Jeff Barr's Blog

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Minichopper Jig

Here are some pictures of the jig that we will use to hold the various pieces of the minichopper frame in the proper alignment to each other while we fit the cross-pieces, the rear wheel assembly, and the drive-train.

Note: Each picture links to a high resolution (1600×1200 pixel) version. Don’t bother with these links unless you are on a high-speed connection.

First, here’s the jig from the front. The vertical bar will be used to center the front forks. The jig is made of 2″ x 2″ square steel stock and some angle iron. Our first jig was built of wood, as recommended in the plans that we started from. This didn’t turn out well at all, and we scrapped it. The metal jig is far more precise, and was easier to build than the wood one.

In the background, you can see our tubing bender. The black blob to the right is our 8 HP engine. We are keeping it covered so that it doesn’t get damaged by the metal shavings in the atmosphere.

Here’s a view from the rear. The square part in the center will be used to hold the frame rails parallel. We worked hard to make each of the pieces square, straight, and true. I think we are within 1/32 of an inch right now (this is a lot harder than it sounds). In the distance you can see our mill. This 1100 lb behemoth will be put to good use as we shape the various brackets for the frame.

Here is the jig with the two frame rails securely clamped to the angle iron. We are planning to mount our tubing notcher on the vertical component, so that we can make a very precise joint.

Finally, here is the business end of the mill:

Now that I have figured out how to upload and post pictures to WordPress, the sky is the limit.