# Chipout when using finger joint jig



## jihhwood (Dec 13, 2006)

Most of my efforts thus far to make finger joints (for the small boxes I make) leave me frustrated. I made a jig that works just fine. The problem is chip-out -- whether I use a 1/4 inch or a 3/8 inch bit (both bits are in reasonably good condition so far as I can tell; I share a shop). I make some boxes from cherry, others from pine; the pine is more troublesome. The jig I use has a masonite (expendable) backing at the point of the cut, so the workpiece is supported there. I've tried using tape on the workpiece. and I've tried making my cut in several shallow passes. What am I doing wrong? Does anyone have techniques that I've not tried? Thanks.


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## bobj3 (Jan 17, 2006)

Hi jihhwood

It maybe your jig is just off a bit,the best one I have found is the the Oak-Park box jigs,quick and easy.
Here's a link to a jig I use and it works great with the Oak-Park jigs.
http://www.routerforums.com/jigs-fixtures/3543-deluxe-push-block.html

Plus here's a tip I use when I run into chip out,I used some 1/8" MDF stock on both sides of the slot.I put on some double sided carpet tape and stick the MDF on, the MDF will make a chip breaker front and backsides.MDF is cheap unlike cherry or other hardwoods. 


But if you are using up to 1/2" stock you may want to take a look at the bit below,it's works great on hardwood like cherry because the bit cleans out the slot quicker and cleaner. 

Box Joint Bit
http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_windo.html

Make perfect box joints with speed and ease by using our precision carbide cutters. 
Strong, beautiful box joints are ideal for jewelry box drawers, humidors and a variety of small projects. 
The long 1/2" arbor holds 5 (5/32") three-wing, carbide-tipped slot cutters, 4 spacers and a ball bearing guide. Use in router table only. 
The bearing is designed for 1/2" depth of cut, but make shallower cuts by adjusting your router fence. 
Use stock up to 1/2" thick. 
For stock from 1/8" to 3/8" replace bearing with bearing #12111- #12114.

Bj


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## Mike (Nov 22, 2004)

I use a piece of 4 x 4" pine as my backer board. This gives great support and keeps the piece square and aligned with the jig. If you twist as you cut you will get tear out. Other than that my best guess is you need a sharpening job on your bit.


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## jihhwood (Dec 13, 2006)

Thanks. I will look into the various options you mentioned. I'm certain this is a solvable problem!

Joe


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