I liked the way my little four bar concept build felt so much, that I decided it was a perfect candidate to upgrade my heat setting capabilities.

A while back, I made this “Heatset Helper” that uses linear rods and linear bearings to provide some nice guided motion for my heat setting needs.

There are a number of things I’ve really liked about this thing, but there are also plenty of things I don’t.

The main issue is how close the base is to the soldering iron tip. That means for that for larger parts, I have to balance the whole thing awkwardly…which kinda defeats the purpose. For smaller parts, it works perfectly though.

Some of the other ‘not so greats’:

• The soldering iron material isn’t high temp resistant, and deforms out any preloads introduced. Causes the bracket holding the iron to loosen over time.
• The iron interface also doesn’t engage enough of the iron’s length. As a result, any looseness in the mount can result in significant angular movement…no bueno.
• The linear rods and bearings work well, but they’re relatively heavy compared to everything else involved, and they make the whole thing a bit awkward to store on a shelf.

So, it’s time for something better, and I think the little jewel bearing four bar setup is a pretty dern good candidate for it.

Here is the super snazzy sketch I made to show the concept…believe it or not, this is the good version. I made this after being (very reasonably) mocked during the live stream when I tried to sketch it :)

There’s a lazy Susan style rotary table at the base. Attached on top of that are two four bar linkages stacked serially, and then out at the end is the soldering iron.

The purpose of the four bars in this application is that they will maintain the vertical orientation of the soldering iron throughout the range of motion. They also will allow me a good range of motion for installing inserts on taller parts (my target for the build is to be able to place an insert in a hole 250mm above the table surface) and for reaching locations all across the work table. No longer shall my heat setting be bounded!!

I’m still not quite done with the design, but it’s comin along!

I decided I’m going to mount the rotary table to a piece of optical breadboard I have layin around. I’m thinking I’ll mount the iron controller on one side of the arm, and a set of storage bins for heatsets, tips, etc. on the other.

For the rotary table, I went with a printed-race bearing concept I’ve used several times before.

Taking a look at the cross-section gives a little clearer view of the configuration of the bearing races. The orange bit on the bottom is the preload ring. It is secured to the red piece (the main moving platform) using six M5 fasteners. The rotary then bolts down to the breadboard with four M6s.