Very impressive. You have done well.
Box joints are much harder to make than they appear, especially these little 1/8" ones.
Mr Krymi was able to adjust his jig without fancy measurement equipment, but I never seem to be able to do it this way. I have all kinds of digital measurement tools and readouts on my power tools to get the results that I want. A machinists caliper will let you measure both inside and outside measurements, so the pins and spaces can more easily be compared. A micrometer measures only outside dimensions, so only the pin width can be measured with it. The relation between the pins and the spaces (saw cuts)
are what is important, and not the actual dimensions of either.
I always make the pins of my box joints a little long and then trim them off flush on the router table, using a flush cutting bit, after the box has been assembled and glued, but they don't need to be as long as in your first picture. By making them just a little long I never have any short pins after the glue up. Be careful not to make them too short, because there is no good fix for "too short" pins after box assembly. You can fill the small voids and chip outs with sanding dust from the same kind of wood, mixed to a thick bpaste with glue and then apply it before the final sanding steps and the joint will look good from the outside after the sanding.
You will do better with a FTG Flat Tooth Ground blade. Your's looks like it is ATG Alternate Tooth Ground from the little triangle voids at the bottom of the cut. I believe that Mr Krymi had a ATG blade in his demo saw. It will leave the bottom of the cuts clean and square. A 1/8" FTG blade is available from several sources. Mine is a Freud LM72R010 (actually 0.0126 width). It does a much better job of cutting 1/8" box joints with smooth sides and bottoms. I have the blade, but it's difficult for me to get my I-Box jig set narrow enough to get the 1/8" box joints to fit perfectly, which is why I've been hoping to find a an Original Mini Fence.
Long cuts will require the jig's white strip to be very parallel to the blade. If it isn't, the cuts will be wider than they should be, making the pins narrower than they should be. Getting them truly parallel with each other should solve your long cut problem.
A sacrificial backer of some MDF or other thin scrap wood will also reduce some of the chipping and.splintering when used behind your work as you make the cuts. If you use scrap wood, keep the grain direction the same as your work. Mr Krymi used 1/4" red cedar for his demonstration wood, because it is soft, cheap, and cuts very clean. Most other woods do not cut as clean this easily.
Please update your profile, at least enough so we know your first name. We have too many members with the first name of N/a. I could guess that it's Clive, but have been wrong before.
@hawkeye10
Don,
This jig was designed for use with a table saw. A 1/8" router bit is available, but they are very fragile, especially if made from solid carbide, and when long enough to use with a jig that's about 5/8" thick, I think this size of box joint is best done on a table saw.
Actually, I tried making larger box joints on my router table and didn't like the result, even though the I-Box jig that I was using is designed for use with either the table saw or router table. It caused too much splintering of the pin edges as the cutter exited the wood. I now only make them on my Unisaw with the I-Box jig and either my Freud 1/8" box joint blade or their 1/4 & 3/8" box joint blade set. It will also work with a good DADO set for wider pins, but I have never used it with either of my DADO blade sets. The I-Box jig has a 1/4" MDF sacrificial backer in it's design to reduce edge chipping and splintering. I use a different position in this sacrificial piece each time that I set up the jig. It's just 1/4" MDF and the first thing that I did when I received the I-Box jig was to get some 1/4" MDF and make a bunch of copies of this piece. They can be used many times before both the top and bottom of each one is completely cut up and needs replacing (they can be inverted). I'm now on my third since getting the I-Box, but I have about a dozen more of my copies left. Incra now sells these for about $3 each in 3 packs, but they are so easy and cheap to make that I will just make more myself when I begin running low. They are just rectangular strips with four countersunk holes in the middle area of each. Cut them to size with a table saw, and then set up stops on the drill press for one of the hole positions, Then drill and flip the piece 4 ways until all four holes are drilled, then change the bit for a countersink, remove the stops from the drill press, and then countersink all four holes of each piece from the smoothest side. Done. I bundle the excess and wrap them with stretch wrap, then put them in my shop cabinet for future use.
Charley
