# need half lap joint jig



## DJeansonne (Mar 27, 2009)

I make a lap joint of two pieces that are angled at approximately 15deg. I do this now on a radial arm saw using a dado blade but the setup takes a lot of time to get the angle accurate. These are for swing supports members.

Does anyone have or know of how to fabricate a router jig to cut half laps on the ends of boards at an angle (not perpendicular)?


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## Gene Howe (Jul 10, 2007)

DJeansonne said:


> I make a lap joint of two pieces that are angled at approximately 15deg. I do this now on a radial arm saw using a dado blade but the setup takes a lot of time to get the angle accurate. These are for swing supports members.
> 
> Does anyone have or know of how to fabricate a router jig to cut half laps on the ends of boards at an angle (not perpendicular)?


Don,
Just my opinion: The RAS is probably your most efficient tool to use. I'm thinking that the length of your legs are probably giving you fits unless you have a system to support them off the RAS table. 
To maintain the 15 deg. angle and keep the RAS at 90 deg., I'd make an aux. "fence" of 3/4 mdf with a miter to give you a 15 deg. angle. Make the fence deep enough to allow the leg to run past and not contact the permanent fence. I'd make the aux. fence long enough to extend from the blade to the edge/side of the RAS table. Just shove the "fence" up tight against the RAS's permanent fence. The wide edge of the "fence" will allow clamping. 

Others may be able to devise a router jig but, I'd imagine that using a router would require much more time for the many passes for depth and width. 

Good luck.

Gene


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## bobj3 (Jan 17, 2006)

Hi Don

The router table is the way to get a nice CLEAN way of doing it,,the RAS will always leave the marks of the blade on the stock 
The jig below is a easy one to make and can be moved and locked easy for the angle you want to use..

I will post one picture but if you want more just ask>or check out my gallery 

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DJeansonne said:


> I make a lap joint of two pieces that are angled at approximately 15deg. I do this now on a radial arm saw using a dado blade but the setup takes a lot of time to get the angle accurate. These are for swing supports members.
> 
> Does anyone have or know of how to fabricate a router jig to cut half laps on the ends of boards at an angle (not perpendicular)?


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## Ghidrah (Oct 21, 2008)

Porter cable has an attachment, (model 7318 tilt Lam trim base) for their Lam routers, (older ones, don't know about the new models) that tilts 30° left and 45° right. So all you have to do is clamp a straight edge for an offset and route away.

I've used mine plenty of times in the past, ensure a nice sharp bit, do a couple practice runs to get used to how it handles and make the stock wider or have a sacrificial piece clamped up for the ends


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## allthunbs (Jun 22, 2008)

DJeansonne said:


> I make a lap joint of two pieces that are angled at approximately 15deg. I do this now on a radial arm saw using a dado blade but the setup takes a lot of time to get the angle accurate. These are for swing supports members.
> 
> Does anyone have or know of how to fabricate a router jig to cut half laps on the ends of boards at an angle (not perpendicular)?


Bon Jour Don:

Have you considered skis?

Salut

Allthunbs


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## DJeansonne (Mar 27, 2009)

*rouer tilt*



Ghidrah said:


> Porter cable has an attachment, (model 7318 tilt Lam trim base) for their Lam routers, (older ones, don't know about the new models) that tilts 30° left and 45° right. So all you have to do is clamp a straight edge for an offset and route away.
> 
> I've used mine plenty of times in the past, ensure a nice sharp bit, do a couple practice runs to get used to how it handles and make the stock wider or have a sacrificial piece clamped up for the ends


This looks like an angle tilt to the edge of the board??? I need an angle on the flat side (3.5" side of a 3/4" x 3 1/2" board). I don't see how this attachment would work? If I am missing it please explain more.


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## DJeansonne (Mar 27, 2009)

*more help with skis*



allthunbs said:


> Bon Jour Don:
> 
> Have you considered skis?
> 
> ...


I was thinking that skis would be the right thing but I need some sort of guide for the skis that sets the angle???? Any ideas?


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## DJeansonne (Mar 27, 2009)

*very possible solution*



bobj3 said:


> Hi Don
> 
> The router table is the way to get a nice CLEAN way of doing it,,the RAS will always leave the marks of the blade on the stock
> The jig below is a easy one to make and can be moved and locked easy for the angle you want to use..
> ...


Bob this looks like something that would work. I wasn't thinking of a router table jig but this has potential.
Thanks


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## bobj3 (Jan 17, 2006)

HI Don

You're Welcome 

I have done it with a plunge router jig,,but it just will not come out right,,1/64" is a big deal when it comes to lap joints..one is not to bad but when you have more than two ,well I'm sure know..as I'm sure you know,once the stock is removed you can't put it back easy  that's why the router table is a great tool to do it with  once set it's set no guessing..

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DJeansonne said:


> Bob this looks like something that would work. I wasn't thinking of a router table jig but this has potential.
> Thanks


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## allthunbs (Jun 22, 2008)

DJeansonne said:


> I was thinking that skis would be the right thing but I need some sort of guide for the skis that sets the angle???? Any ideas?


Ok, this is a bit of creative thinking here. I don't know what router you have so I'll describe how I'd do it and you see if you can make it work for you.

I have a M12V (Hitachi) that uses 12mm rods for the straight edge guide. If I substitute 12mm drill rod or other mild steel rod, thread the ends (12mm rod, 7/16 thread leave a nice shoulder for a washer and reduces the necessity for clamping nuts.

Ok, put your board at the angle you're wanting. (I use cedar shingles stacked to give me the angle. Play around a bit with them and mixing various sizes, you should be able to get an accurate angle. Clamp securely.

Set the depth of cut on your router (now mounted in the skis) to the final depth of cut. Do a few experiments on scraps first and hone your accuracy with that. You should be able to taper something as long as you can support, wedge and clamp.

I hope this makes sense and helps.

Allthunbs


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## bobj3 (Jan 17, 2006)

Hi Don

The M & T jig can do this easy 

see picture below 

Details for Trend® Mortise & Tenon Jig - Rockler Woodworking Tools
http://www.routerforums.com/show-n-tell/10133-birch-m-t-jig.html

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## jw2170 (Jan 24, 2008)

DJeansonne said:


> I make a lap joint of two pieces that are angled at approximately 15deg. I do this now on a radial arm saw using a dado blade but the setup takes a lot of time to get the angle accurate. These are for swing supports members.
> 
> Does anyone have or know of how to fabricate a router jig to cut half laps on the ends of boards at an angle (not perpendicular)?


Hi Don,

Do you have access to Pat Warner's DVD,

He shows how to accomplish what you seem to need. very easy, but I would have trouble describing the method//////

No jigs required.


James


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