I give up on box/finger joints

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Forum topic by Tom posted 09-12-2015 10:53 PM 1923 views 0 times favorited 37 replies Add to Favorites Watch
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175 posts in 1060 days

09-12-2015 10:53 PM

After trying for the 4th time to get finger joints to work I give up. By the time I’d reached the end of the 8” board they were off an 1/8th of an inch. I’ve followed many people on YouTube and I think that all their prefect joints are special effects…or the fact that they all seem to have cabinet maker grade saws and not a cheap Home Depot Ryobi saw.

I”m just not sure what I’m doing wrong. I set the blade to do 3/8” wide cut since I’m using 1/4” poplar boards. I put in my key and measured; the test cut seemed fine. I took some scrap and the joints were tight but worked. When I did my project pieces they’re all messed up. I’m not going to run out to buy a jig since that’’s not in the budget for the few projects I’m going to do. Would using a router table be a better way instead of the table saw? At this point I’m just lost and very frustrated.

37 replies so far

View Dallas's profile


3599 posts in 2487 days

#1 posted 09-12-2015 11:16 PM

It sounds to me like your key is too loose. The cut should fit on easily but with a bit of friction.
If it is too loose every cut you make after the first one will have a compounded error so the farther you go the farther off it will be.

-- Improvise.... Adapt...... Overcome!

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3250 posts in 1988 days

#2 posted 09-12-2015 11:22 PM

I make them on a router table with a jig I made and a spiral router bit.

There is no doubt that it is not easy to get perfect ones and takes a good setup and practice joints.

View waho6o9's profile


8191 posts in 2577 days

#3 posted 09-12-2015 11:44 PM

William Ng has a you tube video and you’ll make it em perfect.

View drewpy's profile


806 posts in 1357 days

#4 posted 09-12-2015 11:48 PM

I make them on a router table with a jig I made – found the idea for my jig on you tube. I just feel more comfortable and confident on a smaller table.

I agree with Dallas, sounds like your key is loose.

-- Drew -- "The greatest wealth is health".

View Tom's profile


175 posts in 1060 days

#5 posted 09-13-2015 12:02 AM

I’ve seen William’s video and he’s like the rest…professional grade tools and years of experience. I’ve looked into making a router table but figure my time and money would be better used either picking one up on Craigslist or the $70 one that Searsh has. It’ll let me (try) to get box joints right and will also give me a nice fens to do other joints.

View gfadvm's profile


14940 posts in 2690 days

#6 posted 09-13-2015 12:23 AM

Starfury, I made a lot of perfect fitting box joints with a cheapo Ryobi tablesaw, Harbor Freight dado set, and a shop made jig. Assuming you attach your jig to the miter gauge, I have several suggestions:
Your key has to be EXACTLY the width of your dado kerf.
The key has to be EXACTLY 1 saw kerf width from the blade.
There can be NO wobble in your miter gauge.
Blade MUST be 90 degrees to the table surface.

I have done box joints on the router table but they are MUCH faster and more repeatable on the tablesaw (the spinning router bit tends to move the stock) and you get more tear out.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

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740 posts in 2850 days

#7 posted 09-13-2015 12:43 AM

Buy an I Box from Incra and a quality stacked dado set and you will cut perfect finger joints on your table saw every time, for ever. I’ve made my own finger joint jig before. After repetitive use it wouldn’t make tight joints. Tried tuning it up a few times but finally gave up and bought the I Box. No brainer, this tool will perform for the rest of my life.,

-- Ken

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5423 posts in 3663 days

#8 posted 09-13-2015 02:30 AM

I just finished three drawers with box joints tonight … I have a Freud box-joint blade set, and a Woodsmith aluminum jig.

Before I got the tools I am using now, I made dozens of drawers and boxes with a cheap set of dado blades from Harbor Freight, and a jig I made out of scraps.

gfadvm is spot on … if the key isn’t exactly the same width as your kerf, you are wasting your time.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View waho6o9's profile


8191 posts in 2577 days

#9 posted 09-13-2015 02:51 AM

View BurlyBob's profile


5494 posts in 2265 days

#10 posted 09-13-2015 02:55 AM

I built box joint jig using the Woodsmith jig kit. It’s got all the hardware and it’s fairly simple to build. It works really well.

View a1Jim's profile


117091 posts in 3577 days

#11 posted 09-13-2015 03:06 AM

Excuse my chuckle but your quitting after 4 trys? .As a person with dyslexic tendencies I may have to try new techniques 50 times or more before I get them to work. As gfadVm said all aspects of the operation has to be dead on accurate, the key.the space from the key and the width of the daddo blade.
Hang in there I know can do it,this apply’s to many aspects of woodworking.

-- wood crafting & woodworking classes

View TheFridge's profile


9477 posts in 1486 days

#12 posted 09-13-2015 03:10 AM

William Ng has a you tube video and you ll make it em perfect.

- waho6o9

it works.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View JAAune's profile


1799 posts in 2317 days

#13 posted 09-13-2015 03:44 AM

Start at the source and work up from there. First make sure the saw is setup perfectly (slots aligned, run-out, etc.) then check on the accuracy of the miter gauge or sled (whichever you use), then confirm the key is perfectly positioned and sized. Last step is to make sure the stock used is perfectly milled.

Many persistent problems are hard to identify because they aren’t caused by any one major error but rather, an accumulation of many small, issues.

Take things slow and work methodically and build a solid foundation before advancing. That saves hours of frustration in the long run.

My first box joints were done on a portable Makita using a standard saw blade that made narrow fingers. Once everything was dialed in, the joints came out perfect. Positioning that key took a while. As everyone else has said. It has to be perfect. An error of .004” will grow into an error of .128” if doing 1/4” fingers across 8” of width.

-- See my work at and

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4139 posts in 2309 days

#14 posted 09-13-2015 07:05 AM

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1028 posts in 1575 days

#15 posted 09-13-2015 07:20 AM

build yourself a crosscut sled,a well made one,not a fancy just well made it will serve you well for years,then go back to the tube or fine woodworking,and fine one of the simple jigs,you may only use the jig one but to get it right it will feel like it’s worth it.
The cheap contractor saw and the 3k SS do the same thing,spin a blade.the cheap saw you just have to tweak them sometimes.

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