# Cutting 3/4" deep Dados



## JohnnyB60 (Jun 15, 2009)

What bit would be the best to make a dado 3/4"deep by 1 1/2" wide? I have a 2HP router.


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## jw2170 (Jan 24, 2008)

JohnnyB60 said:


> What bit would be the best to make a dado 3/4"deep by 1 1/2" wide? I have a 2HP router.



Hi Johnny,

I see that you have not had any replies as yet.

There are many ways to achieve this.

I would say that any straight cutting bit 1/2" or greater will do as long as:
1. It protrudes at least 1" below the base plate on you router.
2. You make a simple adjustable dado jig to set the width at 1 1/2".

One of may ways......

James


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## jschaben (Jun 21, 2009)

JohnnyB60 said:


> What bit would be the best to make a dado 3/4"deep by 1 1/2" wide? I have a 2HP router.


Hi Johnny - I apologize,:'( I'm with James and somehow missed youre first post. You didn't say how long the dado was but it is fairly easy. For 3/4 deep, you will want a fair sized bit, 1/2 or 3/4" in diameter. Preferably a half inch shank. Just need to clamp some guide strips parallel to the dado and start routing. Just where to place the guide strips we will need to know the size bit you are using and what the diameter of the router base plate is. It would also help to know the degree of precision you need to achieve as that could have a bearing on the method used. As James pointed out, there are many ways to do it, just a matter of picking the best and safest.


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## JohnnyB60 (Jun 15, 2009)

Thanks guys, I was cutting a lot of dados that were ¾” deep by 1-1/2” wide and my 2Hp Craftsman Router was having a real hard time of it with a ½” straight slot bit. I was looking around and I found some spiral bits for sale on the internet, but I’ve never seen them before.

I finally ended up using my Radial Saw with a stacked dado set and it was a little scary because the blades were trying to climb up over the wood.

I can’t remember how many cuts I had to make, but I was looking for a fast safe way to do it. I think if I had the correct router and bit, it might have been easier. One of these days I’m going to buy a new router, but that’s another story. :yes4:


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## jlord (Nov 16, 2009)

Hi Johnny,
Making a couple of passes to reach the 3/4" depth would be easier on your router bit also.


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## JohnnyB60 (Jun 15, 2009)

jlord said:


> Hi Johnny,
> Making a couple of passes to reach the 3/4" depth would be easier on your router bit also.


Yes, I’m aware of that and it’s the same thing for using the Radial Arm Saw. 

I just had a lot of dados to do and it was a lot of trouble changing the depth especially with my Craftsman Router. It’s a real pain to change the depth on it. So much so that I usually just set it to 3/8” and leave it like that, but this one time I needed a ¾” deep dado. I have another ¼” router that I use for everything else.


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## BigJimAK (Mar 13, 2009)

Johnny,

You don't say what the shank diameter is for your router. When making full-width cuts like this the cut should be no more than the lesser of the bit and shank diameter. That is, a 1/2" bit cutter with a 1/4" shank (collet) should cut no more than 1/4" deep per cut. Otherwise you risk breaking off the bit. I used to push this until I sheared off my first bit. Fortunately no one was hurt.. now it's my mantra.


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## JohnnyB60 (Jun 15, 2009)

BigJimAK said:


> Johnny,
> 
> You don't say what the shank diameter is for your router. When making full-width cuts like this the cut should be no more than the lesser of the bit and shank diameter. That is, a 1/2" bit cutter with a 1/4" shank (collet) should cut no more than 1/4" deep per cut. Otherwise you risk breaking off the bit. I used to push this until I sheared off my first bit. Fortunately no one was hurt.. now it's my mantra.


Sorry about that. Yes it is a ½” shank. I actually bought the bit for making mortises before I even owned a ½” router. A friend of mine gave me an old Walker Turner drill press and I turned it into a mortising machine. It didn't work too well.

I don’t think there was such a thing as a plunge router at the time. I first noticed a plunge router about a month after I bought my 2hp, 1/2” Craftsman. I should have taken it back and exchanged it for the Plunge but I waited too long. That was probably why I got it so cheap.


