Much simpler to set up and has the sme effect as teh GHT approach in the final analysis.

Neil

The actual angle given in the SB book is 29*, I used that method at first, but now I just go straight in.

Ian S C

When we were apprentices the South Bend book was referred to as "How to Ruin a Lathe" and there were a couple who seemed to take it to heart.

On setting the top-slide to 30-degrees for screwcutting UNF etc, you get the same effect by leaving the top-slide in the "normal" position parallel to the lathe bed. Then for every thou you wind the cross slide in, advance the top slide by half a thou. So if taking a 5 thou cut, advance the top-slide 2.5 thou.

For BSW etc, use a 55 degree tool and follow the above procedure but deduct a gnat's whisker of advance from the topslide.