Journal of 11/01/2014

Lathe and Milling machine are two serious equipment that help the builder can make, design serious machine parts. Both machines provide greater accuracy and precision of parts that is below 0.01 mm.

It’s possible to cut or shape an metal / wooden part at 0.01 mm range. The problem is its unpractical. You only need few basic hand tools to do it: a set of files – flat, square, round, engineering square that has 0.001 mm of flatness, vernier caliper or micrometer that has desired target accuracy you have in mind.

Sometimes I spend half minute to few hours for making flat surface of part by mind numbing filing and repeating measurement of the size and squareness. I use an engineering square and Vernier caliper of 0.05 mm unit. At the moment I manage to remove imperfection of a part between 0.05 mm and 0.1 mm due to limitation of measurement equipment.

Probably half year ago when I seriously started contemplating how to increase building accuracy and precision of my future work pieces.  Decent small lathe or milling that I can depend on costs few thousands of dollars.

One day ‘To buy or to build it?’ internal debating inside my head instantly disappeared when I discovered a hidden treasure of hardcore DIYer, The Charcoal Foundry written by David J. Gingery on the net. Right after I over viewed the book, I ordered all seven books of the series,  Build Your Own Metal Working Shop From Scrap’ in a hurry.

I read through The Charcoal Foundry and wrote down basic materials and tools for the foundry building. At the end of the book David J. Gingery introduced a ball crank that will be used to the lathe described on the second book, The Metal Lathe.

Diagram of a ball crank

A metal ball crank

And the book indeed put burning fire of owning a wood lathe before I begin to build charcoal foundry. Few days ago I decided to build a clone of Jack Houweling’s Mini Lathe on Youtube, which was the simple lathe that I could build it with minimal investment of materials and parts. Actually I spent only three or four dollars for my first wood lathe.

A metalworking lathe from 1911 a = bed c = headstock b = carriage g = tailstock

Building Wood lathe

Use a locking plier – Vise Grip – and strap to lock the power button on.cDSC_0535

Overall size of the lathe is about 700 mm in length.cDSC_0534

Making the drive center

This one is sold around $17 on Amazon.com.

PSI Woodworking LCENTSS22 No. 2 MT with 1-Inch Crown Super Wood Lathe Drive Center

I think I paid about 3,000 KRW ($2.5) for two bolts and matching hexagonal sleeves for the wood lathe construction. One set of bolt and hexagonal sleeve would work as the drive center, which is critical part of the machine.

I removed the bolt head using a hacksaw with 24 teeth blade to build the shaft of drive center.
cDSC_0414

Making claw of the drive center that takes shaft in.

Marking forty five degree lines on it.cDSC_0415

I used bench grinder and files to shape the teeth.cDSC_0417

The homemade drive center is done. But later on I found out that I made one big mistake here. The end point of shaft must be greater than equal to length of the claw so that it can bite a wooden piece firmly while it rotates over few thousands RPM.

The claw’s teeth wasn’t sharp enough and its shape fails to hold small wooden piece whose contact area is less than claw’s maximum diameter. During the two test runs of wood lathe, I had to remove the claw from drive center for cutting wood pieces.

cDSC_0419

It showed near perfect rotation which indeed surprised at me. In lower speed there was noticeable vibration. As the speed went over thousands RPM, the vibration disappeared.

cDSC_0429

cDSC_0426

Making the tailstock

The width of hexagonal sleeve was 17 mm. I drilled a 12 mm hole at the center, drilled 2 mm holes around the hole, and filed till I made the hexagon. This is definitely hard way compared to Jack Houweling’s technique.  Jack Houweling rounded off one face of the sleeve in circular shape then inserted it into the hole using a hammer.cDSC_0435

cDSC_0441 cDSC_0445 cDSC_0449 cDSC_0451

Checking flatness of bottom of the tailstock.cDSC_0455

Making the rail where the tailstock moves.cDSC_0459

Making top plate of front holder that secures the drill

The first version was flat wooden piece, then I made groove that seats on flange of the drill. The diameter of the flange was 43 mm. cDSC_0461 cDSC_0463

I had to install the tailstock holder which isn’t showed in Jack Houweling’s design. It’s intriguing how his lathe overcomes the lateral force of rotating axis and holds the position while in operation.

cDSC_0528

I’ll fixed the flawed drive center firstly, then add essential features to current one during  operations.

Foot switch installation to the drill press

All heavy duty drill press seems to have a foot switch that turns on and off the motor.  I’ve been modifying my little drill press adding features. I bought a functional but worn out foot switch made out of all metal at a scrapyard, paid 10,000 KRW to 15,000 KRW. Hmm, what was I thinking?

The owner’s manual of the drill press is hopefulness when it comes to electric circuits which implies no repair work by the end user.  The power switch is simply a relay that has two buttons – green is on, red is off. Main power cord comes in and two wires go out to the motor, one wire is the common ground which bolted to the metal frame.

I disconnected four wires from the relay, cut them off, connected each wire and taped it temporarily. And I connected two wires of the foot switch to the one wire of power cord.cDSC_0434

cDSC_0432Does the foot switch makes difference of drilling? Definitely.

Rust clean up 

I used to favor brand new tools and materials. Nowadays since I opened up the eye in Open Source Hardware in general, I began to buy scrap metals and used tools. Using apple cidar vinegar or electrolysis seem to be overkill on light rust of metal which is easy to access.

Wire cup brush like the image for angle grinder works good.

BeforecDSC_0550

AftercDSC_0555

BeforecDSC_0551

AftercDSC_0553

About janpenguin

Email: janpenguin [at] riseup [dot] net Every content on the blog is made by Free and Open Source Software in GNU/Linux.
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