Free Plans: Ball Turning Tool Post for the 7x Mini-lathe

I want to tell you about Ralph Patterson’s free plans for a ball turning tool post that will fit a 7-by-whatever mini-lathe, and show you how he used it to fix a broken shower head.  I’ve also included a YouTube video that shows a similar tool post being used to make a ball end for a tool handle.  Near the end of the article you’ll find a link to download the plans for this tool, along with a link to where you can get Ralph’s other plans.  And if you read carefully you’ll also find a link that leads to plans for a ball turning tool that will fit a 9×20 lathe.

This ball turning tool post is part of set of more than 25 free plans Ralph made for some very useful mini-lathe accessories and modifications.  He also designed a boring bar holder, a quick change tool post, a leadscrew hand wheel, two versions of a tailstock lock, a carriage clamp based on Vicki Ford’s design, a die holder, a modification for slowing down the leadscrew feed rate, a file guide, a spindle indexer, a spindle crank, a height gage that uses a digital caliper, an adjustable tool rest for a bench grinder, and much more.  In addition to drawing nice plans, Ralph also did something I think is very smart.  He included photographs with most of them so that those like me, who don’t have a lot of experience reading prints, can easily see how the parts fit together and what the finished project will look like.  He also includes a parts and material list with his more complicated designs, which is something I wish more people did.

The original swivel neck was made from plastic and it broke

Ralph is an excellent CAD drafter, skilled machinist and a gifted designer who knows a lot about mini-lathes.  I’m very surprised that his designs and plans aren’t more widely known.  (I intend to do something about that if he doesn’t mind).

His ball turner is adapted from one that Steve Bedair made for his 9×20 lathe.  If you go to Steve’s web site you will not only find free plans for his design, but also photos showing how it is made and used, along with pictures of some of the things he has made with it.  Besides things like ball ends for handles, this kind of tool post can also make beads on a straight rod, and with a little modification it can also do coves.  They’ve also been used to make the lenses for optical center punches.

Ralph’s ball turner attaches to the top of the cross-slide with a couple of bolts and it doesn’t look like it will be hard to make.  The most critical dimension is the height of the cutting bit and Steve Bedair has a nice picture that will show you how he measured it.  The base has a recess that can probably be bored on a lathe if you have a 4-inch, 4-jaw chuck, otherwise you’ll need a mill and a boring head.

Ralph gives you a choice of four different tool bit holders that you can make.  Three of them use carbide inserts and they’ll require you to mill a number of angles, some rather precisely.  A forth version uses an HSS cutter made from a 3/16-inch drill bit.  Both it and the HSS cutter look like they should be fairly simple to make.

If you would like to get in touch with Ralph or thank him for the plans then the best way to do that is to join the excellent 7×12 minilathe discussion group.

Downloads

Download Ralph Patterson’s Ball Turning Tool Post from MachinistBlog.com (PDF)

You can find all of Ralph’s plans on ToolsandMods.com

Ralph said the carbide insert he normally uses couldn't reach in far enough to cut the ball at the theaded end. So he temporarily rigged up a larger cutter.

The finished repair

If you watch the end of the video you’ll see how the ball unscrews from the shaft it was made on.  You’ll also find some links to other things you can make with ball turning tool post.