Two Blades for Tenons?

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Forum topic by woodworksbyjohn posted 03-31-2011 11:10 PM 4652 views 0 times favorited 23 replies Add to Favorites Watch
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87 posts in 2659 days

03-31-2011 11:10 PM

Topic tags/keywords: tenons freud tablesaw question

This question is more of a curiosity one—I’m wondering how many other woodworkers do what I do to cut tenons on the tablesaw. I use two dado blades with spacers in between so that I can cut the tenon in one pass. Generally slightly oversized so a couple of passes with a rabbet plane is all that’s required for the fit I want.
The reason I ask is because I asked Freud about their box cutting set and mentioned my practice of cutting tenons. Currently I have a 6” dado and am thinking about the 8” for more depth. To make a long story short, I was told that this was not a good or safe practice. I use a Delta tenoning jig and recall an article in Fine Woodworking many, many years ago about this.
How many of you use this technique as well? And, while I’m at it, any reviews of the 8” box cutting set from Freud?

-- John Visit my Blog:

23 replies so far

View DrDirt's profile


4423 posts in 3709 days

#1 posted 03-31-2011 11:19 PM

I don’t use that technique myself, i like to lay the stock flat and use a Dado set, but have seen it used by many including in FWW.
I don’t see where the practice itself represents andy danger so long as you use a good material for your spacer.

Personally I think Freud is doing a CYA move from liability so you could not ever say such a procedure was “APPROVED” by Freud.

-- “The two most important days in your life are the day you are born and the day you find out why.” Mark Twain

View TopamaxSurvivor's profile


18248 posts in 3643 days

#2 posted 03-31-2011 11:19 PM

I am sure if it were safe to do, we could buy tennoning blade sets from all the blade mfrs.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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87 posts in 2659 days

#3 posted 03-31-2011 11:21 PM

Ah yes, forgot all about the old CYA! Guess I’m showing my age because I actually anticipate my coffee being hot without reading the warning on the lid!

-- John Visit my Blog:

View Loren's profile


10269 posts in 3615 days

#4 posted 04-01-2011 12:11 AM

I think perhaps if you the technique without an appropriate
throat plate and/of the part firmly clamped to the tenoning
jig there could be a disaster.

You can do all kinds of stupid things on a table saw if you’re
being stupid about how the tool works. When correctly set up,
most table saw operations are predictable and reasonably safe,
including the dual-blade method of cutting tenons.

View drewnahant's profile


222 posts in 3056 days

#5 posted 04-01-2011 12:24 AM

I think that as lont as the board is securely attatched to a good tennoning jig, it should be reasonably safe. the only danger I see is because there is no throat plate between the blades for the stock to ride on, so if it moves it could drop in, causing kick back, twisting, or just the inability to slide it forward and clear the blade. Nothing in the shop is without risk, but if done properly, this should be as safe as any other table saw operation. of course, you can never predict all the possible dangers until they happen.

View Gregn's profile


1642 posts in 2950 days

#6 posted 04-01-2011 12:47 AM

I use my stacked dado set to make tenons with but I don’t use spacers. I generally use the chippers with the 2 blades to get the width I need or use shims between the 2 blades if they’re narrow tenons.

-- I don't make mistakes, I have great learning lessons, Greg

View mcase's profile


446 posts in 3096 days

#7 posted 04-01-2011 12:52 AM

I use the Freud dial-in dado set for this purpose with custom made metal spacers. The dial-in feature allows for fine tuning and there is no need for any further work.

View tenontim's profile


2131 posts in 3711 days

#8 posted 04-01-2011 01:02 AM

This could turn into one of those “pins or tails first” comments. I always cut my mortises first and cut the tenons to fit. I’ve never used this method, mainly because I use a tenoning jig, which only cuts one side at a time.

View John Ormsby's profile

John Ormsby

1283 posts in 3704 days

#9 posted 04-01-2011 01:11 AM

I would not recommend you ever try this with a tablesaw. This could be very dangerous. Too much constant downward force would be needed to keep the tenon jig from lifting out of the slot. Even with a T-slot it would be dangerous. I only use a sliding table shaper with holdowns to perform this operation. Even with this setup one needs to watch out that the shaper cutters do not try to pull the piece into the shaper. Below are some photos showing the setup. Keep in mind that the guard is off to show the setup.

-- Oldworld, Fair Oaks, Ca

View fussy's profile


980 posts in 3018 days

#10 posted 04-01-2011 02:05 AM


Where’s the sawdust? I don’t see any sawdust! Do you use that stuff?

Looks like good quality tooling. ‘Scuse me. I gotta go wipe up some drool.

Seriously, I looked at your projects and if your shop is as nice as your work, Please don’t post pictures of it. I would drown. And I agree with you; that could be dangerous. I cut most of my tenons on the bandsaw and clean up with a plane.


-- Steve in KY. 44 years so far with my lovely bride. Think I'll keep her.

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John Ormsby

1283 posts in 3704 days

#11 posted 04-01-2011 02:37 AM


The dust collector picks up most of the sawdust on the shaper with this setup. The shaper, in general, runs fairly clean. Any sawdust buildup can cause a lot of problems with running large amounts of pieces. The fence edge must be kept clean. Accuracy is maintained this way.

As far as the shop goes it is a mess right now. I have to much wood inside and extra tooling. I am planning to build another storage shed for the rest of the wood and other things. Hope to have this done this year.


-- Oldworld, Fair Oaks, Ca

View woodworksbyjohn's profile


87 posts in 2659 days

#12 posted 04-01-2011 03:29 AM

Interesting to hear all of your comments. My throat plate is a zero clearance that I made from UHMW. I set up the spacers to get the width between the two blades then raised the blades to cut the throat plate so there is a piece of the plate between the two blades. The Delta tenoning jig is pretty heavy and I control it with both hands and don’t pull the piece being tenoned back across the blades.

-- John Visit my Blog:

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John Ormsby

1283 posts in 3704 days

#13 posted 04-01-2011 05:08 AM


If you are going to dados with the tablesaw this way it would be good to remove a lot of the material with the bandsaw first. This way the blades will not be working so hard on the finish cut.

Another thing to think about is the danger of the tenon jig lifting when the blades start to get dull. They will try to force the jig upward.


-- Oldworld, Fair Oaks, Ca

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87 posts in 2659 days

#14 posted 10-30-2011 05:00 PM

After all this time, this came in from Fine Woodworking:

You can see Garrett Hack using the spacer and two blade technique just as I do. All these responses had me questioning it but I figure that if he and the magazine do it it must not be all bad. Too bad the extreme liability and fear of lawsuits stifles some. I know accidents happen and that’s why they’re called “accidents”.

-- John Visit my Blog:

View gfadvm's profile


14940 posts in 2657 days

#15 posted 10-31-2011 04:06 AM

John, You asked about the Freud box cutter set (8”). I hesitated at the price but finally bought them. I love this set! They are absolutely accurate (1/4 and 3/8”) and leave totally flat bottom in the cut. I now wonder why I waited so long to buy them. I think you will really be happy with this set.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

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