# Floor board repair : female recess/male plug



## matt1710 (Sep 21, 2010)

Hi

I have a small section (about 220 x 30mm - or about 9" x 1") of badly damaged floor that needs repairing. I figured the best thing to do was to make a template out of 6mm MDF, and use a pattern cutting bit to cut a shallow recess in the damaged floor board. I then need to glue a 'plug' into the recess. 

My question is this :is there a trick to making a matching female/male template - or does the kerf (whether it be saw blade or router bit) always make this impossible to do in one step? 

The female recess cut in the floor will clearly have round corners - this in itself might cause a complication when making the male plug. Maybe I'm best just to square up the corners of the recess with a sharp chisel, and then cut a rectangular "plug" a touch too big, and hand plane it to size? 

I have attached a picture of the section of the floor in question. The timber is kauri, a softwood native to NZ - and the bora love it, as you can see! Actually, in terms of bora attack, the pictured section of floor is without doubt the worst (by a long way!) in the house - maybe that's why it failed... The house is over 100 years old - so the floor will be too. I wouldn't need to go too deep - maybe 20mm? I've already scanned the section to make sure there are no nails or other metal in there. The boards are joined via T&G. 

Matthew


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## telephoneman (Dec 22, 2010)

Would something like this not work??

www.cheyennesales.com/catalog/cmtinlay.htm

You would make one template, and use it to route out your floor. Then, you take the spacer ring off the guide bushing and route out your "filler".


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## RJM (Apr 11, 2010)

matt1710 said:


> Hi
> 
> My question is this :is there a trick to making a matching female/male template - or does the kerf (whether it be saw blade or router bit) always make this impossible to do in one step?


No trick - just math.

When using a template to cut a hole (i.e. the female part), the offset is equal to half the difference between the guide bushing OD and the bit diameter. The resulting hole width (or diameter) will be twice this amount smaller than the template dimension since the offset goes all the way around. You need to make your template bigger than the desired hole by twice this offset.

When using a template to cut a filler (i.e. the male part), the offset is equal to half the sum of the the guide bushing OD and the bit diameter. This resulting filler width (or diameter) will be twice this amount smaller than the template since the offset goes all the way around. You need to make your template bigger than the desired hole by twice this offset.

If the template and the bit is the same for both of the above, you have to use a smaller guide bushing when cutting the filler. If you do the math, the guide bushing for the filler piece needs to be twice the bit diameter smaller than the guide bushing for the hole.

Example:
-Hole Guide bushing = 1" OD
-Bit diameter = 1/4"

- The filler guide bushing must be 1"-(2 x 1/4") = 1"-(1/2") = 1/2".

A 1/4" diameter bit should fit inside a 1/2" diameter guide bushing so this solution should work. Make sure you consider the wall thickness of the guide bushing when selecting sizes. If you change the above example to use a 3/8" bit (i.e. change the 1/4" to 3/8" in the above example and do the math), the math still works but you can't fit a 3/8" bit thru a 1/4" bushing (this is actually a nonsense solution but it illustrates the point).

You could also change both the bit and the bushing to get the desired results but it's a bit more complicated. Here's the equation you have to solve:

*D1-d1=D2+d2*

Where:
D1=Bushing OD for hole cut
d1=Bit dia for hole cut
D2=Bushing OD for filler cut
d2=Bit diameter for filler cut

One last thing to consider. If using a bit that has a larger shank diameter than cutting diameter in a plunge router, make sure the shank will clear the bushing ID at the desired plunge depth. You may need to use a smaller shank bit, or larger bushing to get what you need.


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## matt1710 (Sep 21, 2010)

Ah - the issue I have at present then, is that I only have one guide bushing - a 40mm one. Guide bushing are very hard to come by here - and if you limit yourself to metric (I don't want to go near imperial if I can help it!) then it gets even worse...

Looks like I might have to cut the recess, square up the corners and then go down the rectangular block and hand plane route. It won't be as perfect - but it might have to do.


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## RJM (Apr 11, 2010)

matt1710 said:


> Ah - the issue I have at present then, is that I only have one guide bushing - a 40mm one. Guide bushing are very hard to come by here - and if you limit yourself to metric (I don't want to go near imperial if I can help it!) then it gets even worse...
> 
> Looks like I might have to cut the recess, square up the corners and then go down the rectangular block and hand plane route. It won't be as perfect - but it might have to do.


You need 2 templates then.


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## Marco (Feb 21, 2009)

Matthew, this from left field....... what ever you end up fixing the floor with still has to match the original floor or you will see a 9"x1" or larger section that has been patched plus needs to have the joint line.

Do you have wood that matches what is on the floor? If so a 1/8 inch thick piece cut to fit a routed recess that has been squared at the corners will work with some touch up after it has been glued in place

If you do not have the wood that visually matches the existing floor I might expieriment with powdered wood filler mixed with different stains or dyes until they look similar.


