# Tenons on long boards



## TinkerDeux (Aug 20, 2010)

I need to cut 5" long tenons on both ends of 20, 1 1/2" square boards. The tenons will be 1 5/16" square. the wood is poplar and range in length from 48" to 101". I'm trying to find the most accurate and safe way to cut these. The 1st time I did thid I used my table saw, but it was hot a good, accurate, or safe way to cut them. What alternatives are out there to make this many and have them all the same? I have 5 router tables, but like the tablesaw it is really hard to handle 8' boards while moving them across a moving bit/blade. I have the same problem when trying to cut the shoulders off for a 5" long tenon on the band saw. Am hoping that some one here has a good way to use a router to cut these tenons. If it weren't for the fact that they have to fit into square metal sockets, I would just chuck them up in my Leblond metal lathe and turn the tenons round, and know they would be exact. I know a rtound peg will fit into a square hole, and they will be pinned, but the setup time would be slowed down a bunch in lining up the pin holes. Any help would be greatly appreciated!!!


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## bobbotron (Jan 7, 2010)

A while ago I made a router based tennon jig from a free PDF. I can't seem to find it online anymore, but I'll try to take a photo of it for you, I think you could use the same idea to scale up to making any size of tennon. (But, it helps to cut out the bulk waste first, unless you like creating a lot of dust!)


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## rjhorky (Apr 20, 2011)

I suggest you make a jig from 3/4" ply or MDF. I have attached a quick PDF that shows the dimensioned top view (shows the tennoned board thru the hole), a bottom view with the board in place and another bottom view with dimensions. This with a 5/8" OD bushing and 1/2" bit ... and you are money. Best of luck. any questions, let me know.


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## rjhorky (Apr 20, 2011)

*long tenons*

Sorry ,,, found a dimensional error. Please use this file.


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## Phil P (Jul 25, 2010)

TinkerDeux said:


> I need to cut 5" long tenons on both ends of 20, 1 1/2" square boards. The tenons will be 1 5/16" square. the wood is poplar and range in length from 48" to 101". I'm trying to find the most accurate and safe way to cut these.


Hi Ray

From the use I guess that the result doesn't have to be perfect, so I'll give you a jobbing carpenter's approach; set the rebate (dado) stop on your sliding compound mitre saw to the correct depth then make lots of cross cuts moving the timber 1/8in or so each time. Finally clean up with a sharp chisel and shoulder plane. Second approach: use a dado head in a radial arm saw. Third approach: build a basic T-square jig for your router then make your cuts with your router, guide bush and a large diameter bit (32mm or 1-1/4in I'd say) stepping each 3/4in or so in from the last until the required line is reached.

Regards

Phil


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## TinkerDeux (Aug 20, 2010)

Phil P said:


> Hi Ray
> 
> From the use I guess that the result doesn't have to be perfect, so I'll give you a jobbing carpenter's approach; set the rebate (dado) stop on your sliding compound mitre saw to the correct depth then make lots of cross cuts moving the timber 1/8in or so each time. Finally clean up with a sharp chisel and shoulder plane. Second approach: use a dado head in a radial arm saw. Third approach: build a basic T-square jig for your router then make your cuts with your router, guide bush and a large diameter bit (32mm or 1-1/4in I'd say) stepping each 3/4in or so in from the last until the required line is reached.
> 
> ...


Actually they have to be a nice snug fit. They are used to form a frame that a canvas "canopy/tent" is pulled over. the frame has a single slope roof and it attaches to the side of a sheepcamp. Tha canvea atraps down on the oposite side of the camp then goes over the camp and over the frame. The canvas has 2 panels on each of 3 sides, and it attaches to the poles of the frame with ball type bungee cords. the top has 3 sets of 2 pr. of the 1 1/2" x 7' boards that connect in the middle running from side to side, and running front to rear are 3 sets of the boards that are 4' long and 8' long joining at the same location as the side to side boards. Because of the 12' span front to rear and 14' span side to side, the joints have to be pretty tight to avoid too much flexing and slop. When I made the pine prototype, some of the tenons were too loose and it created problems, and ultimate breakage. This is why the new poles are being made out of clear, straight grain poplar with close tolerances on the tenons.


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## bobbotron (Jan 7, 2010)

Hey TinkerDeux, here's a photo of my tenon jig. You put your wood underneath, clamp it up, and then route away with a bushing. Not very pretty, but it works quite well. For a 5" tennon, you might have to unclamp, move the board up a bit, and reclamp.

I was thinking about this, you could probably make something work with a similar set up but use skiis to keep the router a equal distance away from the wood.


Tenon jig by bobbotron1, on Flickr


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## CharleyL (Feb 28, 2009)

A board with a hole in it or a similar jig to the one posted by bobotron above clamped in the right position so that the edge of it can be used to create the shoulder of your tenon, could be used. You would have to repeat the process for all four sides of your stock, but you could likely clamp them together with the jig on top and rout one side of multiple tenons at once.
Keep in mind that your stock thickness will need to be very accurate as well as your jig placement to get accurate tenon dimensions.

If you can use a round tenon, you might consider drilling the end of your stock and then inserting and gluing a dowel of the desired dimension into the hole to create the 5" long tenon. It would be dimensionally more accurate and easier to do than trying to make tenons from the end of the stock.

The last time that I needed to make tenons on long stock I borrowed my neighbor's deck railing and clamped my FMT jig to it so the stock could hang down past the deck while I created the tenon on the end of it. This would be a very accurate way to cut the tenons, but an FMT jig is not designed to cut tenons longer than about 2" max.

Charley


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## bobj3 (Jan 17, 2006)

HI

For me floating tenons is the only way for me..why make it hard to do..

=======


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## jw2170 (Jan 24, 2008)

Ray,

Could you cut the tenons on the band saw with the outer end supported?

You only have to advance the post 5" for each cut.

From the dimensions quoted, you are only taking 3/32 of each side?

Another method would be to clamp a straight piece of MDF along the length of the post, set back 3/32" and trim with a flush trim bit in a hand held router.


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## jw2170 (Jan 24, 2008)

Ray,

Could you cut the tenons on the band saw with the outer end supported?

You only have to advance the post 5" for each cut.

From the dimensions quoted, you are only taking 3/32 of each side?

Another method would be to clamp a straight piece of MDF along the length of the post, set back 3/32" and trim with a flush trim bit in a hand held router.


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