# Adjustable custom housing joint jig



## jlawford (22 Apr 2016)

Hi all- first post!

Thought I'd share the adjustable housing joint jig I finished this evening. There are plenty of designs online (mostly American); I used the plan on woodsmithshop (I can't post links yet) but it's fairly simple to construct.

Oh, and I've owned a router for a week and this is the first jig I've built.  







I've ordered some threaded stud plastic knobs to replace the bolts, and will set in tee nuts instead of using loose nuts.






Needed to cut deeper on this test but it fits well.






The router cuts bang on 90 degrees square! Well pleased. Overall look and finish could be better but it works.


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## CHJ (22 Apr 2016)

Glad it worked out as you expected.

Charley's version (video)


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## MattRoberts (22 Apr 2016)

Nice work on the jig. I made one of these a while ago, but my one was rubbish and very fiddly to use.


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## vanitycat (5 Jul 2016)

jlawford":1e09hjo7 said:


> Hi all- first post!
> 
> Thought I'd share the adjustable housing joint jig I finished this evening. There are plenty of designs online (mostly American); I used the plan on woodsmithshop (I can't post links yet) but it's fairly simple to construct.
> 
> ...



Did you use pine for the edges? If so I would be inclined to swap this out for plywood or mdf to prevent wood movement and dings affecting the accuracy of the jig 


Sent from my iPhone using Tapatalk


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## woodbrains (10 Jul 2016)

Hello,

Am I missing something, but why do they need to be adjustable? Surely the cutter makes them adjustable for the housing size, but the track the router/bush follows is the same. I have a jig fixed for a 30mm guide bush which has served for years for any width housing I need.

Mike.


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## woodenstx (20 Jul 2016)

woodbrains":2y5rjplu said:


> Hello,
> 
> Am I missing something, but why do they need to be adjustable? Surely the cutter makes them adjustable for the housing size, but the track the router/bush follows is the same. I have a jig fixed for a 30mm guide bush which has served for years for any width housing I need.
> 
> Mike.




I guess its more aimed at stock that isnt the same size as the cutter... or the subtle differences between imperial cutters and metric timber etc.

So you have X bush and Y cutter that you always pair the same, then you can simply put the jig over the wood to go in the joint and voila, perfect trench/cut/joint/wtf you wanna call it, every time.

I made a really poor go at my first one but it was actually pretty accurate despite not being pretty :lol:
I'll make a new one using laminate flooring boards in a vain attempt to get some extra depth of cut


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## paulrockliffe (20 Jul 2016)

You don't use a bush, the edge of the router follows the raised guide rail. The cutter then follows exactly the edge of the wider bottom bit of the jig, because it was cut with the router running along the raised guide rail. You then set the width by clamping the piece of wood to be sat in the housing between the two edges, set the edges where you want the housing joint to be cut and run the router through, running against one guide rail, then the other.

It's a simpler setup because you set the width using the workpiece, so no measurement and no adjusting for cutter widths and bush-offsets. And then you put the jig where the cut goes, there's no need to offset it by the gap between bush and cutter.


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## woodbrains (20 Jul 2016)

Hello,

I see, though you dont need to worry about offsets with a bush guided tee square. Just run the cutter through the tee part and that shows you exactly where to line up the guide against your layout marks. Since router cutters only come in (many) fixed sizes, you always have to size your timber to one or other of them, (the one you have!) so an infinitely variable jig is not as useful as first seems.

Mike.


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## paulrockliffe (20 Jul 2016)

OK, I understand what you mean about the guide bush, it's the same principle. 

You don't need to size the timber to match on of the cutters though, so long as you use a cutter that's a smaller diameter than the dado width you can use any size you want. You just use both edges of he jig to give you the right width.


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## Shrubby (21 Jul 2016)

If you add a sacrificial piece to the front fence which you then cut through I find it helps in lining up to your pencil marks without any measuring. 
Matt


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## Eric The Viking (21 Jul 2016)

If you want cleaner edges to the cut, and assuming your cutter is as wide as the slot (designs vary), scribe the edges with a sharp knife before using the router. 

I'm with Shrubby too: tearout at the ends of the housing is almost unavoidable in softwood, unless you use sacrifical strips tight to the edges of the board.


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## Steve Maskery (4 Aug 2016)

The trick for the far end is to come in backwards for a few mm before making the main forward cut.

Although the edge is theoretically the same as the cutter, always, in practice the edge wears a little. The result is that the joint can be a bit tight, causing the board to bend. This is particularly true if you have the cutter sharpened, as sharpening reduces its diameter slightly.

One way round this is to make the jig originally for, say, an 8mm cutter, then when it is a bit worn, recut it with a 10mm cutter, and later again up to 12mm. Or the imperial equivalents, of course.


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