# fitting blum concealed hinges in 16mm mdf



## reck123 (31 Jan 2022)

Hi guys,

So I have run in to a little bit of a problem.I am making some small inset doors for a shelving unit. The material I'm using is 16mm white pre primed mdf. upon drilling the holes for the cup of the hinges the brad point of the forester bit punctures the other side.

To remedy this I found a cheap old china 35mm forester bit and ground of the brad point but i still get a slight impression on the other side ( the cutters inside the outer cutter ring are slightly raised.

I know i probably should of gone with 18mm to avoid this but the cup should seat in the 16mm material with a 2-3mm meat behind it.

can anyone recommend any other methods.

I have a router so could maybe buy a top bearing flush bit and plunge and trace a 35 mil hole on a template. i have 14 doors to do so could take a while.

I also maybe have the possibility to borrow the eco drill jig from blum though I wonder if the jig works for 16mm doors as online it states only maximum thickness.

any advice would be greatly appreciated


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## Doug71 (31 Jan 2022)

The router is the way to go, if all the doors are the same size you might be able to make a template that does both holes at once which could save time  

Something to watch out for is make sure that the router bit is bottom cutting (that you can plunge with it) because a lot of the template ones aren't made for plunge cuts.


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## reck123 (31 Jan 2022)

Doug71 said:


> The router is the way to go, if all the doors are the same size you might be able to make a template that does both holes at once which could save time
> 
> Something to watch out for is make sure that the router bit is bottom cutting (that you can plunge with it) because a lot of the template ones aren't made for plunge cuts.


Thanks Doug that's a good shout using a jig with both hinge placements marked/templated up on it. I have seen special hinge drilling forester bits online which advertise a small brad point bit but still a risky purchase for this application.


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## gcusick (31 Jan 2022)

Rather than a bearing-guided router bit, use a standard plunge bit and a guide bush. If you use a 20mm diameter bit in a 30mm bush, your template will just need a 45mm diameter hole, and you should be able to rout out each hole in just 2 or 3 passes.


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## reck123 (31 Jan 2022)

gcusick said:


> Rather than a bearing-guided router bit, use a standard plunge bit and a guide bush. If you use a 20mm diameter bit in a 30mm bush, your template will just need a 45mm diameter hole, and you should be able to rout out each hole in just 2 or 3 passes.


That seems like a good way to go. I need to get in to the guide bushing game as soon as I get a bigger router, I only have a small makita multi base router which is limited when it comes to guide bushings


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## Spectric (31 Jan 2022)

reck123 said:


> That seems like a good way to go. I need to get in to the guide bushing game as soon as I get a bigger router,


You could easily do it with a 1/4 router which is lighter and can be more easy to handle. If you get guide bushes then don't forget to get a centring cone to ensure the bush is concentric to the cutter. I recently had to cut two recesses in wall paneling at 75mm diameter and 5 mm deep, my 1/4 Bosch router with guide bush and a home made template delivered a great job.


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## Distinterior (31 Jan 2022)

It may be a bit late now but for future reference,....You can get Blum soft close hinges suitable for thinner doors. They only require an 11.5mm deep hole.


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## reck123 (31 Jan 2022)

Distinterior said:


> It may be a bit late now but for future reference,....You can get Blum soft close hinges suitable for thinner doors. They only require an 11.5mm deep hole.


thanks for that tip . it can be a bit of a maze navigating blums products and specs :/


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## pgrbff (1 Feb 2022)

reck123 said:


> thanks for that tip . it can be a bit of a maze navigating blums products and specs :/


I agree. Iget dizzy/feel faint when looking at the catalogue.


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