# Routing large lap joints - lots of them...



## Carrot (Jan 7, 2009)

I am planning a new garden shed.

Part of my design involves quite a lot of cross and end lap joints.

Now I know a lot of people recommend just butt-jointing but it's my project and I'm being stubborn on this one >

If it were just a few joints I would do them buy hand - but having totalled up the timbers and intersections I am looking at about 100 joints :surprise:

To make matters worse, they are big joints - 63mm square and 19mm deep for most of them.

My plan is to clamp multiple timbers together and run the router across them, but with such a large amount of timber to remove and only a cheap router at my disposal, I'm worried it will be too much for it.

I had a thought - If I set my circular saw to a little less than the final depth and make several cuts with it, much like I would when making the kerf's by hand, and then use the router to remove the remainder and set the final depth.

Is this a good strategy do you think?


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## Stick486 (Jan 4, 2013)

Carrot said:


> I am planning a new garden shed.
> 
> Part of my design involves quite a lot of cross and end lap joints.
> 
> ...


have a look see here...
Oliver aka Gaffboat has your method, jig and answer...

http://www.routerforums.com/general-routing/60401-setups-rout-wide-long-area.html


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## Carrot (Jan 7, 2009)

Stick486 said:


> have a look see here...
> Oliver aka Gaffboat has your method, jig and answer...
> 
> [can't post the url ]


Excellent - so I wasn't being daft then - that was practically what I was thinking of doing, but those sketchups sure helped visualise it.


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## Cherryville Chuck (Sep 28, 2010)

It's always a good idea to remove as much of the waste with a more efficient tool no matter what the routing operation. If it's a hole or mortice then drill the waste, skil saw in this case where you have a lap, following a pattern then bandsaw or jigsaw, etc. Routers are a finishing tool. They aren't good at removing a lot of wood.


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## patlaw (Jan 4, 2010)

Cherryville Chuck said:


> Routers are a finishing tool. They aren't good at removing a lot of wood.


That's actually a quite helpful comment for us beginners. Thanks.


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## Stick486 (Jan 4, 2013)

Carrot said:


> Excellent - so I wasn't being daft then - that was practically what I was thinking of doing, but those sketchups sure helped visualize it.


daft is a good thing...
we understand and communicate well in daft here...


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## TwoSkies57 (Feb 23, 2009)

Stick486 said:


> daft is a good thing...
> we understand and communicate well in daft here...


Being multi-lingual certainly has its advantages :grin:


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## Stick486 (Jan 4, 2013)

TwoSkies57 said:


> Being mufti-lingual certainly has its advantages :grin:


being well versed in typonese is a major plus...


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## Carrot (Jan 7, 2009)

I'm multi lingual


I can do British, American and Australian...

As well as endless gibberish!


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## DaninVan (Jan 1, 2012)

Jon, doing multiple timbers at the same time is for sure the way to go!
Gang cutting on jobsites is standard practice, especially for something like you're doing.
I often have to do that on 4 x 4/6x6 posts, where they'll be supporting beams or box joists. Just makes sense; huge time saver, and way easier on your tools.

Here's a discussion on the concept...
contractortalk.com/f14/cutting-rafters-88708/


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## patlaw (Jan 4, 2010)

In hindsight, wouldn't a radial arm saw with a dado blade have been a good solution? That's what Norm would have done in the day.


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## vindaloo (May 30, 2009)

*Here's* another option Jon


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## Stick486 (Jan 4, 2013)

Carrot said:


> I'm multi lingual
> 
> 
> I can do British, American and Australian...
> ...


drooling adds character...


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## Carrot (Jan 7, 2009)

patlaw said:


> In hindsight, wouldn't a radial arm saw with a dado blade have been a good solution? That's what Norm would have done in the day.


Maybe, but I am in Britain, unfortunately we do not have space for entire factories in our back gardens (yards).

I only have hand tools (plus a small, cheap router table) and no space for that really.



vindaloo said:


> *Here's* another option Jon


Stumbled across that when doing my own research, but thanks for the link.


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## Carrot (Jan 7, 2009)

OK, back to the serious stuff...

Based on the above I will saw out and snap off as much as possible and finish with the router.

I presume a straight bit is the best here, bit what size?

My router is cheap, only 1250W (variable speed and soft start though), and has a choice of 6mm, 6.35mm (¼"?) and 8mm collets.


