1.) Why build a lathe? There are several "mini" lathes and mills on the market which cost around $350-500. The lathes are 7" X 10" or 7" X 12". I want both a lathe and a mill. The problem is these machines generally do not come with anything, not even a tool bit. To buy a lathe and mill would cost somewhere around $800-900. Then in order to truly make it usable you need to spend another $800.00 or so to fully accessorize them thus you end up spending 1600 or 2000. By building it yourself you make them all, and anything else you can dream up. Also you get to fiddle and tinker around, something I love to do, Make things. With a foundry, lathe, and mill, you are limited only by your imagination........ 2.) Why modify Gingery's design, especially the lathe's bed? Several reasons. First After researching every site I could find about the Gingery lathe, one problem stood out, the 1/4" bed way had a tendancy to flex, so too did the lead screw. Second Gingery himself in other books in the series, mention that the lathes swing of 7" is a little to small. Several castings for other machines required rounding the corners so they could be turned without hitting the bed. And finally I want something a little longer than 12" as the original design is. To correct both these problems a heavier longer bed and taller headstock is required. Several problems, a longer bed requires a longer casting, maybe to long. a bigger (taller) headstock might be to high for the width. So to make things bigger heavier, and stronger, a 4" wide bed way and bed made of steel would be a good Idea. 3.) Problem with carriage box slide (the part that slides on the bed way). After much fiddling around I got the tolerances down to less than a thousandth of an inch. The way was true and the carriage moved smoothly down the way. the problem was starting the carriage in motion. It stuck. Even loosening the gib screw didn't help, it made it worse. The problem is for some reason I when I scaled up the way to 4" wide by 1/2" thick, I only made the original 3" wide carriage 1/2" wider. This made the box slide 4" by 3-1/2". This caused the carriage to be narrower than its span. I fully understand the problem mechanically in my head but don't really know how to explain it. The carriage twists slightly when you start it, caused by the carriage being to narrow, when I modified the pattern to 4" wide, making the box slide 4" x 4" it solved the problem. I wish I had go a little wider. But it is good enough. |
