Need ideas for what kind of tool (like a drill bit) I can use to cut out inner fender rust that's tucked up behind the wheel flare.

Can't get a cut off disc in there, only a drill. But I don't want to drill holes...more like slice sideways with a bit in order to trace around the rusty metal.

the new tool on the block -- the Roto-Zip -- is more the idea of what I need. don't want to spend $100 for a set up like that, though. Besides, that tool doesn't mention metal work in its featured uses.

Is there some type of sideways cuting bit I can use with a typical 3/8" drill?

/// Drills except for air powered drills are geared down for torque. This low RPM will defeat what you are trying to achieve. I do however have a suggestion. Use a welding grinder and a wire wheel for most of the work. Mine runs at 30K rpm. I use a twisted cable wire cup. As the grinder winds up the wire is spun out and the cup flattens out. There are flat wire wheels also available. These wire wheels throw wires so watch out.

A tool can be made from a stretcher nut (also called union, or joint) since it will chuck in a three jaw drill. Use the largest your drill will accept. The threaded hole is centered so that a threaded bolt can be a shaft if jammed by a regular nut at the drill end. Additional nuts, jam nuts and an assortment of washers put any abrasive material you wish on the other end. The length of the bolt will position the drill relative to the work end. There are abrasive tools such as this already available but they are expensive and never fit the application. A stack of one inch wide heavy sandpaper, fanned for balance, with the working ends tapered rather than square has worked for me.

There is a needle chipper available from Harbor Freight if they are sill in business.

1. Buy the rotozip carbide bit and use it in a dremel moto tool. slower but works. One of these days I'll buy a roto zip or an air grinder or both! Right now my dremel moto tool only works one notch down from full on..something in the switch....

2. Rent a plasma cutter for $25 or so. some of them use 110v, most use 230v. Clearly the best solution...these things cut shee metal like butter and are distortion free.

3. Replace the entire front fender assembly. Yes it's spot welded on, but IMHO it's the best long term solution unless you just want to peddle the car.

What's the largest diameter blade you could fit in there? I'm thinking of one of those little blades like the ones the drywall guys use in those rechargeable saws (About 2-1/2" dia.). They've also got a drill thingy that is about 1/8" diameter that drills into the sheet rock, then cuts sideways for cutting out switch box opennings, etc. I don't know if there are metal cutting versions of these things or not.