slip tennons/loose tennons/what ever you want to call them

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Forum topic by RonGoldberg posted 01-24-2015 05:00 PM 1273 views 0 times favorited 9 replies Add to Favorites Watch
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44 posts in 2327 days

01-24-2015 05:00 PM

Topic tags/keywords: joining

I have a bench top mortise, dado set, table saw, router, etc. For some reason, I always find myself using a plunge router with a jig to make mortise. I used to square the edges of mortise with mortising chisels and create the matching tennons on table saw with stacked dado set. Great.

However, lately, I have gravitated to making the mortises with my plunge router and leaving the edges round and cutting slip tennons. What I like about this method is that the tennons can be adjusted (filed, chiseled, sanded, etc) to help line up perfectly the matching mortises. Glue fills in any gap between the tennon and mortise walls.

So, here is my question and don’t laugh. Am I cheating? Is there a downside to this method. I seems that each tennon ends up being trimmed a little bit for the perfect fit. This really helps in keeping everything align at the correct angle. Oh, and yes, I realize that the Domino (Festool) is screaming at me to purchase it. Wife said NO WAY. I am not a professional furniture maker otherwise I would have purchased the Domino when it came out.

Please just comment on the slip/loose tennon part. Thanks everyone.

Ron in McLean, Virginia

9 replies so far

View jsuede's profile


69 posts in 1193 days

#1 posted 01-24-2015 07:20 PM

I have in the past used biscuits, dowels, dado blade and mortising attachment square cut, and matched rail and stile router sets. I am in my second phase of woodworking after a long break (years of no shop space) with a relatively modest budget for my hobby. I fully intend on using DIY loose tenons in the majority of any new work where applicable (face frame/door construction). I’m also going to forgo purchasing a dovetail jig, but rather do finger joints for drawers. I will dabble in some hand joinery when I see fit and have the luxury of time. In all my research so far I cannot see a downside to using a floating tenon, and if the popularity of the domino joiner is any indication, it is a solid method of joinery. As I understand it most large production solid wood entry and interior doors are produced this way. I would spend no more than $250 for such a purpose built tool, $800 is just too rich for my budget. I already own everything necessary to do DIY loose tenons, so I’m gonna run what I brung and see how it goes. Good luck and let us know how it works for you, I’ll be right there with you.

View ElChe's profile


630 posts in 1305 days

#2 posted 01-24-2015 10:38 PM

If you are deflating your balls in cold weather … Then you are cheating. ;). Floating tenons are as strong as regular tenons in my humble opinion. If it works … It works.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

View AandCstyle's profile


3027 posts in 2226 days

#3 posted 01-24-2015 11:47 PM

Ron, I use floating tenons wherever possible. I think I get a stronger joint since the tenons fit tighter as you mentioned. Also, they are much faster. What’s not to like?

-- Art

View RonGoldberg's profile


44 posts in 2327 days

#4 posted 01-25-2015 08:09 PM

Thanks guys. I agree with all of you. Yes, they are faster and less error prone and can be most easily adjusted.

View pintodeluxe's profile


5624 posts in 2782 days

#5 posted 01-25-2015 08:33 PM

Loose tenons are fine If you don’t want through tenons. The nice thing is you have a mortiser, so you can build with integral tenons if you choose.

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

View runswithscissors's profile


2725 posts in 1994 days

#6 posted 01-26-2015 08:17 AM

A regular tenon (as opposed to a loose one) can be rounded on the edges just like a loose tenon. Easier than squaring a hole with rounded ends.

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

View RonGoldberg's profile


44 posts in 2327 days

#7 posted 01-26-2015 10:36 AM

Did any of you ever consider the domino? Just curious.

View MrRon's profile


4720 posts in 3212 days

#8 posted 01-26-2015 05:42 PM

This post came just in time, for I am building a baby cradle and will be using M&T joints. I have a mortiser, but it’s a HF. I think now doing it with a router may be a better way for me. I have never actually used the HF mortiser since I got it 5 years ago. I only tried sample cuts and they were not very good (poor chisels and bits). I don’t want to take a chance and screw up the project, so I will probably go the router path with round end tenons.

View bobro's profile


320 posts in 1279 days

#9 posted 01-26-2015 06:59 PM

Floating tenons are more than strong enough, and in my opinion both floating tenons and splines are mechanically superior to standard M+T and T+G in certain construction applications.

For example, when you have pieces coming together at an angle, it’s possible that an M+T solution would allow only a little stub tenon, or a tenon with short-grain problems, or insufficient room for a deep enouogh mortise chopped at the angle corresponding to a long-grained tenon on the matching part, and so on. The other options in these cases are swank and time-consuming solutions like the dovetailed pipe joint. And in certain woods and dimensions, the tongue of a T+G can be broken off with your thumb and a hard spline is clearly superior.

Anyway, I think woodworkers probably know in their hearts when they’re “cheating” and when they’re using a wise practical solution.

-- Lao Ma: You are so full of anger and hatred. Xena: Everybody's gotta be full of something.

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