In the following two videos Barry Young walks you through the process of sharpening your twist drills by hand. There are a few other videos on the web showing this process, but none (at least none that I’ve found) show multiple angles and describe the process in as much detail as these videos do.

This is our first major video tutorial project with multiple camera views. We shot it in HD (1080p) with High Def cameras and then uploaded it to YouTube in HD (720p) which is as high a quality as YouTube will allow. But even at 720p the video is better than DVD quality.

Please leave your comments via the forum and let us know what you think. Our next videos will be on grinding your own HSS tooling (RH Tool, LH Tool, and Threading Tool), and then we plan to do a multi-cam video on single point threading.

However, your feedback is critical. We want to know your thoughts, good or bad. It would also be helpful to know if there are any other topics that you’d like to see made into videos.

Thanks!

Tyler and Barry

Video #1 of 2: Sharpening Twist Drills By Hand – Introduction

Video #2 of 2: Sharpening Twist Drills By Hand – Sharpening

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by MadReptillian

This table showing lathe cutting speeds in feet per minute. I use this table to calculate the speed of my lathe and my drills. Yes I am aware they are not as accurate when using them for drills, however they seem to work for me. The proper formula for calculating is as follows:

CS x 12 =   RPM

π x D

CS being ‘Cutting Speed’ which is locate in the table above and ‘D’ meaning diameter of stock

However you can shorten this down to make it easier, π (Pi) has a value of approximately 3.14 and divides into 12 just under 4 times.

So I use this shortened formula for working out my lathe speed.

CS x 4 =  RPM

D

Let say I have 3 inch ally stock and I’m using toolsteel to make the cut.  For roughing the formula would be as follows:

1000 x 4

3.000               =        1333.33 RPM

So 1300 RPM is the rough speed I should be cutting with 3 inch aluminium stock in a lathe.

Now lets say I now have 1.505″ stainless steel and I want to do my finishing cut with toolsteel. The math is as follows:

46 x 4

1.505                   =     122.25 RPM

Easy isn’t it? If your using metric and/or metres a minute for your cutting speed , you might want to convert the numbers above and create your own table.

Hope this helps,

‘MadRep’
About the author

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“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!

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