# Bit for dado in MDF bookshelves



## JFED123 (Apr 8, 2009)

Howdy folks. First time posting.

I was wondering if anyone has any suggestions about what type of bit to use for routing dados in MDF to build bookshelves. Didn't know if certain cutting edges did better than others.

I'm a pretty avid DIY'er with a lot of woodworking/construction :moil: under my belt, but never really used a router much. Thought I might as well ask the pros.

Also, any other suggestions on set up or technique would be appreciated.

Thanks!

JFED123


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## bobj3 (Jan 17, 2006)

Hi JFED123

The one I recommend is the one below,,you don't need to go to deep for the dado's and this bit will do a great job in MDF stock.. 

MLCS dado router bits

And because it has a bearing on it, you can clamp a pair of board right to the board and use the bearing as your guide to get a true strait slot.

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JFED123 said:


> Howdy folks. First time posting.
> 
> I was wondering if anyone has any suggestions about what type of bit to use for routing dados in MDF to build bookshelves. Didn't know if certain cutting edges did better than others.
> 
> ...


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## xplorx4 (Dec 1, 2008)

Greetings John and welcome to the forum, I am sue BJ's info will help you out,


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## Charles M (Apr 10, 2006)

John,

Welcome to the group. I differ with Bob on this one. The bit he posted has its place, namely cleaning up the bottoms of dadoes that are cut by other means, but is not the one I would recommend for making the dadoes. MDF can be cut with most any router bit but to reduce fuzzing of the dado shoulders I would suggest a mortise bit with a little bit of down shear like this:

Freud Tools - Mortising









Note that these are not for plunge cutting.


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## JFED123 (Apr 8, 2009)

Bob, Charles -
Thanks for the inputs.
I figured there'd be different approaches...that's why I asked.

It seems that Bob's approach may be easier for the novice router user, since that bit has a bearing. I'm assuming that lets me put my guide right along my dado line.

Charles' approach will probably give me cleaner cuts, but it seems like my guides need to be spaced with respect to the edge of router's sole plate. Guide position = dado line + sole plate radius - bit radius. Is that right? Seems like that's easier to screw up.

Eventually, I will need to do some hinges too, so the mortising bit may come in handy then too.

Also, I've noticed that some router bits, especially for dados, are labeled with one dimension (1/2"), but may actually be slightly smaller to match thicknesses of sheet goods. Is this common? Is it always indicated as such on the packaging?

Thanks again!

John
(JFED123)


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## bobj3 (Jan 17, 2006)

Hi John

I like Freud bits also,but I also like to do the job easy, the bearing on the bit makes it a easy job,just clamp two boards down in place drop the bit in place and cut the dado,,the bit I posted is a great bit it's set up for 3/16" deep but it will go down to 5/16" deep easy, it will plunge right in but if you want to make a quick jig to take on all the bits for putting in dado's ,see the link below,, it will let you use the plywood bits that are made just for under size sheet goods  the slot can be 1" to 1 1/2" wide in the jig and it only takes a pass with the router/router table to make the jig and it's one you will want to keep around for many jobs not only for dado's, blind dovetails slots,blind rabbit a edge,etc.

H5559 Straight Plywood 3 pc. Set 1/2"

http://www.routerforums.com/jigs-fi...igs-fixtures/2711-dado-jig-plunge-router.html



JFED123 said:


> Bob, Charles -
> Thanks for the inputs.
> I figured there'd be different approaches...that's why I asked.
> 
> ...


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## cbsjoez1935 (Mar 14, 2007)

Hi JFED123

As you can see, there are more than a few ways to do things. I believe Bob's method works well if you are using your router in a hand held operation, while Charles' version can be used that way also, but I would rather do his way using a router that is table mounted. MDF can be brutal on bits, since it is a lot of glue and resins, and you may not want to use a "premium bit" for this operation.

Joe Z.


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## Charles M (Apr 10, 2006)

JFED123 said:


> Bob, Charles -
> Thanks for the inputs.
> I figured there'd be different approaches...that's why I asked.
> 
> ...


