# Tongue and groove tearout



## Mrs C (Jul 27, 2015)

Hi

Help, I am stuck! 

I am routing tongue and groove hardwood planks which are too long to go over a router table. Am using a handheld router with a single tongue and groove bit fitted with a bearing. I have an identical piece of wood for supporting the router so am moving/supporting it along a flat surface.

The finish of cut on the groove is fine, but when i cut the tongue it has a ragged finish on the edge where the cornerof the tongue has flaked/chipped. Its not the end of the world as it will be hidden, but it would be nice if it was a clean cut.

Anyone any thoughts as to what i am doing wrong?

Thanks


----------



## cocobolo1 (Dec 31, 2015)

Does this happen with all the boards, or just some of them?

It could be the direction of the grain causing the trouble. Perhaps try running the router the other direction, as in a climb cut. It may help.

BTW, welcome to our little corner of the web. :smile:


----------



## Stick486 (Jan 4, 2013)

Mrs C said:


> Hi
> 
> Help, I am stuck!
> 
> ...


welcome to the forum Hrs. C...
climb cutting may be the help you are looking for...

.


----------



## Stick486 (Jan 4, 2013)

have you considered splining instead of T&G???
less waste that will seriously add up w/ a lot less mess...

.


----------



## DesertRatTom (Jul 3, 2012)

I now prefer using splines whenever possible. When making very fine measurements such as what you did on the bit, I find it works best to use one of those 6 inch pocket rules with a sliding clip, marked in 32nds. Need a magnifying glass to read it, but it is very accurate for things like measuring small offsets, blade height and such.


----------



## Shop guy (Nov 22, 2012)

Welcome to the forum, Mrs C. I like Stick's idea of using splines the best. Saves material and a lot easier.


----------



## Stick486 (Jan 4, 2013)

splines use up drops and what can be construed as waste...

you can still use the grove cutter to do your splines....


----------



## hawkeye10 (Jul 28, 2015)

Splines would work great as others have said. To do the tongue and groove you might try doing the tongue in two passes. Taking lighter cuts helps problems a lot.


----------



## Cherryville Chuck (Sep 28, 2010)

Welcome to the forum Mrs. C. If you clamped the two boards together tightly then that pressure should prevent the bit from tearing grain out as it finishes the first board. I also prefer to spline however. Much simpler and you'll save about 1/2" of wood for every board you are using. As pointed out that adds up over time. A spline joint is basically the same as a T & G joint, the exception being that there are two grooves and the tongue is free floating instead of attached to one of the boards.

In the case of flooring the tongue is strictly for alignment purposes so it is imperative that you work from the back side of the boards and not the face. The backs must all sit flat on the sub floor and a tongue at the wrong height will lift one of the two boards off the sub floor which will cause squeaking and possibly crack one day. Traditionally hardwood floors were installed and sanded in place to get the top flat. Modern mating methods may be accurate enough to eliminate the different heights problem but it's best not to take a chance.

Since it's only for alignment you could use hardboard or ply for tongues. I had some thin wooden T & G paneling once that perfectly fit one of the slotting cutters in my set so I used it for splines.


----------



## Nickp (Dec 4, 2012)

Mrs C said:


> *Anyone any thoughts as to what i am doing wrong?*
> 
> Thanks


Welcome, Mrs. C...

What is likely happening is the cutter, as it is exiting the cut at a high angle where the grain ends, will lift a slight amount rather than cutting it cleanly because there is no more grain support at the end of the cut. What might help is to take a light initial scoring pass so that the cutter is approaching the grain at a lower angle then "have at it"...

Red Oak is my nemesis when doing the same thing...little slivers want to break off... If they're big enough, I use them for toothpicks 

Climb cutting, as has been suggested, takes care of that because the cutter is cutting down into the grain and therefore does not lift when it exits.

...nope...doing nothing wrong... but just for the heck of it, is cutter clean and sharp...? What about router speed...high enough...? Enough power in the router if you're taking it in a single pass...? Good feed speed...too fast...?

