Wednesday, May 30, 2012

Poor man's lathe

There are times when you need to modify a part in such a way that you need the use of a lathe or CNC machine, but the cost of such a job or the wait time may not be worth it. I like to spend the day in the garage and get things done right away, but I have only the basic hand held tools, not a lathe or even a drill press. So what is a garage hacker to do when a part needs to be turned down on a lathe and you lack such a tool or the patience to wait for the shop to do it for you? Simple - make an impromptu lathe from your hand held drill!

I was working on this massive autonomous robot project and needed to adapt the axles from a pickup truck rear differential to take a set of bearings and sprockets. Sure, I could have sent them to the shop and paid $150 to have them machined on a lathe, but I did not want to fork out the dough any more than I wanted to wait a month to have this done, so I decided to pull a "MacGyver" and machine down the axles without needing a lathe. Impossible do to the precision needed? Heck no! I even added a keyway to each axle using an angle grinder and the end result was a perfect fit.

Let me show you how I adapted the axle shafts shown here to fit onto the 1 inch diameter bearings and sprockets.

A lathe in its simplest terms is a machine that spins a part so that a cutting bit can remove metal a little bit at a time. So, I knew if I could get the axle to spin, then I could just use my grinder to carefully remove the metal around the end of the shaft until it was exactly 1 inch in diameter. At this point, the axles were about 1.25 inches in diameter and tapered. To spin the axle, I welded a bolt to the center of the hub flange and then placed it in the chuck of my hand drill. The axle was then placed into a simple wooden jig and greased so that it would spin freely.

I found the drill spun the axle a bit too fast for my liking, so I needed a way to reduce the speed of the drill to about 120 RPM. Trying to tie wrap the variable trigger in place did not really work out so well, and then I remembered something about the series wound motors in drills and saws - they work with both AC current and DC current. My idea was to just reduce the voltage to the drill motor.

Going from 120 volts AC to 24 volts DC slowed the drill down to the perfect speed, yet gave it enough torque to spin the axles as I held the grinder disc to them. To power the drill from 24 volts DC, I just took two of the four robot batteries (marine batteries) and wired them in series with the drill power cord completing the circuit. I didn't even use wires for the plug; it was just sandwiched between the two battery terminals and held there by friction.

My machining process required shortening the axles and then turning them down to exactly 1 inch in diameter at the last 2 inches on each end. Cutting the axle short was easy; I just spun up the drill and then held the zip disc on the axle until it cut all the way through the axle. I did not need the splined end piece, so it was tossed in the scrap bin.

To machine down the axles, I ran my grinding disc back and forth along the 2 inch section while the drill spun the axles at about 120 RPM. I did not push hard on the grinder, and tried to keep a constant pace as I moved it back and forth along the area to be reduced. After about 50 strokes, I would stop the drill and check the axle thickness using the bearing I intended to install.

Once the axle was just slightly larger than necessary, I switched from the grinder disc to a sanding disc so the final machining could be done more accurately.

Friday, May 25, 2012

May 24 newsletter

Feature article by Brad Graham (Radical Brad):
*** Building a rebar greenhouse - Part 4 ***

In the Atomic Zombie builders gallery
Coming soon - manufactured parts for your bike projects
Head tubes and bottom brackets
Bike builders chat
Spring into bike building - offer ends May 31

This and other AZ newsletters are here.         

Wednesday, May 23, 2012

New Project : Front Runner Recumbent

"I am 50% finished a new bike called "The Front Runner" (front wheel drive recumbent), which will be an easy to build front wheel drive dual 26"/700cc recumbent. I have decided to build this bike after several requests for a Cruzbike style plan."  Read more:  New Project : Front Runner

Tuesday, May 22, 2012

New bikes - Atomic Zombie gallery

Chase Warrior Trike, built by Larry Butterfield

Spinner's Warrior Trike, built by Spinner

Built by whiteGIANT

Check out these and other bike pictures:

Time is running out on this special offer.

Wednesday, May 16, 2012

AZ newsletter May 16

The May 16 newsletter is now online. In this week's issue:

Feature article by Radical Brad: "Poor man's lathe"

Bike builders gallery - see what's in the new gallery
Bike builders chat - from the AZ community

Spring into bike building - DIY bike plans special extended

We're selling bike parts to help you with your DIY projects:
* Manufactured parts for your bike projects
* Head tubes & bottom brackets 4 sale

This and other newsletters are on the main AtomicZombie web site under AZ News:

Friday, May 11, 2012

AZ newsletter May 10

 Feature article by Brad Graham (Radical Brad):
** Building a rebar greenhouse Part 3 **

Manufactured parts for your bike projects:
Head tubes and bottom brackets  
Disk brake adapter, threaded freewheel & hub flange 
Submissions to the new gallery: choppers and trikes
6 for $36 Spring into Bike Building special extended 

Bike builders chat
From our Facebook Fan Page

Wednesday, May 9, 2012

The forum is down

We're back online as of 3:40 pm Eastern Time.


Sorry, our Forum is currently offline!

Something went wrong with our forum webserver late last night, and we are working with the hosting company to sort this out. We hope to be back online later today. Sorry for the inconvenience!

AtomicZombie Krew

Monday, May 7, 2012

Head tubes & bottom brackets 4 sale

We're working with a manufacturer to also make head tube shells and bottom bracket shells weldable-ready. They will have slightly thicker walls so they won't distort during welding.

Since our plans call for head tubes and bottom brackets and some people are having problems salvaging useable bike parts for their projects, we think that offering these two parts for sale makes sense.

If you are interested in these parts, please add your name here so we can gauge interest. 

Read more and join the list: Head tubes & bottom brackets 4 sale

Friday, May 4, 2012

Terminator chopper - recovered

Found in a ditch not far from where we live, super helpful local entrepreneurs went out of their way to return it to us this morning.

There still are good people in the world doing deeds out the kindness of their hearts.

Still missing: two spoked car rims (spray painted metallic blue) and tires from the Gladiator chopper. Stolen at the same time as the Terminator Chopper. Maybe they will find their way home, too.

Wednesday, May 2, 2012

AZ newsletter May 2

Feature article by Brad Graham (Radical Brad):
Building a rebar greenhouse Part 2 

Terminator chopper stolen
New builders gallery: upload your photos
Estonia Warrior tadpole trike
Motorized bikes
Kids' trike in Scotland
Oregon quadcycle
Spring bike building special extended
Manufactured parts for your bike projects
Bike builders chat
From our Facebook Fan Page

6 for $36 Spring Special extended

You asked for an extension of our current spring special, and we said, "Sure!" Due to popular demand, we have extended the spring special until May 31, 2012.

Head over to and check out the variety of DIY bike plans we have. Then, come back to the builders forum and share your building experiences with the community. We look forward to seeing your completed bike projects in the builders gallery.
Thanks for your support and have a fantastic day.

Tuesday, May 1, 2012

May 1 - New Gallery: Upload your photos

The new Atomic Zombie gallery is now online. Members can post and link to pictures, share comments, rate others' pictures and more. You must register as a member of the AZ forum to post in the gallery.

Guests can still view the gallery and use some functions, but to fully enjoy the gallery, please become a member. It's free.

The gallery that we have had for years will be migrated to the new gallery this summer. It will stay online at the main AZ site until all pictures are in the new gallery.

We look forward to seeing your own bikes in our new gallery, and thanks for joining our worldwide community.

Bike building is an international past time.