Wednesday, January 30, 2013

Dressing Metal Tools

Metal on metal is a dangerous combination. Generally, hammers and other striking tools are made of hard steel and the tools they strike are slightly softer steel. This is to prevent chipping; metal shards chipping off of the hammer or tool. But the end result is that the tool eventually starts to look like a mushroom from the softer metal flowing under repeated blows (much like blacksmithing without the heat).

This mushrooming then becomes very dangerous because the metal curls away from the surface being hammered and big pieces can shear off and become shrapnel. Without appropriate eye and face protection one could be blinded.

So what do you do? Throw out the tool as unservicable? Buy a new one to be safe? The answer is no and no. You redress the striking surface. Here is how.

This picture shows a splitting wedge but these tips can be applied to any similar tool such as a chisel or rock drill. As you can see the top (left in this photo) has begun to curl over. This tool is long over due for a proper dressing.

 This close up shows where two pieces of the metal curling have already chipped off. I had loaned this tool out to a relative and he is inexperienced and struck off center when he was splitting some logs. Luckily no one was hurt by this shrapnel. But when the tool was returned I decided to fix the problem right away.

I have an old bench grinder but you could also use a hand-held angle grinder or even a course file.

Metal File, Bench Grinder, and Angle Grinder

The object of dressing a tool is to remove the unsafe metal and return the striking surface to a smooth, safe configuration.  If you use a grinder you have to be careful to not over heat the metal. Go slow and only grind for a few seconds on each angle. Remove small amounts of metal at a time.

Once you have ground off the curling metal your tool should look something like this. It won't be exactly as original because the tool has been reshaped by the hammering and removal of metal. But you can return the basic profile of the striking surface close to the original. As long as you grind or file off all the excess metal you will regain a usable tool.

Once I grind off the curled metal I like to round off the head so that it doesn't get damaged as quickly in the future. This takes a little practice but you just need to slowly roll the surface of the tool across your grinder.

Good metal tools are not cheap so being able to redress your own tools will save you a lot of money. I have cabinets full of tools that others had thrown out because they could no longer be safely used. I picked them up for free, took them home, and spent a few minutes on each tool to redress them. I have far more cold chisels than I could ever use but I'd rather have more than less. If needed I could sell some of them for a few bucks.

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