# Router tear out box joint



## jdmm (Jan 16, 2019)

Tried making a box joint box with a porter cable dovetail jig on a 1x6 piece of oak. Had massive tear-out at medium speed and less but still a lot at higher speeds. I fed it nice and easy but it was chattering like I was working plywood, not oak. All I can think of is I need a better bit? Using that came in a set of 15 from ml woodworking. Maybe I’m doing something wrong? Any thoughts welcome.


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## sunnybob (Sep 3, 2016)

Cutting across end grain with a router you need a backing board clamped tightly to the work piece.
And dont go too slow with the router speed. The faster it spins, the smaller each cut is.
There are charts online that show the best speed for the diameter of each bit.


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## redeared (Feb 7, 2019)

On occasion I have had wood that just wouldn't route nice no matter what I did. I could do 20 pieces from the same stock and then one was a total mess.


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## Mark Jones Ozark (Feb 26, 2019)

Almost all of the Box joint jigs I have been researching use a waste board that is clamped in with the real boards some use them in the front and back as well. 

I have some maple that I can't surface it as it will chip out terribly. Planer does fine on oak and pine and cedar and some of the maple planes fine. It's a wonder some times.

I have been looking at Box joint jigs for a couple of weeks on youtube. I made a dovetail template out of lexan 20" wide. Then one day my bit slid up in the collet and ate a couple of fingers.... Routers eat all kinds of my projects....ha!


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## RickKr (Jun 19, 2018)

Mark Jones Ozark said:


> ...snip...
> I have been looking at Box joint jigs for a couple of weeks on youtube....snip...


Have you looked at the Incra LS Positioner System for box and dovetail joints? I looked at a number of jigs and almost bought the Incra Box Joint jig before I found the LS system. I bought the 17" LS Positioner Wonder Fence system for a router table. Love it. I haven't done a lot with the box and dovetail joints, but I've adapted it to my SawStop JobSite table saw and the crosscut sled and use it more as a precision fence. The LS fence is too long to fit in my crosscut sled, so I pirated the fence from a Kreg bandsaw fence, that I don't use. Since the photos, I have shifted the LS base/slider over close to the near sled fence so the support of the slider is opposite most where cuts happen. 

I very much liked the wide variety of options on width and spacing of the LS system when it comes to the joint making. It is an expensive option and they take a long time to receive after ordering, but I am thrilled with mine. 

Rick


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## CharleyL (Jan 13, 2019)

I've tried routing box joints and never was happy with the results. I even bought the Box Joint Template for my Leigh D4R jig. A sacrificial piece is needed on both sides of the work to prevent tear-out, because the router bit is actually cutting the wood in both directions, and each time you make a box cut joint you need another pair of sacrificial strips. Just the set-up time for me made doing it and getting good results using a router just not worth it.

I can get much better results easier using my table saw. Only one sacrificial piece is needed, and if you don't change any adjustments, the same sacrificial piece can be used over and over. I make a lot of boxes and love making them with nice clean box joint cuts. I have tried many ways, but have settled on using an Incra I-Box jig and usually using the Freud SBOX8 blade set to produce 1/4 or 3/8" box joints. The sacrificial strip is a piece of 1/4" MDF, and it's part of the I-Box jig. Each time that I cut box joints, once I have everything set, including the blade height, I move the piece of MDF to an un-cut position, and then begin cutting my box joints. The piece of MDF can be shifted left and right until the edge has been mostly used up, and then it can be inverted to use for more box joint cutting. 

I bought a 2' X 4' piece of 1/4" MDF from Home Depot for about $5 and used the original I-Box sacrificial strip as a pattern to make more. I don't remember how many that I got out of that 2' X 4' piece, but I doubt that I'll ever need any more in the rest of my lifetime, since I can make about 40 or more different box joint setups using just 1 of those. I've had my I-Box jig since they first came out, and I think I'm on my third sacrificial strip with over a dozen still in the closet. Outside of cutting them to size, they need four countersunk holes drilled in them. One pair of stops on a drill press table will let you drill the first hole, then flip the piece over and drill the second hole. Flip the piece end for end and drill the remaining two holes. Replace the bit with a countersink and remove the fence stops, and countersink all 4 holes from the smooth side of the MDF. I was done making all of them in about an hour. Incra sells them in a pack of 3 for $10 plus shipping. 

Many of my box jointed boxes have even been made from plywood. Years ago when I first wanted to make box joints I can remember someone telling me "You can't make box joints in plywood", but when using my table saw, I-Box jig, and either the SBOX8 blade set or other FTG ground saw blade, or even my dado blade set, I can get good results easily, even in plywood. I now do it frequently using Baltic Birch plywood for the boxes and I can get the same results when using solid hard or soft woods too. The I-Box jig makes it easy to adjust for different sized box joints. I can adjust it for size and then make just one quick test cut to be certain that it is right before doing my project box joints. The I-Box jig changes both the pin and cut width at the same time with just 1 knob adjustment, once the jig has initially been calibrated, so it's easy to change from one size joint to another. I had about 15 shop made box joint jigs before getting the I-Box jig, one for each size box joint. Some worked well, and some were just OK. They all became firewood when I got the I-Box jig, and it saved shop space too. 

Photos speak louder than words. Here are a few. I'm never going back to routing box joints or even shop made box joint jigs.

Charley


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## jdmm (Jan 16, 2019)

Those look nice! I think I will experiment with a homemade table saw jig. Funny how the jig I have cuts half-blind dovetails with no problems, but I guess that is because the horizontal work piece functions as a back stop.
An earlier poster said he lost some fingers when the router shifted, my heart skipped a beat until I realized was talking about the joinery (I hope) !!!
-John


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## Mark Jones Ozark (Feb 26, 2019)

jdmm said:


> Those look nice! I think I will experiment with a homemade table saw jig. Funny how the jig I have cuts half-blind dovetails with no problems, but I guess that is because the horizontal work piece functions as a back stop.
> An earlier poster said he lost some fingers when the router shifted, my heart skipped a beat until I realized was talking about the joinery (I hope) !!!
> -John


I was talking about the lexan fingers of the jig. Watch those Router bits. They will slip up and down in the collet and eat up all kinds of stuff. 
I have all my human fingers in good shape. They are just getting older! Ha!


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## MaintenanceMan (Jun 25, 2010)

I've seen that as a common problem with router box-joint jigs. Most of my experience with box-joints is on the table saw. I recently started using the incra ibox jig and it's great. Highly recommend it.


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