I have been asked a few times to put a tutorial together so here we go.This tutorial is also posted on my web site.http://www.medawebs.com/knives/tutorials/Slipjoint/Slipjoint_Introduction.htm The most difficult part of making a slipjoint is getting the geometries of the tang and spring to work in harmony. Many custom makers are designing their slipjoints so the backspring is flush with the back of the knife when it is opened, closed and at the half stop. The illustration below shows how the dimensions of the tang works in conjunction with the backspring. For illustration purposes, the dotted lines are for reference only. The distances from lines A, B and C to the center of the pivot must all be the same in order to obtain a flush backspring in all 3 positions.Dimension “A” should be approximately 10% longer than dimension “B”. This is to keep the blade from extending beyond the end of the backspring when the blade is rotated. So now you have to decide, which pattern knife will I make? Well, that's totally up to you. For purposes of this tutorial, we are going to make a Texas Toothpick. To get you started, I have made available a full size drawing in PDF. format. http://www.medawebs.com/knives/tutorials/slipjoint/toothpick.pdf If I am going to make more than one of any style knife, I make a pattern out of steel which I can use repeatedly. This pattern is a fully functioning slipjoint. You can use the drawing I have supplied either to make a pattern or just use it to make a knife. First thing I do is to trace the outline of my pattern onto steel that I have marked with red Dykem. For some reason, I like the red better than the blue. You can also use a sharpie to darken the steel for tracing. Cut the blade and spring out as close as you can to the line. Drill your pivot hole in the blade and the center hole in the backspring. Once the parts are cut out, you can profile them just to the line. You want to make sure you leave a bit on there for making the small adjustments. At this point, I grind the inside of the backspring right to the line and finish to 600 grit. The end of the backspring is left a little long and unfinished at this point. We will finish the end later on. Using bushing in slipjoint is a personal preference. Slipjoint knives have been made for decades without them. I like to use them for two reasons. Firstly, I think they add a bit of smoothness to the action. Secondly, the make peening the pivot pin a bit easier. When you use bushings, the final goal is to have the blade rotate around the bushing. The bushing does not rotate around the pivot pin. The only place I have found bushings to date is at K& G Knife Supply http://www.knifeandgun.com/ProductDetails.asp?ProductCode=B2 . They are 3/16 outside, 3/32 inside and 1/8 thick. Please measure these bushings as they are not made with very close tolerances. Drill and ream out your pivot hole to accept the 3/16 bushing. I start with a #14 Drill (.182) and ream to size. I then use a barrel lap and polish the inside of the pivot with Clover 1000 grit polishing compound. The tool shown below is simply a piece of 3/16ths rod threaded with a 1-72 screw. This allows me to chuck the bushing in the drill press and polish the outside to 1500 grit. In order to have the blade rotate on the bushing and not the pivot, the bushing needs to be thicker than the blade. I try to hone the bushing so it is .001 thicker than the blade. When peening the pivot pin, the liners will be resting against the bushing and not the blade which will allow for a smooth action. The tool below is a block of hardened 01 Tool Steel with a 3/16ths hole. This is used to hone the bushing to the exact needed thickness while keeping it square.