I have published an e book entitled “The Four Jaw Chuck – the hidden secret of precision lathe work.”
The three jaw chuck is a convenience tool. It is quick to use because all three jaws move in unison, so that round stock can be chucked quickly, more or less to centre. I say “more or less” because there is a built in ”inaccuracy” in three jaw chucks. It is not really inaccuracy, it is that, because of inevitable tolerances in the scroll, they seldom close dead to centre, usually one or two thousandths out ( 25 – 50 microns). Also, the error is different at different diameters, and often, if a piece of work is removed from the chuck and later returned, it will not be exactly on centre. Three jaw chucks are thus quick and convenient for repetitive round work at one setting, but not for much else.
The four jaw chuck is much more accurate and versatile. That’s why most books recommend that, if only one chuck is to be purchased, it should be a four jaw. Most mention that it can hold rectangular work, and can do eccentric turning work, but the full extent of its versatility is seldom explained.
On its own, its only advantage is that it can hold rectanguler work. But if the work can be set in the chuck to exact measurements, it opens up a whole world of versatility and precision that can’t otherwise be imagined. That measurement is provided by the dial test indicator. The four jaw chuck and DTI should therefore be considered a two-piece combination tool, each as important as the other.
It is the most important lathe accessory, more versatile and useful than all others combined. It is indispensable for serious work, and makes possible a variety and complexity of work, and a degree of precision that cannot be achieved otherwise.
My book is not big at 52 pages, but with 13500 words and 77 illustrations, it explains in detail the advantages of the four jaw, with several working examples. It is not armchair theory – the four jaw chuck was the vital tool for the many parts, jigs and tools I made in my gunsmithing work.
It is a E book, available direct from me, email@example.com, and will be sent by e mail. I will gladly send sample pages to anyone who wants to see the quality of the content before buying.
Payment will be credit card via www.gunownerssa.org. Price is $20. Payment instructions will be sent with the book.