What is this tool called?

[davidgilmour]

I need to widen my '28mm holes" to 30mm. What are these two tools called?
Will they work ? ( picture is from japanese forum )

[danny_galaga]

Reamer (",)

I've used a couple of types. This is the simpler one. The fancier one has four blades that can be set in or out by however much you need, so that it reams a perfectly straight hole. You keep adjusting them out bit by bit. Obviously the one you have makes the hole slightly tapered, but wouldn't matter much in sheet metal and would be much faster.

[PL1]

That tool is a taper reamer/metal reamer like this one -- hope you can find a better price, though.   



You might also want to look at 30mm countersinks like this one or this one.   




Scott

[davidgilmour]

Thanks, it is a reamer. They are very expensive. How about these ones, will they do the hjob too?

http://www.ebay.com/itm/351346466612?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

$10 inc shipping!

[CNC_Tech]

Those are called step drills and yes, they would be the correct tool to use in this situation.  They are designed specifically for drilling holes in thin materials.