A more robust jig gives greater accuracy.
Among the many reasons I invested in a vertical milling machine is the ability to make more robust and accurate jigs. The jigs I’ve made in the past are fine for one or two uses but there are some pieces I will make many times or want a highly accurate assembly. Wood surfaces don’t work well for long term soldering as they get charred or abused from the heat and wear. Naturally, styrene is out of the question for soldering. I discovered the hard way that even certain milling procedures generate enough heat to ruin a jig.

Over the weekend I remade the offset post jig for a third time. This latest version is aluminum and works exceptionally well. The design is the same as previous ones with the offset profile milled on one edge and a shallow recess on the bottom that holds the blank sheet in place. I drilled a pair of holes for two small wood screws that attach the jig to the plywood base. It was an enjoyable afternoon of work.

This aluminum version of the offset jig works better than previous ones. The wooden profile form seen in the upper right was getting very charred and hard to work with. The metal version is more robust and accurate.
The aluminum stock is nothing more than a scrap piece and other than the profiled edge and recess the dimensions aren’t critical although I did match the height of the jig to the finished post. Some of you will wonder whether the aluminum acts as a heat sink. It likely does but with 0.005” brass and a 60-watt iron, I have no issues getting enough heat to the joint.

The aluminum provides a solid, accurate surface to form the angle against. I can apply physical pressure as needed to bring the pieces into alignment. The solder won’t stick to aluminum, so there are no concerns about soldering the part to the jig.

While it’s a simple fixture, the new jig lets me produce parts with repeatable accuracy, which is my goal with any jig I make. With this experience, I see a new road of modeling opportunities opening up ahead.



  1. Simon

    An alternative to to aluminium is something like cloth-grade Tufnol, a material made by impregnating a substrate with phenolic resins. It is also available in paper-based form, but that isn’t so strong.
    You don’t want to breathe in the dust when machining it, but it’s very useful material.

  2. mike

    I’m not familiar with that product name Simon, though it may be called something else over here. It sounds useful. I like the aluminum because it was on hand and provides a solid base for working. It’s also a lot of fun to mill.


  3. Simon

    Boeing use it!
    I believe it is available in the USA.

  4. Greg Amer

    Love a good jig.

  5. mike

    So do I Greg. -Mike

  6. Chris Mears

    I believe the Tufnol product Simon is referring to is also the same material that forms the core of circuit boards. It seems so popular or common in British model railway articles on making track or locomotives but is seldom mentioned in the American press. The only places I ever see it advertised are companies that support British model railroaders though the product itself is something of the electronics industry so perhaps this is a job for that side of eBay or a like provider?

    Aluminum should be just fine though. As you note, it uses materials that you already have on hand, are happy to work with, and in the end produces the tool you need to maintain forward motion in your project so seems to satisfy all the needs one could ever ask for.