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## CooperDBM (Mar 11, 2008)

JohnnyB60 said:


> Yes, I’m aware of that and it’s the same thing for using the Radial Arm Saw.
> 
> I just had a lot of dados to do and it was a lot of trouble changing the depth especially with my Craftsman Router. It’s a real pain to change the depth on it. So much so that I usually just set it to 3/8” and leave it like that, but this one time I needed a ¾” deep dado. I have another ¼” router that I use for everything else.


You could set your router to the full depth and use 1/4" thick strips of hardboard, or whatever, either side of the dado for the router to ride on. Start with two stacked strips to cut the first 1/4", then a single strip to cut to 1/2" depth, etc.


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## BigJimAK (Mar 13, 2009)

Great idea, Dave..


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## Ghidrah (Oct 21, 2008)

In case no one else offered this, try pushing the dado through instead of pulling. As long as the stock is tight to the fence you're good to go.

As long as your familiar with the pull method on a RAS and have the muscle to restrain the saw pulling the blade through the face side of the stock does provide a much prettier cut on the face of the project, but then again you can flip the stock face down and get the same pretty through cut without climb.

I've done tonza RAS dados, the only time I pull is when the stock is too wide to start from the push. It does pay to remove stock in increments, easier on the saw and you and provides you the option to check your cut depth with a template.


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## Hamlin (Dec 25, 2005)

Soft or hard wood? This will make a big difference in how deep to set your passes as well. 

A straight bit will work. I personally prefer using spirals. They give me a "cleaner and smoother" cut than straights. I also like to set my depths to half the thickness of the bit I'm using. Yes, it means more passes but, never burned a bit or broke one either. I should point out, this is just my preference.


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## TWheels (May 26, 2006)

I would use a 1 1/2 in straight bit, with several passes maybe 1/4 then 1/2 then 3/4 in deep. It would be very helpful to have a template guide of, say 1.58 in inside diameter (40 mm) but no such guide exists in North America. Without a template guide I cannot think of any way to make the cut other than on the router table.
I prefer making the full width cut because it is too easy to make the mistake of a climb cut that can be very dangerous. My left forefinger has an altered fingerprint from such a mistake. There have been other injuries more serious than mine, some of which were clearly not due to climb cuts, and in no way do I wish to minimize the seriousness of those injuries or the effects on those valued forum members and others who have suffered such injuries.


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## JohnnyB60 (Jun 15, 2009)

CooperDBM said:


> You could set your router to the full depth and use 1/4" thick strips of hardboard, or whatever, either side of the dado for the router to ride on. Start with two stacked strips to cut the first 1/4", then a single strip to cut to 1/2" depth, etc.


That is a great idea, I must be getting old because I usually come up with ideas like that, but it just didn’t come to me this time.:yes4:


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## JohnnyB60 (Jun 15, 2009)

Ghidrah said:


> In case no one else offered this, try pushing the dado through instead of pulling. As long as the stock is tight to the fence you're good to go.
> 
> As long as your familiar with the pull method on a RAS and have the muscle to restrain the saw pulling the blade through the face side of the stock does provide a much prettier cut on the face of the project, but then again you can flip the stock face down and get the same pretty through cut without climb.
> 
> I've done tonza RAS dados, the only time I pull is when the stock is too wide to start from the push. It does pay to remove stock in increments, easier on the saw and you and provides you the option to check your cut depth with a template.


I have seen some discussion on this and the thought did come to mind. I don’t remember why I didn’t try it but I was cutting two 2x4s clamped together to make a 7” cut. I could have done one at a time, but I thought I would save time as well as avoiding any mistakes like cutting on the wrong side of the line by doing them both at the same time. 

I’m traveling right now in Pittsburgh, but I’m going to give this a try when I get home just to check it out. I already finished the first project, but I’ve had some requests from friends to do a couple more.


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## Ghidrah (Oct 21, 2008)

JohnnyB60,
The only issue I can come up with regarding doubling up the stock is if they're uneven in height or if your RAS table is out of level with the slide.


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## JohnnyB60 (Jun 15, 2009)

Ghidrah said:


> JohnnyB60,
> The only issue I can come up with regarding doubling up the stock is if they're uneven in height or if your RAS table is out of level with the slide.


Actually that was an issue because I was using rough sawn lumber, but then I realized that I didn’t care about the depth as much as the thickness of the remaining wood. Now that I think about it maybe the RAS was the best way to go for this project anyway


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