Author Topic: Tongue & groove fit (Read 4453 times)

David Freed · « **on:** February 25, 2008, 12:21:57 pm »

I have always had the understanding that the tongue on a t & g floor was supposed to fit snuggly into the groove to hold everything firmly in place and get a smooth surface. I have a carpenter telling me that it is supposed to be a loose fit to allow a very slight amount of up and down movement. I would like to here your opinions. Thanks,

David

beenthere · « **Reply #1 on:** February 25, 2008, 01:10:54 pm »

Snug will be harder to lay (slight warp from wood movement since moulding the flooring), whereas loose will be easier to lay....so, you can take your pick as to the one you want. I can see the carpenter wanting the "easier" to lay and not being so concerned about the slight movement later on.

flip · « **Reply #2 on:** February 25, 2008, 02:19:15 pm »

That's always what I look for in a wood floor, some up and down movement

The wavyness is neat under my feet. Serious though, sound like someone is feeding you a line of scrappola. What ever the cutters are set up for is what it should be IMHO.

David Freed · « **Reply #3 on:** February 25, 2008, 03:02:24 pm »

The knives are what brought this subject up. The set I've had for a while were not quite as snug as I thought they should be, but it was so slight I didn't say anything. I ordered a second set to have a spare set and the fit is looser than the first set on top of being a 1/4" shorter, which means when we change knives we have to reset the fence. I don't think they are being very accurate when they make them. The type of knives I am using is bullnose tongue and wedge shaped groove so installation isn't a problem. I should rephrase my original post also. He didn't actually say he thought the floor should move. He said he thought the 1/32" to 3/64" of slop was alright.

Brian_Rhoad · « **Reply #4 on:** February 25, 2008, 05:15:59 pm »

When the floors he installed start squeeking, I hope his customers force him to replace the floor for free! Thats on of the problems today. Nobody cares about quality anymore. Sloppy work and take the money and run.

Justin L · « **Reply #5 on:** February 25, 2008, 08:50:02 pm »

When I check a short sample, the fit is a bit loose. When I try 3-4' long pcs, it is more snug due to slight bow. I'll measure tomorrow(if I remember:) but I'll bet my tounge is about 1/64-3/128" (OK, less than 1/32) thinner than the groove. 1/32" of slop would be too much IMO.

Mine is also a round tounge with a wedge groove. I set it up so the tounge will hold the grooved pc tight to the floor when put installed- the bottom of the tounge is tight against the bottom of the groove. Not too tight, or the tops don't line up and it's hard to install.

Are you using pairs of knives? If they are missaligned they will make the groove bigger or the tounge smaller. I use a straight edge against the cutterhead to push the knife into place, and check it after they are tightened(mine move sometimes when tightening)

Dave Shepard · « **Reply #6 on:** February 25, 2008, 10:04:12 pm »

I had this conversation last week with a friend who is a carpenter. The groove to tongue was very sloppy. It was v-groove that they were using for flooring, lumberyard said they only carry v-groove, just flip it over for flooring. Quality was poor in other regards, but all that is available. How much cup is normal after running through the moulder? These boards were noticeably cupped. They were white pine. I got the usual statement that paying a little more for a better product would be worthwhile to him, saves time in the long run. I have talked to many people that feel the same way about not being able to get the quality they want, sounds like there is a void in the market.

Dave

David Freed · « **Reply #7 on:** February 26, 2008, 06:26:35 am »

Justin,

I am using pairs of knives in a Logosol side head. There are holes in the knives that slide onto pins on the head. If the knives aren't right, you can't move them. These knives are not from Logosol either. They don't have this type of t&g.

Cedarman · « **Reply #8 on:** February 26, 2008, 06:45:39 am »

On our moulder, small Dominion Midas 2x6, I can adjust the knives to where ever I want them. It takes about an hour to tweak the knives to get just the right fit. For flooring, I want the boards to fit snugly, not where you have to hammer them together, but also not movement up or down. A short 1 foot piece should go together easily, but not require pushing hard. For paneling, I let them be just a tad more loose. Also, your knives will wear on the edges, just a little. This will cause the groove to get a little narrower and the tongue to get a little wider. Check your boards periodically during the run to make sure things don't change. A diamond hone is very helpful.

