The Fine Old Art of Pinning
Craftsmen began using sockets and pins in the early ages to build structures.
The group of framebuilders that were my Dad's buddies used to brag that they fit their frames together so well that all they needed was to be pinned and you could get on one and ride it.
That was a long time ago.
The fact is that frames have been pinned since the beginning and many builders of renown never used a Jig. They just used a straight edge, a hook to hang the frame from and PINS........
by step process of Pinning for accuracy and to prevent damage, and Most of all to set pins to hold precise alignment during joining.
Beginning the pinning process correctly starts prior to most of the construction of the frame.
How can this be you might ask?
Often overlooked but very important is to determine where you are going to pin before you even start cutting
your lugs. Locate the positions where you will place your final pins and using the drill provided {the one with the slanted bevel cut into it, in the chuck end of the drill} drill the lug, deburr the holes inside and out and then proceed with the frame pre-construction. {Often times in intricately cut lugs, attempting to drill them after preparation can be difficult and might cause damage.}
The next step in pinning will be after all other joining preparations have been performed and you are ready to jig up the joint {lug and tubes}.
At this point, flux the tubes and lug as if it was going to be joined at that time and holding the joint in alignment firmly, use the second drill provided {the smaller one without the code notch}.
Drill through the first holes with the second drill being very careful to just penetrate the tubing and not go all the way through both sides of the tube. {I put a little piece of masking tape on the drill so I know when I have gone all the way through on the one side}
If you've chosen to use opposing nails, which is my preference, insert a nail in each hole and very gently tap them with a small hammer. DON'T SET ONE SIDE ALL THE WAY FIRST.
Once you are satisfied that the nail is beginning to grip, tap them the rest of the way in firmly.
Knowing when the nail or the pin, as we call them, is set well enough takes a little practice but basically you should have no wiggle in it and it should be quite rigid and twang when you tweak it.
Pin locations can dramatically determine the effectiveness of maintaining the alignment during heat up.
Rule of thumb, each socket should have at least two opposing pins if possible. If the socket itself is fairly loose on the tube, more pins may be needed. If the lugs are very tight and have angles that are very close to your final plan or some lugs such as seat lugs may only need a single nail top center in the back near the crotch to hold the top tube.
The final step and don't forget this one is to liberally reflux the pin and the area around it then join.
Starting from the outside, you may bite them off but don't twist them off or bend them off. Then simply file them and sand them flush with the surface of the lug {Note: at this time you want to observe that the joining material has fully surrounded the pin. If there is a void there, you didn't flow your joint properly and yes during joining you can flow a little of the rod to the pin, never however direct your torch directly to the pin and super heat it. That will cause the pin to char and not become part of the structure.}
Finishing inside creates the greatest fear but it is really quite simple to do. Any rotary tool that can be inserted into the head tube or seat tube will remove and allow you to make the tip of the pin protruding through flush
{I use a dremel and two 409 wheels piggy backed on the dremel arbor. 420 wheels also work or most any sanding drum on most any rotary device.
Another method of getting started on the inside removal but requires a bit more skill and could cause damage
is to remove most of the tip protruding through with a small and freshly sharpened {very sharp} cold chisel.
{ I curved mine so that it hugs the inner wall of the tube}
Well now that you are finished pinning your first frame, visit my web pages for more photo's of pinning methods and inexpensive home made tools including a very easy to make lug holder {lug vice} from wood dowel.