Sunday, September 5, 2010

Step by Step: Pinning

     No matter what draws you to our hobby or what segment of the hobby you enjoy you will inevitably encounter metal models. If you prefer gaming you will most likely have at least one or two models in your army/force that are metal. If you prefer the modeling/painting aspect, some of the most dynamic and interesting models are made of metal. So you will find over time that super glue just does not hold well enough for those pieces such as arms, hands, or whatever you have. Well pinning is a good way to overcome this.

     Basically pinning is the process of drilling a hole in both pieces to be joined and gluing a piece of wire or rod in the hole. This increases the amount of area that has glue on it, and thus strengthens the hold. This post will cover the steps I take when pinning as well as some of the pitfalls I have learned to avoid along the way.

     First off you are going to need some tools. Well to drill the holes you will need a device called a pin vise. A pin vise is simply just a really small hand drill. It has a collet (the piece that holds the drill bit) and often has a rotating ball or knob on the other end. This allows you to twist the vise while applying pressure with the palm of your hand.

Click for larger version with sizes.
      Once you have a pin vise you will need drill bits, and something to use as a pin. I am not sure about where you live, but in the town I live in we don't have many local sources for drill bits as small as I use. Fortunately if your FLGS does not sell the bits there are several online vendors that do. I prefer to buy from a site called Widget Supply. They have a good assortment of bits and their prices are pretty decent. They normally run about $2.30 for a pack of ten. 

     Drill bits this small are often measured in wire sizes or wire gauges. After a bit of experimenting I managed to find the sizes that work for the materials that I use as a pin. I have seen people buy brass rod to use as a pin. I tend to prefer cheaper and more commonly available options. I use either a large paper clip, a small paper clip, or a simple stick pin. They are all readily available at your local mega store and they are extremely cheap. You get 100 paper clips for less than a dollar and the stick pins are similarly priced.

     For the pins I use I have found that the following bit sizes are pretty close to perfect; Size #53 for a large paper clip, Size #63 for a small paper clip, and size #71 for stick pins.

     Now that we have the tools out of the way lets get to the good stuff. For this example I will be using a out of print Rackham Orc Brute. This model has a two piece arm that will work great to show you what to do. Now most of the time you will have some sort of ball and socket to work with. When this is the case we start with the ball portion of the model. If you have two flat sides to a joint the process is pretty much the same but it does not really matter which side you start with. After I figured out roughly where the arm will go I used my vise to drill a hole into the shoulder. Remember, do not apply too much pressure on the drill bit. Let the tool do the work or you take a chance on breaking the drill bit. These bits are not made for a lot of force, and they break easily and are a pain to get out when that happens.

     Once I have the hole drilled we need to figure out where we need to drill into the arm so we can match them up. I start out by putting a piece of pin in the hole I just drilled. I tap down on the end of it to make sure it is all the way in the hole. It is important part that I will explain later, just make sure the pin is as far in the hole as you can get.

     Now we cut the pin down really close to the model. Do not apply any glue yet as we will remove this pin later. We just need to make the other side of the joint so we can see where to drill.

     Now we have to prepare the arm section. This step you may be able to skip once you have more practice, but it is really good use when you are learning. Take the socket section of the join and color the inside of it with a black marker or some thin paint.

      Once it is dry I take this part and press the colored area up against the pin we left in the body. Once you get it as close to where you want it as you can apply pressure. This will press the pin into the colored area marking it where we need to drill. This is why we tapped the pin down well into the hole before we cut it. If you do not, then at this step you may press the pin further down into the hole making it all but impossible to get out.

     You can see here how the pin left a spot showing through the marker. Now we know where to drill.

     Now with the spot marked we can drill the hole for the arm side. You want to drill as straight as you can, and be careful that you do not drill to far in and come out the other side.

     With the hole drilled into both sides we can start gluing. First I remove the small pin we cut and used to mark the arm section. That was simply used for that mark and is much too small to be used as a permanent pin. I apply some glue to a new pin and insert it in the hole.

     Once the new pin is dry I cut it to a rough length that I think will fill the hole. Then I dry fit the arm onto the pin. If needed I cut a bit more off the pin until the arm fits properly. If you need too you can bend the pin a bit to make sure a good tight fit. Finally I apply some glue to the pin and the metal on the model and put the two pieces together. Let it dry and you should have a good firm joint that should resist most bangs and knocks.

     Well I hope this helps you. Feel free to post any questions if you have any.


Papa JJ said...

Great article, MM! I've had a lot of trouble over the last year getting the collet of my pin vise to hold onto the drill bits that I want to use. When I press down to begin drilling, the bit will not hold and slides further into the drill instead of boring into the metal. I thought I had broken something or somehow worn down the collet and so purchased another pin vise, but the same thing happened to that one as well within minutes of me taking it out of the package. I've been told I can solve this slipping problem by wrapping a little piece of scotch tape around the bit where it would be held by the collet. I'm curious if you have any other solutions I could try out, but I'm mainly interested in finding out what I'm doing wrong to cause this in the first place. I've had no trouble pinning in the years prior to this and do not understand why this has only become a problem for me lately. Thanks, I appreciate whatever thoughts you have on this... and thank you for the article, too!

Master Manipulator (every store needs one) said...

I know this may sound simple, but are you using the correct side/size collet? Several of the vises on the market have a second collect stored in the handle as well as each end of the collet being a different size. It might be something as simple as changing to a smaller collet. I know some of my smallest bits fit into two different sides/sizes of collect but one of them slips fairly badly.

Other than that I am not sure what to tell you. You might try the tape trick, but to me it seems like there may be something else going on. When the end is tightened down properly the bit should stay in place.

Papa JJ said...

Yeah, I checked to make sure it wasn't something simple like that but unfortunately it seems like that wasn't the problem. I too feel like something odd is going on the cause of which I must be overlooking as I never had this trouble before. I'll keep trying to figure it out and in the meantime test out the tape idea. Thanks for your help on this, I appreciate the suggestion.