Pinning 101

I wanted to address this in a brief article, even though there are many other, more comprehensive tutorials available. In short, pinning refers the the addition of a metal pin to a joint to add strength. Typically, I do this with large load bearing joints that might not have enough surface area for super glue to create a solid bond. For example, I recently used pins on the the knee joints of my Barbed Hierodule, the waist joint of an OOP Hive Tyrant, and the waist joint for some Zoanthropes. In all cases, these were small areas supporting heavy head/upper body sections.

Step-by-Step

There are a couple of ways you can make a pin. You can go as simple as a paper clip and wire cutters or be a little more elaborate. I tend to use thicker brass rod and a miniature pipe cutter.

1. First, make your holes. Use a sharp scribe to mark the middle of each piece and then find an appropriately sized drill bit for your pin vise and drill a hole about 1/8" into the piece. You should already know what material you're using for the pin, so you can use a short length to check depth and fit. Ideally, the pin fits snugly into the hole but doesn't need to be forced in.
2. Now, cut your pin. Depending you can actually transpose steps 2 and 3 if you have a pretty good idea of what you need. I like to 1/16" brass rod and a miniature pipe cutter. I find that a wire cutter tends to mushroom the cut end of the pin too much. The pipe cutter takes a little longer, but leaves a very nice cut that just needs a little bit of filing at the end. Why do I file the end of the pin? If you leave it mushroomed out, the ends will be thicker than the rest of the pin, which will require a larger hole and therefore a less secure fit. A little bit of prep really does result in a stronger join. Here are two pins cut and ready for gluing.



3. Test fit the pin into both sides of the join and check for fit and gaps. Remember, test fit twice, glue once.
4. Glue the pin into one end of the joint. I typically glue the pin into the meatiest half of the join first and usually use a pair of pliers to hold the pin while I insert it, otherwise I get superglue all over my fingers.
5. Test fit the other half of the join again and either deepen the hole or file down the pin as needed. If you find that the gap is still too large or there are gaps in the join where pieces won't touch, you can use a little ball or donut of green stuff to fill the gap. Green stuff and superglue work pretty well together to make a strong bond.

That's it.

Post Mortem

None.

Notes

Last updated	4/18/09
Author	Michael Kan
Pre-requisites	None
Related Articles	None