How to Build a Motorcycle JigPosted by monsterguide
How to Build a Motorcycle Jig
If you would like to build a motorcycle frame, one of the most effective ways to do so is to first build a motorcycle jig. A motorcycle jig holds the parts of the motorcycle frame in place to fit and tack welding. One important thing to note is that a motorcycle jig doesn’t hold a frame together for welding; you will need to build a welding fixture which accomplishes this task.
Building a Motorcycle Jig
A motorcycle jig can be created with two main pieces of 5 inch steel mill channel. These two pieces of 5 inch steel mill channel provide the foundation necessary for other parts that will be attached to the jig. The jig will accomplish a few things; it will be able to locate the neck, including both the rake angle and height holding it in place. The other tasks this jig will accomplish are to locate the rear axle height and locate and level both bottom rails.
The Neck Jig Post
The neck jig post should be made of 1/8″ wall steel tubing with the measurements of 2″x 3″. You can use two plates to clamp to the vertical 5 inch steel post. This will allow you to vertically adjust the height of the neck. Use a 3/4 inch rod on a pivot to follow through the neck of the frame.
The Axle Post
The axle post is made of 1/4 inch steel tubing that is 2 x 4 inches. Two 3/4 of an inch axles is what holds these axle plates level using axle adjustment slots. You can use spacers and shaft collars to keep these axles in place.
Take a 1/2 inch steel plate and weld a 1/2 square tube to it. The purpose of this step is that you should enable the plate to move or be jacked up vertically for both leveling and small adjustments. When building the axle posts, make sure that the posts can be moved in any direction (forward, backward, up and down) as needed. In addition, you can also add spacers which should go under the 1/2 inch steel plate on the axle post. You can drill bolt holes in small increments to set spacing.
The Engine Fixture
Focusing now on the lower rails, the lower rails should be set up with 1-1/4 inch steel stubbing. The engine bar should be made from 1 x 4 inch steel bar. You should create two lower rails that are held apart with 1-1/4 spacers. Once all these components are assembled, pass through the bottom of the channels, a threaded rod. Use a piece of angle
and nut to secure the bolt. Now secure the engine plate to the fixture using four setscrew jacks that should be built at each of the corners on the engine plate. Use a drill to create these setscrews. This will enable you to adjust the fixture. It should be noted that your steel jig has lots of adjusters to make sure that your frame is held correctly.
Unfortunately steel is not very square and level, so these adjusters will make sure that your bike will lie flat on the engine plate. In some cases, you will require the use of shims to get things perfect.
Build Your Jig to Accommodate the Frame you are Building
It should be noted that certain bike frames such as a fat tail, may require specific types of jigs. Make sure you take into consideration the measurements of the frame you will build to ensure that your jig will accommodate it correctly.
Some Things to Remember
Make sure that you measure and build your jig extremely accurately. The more accurate your jig, the better it will accommodate your motorcycle frame. It should be noted that building a jig can require detailed plans and templates. You can find a variety of templates and plans on the web, even created especially for the style of motorcycle frame you would like to build.
Images of a Motorcycle Jig