Cutting tenons

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Forum topic by Gerald Thompson posted 04-14-2014 09:50 PM 2448 views 0 times favorited 12 replies Add to Favorites Watch
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Gerald Thompson

918 posts in 2200 days

04-14-2014 09:50 PM

I have had nothing but problems cutting tendons on my table saw and router table. With the router table I have used a coping sled with a two cutter bearing bit. I have yet to get a tendon set up and final cuts made in under 30 min. Even with a backer board I get tear out.
I have a cast iron tendon jig to cut tendons with. I still get tear out with a backer board. I have tried a stacked dado set up and a rip blade. I used the rip because of the flat cut. If I use a cross cut, as I recall, the shoulders end up not flat due to the tooth configuration. All still give me tear out. It has been the same with both walnut and cherry.
I am to the point I don’t even want to try anything involving tenons. The tenons I am cutting are small, < 1/8’’ thick and about 3/8’’ long. I can get it done after much too long and it is a step in the clock cases we have been making I dread and we have three more to build. We have done five so far. This is the sixth and everyone has been a trial at this point.
All the tools are sharp and all is square. I have thought of going Neander but all I have is a Japanese saw and I do not do well with it and do not want to invest in a tenon saw that will hand next to other tools I don’t use.
How about using a miter fence and after sneaking up, using a test piece, cutting them that way? What blade would serve best.
It seems that after all this cutting I would have figured something out that works.


-- Jerry

12 replies so far

View Hammerthumb's profile


2836 posts in 1941 days

#1 posted 04-14-2014 10:14 PM

Jerry – have you tried making the shoulder cuts first to establish the depth before cutting the waste off with the tenon jig?

-- Paul, Las Vegas

View Gerald Thompson's profile

Gerald Thompson

918 posts in 2200 days

#2 posted 04-14-2014 10:26 PM

No. All instructions/videos I have seen show doing the tenon cut all at once. I don’t have any idea what blade to use. I feel that cutting a shoulder first is another step to fiddle with and make more mistakes. If I cut the shouder first I had just a well go on and cut the rest of it while I’m at it.
That begs the question, why use a tenon jig?

-- Jerry

View pintodeluxe's profile


5620 posts in 2779 days

#3 posted 04-14-2014 10:54 PM

The easiest way I know is with the dado blade and a good miter gauge at the tablesaw. Just use a sacrificial fence on the miter gauge, and that should eliminate tearout.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Nicky's profile


695 posts in 4058 days

#4 posted 04-14-2014 11:05 PM

A couple of tricks that have worked for me….

I leave the width of my styles or rails a little over the final dimension, then a few passes over the jointer or hand plane to final dimension after the tenons are cut. I always do the shoulder cuts first. I’ve got the fence on my tablesaw accurately tuned. The kerf on my blade is 1/8”. I have a spacer block that is 7/8”. I can now use the rule on my TS to dial in the shoulder cut. So if I wanted to cut a 1” shoulder, my fence gets set to 2” and I reference the cut from my 7/8 block clamped to the fence. I always use a backer board to minimize the tearout.

I use a Freud 60t blade to cut the shoulders, then use my tenoning jig to cut the tenon. I like a blade with a negative hook for this operation.

I mill my stock at the same time to be consistent. Still, I get variations. I’ve learned that a good shoulder plane makes the final fitting an easy task.

I also do these with hand tools, especially when I only have a few to do. Even with hand tools, it takes time to lay these out.

Jigs are great for creating more consistent results. If you’re cutting a lot of joints, it helps.

-- Nicky

View Hammerthumb's profile


2836 posts in 1941 days

#5 posted 04-14-2014 11:06 PM

Depending on the piece, I will sometimes make the shoulder cut prior to using the tenon jig. It will help to eliminate tearout. Also, it will make a cleaner cut on the shoulders.

The technique that pinto recommends is also an excellet way to cut tenons. I use that technique when I know that I will have a lot of tenons to cut, as I am lazy about changing blades on the table saw.

Another thing you might try is to scribe the shoulder lines with a marking gauge, as a scribed line will help eliminate tearout.

