by Glenn W.

Material: Steel

Units: (in)

This Craftsman-style circle cutter is designed to be used in a standard Drill Press or Vertical Milling Machine only.

It is designed for cutting 1″ to 6″ diameter holes in sheet metal, brass, copper, plastic, wood, or other composite materials. You can also cut 1″ to 6″ diameter circular disks or wheels. This tool is only recommended for material thicknesses of 1/8″ or less.

Some examples of practical uses for this tool are:

• Cutting holes in automotive dash panels to fit around gauges.
• Cutting holes in sheet metal where hoses will pass through
• Cutting wheels for toys.
• Cutting round discs in aluminum for making fly-fishing reels.
• Practical uses are endless …

This tool is fully adjustable for cutting diameters from as small as approximately 1″ to as large as approximately 6″.

By simply grinding the proper angles and reliefs on standard 1/4″ HSS tool bits you can cut perfect holes or round discs, depending on the orientation of the tool bit cutting edge.

The attached set of drawings and assembly plans are based on a Sears Craftsman tool, model #25293 (pictured above). However, the design, dimensions, and components have been modified for improved performance and safety.

Proper cutting speeds, cutter relief angles, etc. will need to be established and adjusted according to the job at hand and the material being cut.

Important Notes:

• Speed of drill press or milling machine should NOT exceed 500 RPM when using this cutter.
• Always wear safety glasses when using this tool.
• Use of cutting oil or coolant will greatly improve cutter performance when cutting metals.
• Not recommended for materials thicker than 1/8″.

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A few months ago I contacted Gary Sneesby from Eccentric Engineering to see if I could write a review of their Diamond Tool Holder. I had heard great things about tangential tool holders, but I was still a bit skeptical and didn’t know quite what to expect.

The tool took about 10 days to arrive, which I thought was fast considering it came all the way from Australia to Seattle. You can also buy the Diamond tool holder from a local UK or US distributor (see the Eccentric Engineering website for details). Either way the tool is about the same price, but you might get it quicker and pay a bit less for shipping if you order from your local distributer.

The tool comes with a the tool holder, an allen key, a quality HSS tool bit (8% Cobalt), the grinding jig, and full color instructions with pictures to hang by your grinder.

So, how well does it work? Exceptionally well!

Here’s why I think this tool is great for the beginner:

1. It’s very easy to grind using the included jig.
2. It produces an exceptional finish. I consistently get as good (or better) a finish using the diamond tool holder than I get using a properly ground HSS tool bit.
3. It’s very rigid allowing for deeper cuts. I can take cuts of about .015-.025 deep on my small lathe using a conventional HSS tool bit, but I can remove nearly twice as much with the diamond tool holder (.030 to .050) depending on the material I’m cutting – without chatter!
4. The grinding jig can be used to easily grind 55 and 60 degree threading tools for use with the diamond tool holder.

Eccentric Engineering has a promotional video that they put together that shows all the features of their diamond tool holder. The video seems a little dated, but it’s well done and worth watching.

They show the tool being used on a larger lathe where they take very deep cuts (as much as .100 at a time). I wasn’t able to achieve cuts that aggressive, but I have a much smaller, less rigid lathe in my home shop than what they used in their video. And since many of you have a lathe similar in size to my 10×22, I thought I’d make my own video showing the results I was able to achieve, and therefor the results you should be able to expect with a similar sized lathe.

My video is a bit long (sorry) so if you get impatient just make sure you watch the last 2 or 3 minutes where I show how well the tool cuts cast iron.

My overall impression is a positive one. The tool is well made and of excellent quality. I really do get exceptional results with it. As to the grinding jig, my first impression was that it was a bit wonky with its use of a cap screw to adjust the angle for grinding a threading tool. But after using it I realized that it’s not wonky at all. But rather a simple and elegant solution.

