I have an exterior door that has a wooden threshold inserted in an aluminum frame. The wooden insert is adjustable with four aluminum screws. The screws rusted to a steel nut that was in lower aluminum frame. All four screws are broke. The woodedn threshold (oak) is in good shape but I need screws or something to raise it up. What should I do?

I could repair a threshold like you describe but it is not cost effective. You can buy a replacement for about $20 and do it correctly.

Aluminum doesn't rust. It might corrode when next to steel, though.

I'm going to send you here:

Categories- SmallParts.com (http://www.smallparts.com/s/16310161|468240?refinementHistory=subjectbin%2Cbra ndtextbin%2Cenc-merchantbin%2Cavailability%2Creview-rating%2Cdate%2Cis_prime&searchKeywords=nuts&searchNodeID=317399011&searchRank=relevancerank&searchSize=20&searchBinNameList=subjectbin%2Cbrandtextbin%2Cenc-merchantbin%2Cavailability%2Creview-rating%2Cdate%2Cis_prime)

They have self clinching nuts. Basically, you drill a certain size hole and draw up the nut. The serrations hold it in place.

You can take a picture and post it using "Go advanced/manage attachments". If you need to re-size, you can use www.irfanview.com.