# Jig for large tenon cut



## Dylan JC Buffum (Jun 9, 2019)

I’m making a large octagonal chandelier for a family member. It’s about 5’ across, and each side is a piece about 24” x 4” x 3”. I’m joining them with a finger joint. Here’s a previous thread about the project with a rough sketch: https://www.woodworkingtalk.com/f9/wagon-wheel-light-fixture-218085/

Here are photos of a test piece I did this weekend; it took all day Sunday. I have to do eight of these joints. 



















My stationary tools are limited to a compound miter saw with a 18” crosscut capacity, and a shop-made router table with (almost) parallel tracks and a massive fence. I have plenty of hand tools.










I’ve got a workable jig for the mortise. 










The mortise on the test piece was labor intensive, because I’m removing a lot of material and it takes a lot of cuts. But it came out very clean and precise, and I’ll be able to replicate the mortise exactly the same on each piece.

For the tenon, I can rough the joint fairly easily on the miter saw (though the rip cuts are very hard on the saw). 










But I’m struggling to clean it up with precision and repeatability.

Part of the problem is that the router table is narrow, and the large workpieces hang off the edge, making them hard to stabilize. I think I’ll need to make a sturdy sled, but in these days of quarantine I’m working with limited materials available in the shop. I don’t have any material to make sled rails for the tracks in the router table. I was trying to use the fence as a guide, rather than the tracks, but cant find a good way to make that work.

Ideas? Suggestions?

(Edit: thanks to Gmercer for fixing the photo orientation!)


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## Tony B (Jul 30, 2008)

I'm looking at your mortise jig on router table. Is there any reason you can't do a similar jig on your table saw. On the table saw, you can do both mortise and tenon. I believe the mortise being open ended is actually a bridle joint also called a saddle joint.
If you had a dado set it would be much faster.


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## Dylan JC Buffum (Jun 9, 2019)

Tony B said:


> I'm looking at your mortise jig on router table. Is there any reason you can't do a similar jig on your table saw. On the table saw, you can do both mortise and tenon. I believe the mortise being open ended is actually a bridle joint also called a saddle joint.
> If you had a dado set it would be much faster.


I don’t have a table saw. Trust me, if I did, I wouldn’t be going through this complicated process with the router.


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## gmercer_48083 (Apr 9, 2016)

Dylan, Corrected orientation.

Your jig looks workable... Fasten a guide rail to the bottom of the sled to guide it with miter slot. I would rough out the mortice first to remove most of the waste and use the jig for the final finish/cleanup.

I suggest doing the mortice first, then fit the tenon to it.


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## Dylan JC Buffum (Jun 9, 2019)

How do you fix the photo orientation? I’ve been trying to figure that out for months.


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## gmercer_48083 (Apr 9, 2016)

Dylan, Using a slide type miter saw for ripping like that could be dangerous, because you are depending on the slide lock to prevent the blade from creating a climb cut... where the saw would suddenly try to attack you if it does not hold!

I suggest sawing by hand if you have a vice, since you don't have either a table or band saw. (pioneers didn't have power tools)


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## gmercer_48083 (Apr 9, 2016)

Dylan JC Buffum said:


> How do you fix the photo orientation? I’ve been trying to figure that out for months.


On your computer... open the file in a photo viewer/editor, then even if it views upright...rotate 360 degrees, then save. once you have done that you can upload to the forum. The camera in a cell phone will take photos that are sometimes not oriented correctly sometimes.


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## Dylan JC Buffum (Jun 9, 2019)

gmercer_48083 said:


> Dylan, Using a slide type miter saw for ripping like that could be dangerous, because you are depending on the slide lock to prevent the blade from creating a climb cut... where the saw would suddenly try to attack you if it does not hold!
> 
> I suggest sawing by hand if you have a vice, since you don't have either a table or band saw. (pioneers didn't have power tools)


Ooh, good warning, thanks. I can probably rig something to prevent that, but if not, I’ll find another solution.


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## gmercer_48083 (Apr 9, 2016)

Dylan JC Buffum said:


> Ooh, good warning, thanks. I can probably rig something to prevent that, but if not, I’ll find another solution.


May be able to put a block of wood between the slides.


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## Dylan JC Buffum (Jun 9, 2019)

gmercer_48083 said:


> May be able to put a block of wood between the slides.


That’s what I was thinking.


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## woodnthings (Jan 24, 2009)

*I must give you credit!*

Your limited range of power tools still came through in great form. I don't know if any other machine would have made the joinery any easier, with one exception ..... a radial arm saw with the blade laid over horizontally. That way the work stays flat on the table and is a bit saferand less cumbersome. If you can "obtain" one I highly recommend it, they are practically giving them away on Craig's List. DAMHIKT I have 5, maybe 6 ....... :surprise2:


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## Dylan JC Buffum (Jun 9, 2019)

The cheeks are super tight and flush. I’m really happy with that. It’s the shoulders on either side of the tenon that are giving me trouble. 

So after removing the bulk of the material with the miter saw, I want to lay the piece on its side on the router table and clean up the cheeks and shoulders to get just the right width and depth. It’s simple enough to get the cheeks clean because the router bit if a fixed height above the table. No problem.

But getting the shoulders to be even with one another is a puzzle I can’t solve. I need to find a way to set up a guide using either the fence or with a sled, that positions the piece perfectly AND is reversible. When cheek A is down, the angle has the workpiece raked back; when you flip it over so cheek B is down, the angle has the workpiece raked forward (unless I could work on the other side of the bit, which I can’t because this is a countertop).