-- Paul, Las Vegas

View TheDane's profile


5399 posts in 3629 days

#6 posted 04-14-2014 11:08 PM

Jerry—I always cut the shoulder first, then use my cast iron tenon jig to do the cheeks. I use MDF backerboards on both my miter gauge and tenon jig. I usually just use the 50-tooth combo blade that is normally in my saw.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View Gerald Thompson's profile

Gerald Thompson

918 posts in 2200 days

#7 posted 04-14-2014 11:15 PM

I will not get back to into the shop and try cutting the shoulders first. I will use my crosscut blade then use the jib for the cheeks. I will also scribe a line and use a backer board. I only have two more to cut and I am tired of covering up tear out.
Thanks to all of you for your help. The 1840 Shaker clocks come out beautiful. It is a great design and we are making several for family and friends.

-- Jerry

View Pie's profile


187 posts in 3371 days

#8 posted 04-14-2014 11:19 PM

I think you need to see a dentist about your teeth. Maybe you should use tools instead of your teeth to make the tenons LOL! I second the tips here!

-- Pie

View Loren's profile


10262 posts in 3614 days

#9 posted 04-14-2014 11:21 PM

You need to use a zero-clearance fence to cut tenons vertically
on the router table with minimal tearout. In any case, it’s tricky
to get the depth just right. I’ve cut them horizontally in a few
passes using a fence to delineate the shoulder. It works well.
you can make a skim cut on the shoulder at 1/32” depth, then
saw out the waste on the bandsaw, then sneak up on
final depth on the router table. Paper shims under the
work gives a bit of fiddle room and hand pressure a little more.
You can really get a great fit this way. Gary Rogowski
described the method in his book “Router Joinery”.

Dialing in a table saw jig to cut tenons accurately can be
a hassle. Understand that your stock is likely to vary slightly
in thickness in relation to the price point of your thickness
planer, so if you flip the tenon stock to cut the second
cheek, the thicknessing errors will affect the tenons. Thus
it’s probably better in many cases to gang cut one set
of cheeks, then set up for the second cheeks and do
those all together, or make a shim thicknessed to your
tenon width minus your sawblade width to stick in
your jig to cut the second cheek.

View Gerald Thompson's profile

Gerald Thompson

918 posts in 2200 days

#10 posted 04-15-2014 12:59 AM

I saw a Dentist and that’s what happened.
I am going to pass on the router table. I am going to cut the tenons on the table saw with the piece flat and nibble it out from the shoulder. The tenons are only 3/8’’ long and about 7/8’’ wide. I will use MDF for backing and my cross cut blade. I have a shoulder plane to adjust things as needed.

-- Jerry

View bbc557ci's profile


595 posts in 2040 days

#11 posted 04-15-2014 03:04 AM

What Loren said in paragraph no. 2.

Several times I’ve cut tenons using a shim the same thickness as the tenon, and results are good. But the last couple of times I needed/did tenons, I did a loose tenon way/system, which I found to be less tedious and I get a good and consistent fit. In fact at some point I’d like to put together a horizontal routher jig, which I think would make cutting mortises on longer stock pretty easy, and therefore easier to go with loose tenons more often.

-- Bill, central where near the "big apple"

View runswithscissors's profile


2724 posts in 1991 days

#12 posted 04-15-2014 07:04 AM

For quite some time now I have been cutting tenons with my shaper (originally used a router table, but the principle is the same). I can cut an entire cheek and shoulder with one pass, then flip the stock over for the other side (in some circles this is known as “turning the other cheek”). I use a tenon jig made for a TS, and have modified it for the shaper. The mod allows me to cut edge shoulders just as easily. The modification disables the tilting feature of the tenon jig, so I don’t do angled tenons.

The key to avoiding tear out is to employ that bugaboo of all router/shaper users, the dreaded CLIMB CUT. Yes, it requires careful feeding to avoid having the bit just suck the wood right in, but it’s not that hard. When I’m cutting a lot of tenons, I sometimes hang a sash weight over the end of the table (through a sheave so it can run smoothly) to help counter the pull. I McGyvered a dust collector fitting to catch the chips, which really spray out, but the throat is a bit small and it sometimes chokes.

I use straight router bits, an inch long or more, and 1 to 1.5 inch diameter. The bigger bits are somewhat better on the shaper because of the machine’s lower rpms, but both are satisfactory.

All the stock has to be milled to the same thickness, as mentioned above, but that’s true for most any method, except the one that uses two cutters, with the tenon being formed in the slot between.

I haven’t cut tenons as tiny as the ones you’re doing, Jerry, but don’t see why it wouldn’t work.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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