John,

You may notice that on the page I linked there are bits both with and without bearings. In fact, the Freud version of the one Bob posted with the very shallow cut depth is there, too. They are all considered mortise bits but I think the taller carbide heights are more versatile.


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## JFED123 (Apr 8, 2009)

Charles -
Thanks for pointing that out. I did not see the bits with the bearings at first.
However, looking at the Freud chart, I didn't see what I need with the bearing.
My router takes a 1/4" shank, and I'll be working with 3/4" MDF (which I guess is actually23/32").

Looks to me like Freud has a 3/4" w/ bearing or 23/32" w/o bearing.
Am I missing something?
I'm sure SOMEBODY makes a 23/32 w/ bearing, right?

Thanks,
John


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## gazippoman (Feb 13, 2009)

bobj3 said:


> Hi John
> 
> I like Freud bits also,but I also like to do the job easy, the bearing on the bit makes it a easy job,just clamp two boards down in place drop the bit in place and cut the dado,,the bit I posted is a great bit it's set up for 3/16" deep but it will go down to 5/16" deep easy, it will plunge right in but if you want to make a quick jig to take on all the bits for putting in dado's ,see the link below,, it will let you use the plywood bits that are made just for under size sheet goods  the slot can be 1" to 1 1/2" wide in the jig and it only takes a pass with the router/router table to make the jig and it's one you will want to keep around for many jobs not only for dado's, blind dovetails slots,blind rabbit a edge,etc.
> 
> ...


bobj...i tried to follow your link, but it didn't take me anywhere! If you don't mind reposting the link, I would appreciate it. I used search to try to find it, to no avail.

Bill


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## bobj3 (Jan 17, 2006)

HI Bill

Try this one 

http://www.routerforums.com/jigs-fixtures/2711-dado-jig-plunge-router.html

=========


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## Hamlin (Dec 25, 2005)

JFED123 said:


> Charles -
> Thanks for pointing that out. I did not see the bits with the bearings at first.
> However, looking at the Freud chart, I didn't see what I need with the bearing.
> My router takes a 1/4" shank, and I'll be working with 3/4" MDF (which I guess is actually23/32").
> ...


Hi John,

MDF is true actual size. So, if you're routing 3/4" MDF, it's actually 3/4".

Since your router is only a 1/4" shank size, take multiple passes.


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## JFED123 (Apr 8, 2009)

Bill -
Looks like Bob double-pasted the URL. Try this:

www;routerforums;com/jigs-fixtures/2711-dado-jig-plunge-router;html

Replace each ; with .

(Since I don't have 10 posts yet, the forum software won't let me post the actual URL with the periods.)

John


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## Charles M (Apr 10, 2006)

John,

3/4" diameter is the smallest bearing guided mortise bit that I am aware of from any supplier. My suggestion is to either use the edge of the router or a template guide bushing to guide the cut.


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## JFED123 (Apr 8, 2009)

gazippoman said:


> bobj...i tried to follow your link, but it didn't take me anywhere! If you don't mind reposting the link, I would appreciate it. I used search to try to find it, to no avail.
> 
> Bill



Bill -
The forum software won't let me post the exact URL because I don't have 10 posts under my belt yet, but here it is anyway. Looks like Bob double pasted the actual link name.
John

Put in periods where I have plus signs:
www+routerforums+com/jigs-fixtures/2711-dado-jig-plunge-router+html


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## JFED123 (Apr 8, 2009)

gazippoman said:


> bobj...i tried to follow your link, but it didn't take me anywhere! If you don't mind reposting the link, I would appreciate it. I used search to try to find it, to no avail.
> 
> Bill


Bill -
If you right click on the link and look at properties, you'll see that Bob double-pasted the URL.
I would repost it myself, but the forum software and/or moderator is not letting me post URLs until I get at least 10 posts under my belt.

Hope this helps.

JFED123


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## JFED123 (Apr 8, 2009)

Hamlin said:


> Hi John,
> 
> MDF is true actual size. So, if you're routing 3/4" MDF, it's actually 3/4".
> 
> Since your router is only a 1/4" shank size, take multiple passes.


OK, cool.
I was wondering about that.
Thanks!


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