# Routing MDF



## dmparrott (May 30, 2008)

Hi Guys,

I'm a new member here and I have a fairly simple question: What is the best type of bit for routing through 1/4" MDF? I would guess it might be a 1/4" or 3/8" carbide up-spiral bit. I wanted to know what others use and the results they get. What bits (brand) would last the longest in your opinion? Thanks.

Dennis


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## bobj3 (Jan 17, 2006)

Hi Dennis

A standard bit will do the job just fine,, MDF is Hard on router bits , I would not suggest you use the high price carbide up-spiral bit just pickup SOME standard router bits..

Not the real cheap ones but some good ones...

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## Dr.Zook (Sep 10, 2004)

Welcome to the forums Dennis.


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## cbsjoez1935 (Mar 14, 2007)

Hi Dennis,

I am not sure if I read your post correctly. Are you intending to use the router and bit as a drill to go through the MDF or looking to rout dados, through slots and rabbets. Bob is right when he says do not use the high end bits on this stuff, since it will dull them real fast. I used 3/16" and 1/4" spiral upcut bits, from MLCS. They are pretty reasonable to start with. What I found is do not cut too deep into the 1/4" MDF to start with. Take shallow cuts and work your way down to the depth you need. I thought I could cut a 5" slot through 1/4" MDF with a 3/16" bit in one pass. If you want to see a bit turn bright red, smoke the MDF and then turn black and useless, you can do this also. We live and learn by our mistakes.

Joe Z.


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## Hamlin (Dec 25, 2005)

Hi,

I would suggest either using a mid price ranged straight bit. Save your spiral bits for other woods. Most definetly take mutliple passes. There isn't much that MDF doesn't like to "ruin", other than a good hammer an chisel.


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## dmparrott (May 30, 2008)

Thanks for your replies. My intention is do some profile routing where I would be cutting through the full 1/4" thickness of the MDF. Actually, I plan on doing this on my CNC router that I built recently. I'm using a Porter Cable 5-speed 3-1/4 hp router as the spindle. From your posts, it sounds like it would be better to maybe cut these parts out in two passes at 1/8" deep per pass. I was hoping to do it in one pass but that may burn up the bits quite fast. What would you recommend for spindle speed and feed rate in this scenario? Thanks.

Dennis


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## bobj3 (Jan 17, 2006)

Hi Dennis 

You may want to check out the bits made for CNC machine...

http://www.precisebits.com/products/carbidebits/taperedcarve250b4f.asp

Chip-breaker Router Bits

http://www.precisebits.com/products/carbidebits/fcrouter.asp

http://www.thinktink.com/stack/volumes/voli/store/routbits.htm

I can't say what the feed rate should be , but you will need to check out your software for the CNC machine..

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## crquack (Oct 10, 2008)

I have just joined and read this thread with interest - unfortunately *after* I cut a circle out of 3/4" MDF using my spiral up-cut bit.

I was interested to hear that MDF is hard on the bits. Why is that? Is it the binding substance? My bit went through the MDF like through butter so I cannot see hardness being an issue.

BTW I am pretty sure that the stuff *was* MDF...it looks like it and was sold to me as MDF


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## bobj3 (Jan 17, 2006)

Hi crquack

Save your spiral bit for real wood,,,I use alot of MDF stock and it's hard on router bits , it's the "substance" ( Glue and sand and dirt ) they just can't get it all out of the man made woods..do this for a test, take some 3/4" thick MDF and rub it on some real wood it will act just like sand paper ( 5000 grit) you will need to look real hard but you will see it...they press it down but once you cut it on the table saw you have open it up, rub your finger over the edge and it will be just a bit ruff..unlike real wood...you can do the same test with a router bit...


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crquack said:


> I have just joined and read this thread with interest - unfortunately *after* I cut a circle out of 3/4" MDF using my spiral up-cut bit.
> 
> I was interested to hear that MDF is hard on the bits. Why is that? Is it the binding substance? My bit went through the MDF like through butter so I cannot see hardness being an issue.
> 
> BTW I am pretty sure that the stuff *was* MDF...it looks like it and was sold to me as MDF


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## Ken C. (Feb 24, 2017)

Hi, new reader here. I have been making raw mirror frames for a person out of scraps of MDF that he brings me from his other projects. I have noticed at least 3 different work-ability characteristics among the scraps - depending apparently on the manufacturer and/or the base mix of ingredients that they use to make the stuff. One type, as a responder said above, cuts "like butter", smooth and easy - making a granulated type of dust ( more like particle board ). There's no drag on the router bit and a lot less heat - bits last longer. The worst of the three types cuts like it made out of pressed layers of paper, does not cut cleanly or easily. It grabs at the bit, runs noticeably hotter ( the cuttings almost burn your skin as they come off the bit ). This MDF puts more dust in the air and is harder for the vacuum attached to my router to contain - I hate this one! The third type is more or less in the middle. The scrap provider does not know the source of the various types, he just buys the MDF stock that the local yard has at the time. I am planning to speak to the buyer(s) at the lumberyard so as to reveal the source of the "good MDF". Long story short: Not all MDF is created equal. Ken C.


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## RainMan 2.0 (May 6, 2014)

Welcome to the forum Dennis Ken , and your right Ken , I've noticed a difference in the quality of MDF around here to . Some had almost what looked like to be layers in it , especially if you droppped it on a corner . There is also one called MDF light , which is half the weight and cuts like butter . 
I find if the sides are a bit darker than normal , than it's garbage . At least in my experience. 

