Tongue and Groove: Slot cutter or tongue and groove set?

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Forum topic by John146 posted 04-17-2017 03:46 AM 2212 views 0 times favorited 7 replies Add to Favorites Watch
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90 posts in 1049 days

04-17-2017 03:46 AM

So I’m about to make my first tongue and groove project, and I’m trying to figure out how to actually make them. I bought myself a slot cutter for the router, because I figured I could make the ‘tongue’ myself quite easily by simply using a straight bit on the router table, and adjusting the bit’s height to 1/4 and the fence’s depth to 3/8, and simply hog away the material on either side to produce a 3/8 tongue.

However, I was just about to start using the slot cutter, and started wondering whether I should’ve just gotten a tongue and groove set instead (for $80, compared to the slotting cutter set, for $30ish – both Freud). I’m mainly wondering about variation in the wood’s thickness causing the tongue to be a bit too thin. All my wood is planed and should be within 1/64th of each other within thickness (more realistically, 1/128th). Assuming I just set my straight router bit to shave off 1/4 on either side for a tongue, would I run into problems with a loose fit (and should thus get a T&G set and return the currently-unused slot cutter), or are these numbers not a big deal.

-- John 14:6

7 replies so far

View TungOil's profile


1371 posts in 1099 days

#1 posted 04-17-2017 03:54 AM

You didn’t say what you are making, but would a loose tenon work? Then you can use your current slot cutter on both sides.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

View John146's profile


90 posts in 1049 days

#2 posted 04-17-2017 04:03 AM

I’m making a frame-and-panel style kitchen island. I hadn’t thought about using a loose tenon yet – but I would imagine it would be messy for this kind of project. Besides, I really want to try my hand at tongue and groove :).

I also realize that it’s not technically tongue and groove: it’s rail and stile plus some rabbet-and-groove joints. The way the rails would mate with the stiles would be similar to “tongue and groove”. The rabbet I would need to cut with a straight bit anyway (I wouldn’t be able to use the “tongue” bit there).

-- John 14:6

View bandit571's profile


24371 posts in 3287 days

#3 posted 04-17-2017 12:52 PM

Match plane work…

Less sawdust, very little noise..

Depends on where you plough the groove..

Takes two cutters, is all.

-- A Planer? I'M the planer, this is what I use

View TungOil's profile


1371 posts in 1099 days

#4 posted 04-17-2017 02:20 PM

ahhhh, OK.

For frame and panel construction I always use a true tenon on the ends of the rails. I prefer to do mine with a dado stack in the TS but I think you could also do it with the router table as you have mentioned. be sure you use a coping sled for the end grain cuts (both for safety and quality of cut) with a sacrificial backer behind the rail or it will blow out. If you plough the grooves first, it makes setting up the depth of cut for the tenon easier since you can sneak up on the exact depth using the groove as guidance.

I’m sure you already know this, but for the benefit of those that might be new to this, be sure to allow room for the panel to expand and contract when you cut the rabbet and fit the panels into the frame. Wider panels require more room for expansion. I like ‘space balls’, they help keep the panel centered and prevent rattling. Alternately, consider using a 1/4” plywood panel instead, then you don’t have to worry about expansion/contraction issues.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

View bonesbr549's profile


1586 posts in 3671 days

#5 posted 04-17-2017 02:33 PM

In my opinion it just depends on how you value your time. I’ve done it both ways. If you use a router table then u can use the slot cutter get it close to center, then run your piece, flip it end-to-end, and run it again. You will know its centered. You could use it again with a good rail system and sneak up on the tongue flipping end-to-end till it fits snug.

The advantage of the set is once its set you just go. So its speed .vs. $$, but at the end of the day your time is worth something ??.

Now doing it without the set free’s you from fixed sets per material width and for me I rarely have 3/4” material.

I do have multiple sets and have even used a rabeting bit to do it before with a slot cutter.

I’d recommend whiteside bits.

Good luck and cheers.

-- Sooner or later Liberals run out of other people's money.

View John146's profile


90 posts in 1049 days

#6 posted 04-17-2017 02:43 PM

I don’t own a dado stack yet. I’ve been meaning to get one, but they seem to be around $100, and I’d like one that does truly flat bottoms so I can do things like box joints and such (and those reach the $200+ range). I also keep doubting the accuracy of my fence – but that’s not a problem with a router table. But I recently replaced my saw so it has a better fence.

Now that you’ve made me think here, a ‘tongue’ here is essentially just a tenon, and for that I can use my shop-made tenoning jig—for which I can use a regular blade, though it would require multiple passes.

I do plan on using 1/4” plywood this time. For my last frame-and-panel project (which was also my first one!) I used a raised panel with a cheap raised panel bit.. that was not too fun, I had to sand the tenons and grooves so that they would fit together. I also felt bad using so much material for the panels.

-- John 14:6

View pintodeluxe's profile


6033 posts in 3417 days

#7 posted 04-17-2017 02:50 PM

Get a good dado set. I wouldn’t build cabinets without one.

Assuming you have a decent tablesaw, a dado blade will be the easiest and most consistent way to mill rabbets, dados, grooves, and tenons. I have a nice router table too, but there is a lot more space on a tablesaw to support large workpieces.

Good luck.

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

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