“How do I set my lathe so that I can take very fine cuts?”

This question comes up occasionally on the forum and I’ve seen it addressed in books, but I’m not sure if I’ve ever seen a video of the process, so I decided to make one.

Setting up your lathe to take very fine cuts is a simple process. The quick version is this: By setting your compound at an angle of between 5° and 6° you’ll be able to use the dial on the compound as a very fine feed, advancing the tool in tenths for every thousandth you turn on the dial.

This is sometimes referred to as “Slewing the compound”. Although I’m not sure how technically accurate the term “to slew” is when talking about lathes. This could be slang for all I know and to make matters worse I’m not sure if it’s American slang or Brittish slang (as I have read dozens of books from both sides of the water), so be careful if you decide to break out the term in a shop full of machinists. You might get some funny looks.

I’ve seen this process described in multiple books, including the Machinist’s Bedside Reader by Guy Lautard, and in Lathework a Complete Course by Harold Hall. Both of which are excellent books. The first book by Lautard shows you the math behind the process I’ve outlined here and uses imperial (inch) measurements. The second book by Hall describes a slightly different method and is written for those who work in metric.

Anyway, if your compound is set at 5.75° and you advance the dial on your compound .001″, the tool bit advances toward the part .0001″ thus taking a very fine cut.

That’s as easy (or as complicated) as it gets. For most of you the image above will be enough of an explanation, but for those who require a little more reinforcement of the concept, here’s a “short” video of the process. I took 8 minutes to explain what should have taken 60 seconds. It seems I need to work on being succinct and not sounding deadpan. But hey, we all have our things to work on, right? Bueler … ?

Setting your compound to exactly 5.75° isn’t critical, somewhere between 5° and 6° will get you very close. You can also use this process for metric cuts.

Do you have a different method that you like to use? Please leave a comment on the forum. We’d like to hear it!

To leave a comment join the forum discussion on this post

Those of you who frequent the forum may have already seen this nifty little project, but I thought I’d share it with the rest of you.

Vernon Peterson came up with a great idea when he decided to build a base for his Magnetic Drill. Personally I’ve always wanted a Mag Drill, but I’ve never had a project that required one so it was a hard purchase to sneak past the wife. But with Vernon’s base I could totally justify adding a Mag Drill to my shop because it would double as a second drill press!

Here’s a video of Vernon’s creation:

Vernon originally posted this project to the forum here, but I liked the project so much I felt it needed to be featured on the home page.

I hope it inspires those of you who own a mag drill to pull it out, dust it off, and turn it into a more frequently used tool in your shop.

You can download plans to make your own below.

  Mag_Drill_Base_-_Drawings.pdf (981.4 KiB, 205 hits)
NOTE: You need to be a registered member (and logged in) to download this file. You can register or log in using the "Log In" section located in the upper left corner of the site (don't worry, it's free to register and your email address will be kept private). Please note, subscribing to the RSS feed is not the same as registering. Also, registering for the site will grant you forum access, allowing you to log into the forum using the same username and password you used to register for the site.

To leave a comment join the forum discussion on this post

Barry Young (author of the “Norman Newguy” column) walks us through the various stones he keeps in his tool box. His stones range from rare Hard Arkansas to cheap dollar store stones. Barry not only discusses different stones and their uses, he also explains how to flatten badly worn stones, how to tell natural stone from man-made, etc. He also gives us his recommendation for the first stone a hobby machinist should buy.

You’ll also get a little humor along the way – something that is usually missing from most machining-related videos. What stones do you have in your toolbox? Feel free to add your “two cents” by visiting the forum topic related to this video.

Enjoy!

To leave a comment join the forum discussion on this post