Using the grinding jig is as advertised – extremely simple to do. And the bit seems to hold an edge longer than my hand ground HSS tool bits do. In fact, I’ve been using the original bit for a few months now on Steel, aluminum, brass, bronze, and cast iron and I haven’t needed to re-grind it yet (although I have touched it up occasionally with a diamond hone). Initially I was concerned that the one-size-fits-all approach with the 12 degree rake and relief angles would be very effective on some meals, but less effective on others. After all, a HSS tool bit properly ground for steel has slightly different rake and relief angles than one ground for aluminum or brass. Right? But it turns out that 12 degrees is a very good compromise across all the metals I’ve tried so far.

I don’t have anything negative to say about the diamond tool holder from Eccentric Engineering. It performs as advertised and has exceeded my expectations. In fact, I am planning on purchasing a second one so that I’ll have one tool holder for a square bit and one for a round bit. I tend to switch back and fourth between a round and square bit a lot depending on the job, so it would be nice to have a dedicated quick change tool holder for each pre-set to centerline.

As for my two friends with over 50 years of machining experience? They were impressed too. They haven’t bought their own yet, but then again they get a kick out of grinding their own HSS tool bits and drills. They were convinced that a properly ground HSS bit would give better results than the diamond tool holder.

So I challenged one of them to grind a fresh HSS bit for steel and put their grinding skills to the test. The result? The finish was comparable but the chips coming off of the diamond tool holder were smaller and took more of the heat with them (turning a darker blue) than the chips from the hand ground HSS bit. The lathe (a restored Atlas) also seemed to labor less using the diamond tool holder, and deeper cuts were possible without chatter. I should give credit here to my friend Barry, his HSS bit did produce a similar finish. But he still spent a few minutes grinding it to shape. At least twice as long as it takes to grind one using the diamond tool holder jig.

So if you’re one of those guys that thinks he can grind a drill bit just as good by hand as someone using a professional drill sharpening machine (and I’m not talking Drill Doctor results, I’m talking DAREx) than stick with grinding your HSS tool bits by hand. But for everyone else, I’d highly recommend the diamond tool holder from Eccentric Engineering! You won’t regret it.

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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.

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By now you’ve all probably come across Dave Gingery’s book on building a metalworking lathe from scratch. Michele from Belgium seems to have done just that, but he didn’t use Gingery’s plans. He made his own!

Michele states that the dimensions for his lathe are a peak of 130mm (which I assume means a swing of 260mm?) with an overall bed length of 1000mm. That roughly translates to a 10″ x 40″ lathe.

But this isn’t the only thing Michele has build from scratch. He also constructed a clockmaker’s gear cutter, the plans for which I posted here last year.

Michele provides plenty of pictures and details for this lathe on his website, which can be found here (English translation) or here (original French). You can also find other versions of the plans for the lathe (DXF, DWG, etc) on Michele’s site, as well as other projects that you might be interested in.

Oh, and this probably goes without saying, but his plans are in French. That shouldn’t pose much of a problem, but I thought I’d mention it.

Thanks for sharing your plans Michele! I’m sorry it has taken me so long to post them.

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The aluminum body of the die holder holds the die perpendicular to the axis of the spindle rotation and rotates freely around a steel shaft firmly inserted into the tailstock. This ensures that your part is threaded perfectly.

Here’s a picture of the Die Holder with a 1.5″ die inserted:

Here’s a picture of the Die Holder flipped 180 degrees with a 1″ die inserted:

I got the idea from Steve Bedair’s Die Holder and I adapted it to look similar to a smaller die holder sold here by LittleMachineShop.com.

I created the plans myself using Autodesk Inventor. It was my first attempt using the software, and my first time drawing up plans for the machine trade – so if there are any errors please let me know and I’ll do my best to fix them.

Here are the plans (in PDF format):

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But as you can see from the pictures, it works just as well for smaller items.

If you decide to make your own please take a few pictures of the process and post them to the forum!

Note: There is a file embedded within this post, please visit this post to download the file.

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Mike also shared a set of plans for a nifty machinists scribe that nests inside it’s own handle when not in use.

Thanks for sharing your plans with us Mike!

If you’re an instructor like Mike and you’d like to share your student plans with the site, please feel free to submit them using the “Submit Your Plans” tab at the top of the page. I’ll provide a link (and thus free publicity) back to your school or website. Every submission helps this site grow. Thank you for your support!