So I need a way to make sure I get exactly the same cut in reverse for both cheeks, and I’m not sure how to do that.


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## Dylan JC Buffum (Jun 9, 2019)

Photos for clarity. 

The first is the basic idea for cleaning up the cheek and shoulder on side A.










Then, if you just flip the piece, you see that side B is oriented in reverse.










So I need a jig that also reverses to hold the piece like such:










This is just a test piece. The actual work pieces are longer, so I’ll have even more trouble with stability. I think I need to add width to the router table.

(I’m going to post this and then see if I can edit the photos to get them upright)


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## woodnthings (Jan 24, 2009)

*Consider using the front edge of the table ......*

The front edge of the table would be a better "fence" in my opinion. 

So, then make a symettrical angle guide from plywood that rides a long strip attached to the bottom. The guide will have a strip, which is a secondary fence for the each correct angle. You can control the depth with the router table fence if you want. Hope this makes sense to you..... :nerd2:


It would look something like this with a guide strip attached underneath:


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## TomCT2 (May 16, 2014)

gmercer_48083 said:


> On your computer... open the file in a photo viewer/editor, then even if it views upright...rotate 360 degrees, then save. once you have done that you can upload to the forum. The camera in a cell phone will take photos that are sometimes not oriented correctly sometimes.



actually that can get you fooled. cell phones are one issue - the bigger issue is MicroSoft Windows.
Windows will "auto rotate" pictures so the _look_ right on your display, but the 'file orientation' hasn't changed and when uploaded it's whack-o


no relationships, but freeware IrfanView will display the pix as it will "upload" - and you can rotate left/right + save in original folder|yes overwrite and that'll work.
it also lets you crop
and resize
and if you download all the whizbangie options, Save for the Web reduces the size megatrifically - faster uploads....


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## Dylan JC Buffum (Jun 9, 2019)

So your suggestion to use the countertop edge rather than the fence seemed sound. I went out and piled together these parts, and I think I can make it work:










Right now there’s a piece of 3/4” MDF which will be the guide that runs along the edge of the countertop. On top of that is 3/8” plywood. I’ll get the 45º angles dialed in. The whole thing is on top of a wheeled cart with an adjustable height. Then I’ll use the fence on the other side of the router as a stop to control the depth.


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## woodnthings (Jan 24, 2009)

*That's what I had in mind!*

That should work for your depth control on the faces and the depth on the angles. You could stop the cuts on the router a little short on the angles and make them using the miter saw if you are concerned about being very precise....maybe?


:|


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## homestd (Aug 24, 2018)

By all means make a sled. When doing large pieces the size itself increases the likelihood of something happening and you're running a tall, thin bit to take out a lot of wood. What you need is a router that turns the other way( I don't know if one is made) but I used to work on a two headed shaper where they turned in different directions. You definitely need something strong and precise and reversible. And be careful with that tall bit!


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## woodnthings (Jan 24, 2009)

*I don't know what a reverse rotation would do here?*

Here's the jig he constructed with my advice:


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## Dylan JC Buffum (Jun 9, 2019)

woodnthings said:


> Here's the jig he constructed with my advice:


I don’t know where the photo went. It was in my post, but now it’s gone. And now I can’t edit it anymore.

To be clear, I haven’t built that jig yet. I just put some scraps in a pile to visualize what I’m aiming for. The build will be over the weekend.


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## Dylan JC Buffum (Jun 9, 2019)

Still needs a little tidying in the joints, but ...


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## Tony B (Jul 30, 2008)

Not having a table saw to do what you did - yuou have my admiration.


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## Dylan JC Buffum (Jun 9, 2019)

Tony B said:


> Not having a table saw to do what you did - yuou have my admiration.


Thanks! It was pretty labor intensive, and the joinery isn’t going to win any awards. But the piece is going to be “rustic” and hanging fairly high, so I’m pretty satisfied. And the joints are beefy and solid and strong, even though they’re not perfectly fitted.

Next step is attaching the hub with iron pipe spokes and drilling for the wires and sockets.


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## DrRobert (Apr 27, 2015)

Hey, Dylan. You’re approach is well thought out. That said, how many tenons do you need to cut & how many could you cut by hand in the time it takes to figure out the jigs/make test cuts, etc? 

Hand work is just as accurate, and in many cases, more accurate than by machine.

Re: Getting the tenon cheeks to match.

Don’t try to dial it in totally with saw cuts. Layout the mortise and tenons with knife lines using a square, get close with saw cuts, pare the cheeks to then knife line with a chisel. Leave tenon thick.

Brings up the point that tasks like this are as much about accurate layout as jig making.

Do the mortises first, tune up the tenon to fit using sharp chisel, rasp, block plane or combination of all 3. A rabbet block plane is the perfect tool for large tenons.

Think about cutting the tenons with a handsaw!


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## Dylan JC Buffum (Jun 9, 2019)

DrRobert said:


> Hey, Dylan. You’re approach is well thought out. That said, how many tenons do you need to cut & how many could you cut by hand in the time it takes to figure out the jigs/make test cuts, etc?
> 
> Hand work is just as accurate, and in many cases, more accurate than by machine.
> 
> ...


So, I did rough cut the first two, and then used a chisel and mallet to fit them, and those two are the tightest fit. But each one took me massive amounts of time.


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