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## bobj3 (Jan 17, 2006)

Your making a very job with a router to hard,inlay work with a router and the right guides,, it's a very easy job..

The template can be any size,you just need the right guides.

Router Forums - View Single Post - inlay bushing math

Amazon.com: Trend INLAY/KIT/A Carbide Spiral Bit and Bushing Kit for Inlay Templates: Home Improvement

=========


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## matt1710 (Sep 21, 2010)

Marco said:


> Do you have wood that matches what is on the floor? If so a 1/8 inch thick piece cut to fit a routed recess that has been squared at the corners will work with some touch up after it has been glued in place
> 
> .


I do have some of the original flooring - found it under the house, so it should match reasonably well. I guess I could scribe a thin joint line in - but in reality, it's going to be obvious that it's a patch so scribing a joint line might be a waste of time. 

Matthew


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## matt1710 (Sep 21, 2010)

bobj3 said:


> Your making a very job with a router to hard,inlay work with a router and the right guides,, it's a very easy job..
> 
> =========


Bob - can you please fix that sentence?! I'd like to know what you're suggesting. "I'm making a very easy job hard"??


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## jschaben (Jun 21, 2009)

matt1710 said:


> I do have some of the original flooring - found it under the house, so it should match reasonably well. I guess I could scribe a thin joint line in - but in reality, it's going to be obvious that it's a patch so scribing a joint line might be a waste of time.
> 
> Matthew


Hi Matt - let's not overcomplicate things. You are on the right track to start with, route a recess (or is it rebate) over the damaged area...yes it will have round corners based on the radius of the bit you use. Then just cut a plug on the saw the same size. I usually measure from the fence to the nearest tooth to eliminate kerf issues. To deal with the round corners you can either round off the corners of the plug or chisel the corners of the rebate square. Rounding the corners of the plug is easily done on the router table if you have a roundover bit of the correct radius, just run it through standing on edge perpendicular to the fence, using a push block. Otherwise you can round it over with a sander, file....... what have you although the roundover bit will give the most accurate radius. Good Luck


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## matt1710 (Sep 21, 2010)

Ok - plenty of advice here, as usual - thanks! As I don't have the guide bushings, I'll try John's method above - including using a roundover bit - hopefully I have one that matches the bit I intend to use to cut the rebate. 

Matthew


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## paduke (Mar 28, 2010)

When faced with similar circumstances on the job the flooring contractor removed the board and replaced it with a board that had the underside female lip removed But we were sanding the whole floor. We call an inlay patch a Dutchman (given their reputation for frugality) and I have never seen a dutchman that didn't look like a patch So any inlay work should at least equal the width of flooring boards and go the length of shortest stock in the floor to really hide the patch


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## CharleyL (Feb 28, 2009)

I agree. You should remove the whole width of the board for a distance close to the length of the short existing boards in the floor. You should also square cut the ends and slightly round the edges of your patch to match, as closely as possible, the shape of the damaged piece of floor that you are removing. It's best to remove the full thickness of the board, but a patch can be made that will last if you make it at least .200 thousandths thick and glue it in. Set weights on top to hold it tightly in place until the glue dries, and then make any touch up and refinishing that may be necessary to match the existing floor. If you will be re-sanding the whole floor, make the patch slightly proud of the floor so it can be sanded to the same height when the floor is sanded.

Charley


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## matt1710 (Sep 21, 2010)

Thanks for this extra advice re dimensions of patch. We're not sanding the entire floor after patching.


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## RJM (Apr 11, 2010)

CharleyL said:


> I agree. You should remove the whole width of the board for a distance close to the length of the short existing boards in the floor. You should also square cut the ends and slightly round the edges of your patch to match, as closely as possible, the shape of the damaged piece of floor that you are removing. It's best to remove the full thickness of the board, but a patch can be made that will last if you make it at least .200 thousandths thick and glue it in. Set weights on top to hold it tightly in place until the glue dries, and then make any touch up and refinishing that may be necessary to match the existing floor. If you will be re-sanding the whole floor, make the patch slightly proud of the floor so it can be sanded to the same height when the floor is sanded.
> 
> Charley


I think you have an extra decimal in there ....


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## RJM (Apr 11, 2010)

bobj3 said:


> Your making a very job with a router to hard,inlay work with a router and the right guides,, it's a very easy job..
> 
> The template can be any size,you just need the right guides.
> 
> ...


I think this is what he meant:

You're making a very easy router job too hard. Inlay work with a router and the right guides is very easy.



Assuming you meant my explanation was complicating this, I have to disagree. I just explained the how to find the right size guides. An inlay bit and bushing kit works the same way.