David Freed · « **Reply #9 on:** February 26, 2008, 08:18:56 am »

With our first set of knives the flooring slid together very easy and there was no noticable movement on pieces longer than a foot or two. Since we sell long length flooring ,that was ok. This second set of knives is not as tight, and I tend to be picky about things like that. I am trying to sell better quality flooring than a lot of the stuff on the market now, but a lot of the time when someone sees that quality means more money, you never hear from them again.
I realize that the knives will wear and change the fit slightly, and we do spot checks as we are running, but it hasn't changed enough to cause a problem. We hit a staple and had to switch knives and that is what started the whole problem. I just assumed two sets of knives with the same part # would be identical.

raycon · « **Reply #10 on:** February 26, 2008, 04:04:42 pm »

I was told .020" cutter tolerance was to loose.
Trying .005-.010 next run. Which won't be for a bit--P&Z issue to resolve.

jdtuttle · « **Reply #11 on:** February 26, 2008, 10:13:12 pm »

As a carpenter & one who has installed a few T&G floors it has been my experience a little play is a good thing. I have seen floors installed that were tight on installation. On one repair job I did the boards were not allowed to acclamate properly before installation. After a couple months down the boards acclamated and all the T&G joints buckled. If there was room for expansion (loose joint) the flooring would have been OK. Total tear out and re-do.
jim

woodworker9 · « **Reply #12 on:** February 27, 2008, 04:58:27 pm »

I hate to contradict anyone here, but I'm going to have to. On a T&G floor, you want the fit to be snug. It should need to be tapped in, but no pounded in. If the tongue is skinnier than the groove, and allows for vertical slop, then the quality of flooring is poor. The whole purpose of only nailing one side (tongue) is that the groove will hold the adjacent piece solidly to the floor.

The floor is going to move across the width of the boards. There is nothing you can do about that. They're wood!!!

That's why it is so important for the flooring to be properly acclimated to the room it's being installed in. There are a million and one shortcuts to take by flooring installers, and most of them lead to trouble. If the joints are loose, you're going to have a squeeky floor that talks to you for the rest of it's life. A properly acclimated product with a proper installation with tight tolerances leaves a professional job that will last a long time. Anything else you're being told is all a bunch of balogni.

BTW, I installed hardwood floors professionally for about 12 years. Not that it matters....

Justin L · « **Reply #13 on:** February 27, 2008, 09:52:42 pm »

Wouldn't it just be easier to pull the staples out first? Sorry

I planed a 4 foot board for a guy lately, made my $5 bucks & then noticed a line on all the boards from then on...

I use carbide for T&G since the runs are usually longer and I don't want to have them wear out before the run is over, or sharpen them each run. That may not have helped the staple though...

I'll try again TOMORROW to measure my T&G fit

I think I'd have the send the knives back if they don't fit right

To defend my honor(or pride, whichever) I do want the tongue side of the flooring to hold the groove side down tight to the subfloor when being installed. Maybe I need to look a little closer at it...

In a way, the bottom part of the groove is a tongue that fits into the space below the tongue. $:-\$

Cedarman · « **Reply #14 on:** February 28, 2008, 07:17:33 am »

On our moulder, I run 2 knives per head. I have the knives that make the groove to make it smaller than the knives that make the bead. If I left them this way, I can not slide the two pieces together. I can slide one of the groove knives off center to make a slightly wider groove. With trial and error I can make the fit too tight, snug, or loose. Snug for flooring, lightly snug or a hair loose for paneling. It is amazing what .01" will do for snugness.

The guy that make our flooring back in 92 made it way too snug. They had to be pounded together which slightly raised the edge. We had to sand the floor a lot to get it right. But we have never had a squeak either.

woodworker9 · « **Reply #15 on:** February 28, 2008, 03:08:59 pm »

Cederman

You are dead right about the .01 measurement! I'll tell you this from experience. The last thing in the world you want to do when installing T&G is to need to use a shoulder plane on every stinkin' tongue to get it to fit without splitting the groove on the adjacent piece. I finished that job out of sheer stubbornness and personal pride. Cost me an extra day of labor. And, I never bought flooring from that co. again.

Cedarman · « **Reply #16 on:** February 28, 2008, 03:21:24 pm »

We messed up one time too. We took a router table and got the right size bit and slid every board across to enlarge the groove. What a PITA! Made sure we double checked from then on.

David Freed · « **Reply #17 on:** February 28, 2008, 08:17:27 pm »

Thanks for all the replies. As far as the tongue swelling after installation, I would think that if moisture was going to be able to reach the tongue of one board, it would also get to the grooved board that the tongue is in and they would both expand the same. As some of you have already said, that is one of the arguements for a snug fit. I am going to see what my resharpened knives look like before I call the company again. Thanks again.

treenail · « **Reply #18 on:** March 01, 2008, 02:06:22 pm »

Have installed thousands of feet of tongue and groove flooring, and I have always liked working with it a lot better if it is just lightly snug. It is noticable after a while, that my matched molding cutters do wear after a while, when producing flooring and that can change the fit from time to time regardless of good intentions.

Handy Andy · « **Reply #19 on:** March 02, 2008, 11:25:11 pm »

I like my fits tight enough they just pop together. The next floor I lay, plan to run a bead of glue along the bottom side of the groove. Then the floor will be glued together, and won't be able to gap after you have been running your furnace most of the winter. Makes the floor into a solid piece.

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Author Topic: Tongue & groove fit (Read 4453 times)