Just thinkin' of the basics...


----------



## David Dickson (Oct 30, 2015)

*Longer infeed / outfeed*

I am in the process of rebuilding the base for my router table, so I can't show any pictures right now. But the ends of my RT have mounting points. 2 years ago I went to my local big box store and found two identical offcuts of kitchen worktop which were 6' by 1' and mounted bolts in the end to match the mounting points in the RT. Then I built supports for these extensions. So I had a 6' infeed table, 2' of router table top and 6' of outfeed table. This allowed me to run 8' to 10' stock over a roundover / chamfer / ogee bit for the shaping I wanted. The results looked a lot better than the rig, but it worked and that is what I needed. I'll try to do a mock-up later in the week, but it won't look too pretty either, as the new RT base is still a work-in-progress.
:crying:


----------



## Mrs C (Jul 27, 2015)

Wow, many thanks for all the help!

To answer the questions. The bit is clean, am using a slow speed as I was geting scorching. I love the idea of an enormous router table feed, but unfortunately my workshop is only tiny ( i have to go outside to turn the boards round 🙃) 

I like the idea of splines, will go and experiment! 

Many thanks again.


----------



## DesertRatTom (Jul 3, 2012)

Forgot to say hello and welcome to the Forum. Isn't it great to get so much help just by asking?


----------



## David Dickson (Oct 30, 2015)

*Longer infeed / outfeed mockup*

I managed to do a quick mockop of the router table, but nothing is bolted down yet, so I can't actually use it.

The first picture was taken from the Outfeed side of the RT, where you can see the infeed table on the far side.

The second picture was taken by stepping back about 6' from the operating position, with the infeed table balanced on top of a roller stand. Underneath the RT you can see an old postroom / mailroom trolley that my last employer was throwing out (because one of the wheels was loose - I tightened it up with a spanner and it works perfectly). I think that a couple of chocks wrapped around the front wheels should keep it from moving, but I will do some careful testing with the router unplugged to make sure that it is safe *before* I use it.

The third picture was taken looking along the infeed table towards the RT. In the background, you can see the side door to my garage, where I store all of my equipment. It is fairly full, so I have to move anything I want to use out onto the patio, hence the trolley for the RT, an almost identical one for the bandsaw and an old catering trolley for my sliding compound mitre saw. When it is raining, I stay in the garage and use hand tools, or tidy up after the last session.

I dismounted the infeed table and flipped it end-for-end for the fourth picture, so that you can see the heads of the hex bolts screwed into the end, and how they line up with the mounting slots on the side of the RT top surface.

The two offcuts of kitchen worktop cost me £1 or £2 each. The edge banding was £3 or £4. The bolts cost about £2. So the total cost was under £10, or under US $15. I still have to design and build the supporting legs for both sides, but that should not be expensive. The supports from the old base will not work with the new base.


----------



## Herb Stoops (Aug 28, 2012)

Good job, that is a long infeed table. How are you going to support the wood on the outfeed side? 

Herb


----------



## David Dickson (Oct 30, 2015)

Thank you, Herb,
I managed to buy two identical offcuts of kitchen worktop, so I have both an infeed and an outfeed table. When they are both mounted, the whole thing is 14' long. I only have one roller stand, and the old supports don't work with the new base (different height), so I couldn't photograph them both mounted at the same time. You will just have to imagine it, for now.
:smile:


----------



## CharleyL (Feb 28, 2009)

Another thing to try -

Attach a board about 1/2 the thickness of the final tongue length to the fence on your router table. Make the first pass with your board against this. Then remove the fence board and make a second deeper pass against the router bit bearing. Lighter cuts and two passes will change the angle of the router bit cut and reduce it's likelihood of splintering the edge of the cut. Always use a push block of similar material so the cut doesn't stop at the end of the board, but slightly into this push block to keep the very end of the cut from splintering.