If you have an inlay kit available, it would be easier since the math is built in and you don't have to change, or re-center a guide bushing; however, if you want to make a specific size hole, you would still need to figure the offset to determine the size of the template. In this case, you still need to know the math.


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## pal (Feb 13, 2008)

Hi Matt, Try here for the guide bushings. http://www.norwesttools.com.au/?page=shop/browse&category=accessories_templateguides they post internationally.

Regards 

Harold


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## matt1710 (Sep 21, 2010)

Thanks Harold - might drop them a line.


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## jschaben (Jun 21, 2009)

pal said:


> Hi Matt, Try here for the guide bushings. Norwest Tool Centre - Professional Quality Tools :: Template Guides they post internationally.
> 
> Regards
> 
> Harold


WOW - those boys are right proud of their guide bushings. Is that what you guys in OZ typically have to pay for the things?


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## Marco (Feb 21, 2009)

jschaben said:


> WOW - those boys are right proud of their guide bushings. Is that what you guys in OZ typically have to pay for the things?


Did you see the prices on that web site? Wow! You can get a Dewalt DW734 Planer for $303 at Lowes Shop DEWALT 12-1/2" Thickness Planer at Lowes.comand the same tool on that web site Norwest Tool Centre - Professional Quality Tools :: DeWalt DW734-XE Portable Thicknesser 317mmfor $977 US Dollars.

Those boys have to pay big money for their toys!


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## matt1710 (Sep 21, 2010)

Yes, we get shafted for living in such a beautiful, unspoiled paradise with hardly any people. The price we pay for goods is often exorbitant! That's why I try to import as much from the US as possible - however some items (heavy & large) aren't viable to import. Then there's the power difference (110V vs 230V) to consider as well...and the import duties...if they catch you!


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## pal (Feb 13, 2008)

Yep fellers thats what we have to pay. The retail outlets in Australia seem to work on a small turnover with a big price where as in the US they seem to work on small price with a large turnover. Most of the items that i purchase from the US i can buy at less than half price most of the time and add postage still land it here at about two thirds the price I would have to pay if I bought it here. An item as an example Incra metric Hingecrafter drilling guide here in Au. was $169.00 + postage $12.00, brought in from the US $85.66. This includes the postage. Here in Au if the import is under $1000.00 we don't pay the 10% import duty.

Regards

Harold


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## matt1710 (Sep 21, 2010)

Pricing in NZ is almost certainly even higher than Australia, as our population is less than 25% of Australia's - so an even small market, further away. Unfortunately our import taxes kick in at about $350 - wish it was $1,000! That said, I get most things brought back from the US from friends and family who travel there often - or I get my sister-in-law who lives in Minnesota, to disguise the package and send it on - less chance of the Customs crew detecting it as purchased merchandise. 

Still, I'd rather be here than there!


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## jschaben (Jun 21, 2009)

pal said:


> Yep fellers thats what we have to pay. The retail outlets in Australia seem to work on a small turnover with a big price where as in the US they seem to work on small price with a large turnover. Most of the items that i purchase from the US i can buy at less than half price most of the time and add postage still land it here at about two thirds the price I would have to pay if I bought it here. An item as an example Incra metric Hingecrafter drilling guide here in Au. was $169.00 + postage $12.00, brought in from the US $85.66. This includes the postage. Here in Au if the import is under $1000.00 we don't pay the 10% import duty.
> 
> Regards
> 
> Harold


That sux... What's weird though is I ordered some flea medication for the fur kids. Here, it runs about $15/dose or $180 for a dozen. I did some internet shopping and found it for $112 + $6 ship I think. It arrived last week from NSW, AU.... go figure


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## matt1710 (Sep 21, 2010)

Well, they do have massive critter problems in Australia, as well as a healthy collection of the most poisonous snakes, spiders, scorpions.... I guess controlling them needs to be affordable. Australia was a penal colony, whose original inhabitants were hand-picked by Britain's finest judges - so it's no wonder they needed some hardcore critters to keep them under control! ;-)

Thankfully, in NZ, we have only one poisonous spider (and it's so rare I've never seen one), no snakes, crocodiles, marauding sharks...just plenty of sheep!


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## jw2170 (Jan 24, 2008)

And you have to keep an eye on them sheep,,,,,,,,

BTW, I bought some Makita guide bushings from Total Tools here in Sydney for Al in SA.

Around the same price as Norwest Tool centre..

PM me if you want some help.


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## Cassandra (Mar 15, 2006)

Lee Valley Tools - Inlay Bushing Set

http://www.leevalley.com/US/wood/page.aspx?p=41779&cat=1,43000,51208,41779


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## Marco (Feb 21, 2009)

Alright Matt, How did the patch job look when finished? Did you go with John's suggestions?


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