Would it even fit in there? I think your out of luck.

You would be able to find the reverse 1/2 to 1/4.

I was wondering if there was bassically some piece to add on to the bit that would reduce it to a 1/4

Of course, I should probably re-stock my first aid kit before I try something like that.

Not to be messed with. Use this as an excuse to buy a big one.

but I thought I would ask.

maybe even your will.

If there were an adapter to upsize the collet, the motor might not be able to handle the new stresses for the bigger job. Besides, such an adapter would have problems fitting the work and have built in instabilities causing catastrophe if things flew apart at router speeds.

I'm guessing you found some humongous dado or shaper bit-- they take serious power to work and need stability. You've never really crapped your pants until you had kickback with one of those things.

However, for under 150 bucks you can have the best of most worlds-- a Sears 1/2" variable speed router with both collets, and an extra plunge base to boot:

http://www.sears.com/craftsman-14-amp-2.5-hp-fixed-plunge-base-router/p-00927680000P?prdNo=38&blockNo=38&blockType=G38

I was tuning up an old Ryobi that I pulled out of storage.

I was pretty sure that this would be a bad idea even as I posted. Be assured that I DO NOT plan to follow through with it.

cheap, but not bad for occasional use. Made a lot of stuff with it, and even managed to get it to work quite well on a cheap router table.

But, if you're going to get serious, like with those big bits, you gotta get the right tool. I've always suspected Ryobis, and other cheap ones, would have bearings and such that wouldn't last. They wouldn't necessarily kill you, at first, but cutting accuracy would go after a while. Even the Craftsman I suggested earlier might not be the choice for a woodworking pro.

But it's fine for you and me and the occasional project.

Have fun making stuff. I miss my old woodshop.

It wouldn't be safe to build such a thing - when you press the bit into the workpiece (or the workpiece into the bit, if you've table-mounted the router) it'd cause forces that would shatter the motor shaft. This would damage your person in possibly fatal ways.

You need a 1/2" shank router to use that bit. I always liked the Porter-Cable 690.

A half inch router bit is made for the half inch router. You can go down, but not up.

Quarter-inch routers use "split shank chucks." They build the motor with a hollow shaft, make a cut at the end so you can squeeze the sides together, and add a nut that lets you tighten the shaft around the bit. The motor shaft is the jaws of the chuck.

Half-inch routers use "three piece chucks." The end of the motor shaft has a cone machined into it. The jaws of the chuck are machined to a cone that matches. As you tighten the chuck nut, the jaws are forced into the cone and tighten themselves around the bit. They can make the hole in the chuck jaws any size they want.