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Mike White from the Franklin Technology Center in Joplin Missouri sent in this set of plans for a nifty collapsible scribe. What’s neat about this particular scribe is it’s ability to collapse down and nest inside itself. It reminds me of those hammer/screwdriver combos where the screwdrivers are nested inside the handle of the hammer. However, like many combination tools the ham-driver was never a good hammer or a good screwdriver. It was a mediocre combination of both. But I digress …

This scribe design solves the problem I have with my current $5 scribe – it protects me from getting jabbed with the point when not in use. Sure my $5 scribe came with a protective rubber tip. But I lost it within a few days somewhere in a pile of swarf. With this setup I’ll be able to slip my scribe into my bib overall pocket next to my scale and never poke myself!

My only question for Mike is what method do you recommend to harden the scribe? Keep in mind that people making the scribe may have no experience whatsoever in hardening. So an explanation of the cheapest/easiest/safest technique would probably be best.

Mike also shared plans for a machinists hammer (ball peen style) which I’ll post in a few weeks. Thanks for sharing your plans with us Mike!

If you’re an instructor like Mike and you’d like to share your student plans with the site, please feel free to submit them using the “Submit Your Plans” tab at the top of the page. I’ll provide a link (and thus free publicity) back to your school or website. Every submission helps this site grow. Thank you for your support!

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Material: Steel
Units: (in)

I’ve seen many ball turning designs as I read through the back issues of Home Shop Machinist and Projects in Metal, but I’ve never seen one as simple and effective as Steve Bedair’s Ball Turning Toolpost.

Steve runs a website dedicated to 9 x 20 lathes and it’s full of great information. If you’re interested in this project, be sure to check out the other projects Steve has listed on his site.

Note: Because this project requires both a lathe and mill to complete, I’m listing it under both categories.

Here’s an image of Steve’s Ball Turning Toolpost in action:

And here’s a YouTube video clip of the toolpost in action:

Excited yet?

Here’s the link to the plans so you can create your own! If you want a detailed walkthrough of the process, be sure to visit Steve’s site.

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Scales come in different lengths, graduations and finishes. And you can buy a rigid or flexible one to suite your needs.

If your just starting out consider getting a 6″ 5R or 16R flexible scale. I find black scales with white lettering the easiest to read. SPI makes an EZ-View that is inexpensive, accurate, and easy to read.

What’s the “5R” or “16R” mean?

English:
3R: 10ths and 50ths (front), 64ths and 32nds (back)
4R: 8ths and 16ths (front), 64ths and 32nds (back)
5R: 10ths and 100ths (front), 64ths and 32nds (back)
9R: 16ths and 32nds (front), 64ths (back)
16R: 50ths and 100ths (front), 64ths and 32nds (back)

Metric:
E/M: 32nds and 64ths (front), 1 mm and 0.5 mm (back)
D/M: 10ths and 100ths (front), 1 mm and 0.5 mm (back)
M: 1 mm and 0.5mm (both sides)

So as you can see, the 5R and 16R scales are the only English scales with 100ths, which (although hard to read) is useful to have on a scale. Of course, if you’ll be working with metric measurements, you’ll want to go with an E/M, D/M, or M scale (English/Metric, Decimal/Metric, or Metric).

Quality Brands:
Starrett
Brown and Sharpe
Lufkin
Mitutoyo
Fowler
SPI (Makes the EZ-View – $5)

Where To Buy:
Check ebay.com first if you’re looking for a high-end brand like Starrett. Otherwise try one of the tool suppliers, like MSC / J&L Metalworking.

One final note on scales, it’s handy to have a “hook rule” in your toolbox. They are a bit harder to find and you won’t use them as often, but when you need one, you need one. The picture shows the 3 scales I use (the one on the left is a flexible SPI, the one on the right is rigid SPI, both are EZ-View), and a Lufkin hook rule in the center. Notice how the hook rule is very thin with a small hook on the end. Also, you can see from the picture how much easier it is to read a black scale vs a silver one (although the Lufkin is very old, so that has something to do with it too).

That’s just about everything you need to know about scales. If anyone has anything to add, feel free to post a comment.

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