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## Quillman (Aug 16, 2010)

Did this one with a big 14 degree dovetail bit.
Wastes a lot quickly and the lap wedges. It resists twist and assembly is twice as easy as a standard flat lap.


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## Mike (Nov 22, 2004)

Neat idea Pat. I may make use of that soon.


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## Carrot (Jan 7, 2009)

Quillman said:


> Did this one with a big 14 degree dovetail bit.
> Wastes a lot quickly and the lap wedges. It resists twist and assembly is twice as easy as a standard flat lap.


That's OK for the end laps, but I have a lot of cross laps and only a fraction of end laps.


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## vindaloo (May 30, 2009)

Carrot said:


> OK, back to the serious stuff...
> 
> Based on the above I will saw out and snap off as much as possible and finish with the router.
> 
> ...


You can either use a straight bit or a flush trim bit.

Using a flush trim bit, grad a flat peice of scrap sheet material and line the straight edge up with the edge of the lap, the run the bearing on the flush trim bit along the sheet material.

Using a straight bit you would need to make the guide, that the router would run along, the same distance from the edge of the lap joint and the distance from edge of router base plate to cutter.

Wealden do some lovely bits. I've tried the cheaper one from faithful and silverline, but they are really 'disposable'.

See *here for 8mm shank straight*, *here for 1/4" straight*, and *here for trimmers*.

They do next day delivery included. Just a minimal postage charge for orders under £15.00 but, trust me, when you see the quality and what they have you'll spend more than that


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## mgmine (Jan 16, 2012)

Will your base fit into the space that you need to route out? You can build a jig but it sounds like a lot of moving and adjusting to me which equates to a lot of time. I would do as you plan and make a series of cuts with a circular saw but I would use a chisel to knock the waste out. It's going to be a shed so it doesn't have to be furniture grade smooth. If you want it smoother use a block plane or a belt sander. Sometimes what seems like the quickest way takes the longest time. A band saw would be the perfect tool for this project.


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## BIGROMO (Mar 16, 2015)

Have you considered trying to use a dado blade in your circular saw? I have been thinking about doing something like this and trying to use one of the wobble dado blades that you adjust to width in a regular circular saw (not sure yet may have to modify the spacing on the bottom support or remove the blade guard that kicks up out of the way as you move it into the piece). I also though using a regular stackable dado blade or some of the components would work. It certainly works in a radial arm saw but I wanted something quick easy and portable to accomplish this and I'd dedicate an inexpensive circular saw to it and leave the blades in it.


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## Quillman (Aug 16, 2010)

"That's OK for the end laps, but I have a lot of cross laps and only a fraction of end laps."
****************************************
Still applicable (14° DT). Middle of the board excavation can also be wasted with the DT bit.
Now the edges of your rail (also fully or partly dovetail profiled) slide into the excavation & they're stuck there royally. More work, but stuff that lasts always does.


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## Cherryville Chuck (Sep 28, 2010)

BIGROMO said:


> Have you considered trying to use a dado blade in your circular saw? I have been thinking about doing something like this and trying to use one of the wobble dado blades that you adjust to width in a regular circular saw (not sure yet may have to modify the spacing on the bottom support or remove the blade guard that kicks up out of the way as you move it into the piece). I also though using a regular stackable dado blade or some of the components would work. It certainly works in a radial arm saw but I wanted something quick easy and portable to accomplish this and I'd dedicate an inexpensive circular saw to it and leave the blades in it.


I don't think you could add any extra blades onto a circular saw. The thrust washer that holds the blade on doesn't have a round hole. It has two flat sides on all the ones I am familiar with. Extra blades would prevent the flats on the washer meshing with the flats on the arbor and the blades would just spin on the arbor then.


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## DaninVan (Jan 1, 2012)

*Holy Hanna!*

Unless you've got a lot of spare change...

Didn't even know this existed! :surprise:


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## Stick486 (Jan 4, 2013)

that is one dangerous piece of equipment....


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## Carrot (Jan 7, 2009)

vindaloo said:


> You can either use a straight bit or a flush trim bit.
> 
> Using a flush trim bit, grad a flat peice of scrap sheet material and line the straight edge up with the edge of the lap, the run the bearing on the flush trim bit along the sheet material.
> 
> ...


