Routing cutout on MDF

[Steven J Corpstein]

Which router bit would be best for routing the cutout for a router table? I want a good clean, crisp edge when done. I thought maybe a down spiral straight bit?

[Jim Becker]

Spirals are nice for a clean cut. Be sure to use one that is the correct radius for the plate you intend to inset, however...they are all a little different and when you route the lip that holds up the plate/lift, you want the corners to match.

[Paul Girouard]

I thought maybe a down spiral straight bit?

I say a up cutting spiral you want to pull the chaff up and out of the cut. Jim's point of corner radius matching is a good one.

Square cornered steel , is in hinge leafs , door strikes , your router base / holder and the like are much easier to deal with IF you don't have the right router bit.

But they must figure they know what raduis bit they use and order the same matching raduis on the parts they supply. Doesn't always work out that way but that's another rant

[Bill Huber]

Spirals are nice for a clean cut. Be sure to use one that is the correct radius for the plate you intend to inset, however...they are all a little different and when you route the lip that holds up the plate/lift, you want the corners to match.

So which spiral do you want, the up of down.

I would think you would want to push the cuttings down but is that a down spiral or an up spiral.
Now when you put the router in the table that same bit would work as a up spiral.
I am just trying to find a way to get this in my head.

Can I say that any time the cuttings are being pushed away from the base that is a down spiral.

And any time the cuttings are being pull to the base that is an up spiral.

[Bill Huber]

I say a up cutting spiral you want to pull the chaff up and out of the cut.

But would not pulling the wood UP give it more of a chance to pull out cheaps.

So would you not want to cut down on it?

This up down really gets me screwed up for some reason. I guess it would more screwed up then I am.

[Paul Girouard]

But would not pulling the wood UP give it more of a chance to pull out cheaps.

So would you not want to cut down on it?

This up down really gets me screwed up for some reason. I guess it would more screwed up then I am.

Spiral bits cut wood and MDF "like butter" sharp new ones anyway.


I have a router table , (sort of on my table saw bed used with the fence system but I seldom use it , to much of a PITA to set height etc , maybe IF I had one of these new bases to adjust height etc I'd use it more ) So I do all / most of my routing what I guess I'd call the "normal way" , holding the router.

So if your buying this bit and will be using it with the router inverted (once your table is built) the down cutting bit , as I think your trying to say will pull the chaff away from the router itself , and a down cut bit may serve you better long term.

That is assuming you'll be running a vac with a shroud to suck chaff away when using the router table .

Bottom line IMO if the bit is new either bit will cut MDF , P.Lam or solid wood without chipping , feed rate and direction would be more important than spiral direction.

Also remember a down cutting bit will "self feed" / pull itself down so MAY have a tendency to grab the stock . Sort of like a agressive auger bit will pull the bit into the stock , not a perfert example the router bit won't be as agressive but will still tend to pull itself in .


Hope that helps , as it is confusing to write all this down in a way that easy to understand , at least for me , YMMV

[Steven J Corpstein]

I figured since MDF edges tend to separate easily, if I use a down spiral with good dust extraction, I'd get a cleaner edge on top which is where it counts? I plan on laminating it top and bottom when done with the fabrication.

[Paul Girouard]

I plan on laminating it top and bottom when done with the fabrication.

As in plastic laminate? If so I'd lay the P.lam then rout it out all at once. Resetting your jig in exactly the same place will be hard , also IF you do rout out the MDF first , what type of bit would you rout out the lam with?

A bullet bit won't do the shallow edge / let in area that I think you'll be having to clean out? I could be wrong as I'm guessing on exactly how the let out area and router holder plate intergrate.

[glenn bradley]

I figured since MDF edges tend to separate easily, if I use a down spiral with good dust extraction, I'd get a cleaner edge on top which is where it counts? I plan on laminating it top and bottom when done with the fabrication.

I second the idea of routing after the laminate is on. Down cut would be my preference to avoid pulling the edge of the laminate. Remember that once your cutout is done, the next thing you'll do is rabbet the ledge so your concern may be moot as the rabbet bit will be straight or shear edged.

[Paul Girouard]

Remember that once your cutout is done, the next thing you'll do is rabbet the ledge so your concern may be moot as the rabbet bit will be straight or shear edged.

That's IF he has the right bearing to cut the right side to side rabbet , and IF the rabbeting bit will result in the right radius ! And maybe that's all much to do about nothing , it is just a router table eh !

[Joe Spear]

If you're using a template to guide the cutout, you could cut it a little proud with a jigsaw first to get out the bulk of the material and then use a pattern bit to clean it up to the line.