# Difference in swelling by species - White Oak tongue in Brazilian Walnut?



## lk23cix (Sep 13, 2015)

I'm laying down a hardwood floor (red oak), and I was thinking of doing a border with some leftover 3-1/4 Brazilian walnut, which I'd cut in half lengthwise to get approx 1-1/2 border.

By cutting the boards in half, I lose half the tongues and half the grooves. Routing the grooves is no problem (other than taking a few more passes - the walnut is pretty dense), however, routing a tongue would mean losing width. I don't really want to go skinnier than the 1-1/2.

Typically when reversing direction while laying down flooring, I'd just rip a spline on the table saw, and glue it into the groove. I've never worried about it, because I've always used the same species.

Would it be ok to glue a red/white oak spline into the groove of the Brazilian walnut, or would I have to worry about the two species swelling at different rates when the seasons change? 

Thanks!


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## DonkeyHody (Jan 22, 2015)

The Coefficient of Expansion for Brazilian Walnut (Ipe) is about 8 where Red Oak is about 11. However, the tongue and groove pieces will be so small that the difference shouldn't be a problem. 

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch03.pdf


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## boogalee (Nov 24, 2010)

If your border is against the wall you can use the tongue on one side and the grooves on the other.


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## andysden (Aug 9, 2011)

if you place the tongue half cut edge of the trim against the wall and the cut edge of the grove at the other wall place the tongue on the starting wall start laying the floor when you get to the grove end cut to a tight fit then start at that end with the tongue this will interlock the floor together when finished that row repeat process until done then add the other trim Andy


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## Cherryville Chuck (Sep 28, 2010)

I don't think expasion is your problem. I think getting all 4 borders the same width (or length at the sides) is your problem. Unless all 4 sides are equal Ithink it might look unbablanced and getting all 4 sides equal could be a lot trickier than it sounds like since you would have to estimate how wide the final board will be.


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## lk23cix (Sep 13, 2015)

Good point Chuck. I've lucked out in the past when doing a herringbone border; the room was very close to square. But it was all white oak, so even if it was off a little off, you wouldn't notice it as much. With walnut, it'll be a lot more noticeable.

I plan on doing 3 rows of red oak around the edges of the room, then the walnut border, one more row of red oak around the perimeter, and then all rows on the inside going one direction , like this -








Because of where the border will be, each piece of the border will need a tongue and a groove.

When doing a border like this, on some corners, the tongues and grooves don't match. Where ever there is tongue to tongue, I plan on removing one of the tongues and routing a slot so I get a nice tongue and groove connection. In the past, I've just hacked the tongues off and glued them together . It has held up to date, but I'd rather have a tongue and groove connection every time two boards meet.

To your point Chuck, because this border is so different in color from the red oak, it will show a lot more of the room is out of square.

I plan on making most outside row completely square, even if I have to taper it a little on one side, that way everything should be completely square from that point inward. Would that look weird in contrast to the wall though if it was severely out of square?


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## Cherryville Chuck (Sep 28, 2010)

What you had in mind is a little different than I thought. I thought you would be at the very edges. You should be able to get that close enough that it won't be noticeable. I would change one thing I think. Where you have the boards crossways inside the walnut I think I would butt them up to the walnut instead of the oak. The reason being that you will need to be deadly accurate cutting and any variation will be harder to spot against the darker walnut than against the light coloured oak.


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## DonkeyHody (Jan 22, 2015)

lk23cix said:


> I plan on doing 3 rows of red oak around the edges of the room, then the walnut border, one more row of red oak around the perimeter, and then all rows on the inside going one direction , like this -


I'm afraid of expansion where you have all those end grain boards joining the edge grain of the border. Each board will swell or shrink in width but not in length. This is a much bigger issue than your original question about different species. I wouldn't try it that way.


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## lk23cix (Sep 13, 2015)

Cherryville Chuck said:


> What you had in mind is a little different than I thought. I thought you would be at the very edges. You should be able to get that close enough that it won't be noticeable. I would change one thing I think. Where you have the boards crossways inside the walnut I think I would butt them up to the walnut instead of the oak. The reason being that you will need to be deadly accurate cutting and any variation will be harder to spot against the darker walnut than against the light coloured oak.


That pattern actually might look even sharper than what I had in mind, here's an example- 









I think I will try it like that and if I have the chance, post the results.


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## lk23cix (Sep 13, 2015)

DonkeyHody said:


> I'm afraid of expansion where you have all those end grain boards joining the edge grain of the border. Each board will swell or shrink in width but not in length. This is a much bigger issue than your original question about different species. I wouldn't try it that way.


Can anything be done to mitigate this when doing a hardwood floor with a border?


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## DonkeyHody (Jan 22, 2015)

lk23cix said:


> Can anything be done to mitigate this when doing a hardwood floor with a border?


I don't have an answer except don't glue the end grain to the edge grain so it can float. But you still may end up with gaps somewhere later on.


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