Please don't take this the wrong way, I'm not being a grammar nazi or anything, I just want to make sure I am understanding what you are saying.

Should that have read...

_Using a flush trim bit, gra*b* a flat piece of scrap sheet material and line the straight edge up with the edge of the lap, the*n* run the bearing on the flush trim bit along the sheet material._?

If not, what do you mean by "grad"?




mgmine said:


> Will your base fit into the space that you need to route out? You can build a jig but it sounds like a lot of moving and adjusting to me which equates to a lot of time. I would do as you plan and make a series of cuts with a circular saw but I would use a chisel to knock the waste out. It's going to be a shed so it doesn't have to be furniture grade smooth. If you want it smoother use a block plane or a belt sander. Sometimes what seems like the quickest way takes the longest time. A band saw would be the perfect tool for this project.


Not quite sure how a band saw would be good here - apart from the fact I have neither the space or the cash - I will be working with 3m+ (10'+) lengths - a bit unwieldy to put on a band saw I think.

However, you do make a valid point and a chisel or plane may be a better option. At 63mm, I don't think there is any router barring a Dremmel or it's clones that would fit in the gap. Although, I am considering that one of those reciprocating "multi tools" might work here...



BIGROMO said:


> Have you considered trying to use a dado blade in your circular saw? I have been thinking about doing something like this and trying to use one of the wobble dado blades that you adjust to width in a regular circular saw (not sure yet may have to modify the spacing on the bottom support or remove the blade guard that kicks up out of the way as you move it into the piece). I also though using a regular stackable dado blade or some of the components would work. It certainly works in a radial arm saw but I wanted something quick easy and portable to accomplish this and I'd dedicate an inexpensive circular saw to it and leave the blades in it.


I'm afraid to say I value my fingers/sight/life too much to try this.

I briefly looked into this, but stacking blades on my saw is out of the question and I wouldn't touch a wobble with a barge pole. Anything that adds vibration is bad IMHO.



Quillman said:


> "That's OK for the end laps, but I have a lot of cross laps and only a fraction of end laps."
> ****************************************
> Still applicable (14° DT). Middle of the board excavation can also be wasted with the DT bit.
> Now the edges of your rail (also fully or partly dovetail profiled) slide into the excavation & they're stuck there royally. More work, but stuff that lasts always does.


I understand that the DT will excavate the bottom, but I am still struggling to understand how it will work with a cross-lap in the centre of a structure.

If I understand it correctly, the whole point of a DT is that the 2 pieced have to slide together rather than press together.

I don't see how I can make a dove tail in the centre of a piece of timber and expect to be able to slide it in to the receiving part of the joint unless I bevel the entire length of the timber to match.


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## Quillman (Aug 16, 2010)

That is right (the whole length), but it needn't be the full thickness.
The stick can rest proud and still do its thing.
Especially in a gate. Spend some time experimenting.
That's where the real merit of woodworking is.


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## vindaloo (May 30, 2009)

Carrot said:


> ............._Using a flush trim bit, gra*b* a flat piece of scrap sheet material and line the straight edge up with the edge of the lap, the*n* run the bearing on the flush trim bit along the sheet material._?.......


Yep that's right. You no speaky typonese yet? You will soon on here. :grin:


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## Carrot (Jan 7, 2009)

vindaloo said:


> Yep that's right. You no speaky typonese yet? You will soon on here. :grin:


Oh, typonese...


Can you help me out with the specific dialect?

Are they the hairy, knobbly or knock type of knees?


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## woodknots (Mar 7, 2012)

Carrot said:


> Oh, typonese...
> 
> 
> Can you help me out with the specific dialect?
> ...


Jon:
I think they are the bees knees.


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## mgmine (Jan 16, 2012)

_Not quite sure how a band saw would be good here - apart from the fact I have neither the space or the cash - I will be working with 3m+ (10'+) lengths - a bit unwieldy to put on a band saw I think.

However, you do make a valid point and a chisel or plane may be a better option. At 63mm, I don't think there is any router barring a Dremmel or it's clones that would fit in the gap. Although, I am considering that one of those reciprocating "multi tools" might work here...
_

The length would not be an issue but since you don't have one it's not an option. As far as using a multi tool it would take forever. They are great for many things but very slow at cutting wood like this.


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