Charley


----------



## DesertRatTom (Jul 3, 2012)

I was watching a Mark Sommerfeld video in which he explained that the tongue cutter of conventional design will produce tearouts and splintering. It is a function of the way the blade on the bit goes through its motion. The first half the cut the cutter is cutting into the grain, the second half of the rotation, the cutter is outward and often produces a rough edge when it catches any raised grain. Sommerfeld said they have developed a bit that doesn't do this, I think it entails a very slight roundover of the cutter tip so it is not catching any grain. I think it would be good to affix sandpaper to a thin srip so you can run it over the tongue's edge. Not really necessary, but why not?


----------



## CharleyL (Feb 28, 2009)

There are also tongue and groove bit pairs that have a slight taper on the sides. If I was making tongue and groove flooring I think I would want a pair of these. They would not only reduce the splintering of the tongue when made, but the boards would fit together easier with the slight taper in the tongue and groove design. 

Charley


----------



## DesertRatTom (Jul 3, 2012)

@CharleyL Thanks, didn't know about the tapered bit.


----------



## CharleyL (Feb 28, 2009)

Here is a set with a combination of what Tom and I have been discussing. In this one, the tongue is slightly rounded, and with a nail slot. The groove looks straight sided, but I believe that it has a one degree or so taper to minimize chipping/splintering. It seems to be available from several sources, but Infinity shows a good picture of the resulting cut.
I can't find any reference to the taper that I was referring to, but can remember it being discussed 10 or more years ago.

https://www.infinitytools.com/Tongue-Groove-Flooring-Router-Bits-w_-Nail-Slot/products/1816/

Charley


----------



## Mrs C (Jul 27, 2015)

Hi, I am about to do my second set of t&g boards for my next door and will have a go with splines instead of traditional t&g.

I am hoping that you can answer a couple of questions for me.

1) Am I ok to use marine ply for the splines? There will be a 3mm gap between the boards for expansion, and am assuming that if anyone notices they will be too polite to say so! The boards are oak, is there any structural reason not to do so?

2) Can I do my splines in bits? My boards are 1.5m long (5 feet in American) and I have lots of bits of marine ply but nothing that long! 

Many thanks


----------



## Stick486 (Jan 4, 2013)

Mrs C said:


> Hi, I am about to do my second set of t&g boards for my next door and will have a go with splines instead of traditional t&g.
> 
> I am hoping that you can answer a couple of questions for me.
> 
> ...


how wide and thick are the boards???
what are the sizes of the doors???
if you go w/ ply you'll have to undersize the splines to allow for the oak to move...
what are you doing the edges/perimeter in/with???

1) I have never used ply for unglued floating splines so can't say...
2) yes you can as long as the bits aren't real short... say under 30CM long...

consider a solid glued up panel...


----------



## Mrs C (Jul 27, 2015)

Hi

The boards are 100mm wide and 20mm thick. It is a traditional framed braced external door, with the sides and top 100mm x 45mm, bottom is 200x45mm. I have 6 t&g/splined boards running vertically across the middle, suppoted with 2 diagonal braces at the rear plus horizontal center bit.

Many thanks


----------



## DaninVan (Jan 1, 2012)

Welcome, Mrs. C!
No problem at all using shorts for splining. Having said that, if the grooves are a bit sloppy you could end up with the splines sagging slightly at different points making for annoying assembly.
If the outside edges of the splines are tapered slightly at the very edges of the long sides that should make for easier insertion into the grooves (as previously mentioned by others).
Marine ply is excellent quality and has *waterproof* glue. Not many of us have that just lying around as scrap! 
If you have picture on your own harddrive, you can insert them into that space below that says 'Drag and Drop Upload'.
Personally I just drag mine off my desktop, after I've reduced the page size (Very top of your screen...right side.)


----------



## Stick486 (Jan 4, 2013)

glue your splines...


----------



## Mrs C (Jul 27, 2015)

Thank you both, will go and play!


----------

