# Routing Half-lap Joints



## Chuck50 (Dec 8, 2012)

Hey Guys,
Got a question. Is there a "safe" way to cut half-lap joints on the router? I thought it would be rather straight forward but when I tried it, my results were not good and I really thought I had tore something up.lol I tried using my tablesaw miter guage to cut the ends of the rails of a picture frame I am using to frame a jigsaw puzzle I made on the scroll saw. 
The wood was Purpleheart 3/8 thick, I measured the depth of the cut from the end of the peice, the highth of the cut for half lap, set it all up on the router, making sure my fence was not in contact with the wood, began my cut at the line for my depth of cut first. In hind site I think I should have began at the end of the board and worked it back to the depth I wanted but still don't know that I would have gotten the results I was looking for. The bit, 1/2" straight bit, pulled the board towards itself, therefore I did not get a straight cut on my first pass,( I was trying to get a full width cut with it also). Then on my second attempt with a considerably smaller width of cut, It tore out the remainder of the board and I thought I had lost an arm or something with all the racket it made throwing that little peice of wood around....needless to say, I still have no half-lap joint for my frame... I am very inexperienced with the router table and would welcome any advice or help in getting this done right and safely. Thanks

BTW - I am using a Craftsman Professional router and router table, the router had speed adjustment and soft start, would the speed setting for the type of wood have had an effect on my results???


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## jschaben (Jun 21, 2009)

Chuck50 said:


> Hey Guys,
> Got a question. Is there a "safe" way to cut half-lap joints on the router? I thought it would be rather straight forward but when I tried it, my results were not good and I really thought I had tore something up.lol I tried using my tablesaw miter guage to cut the ends of the rails of a picture frame I am using to frame a jigsaw puzzle I made on the scroll saw.
> The wood was Purpleheart 3/8 thick, I measured the depth of the cut from the end of the peice, the highth of the cut for half lap, set it all up on the router, making sure my fence was not in contact with the wood, began my cut at the line for my depth of cut first. In hind site I think I should have began at the end of the board and worked it back to the depth I wanted but still don't know that I would have gotten the results I was looking for. The bit, 1/2" straight bit, pulled the board towards itself, therefore I did not get a straight cut on my first pass,( I was trying to get a full width cut with it also). Then on my second attempt with a considerably smaller width of cut, It tore out the remainder of the board and I thought I had lost an arm or something with all the racket it made throwing that little peice of wood around....needless to say, I still have no half-lap joint for my frame... I am very inexperienced with the router table and would welcome any advice or help in getting this done right and safely. Thanks
> 
> BTW - I am using a Craftsman Professional router and router table, the router had speed adjustment and soft start, would the speed setting for the type of wood have had an effect on my results???


Hi Chuck - I've never used purpleheart (200 mile to nearest supplier) but I understand it's pretty tough stuff. Likely starting at the end and working toward the final cut would have helped. I suspect though, that the table saw miter guage wasn't providing enough support close enough to the cut. For cuts like that on the router table, I use a large push block. Mine has a replaceable sacrificial face so I cut right into it and get support completely through the cut. Also helps with tear out.


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## Mike (Nov 22, 2004)

Chuck, purpleheart machines very well and is easy to work with like walnut. You need to use a backer board to prevent tear out like with most woods. The method John posted works like a champ. Cut the end of the board first and adjust your fence back in steps/passes as needed until you reach the full depth required. Leave your miter gauge on your table saw.


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## Chuck50 (Dec 8, 2012)

Thanks John, the pic was VERY helpful. I think I can make something simular. Did you use a key hole bit to make the channel for the sacrificial face? Also, does it matter what type of wood I use for this face?


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## Chuck50 (Dec 8, 2012)

Thanks Mike, all the advice is appreciated.


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## bobj3 (Jan 17, 2006)

Lap joints are easy with the jig below.

Router Forums - View Single Post - New Beaded Face Frame System

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## Cherryville Chuck (Sep 28, 2010)

I use a method similar to John's except that I just use a square piece of mdf, ply, or particle board and hold my piece against it as I push both along the fence. If you look at John's jig you can see which way it is feeding into the bit. Were you going the same direction? If not, that is why you were being tossed around. Having the bit completely surrounded by wood without adequate holding power can cause a bit to wander too.


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## MAFoElffen (Jun 8, 2012)

*** Caution- Wear latex gloves, goggles (at least safety glasses) and a dust mask. ***

Most people are reactive to the dust. Nasal inflammation, eye irritation, nausea.. some people are reactive to the splinters.

Very beautiful wood. With Purple Heart, to prevent burning, ensure you have a sharp bit, take small bites, may have to lower the bit speed down.

An even simpler jig (like Charle's post) is to use a square piece of stock (90 degree corners) to use as a sacrificial support block. Use the sacrificial piece against the fence. Work against the fence and the support block. Continue the cut into the support block. That will act as zero clearance to prevent breakout. 

My "made" jigs are like this, with a replaceable insert to use as sacrificial.


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## Phil P (Jul 25, 2010)

MAFoElffen said:


> *** Caution- Wear latex gloves, goggles (at least safety glasses) and a dust mask. ***


I'd add to that - AND USE A DUST EXTRACTOR/VACUUM CLEANER CONNECTED TO THE ROUTER

Regards

Phil


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## jschaben (Jun 21, 2009)

Chuck50 said:


> Thanks John, the pic was VERY helpful. I think I can make something simular. Did you use a key hole bit to make the channel for the sacrificial face? Also, does it matter what type of wood I use for this face?


Hi Chuck, yes, I just used a fairly large keyhole/slot cutter (5/8" CD I think). Wouldn't have to be that large though. Sacrificial face is just 3/4" MDF. I like the slot mounting, when it gets chewed up I just whack off the end and slide it down.


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## Quillman (Aug 16, 2010)

Done with a heavy x-cut sled. Success possible with a hand router but with a sled you can manage tearout, squareness and precise depth of cut.


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