Chop saw jig for cutting A fletching slit in poly pipe
You will need a single or compound miter chop saw. 10'' or 12'' is preferred.
Exact procedures for making this jig cannot be shown due to the fact that every chop saw is different. However the principal remains the same, and I will attempt to make it's construction clear. It's construction looks rough, but it does the job well.
Getting the correct depth and location of the slit is a matter of trail and error. Only use fresh scrap poly pipe for every cut, to check the set-up. Never attempt to Re-Cut an existing slit. The saw can bind on the poly pipe and throw it across the room, break the jig, and/or harm the user. Even in the best cases, a Re-Cut slit will be incorrect.
The object here is to create two slits near the end of the shaft to accept the fletching.
Setting an angle on the miter will cause your arrows to spin, and give a true and stable flight. You can acheive a left or right spin depending on which way you set the miter.
A jig will allow you to make an infinite amount of "matched" arrows easily.
You need to mount a V-groove perpendicular to the fence on the chop saw, make an End Stop, make a Depth of cut Stop, and a Locator Hook to position the pipe to cut the slit on the opposite side.
What is shown here, is a 2x4 attached to the fence with screws from the back of the fence, through holes in the fence. This method allows the jig to be removed and replaced from the saw as needed, without dismantling the jig.
Next is the V-groove. On this model the V-groove is achieved by attaching two pieces of triangle stock directly under, and centered on the saw blade.
The End Stop on this model is the protractor of the saw, but it can be a block of wood or a screw in the desired location.
The Depth Stop (barley shown here) consist of two blocks of 2x4 attached to the base 2x4, with a 4'' lag screw that touches the motor housing of the saw. The screw can be turned either way to achieve the desired Depth of Cut. Try to have the lag screw hit metal as opposed to plastic.
The Locator Hook is a piece of wire coat hanger attached with a screw. I'll go into it's purpose further in the instructions.
Using and adjusting the jig
Make what you've seen here minus the Locating Hook. Set the Depth of cut Stop by lowering the blade until it just touches the bottom of the V-groove. Then turn the lag screw out until it touches the motor housing of the saw. Raise the saw and turn the lag screw out one more turn. Recheck the depth by bringing the saw down on the lag screw firmly and observe the distance of the saw blade tip from the bottom of the V-groove. The optimal distance will be about 1/2'', but this is still preliminary. (Note: it may be necessary to use a longer or shorter lag screw but try to keep at least 2'' of lag screw in the wood for durability)
Set the miter to the desired degrees. (I recommend 5 degrees) Place a piece of poly pipe in the V-groove and push it against the End stop. Hold onto the pipe firmly, turn on the saw, and plunge slowly into the pipe until you feel it hit the Depth Stop. Watch that the saw blade does not hit your hand. With the saw still running, raise the blade out of the pipe.
Check the following:
Does the saw blade cut the underside of the pipe? If so then adjust the Depth Stop "up", and try again with a fresh pipe.
Is the slit the desired length? (I shoot for 5'') If not then adjust the Depth Stop. Up for a shorter slit, down for a longer slit. Go easy, a slight turn of the lag will yield much slit length.
Once you have the desired slit length, check the location from the end of the pipe. It should be no closer than 2'' from the end. Adjust the End Stop accordingly. Moving the stop back, will move the slit forward, and moving the stop forward, will move the slit back. Cut a fresh pipe and check again.
When you have these two aspects at their desired settings, it will be time to make the Locator Hook. Poly Pipe is labeled with printing in a straight line. Place a piece of pipe in the V-groove with the printing exactly at the bottom of the V-groove, cut a slit. Now turn the pipe 180 degrees, so that the printing is at the top. Check that there is slit showing on the underside. (If there is not then your jig is too deep and you need to remove it and "rip" the face of it down until there is slit showing.) Fabricate a Hook as seen in Photo #3. The Hook should only go into the pipe slit partially and not be able to completely enter the pipe. Set the pipe in the V-groove so that the printing is at the top. Set the Locating Hook in the slit and insert the screw into the base 2x4. The Hook should be snug on the screw, not sloppy.
Checking the Locating Hook setting.
The locating Hook allows you to get perfectly located slits quickly, without the hassle of aligning the printed line.
Cut the first slit in the pipe. (It is not necessary to align the printing on the pipe) Rotate the pipe 180 degrees, swing the Locator Hook into the slit and exert slight clockwise rotation on the pipe to take up any slop in the Hook. Cut the second slit. Remove the pipe and insert a Popsicle stick, hacksaw blade (or the like) through both slits. Set the stick perpendicular to the pipe, and look at it from the end of the pipe. It should appear to pass through the center of the pipe. If not then repeat the above procedure with a counterclockwise rotation instead. If that works then always use a counterclockwise rotation. If not then the Hook may need to be re-fabricated or the screw moved.
Always clean the saw chips out of the pipe, and cut off any stragglers.
Always use SCA approved fletching materials for combat. I use "DOVE FOAM", but this method will work for most any foam.
Cut a "Two-Liter" pop bottle into a strip that is 4-7/8'' wide (for a 5'' slit) and as long as possible. Fold the strip in half width-wise, and crease it flat. Lets call this the sheath.
Insert the folded end of the sheath through both slits and pull about 1'' out. Cut the "DOVE FOAM" into 5'' wide strips, and as long as possible. Open the ends of the sheath and insert the end of the foam strip. Pinch the sheath closed on the foam, and pull the sheath through and out of the pipe slits. Relieve the stress in the foam by sliding it endwise in the slits. Trim the foam to the desired shape. (Avoid square or acute corners on the foam, for safety and durability) Practice will reveal at what length to insert the foam into the sheath and/or proper sheath length, for conservation of foam. For best results, always plan on trimming the foam to shape.