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I just responded to another post "Box Joint Jig" on this forum, with pictures of some of my box jointed projects, made using an Incra I-Box jig and Freud SBOX8 blade set. I gave up trying to make box joints with a router and Leigh Box Joint Jig template for my D4R jig. You will get far better box joints using the Incra I-Box jig on a table saw with a blade set like the Freud SBOX8 than I ever got when using a router. Please read my reply to this other post.
Charley
Contributor
I use my table saw with a Freud box joint set and a shop made jig. Works like a charm.
15226667349_c4cac1902a_c.jpg 4964851384_bc9d3112e9_c.jpg
Sharp solves all manner of problems.
Originally Posted by John TenEyck
+1. I gang parts on the tablesaw but, would be reluctant to do this on the router table. My table motor is powerful enough but, burning becomes a concern IME as the feed speed is slower than on a tablesaw.
"A hen is only an egg's way of making another egg".
– Samuel Butler
Contributor
Incra suggests ganging parts together, when possible, for cutting box joints and dovetails on the router table with their jig. I've been doing it that way for at least 10 years and have had no issues with bits burning.
John
Excellent. It is great how a little info on the forum can potentially change your approach to a task. I'll give it a whirl next time.
"A hen is only an egg's way of making another egg".
– Samuel Butler
Member
Use a router, you don't have a table saw. A better question would have been, how to produce finger joints efficiently?
What quantity is production?
[OP]
Member
Who knows since it's an item not yet in production... just a dream in my heart and a prototype (small guitar amp) I've made one of... on the second question that is. But if I'm going to set up to build something, I'd like to set it up to be easily scaled for production the first time if at all practical. The difference in cost between router setup and a used table saw setup isn't much in the grand scheme.
The thing that got me with the router is that I can only do 2 pieces at a time and that there's tear out on the toward me side (which isn't protected with a backer board).
Contributor
Who knows since it's an item not yet in production... just a dream in my heart and a prototype (small guitar amp) I've made one of
The thing that got me with the router is that I can only do 2 pieces at a time and that there's tear out on the toward me side (which isn't protected with a backer board).
That really isn't the case. You can gang up at least 6 parts and clamp them together. Here's an old photo when I was cutting some dovetails:
IMG_3327.JPG
It's no different when cutting finger joints. The backer board is part of the right angle jig the parts are clamped too. I'm using an Incra jig here but it's no different if you are using the classic style jig with a fence and key. The piece closest to the fence indexes over the key; the ones in front are automatically aligned as long as you have clamped them together correctly. For finger joints on the router table I put a backer on the front and fence itself is the backer on the exit side.
But you asked which approach is faster and that would be the tablesaw. Same method if using the classic style jig either way. Here's a picture of the Stump Nubs tablesaw finger joint jig. You can see how it's designed so that parts can be ganged together for cutting.
IMG_3545.JPG
John
Contributor
Use an upcut spiral bit.
Member
With a router, you really need a sacrificial backer on both sides of the work to get clean sharp cuts, even if you use a spiral bit. A router bit cuts in both directions as it passes through the wood and the exit of the cutter is what causes the tear out. When box joints are cut on a table saw, the blade is only exiting the wood on the side nearest the operator, so that is the only side that needs the sacrificial piece.
Please see my post here https://sawmillcreek.org/showthread....-box-joint-jig I posted photos of box joints that were made on my table saw using a Freud SBOX* blade set and an Incra I-Box jig, which has a sacrificial backer included in the jig for the exit side of the blade. Using a new position of the sacrificial backer each time right after the jig and saw are set up, and just before cutting the work at that setting will get you the cleanest box joints. I can get perfect box joints with this combination as evidenced in the photos that I attached to that post.
Charley
[OP]
Member
Exactly. This is my beef with the router. I'm going to ditch the router comb in favor of a TS when it comes time to do box joints again. I was just making sure that I wasn't missing anything.
One trick I did forget about is Larry Edgerton's mention of the upcut spiral. That would no doubt improve things. They're not common (or cheap) however with bearings between the shank and cutter.
Member
Again, a router bit (even an up spiral) cuts in both directions at once. It cuts into the wood at the same time the blade is also cutting out of the wood. A sacrificial piece is required on the face side of your work, not to prevent splintering where the bit's blade enters the wood, but where it exits on the other side of the bit. Then you need the second sacrificial piece on the other side of your work to prevent the same problems as the bit exits the work, because it again it cutting out as well as into the wood at the same time. You need the surface of your work protected on the left side of the cut as the bit enters the wood, and on the right as the bit exits the back side of the work.
A table saw blade only cuts in one direction (down) into the zero clearance insert in the table. Here, the teeth are exiting the work on the back side of the work, and the zero clearance insert is protecting the edges on the back side of the work from chipping. In a box joint jig the table saw blade also exits the work only in one direction, so a sacrificial zero clearance function only needs to be provided on that side of the work, and the Incra I-Box has this sacrificial insert designed into it. All you need to remember to do is to position it to a fresh position after you have the jig and saw blade height set up and just before you begin cutting your box joints.
If you want to use the Incra I-Box jig with a router table and bit, you need to do this with the internal sacrificial strip as well as have a second sacrificial strip attached to the back side of your work piece to prevent chipping out of the back side as the bit exits your work. Since this second sacrificial strip has no way of being held in the exact same position after every cut, it needs to be temporarily attached to your work piece, and will need to be replaced every time you are about to begin cutting your next work piece. The sacrificial strip inside the I-Box jig is held in a constant position in reference to the jig, so it can be used over and over for the duration of that bit and setting use, but may begin to wear out some if used constantly for many hours of cutting at the same jig and bit settings.
Charley
Contributor
Your theory is flawed by reality. Have been doing box joint drawers on a JDS for years and have absolutely zero problems. Thousands of drawers in all kinds of species. I did it on the tablesaw when I started because that is what I had but I certianly will never do it that way again.
Contributor
You can avoid tearout on a Leigh type jig by doing a shallow climb cut from right to left before making the full depth cut.
Contributor
I've only done several hundred drawers but in my reality I get chip out on the infeed side on the router table no matter what type of bit I use. It's most pronounced with plywood but solid wood isn't immune either. If you are saying you don't then you must be doing something differently and I'd love to know what it is. For reference, I'm taking about full depth, one pass cuts.
John
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