USE GLUE
LITLTE TRICK : put a layer on the edge – let dry 10 min – then another layer of glue.
Video
https://www.kregtool.com/store/c20/kreg-jigreg-screws/#tab1711
STEP ONE: Measure the width of your work piece. The first step in using your Kreg pocket hole jig is to measure the thickness of the material you will be drilling into. You will use that measurement for the next two steps. For our example we will use a measurement of 3/4 inch. Your pocket jig includes drill, collar and allen wrench.
STEP TWO: Set up your drill bit. The drill bit that came with your Kreg pocket hole jig has two pieces: the drill bit and the stop "collar" which slips onto the smooth part of the drill bit. Your pocket jig also came with an allen wrench that fits into the hole on the side of the collar. Use your allen wrench to loosen the collar by turning it to the left. As soon as you can move the collar up and down the drill bit, stop turning. Look at your drill bit. The very tip of your bit will drill a short, narrow hole. The wider, longer section in the middle of the bit will drill a bigger hole. That bigger hole is the "pocket" that will hide the pocket holes screw.
Find the mark that's right for your plan. Your pocket jig has scale markings from 1/2 inch to 1 1/2 inch molded right into the base to make setting up the drill bit very easy. Lay your drill bit in the slot of your pocket jig. Line the very first part of of the wider section of your drill bit with the 3/4 inch marking. While holding your bit in place, slide the collar toward the tip of the drill bit until it is stopped by the front end of the pocket jig. Make sure the hole in the collar is visible. Still holding the bit in place, use your allen wrench to tighten the collar in place by turning the allen wrench to the right. Once your collar is tight, double-check that your drill bit is still lined up at the 3/4 inch mark. Your drill bit is now ready to drill the right depth required by your plan! Insert the drill bit into your drill and tighten it securely. The Kreg pocket hole jig has adjustments for drill angle.
STEP THREE: Set up the drill guide on your pocket jig. We will use the same 3/4 inch measurement from Step One. Loosen the brass nut near the top of your Kreg pocket hole jig, so that you can move the drill guide up and down. Find the 3/4 inch mark on the side of the drill guide, and then tighten the brass nut to hold the drill guide in that position. Your drill guide is now ready to drill your pocket holes at the correct angle.
STEP FOUR: Position your piece in your Kreg Pocket Hole Jig. With the adjusted drill bit securely fastened in your drill, put the drill bit into one of the guide holes. Start the drill. When it reaches full speed, slowly lower it into the wood. To keep wood chips and sawdust from accumulating in the guide hole, bring the drill bit partway up several times as you are drilling each hole. Your Kreg Pocket Hole Jig makes fast work of these holes. Unclamp and move your workpiece so that you can drill the rest of the pocket holes needed on that piece.
Pocket-hole pointers
https://www.woodmagazine.com/woodworking-tips/techniques/joinery/pocket-hole
Whether you own a pocket-hole jig or are considering buying one, these shop-won insights will help you get more from your jig.
WOOD Magazine StaffMarch 29, 2019
Prepping the stock
Make precise, square cuts. When making projects with right angles, such as cabinets or face frames, square cuts ensure square assemblies. Set your tablesaw's blade precisely 90° to the tabletop before cutting parts to size, and make sure your miter gauge is exactly 90° to the blade. Anything less will result in gaps or unsquare joints. If you cut stock on a mitersaw, tune it up as well.
Plan your work, work your plan. After cutting but before drilling, lay out project parts in the orientation you want, and then mark the back faces, as shown below. Be sure to also draw other layout marks, such as where a middle rail lines up with the stiles. Then drill pocket holes into the marked faces to prevent accidentally drilling into the best face.
Grab the best grain. Drill pocket holes so screws thread into edge or face grain for maximum purchase; avoid screwing into end grain, as shown below.
These screws won't hold as wellthreaded into end grain. Instead,drill the pockets on the rail anddrive screws into edge grain ofthe stile.
Drilling the holes
Set the correct pocket depth. For strongest joints, set the stop collar according to your jig's instructions. The pilot point should stop 1⁄8 " from the workpiece's end or edge, as shown below. Check this each time you use the jig to avoid accidentally drilling too deep.
High speed = cleaner holes. A corded drill bores a cleaner hole than a cordless one because of its faster bit speed. Excessive tear-out around the pocket could indicate a dull bit. Keep a second bit on hand so you can switch to it when the first begins to dull.
Smooth the way. Before drilling, spray the bit with a dry lubricant, such as Bostik DriCote, to reduce drilling friction and prolong sharpness. Repeat after every 20 or so holes.
Clear chips frequently. Pull the bit out when you've reached about half depth to clear the chips; then finish drilling. This reduces friction and bit dulling.
Match up different thicknesses. When joining boards of two different thicknesses edge-to-edge or end-to-edge, as shown below, set the pocket-hole depth for the thinner board. If joining boards end-to-face or edge-to-face, such as in a table apron to the top, set the depth for the thickness of the board with the pockets, regardless of which is thinner, and then use a shorter screw if necessary.
Screw and glue
Choose the right screws. Coarse-thread pocket screws hold best in softer woods, such as pine, cedar, and poplar, as well as plywood; use fine-thread screws for hardwoods. Choose the length based on the workpiece thickness, as shown in the chart below.
Use fine-thread screws forhardwoods. Use coarse-threadscrews for softwoods, MDF,particleboard, and plywood.
Most pocket-hole screws come with an oversized washer head for increased contact with the pocket shoulder, but you can also get screws with a smaller pan head for use with shallow pockets where a washer head would protrude above the workpiece surface. For outdoor applications, choose stainless steel or coated screws. Never use drywall screws — they break easily while driving, and their tapered ("bugle") heads can split the bottoms of the pocket shoulders.
Don't forget the glue. Screws alone make a plenty-strong pocket-hole joint, but adding glue helps prevent a joint from opening up due to seasonal shrinking and swelling.
Assembling the joints
Clamp across a joint whenever possible, see photo below, to avoid the parts creeping out of alignment as you snug up the screws. Clamp parts to a perfectly flat surface so the front faces align. (If one of the parts is offset, shim below it, if needed.) When screwing an edge to a face, such as the table shown below, always clamp the assembly securely before driving screws.
Learn to drive a clutch. Although handy for driving fasteners, avoid using an impact driver for driving pocket screws. Because you can't see the screw snug up against the pocket's shoulder, the tool's high torque can easily strip out the screw hole. Instead, use a drill or cordless screwdriver with an adjustable clutch, set to pull together joints without stripping out the holes.