I have used numerous Freud bits for MDF with little issues . 
I used to buy these bits called "exchange a bit " , if I was concerned about dulling them .
They would get dull and burnt and you just take them back to home hardware and for a smaller fee they exchanged them


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## Cherryville Chuck (Sep 28, 2010)

Hi Ken and welcome. There is a cabinet grade for making doors out of and it leaves a finer finish than regular but I don't where it would fit in that list.


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## 197761 (May 2, 2017)

Well, this is not good news. I just bought a primed MDF 1" x 2" to make a picture frame..guess I should have bought real wood?


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## hawkeye10 (Jul 28, 2015)

Ken C. said:


> Hi, new reader here. I have been making raw mirror frames for a person out of scraps of MDF that he brings me from his other projects. I have noticed at least 3 different work-ability characteristics among the scraps - depending apparently on the manufacturer and/or the base mix of ingredients that they use to make the stuff. One type, as a responder said above, cuts "like butter", smooth and easy - making a granulated type of dust ( more like particle board ). There's no drag on the router bit and a lot less heat - bits last longer. The worst of the three types cuts like it made out of pressed layers of paper, does not cut cleanly or easily. It grabs at the bit, runs noticeably hotter ( the cuttings almost burn your skin as they come off the bit ). This MDF puts more dust in the air and is harder for the vacuum attached to my router to contain - I hate this one! The third type is more or less in the middle. The scrap provider does not know the source of the various types, he just buys the MDF stock that the local yard has at the time. I am planning to speak to the buyer(s) at the lumberyard so as to reveal the source of the "good MDF". Long story short: Not all MDF is created equal. Ken C.


All men are created equal but not MDF. What gives here? I no there is a difference but don't know what so it will not be long and someone will answer your question. So welcome to the forum, it's a great place.


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## Cherryville Chuck (Sep 28, 2010)

I know of 3 grades. There's lite which you feel when you lift the sheet. It's not nearly as dense and doesn't rout great. Then there is the regular and a denser (I suspect) grade that is used for cabinet doors that does rout well. I'm not in the habit of making cabinet doors out of mdf but one of my uncles who is a professional woodworker does regularly. I really only know what I've seen him working with.


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## DesertRatTom (Jul 3, 2012)

DerSchuhmacher said:


> Well, this is not good news. I just bought a primed MDF 1" x 2" to make a picture frame..guess I should have bought real wood?


My wife's an artist so I make a lot of picture frames. I would never consider making a frame of MDF. It is far too fragile. I do use a fair amount of pine, but prefer other hard woods for the most part. 

I now mill some of my own frame material, sometimes mixing woods. To allow for the thickness of the canvas stretcher, I usually use pine cut to size, glued to the back of the frame. If the frame is pretty wide, I won't run the thickness piece the full width. But if I miter that back piece, I will cut in a spline in the corners for strength, and that is always a good hard wood. Sometimes I cheat and lay the ends of the thickness piece across the front miter to add strength, particularly if the front piece isn't really thick enough for a spline.


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## 197761 (May 2, 2017)

Something told me to get pine and yet so many on other sites were bragging about MDF. UGH This particular painting doesn't warrant a more expensive frame, really. But in the future, if I have something really worth it, I will use the better stuff for sure. Thanks for your advice DesertRatTom! I should probably do something for the back, attached to the frame, because this particular painting is only on canvas board and has warped a bit. Maybe, that will help bring it back to flat, or close to it.


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## permo (11 mo ago)

dmparrott said:


> Hi Guys,
> 
> I'm a new member here and I have a fairly simple question: What is the best type of bit for routing through 1/4" MDF? I would guess it might be a 1/4" or 3/8" carbide up-spiral bit. I wanted to know what others use and the results they get. What bits (brand) would last the longest in your opinion? Thanks.
> 
> Dennis


I would go with a 1/4 spiral upcut or downcut bit depending on your application. I cut alot of 3/4" mdf with these bits.


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## DesertRatTom (Jul 3, 2012)

For frames, you might consider checking out the pine decorative materials they sell at the bigbox stores. They come in 8 foor lengths, and have been milled with some fancy textures. I have seen them used as chair rails. Be very careful if you use them to select only very straight stock. About one in three are straight enough. Be fussy. And you'll probably need two to make one frame. You measure the dimension of the frame, add one eighth inch, then double the width of the material.

These are OK for canvas board, but way too shallow for canvas on stretchers. For that, I found nice, fairly cheap pine and cut it into strips and glue that to the back of the frame to hold the canvas. You probably shouldn't sand the textured stock, but seal it carefully and stain it. I like a semi to glossy surface, and for that I use self leveling urethane. 

Cutting perfect 45 degree miters is a challenge. You need to have a really good saw and an accurate miter gauge. I rough cut the miters on a chop saw, then cut to exact length either on a carefully set up Rockler table saw sled. However, my wife bought me something called a Lion Miter trimmer (pix below), that has two sliding ultra sharp blades and a steel guide so it cuts a perfect, glass smooth 45 degree miter. My wife bought it for me. 

You have to make sure that the two long pieces and two shorter pieces are of equal length on each side. If one side is longer, it will not go together righjt










This is the kind of precision miter gauge you need to cut exact 45 miter joints.


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