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Tungsten Carbide and screw dissolvers?

Hammer2017

By Hammer2017
in Tools & Equipment

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Hammer2017 Member

Hammer2017

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Hi,

I've an old chronograph screw shoulder cutter. One of the cutters has a screw end twisted off and jammed in it (came like that - wasn't me!). The cutters are, I believe, made of tungsten carbide. I'm assuming the screw is steel. A replacement cutter will cost more than the entire unit did, so I want to try a repair first. Options are drilling out the screw shaft, or trying a screw removing fluid.

I've heard good reports about Alum dissolving steel screws, but was wondering if it will act on the tungsten carbide of the cutter also and destroy it? Anyone any ideas? The same question goes for the fluids like the Bergeon one, if anyone has any experience with them.

I'm willing to take a chance on this, as the cutter is unusable and will have to be replaced as it is, so it's worth taking a chance on repair methods. Thanks for reading!

Mark

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frenchie Distinguished Member

frenchie

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I say try it. Leave it in the alum solution for a couple of hours, you'll see right away if it's reacting (the steel screw will turn black)

A quick internet search seems to suggest that the only way to dissolve tungsten carbide is to use a really strong acid (sulfuric, hydrochloric...).

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Sleeper Member

Sleeper

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back and forth cold to hot may do it. Put it in the deep freezer then in a warm oven 105c/220f degree. It may work it loose. The two metals expand and contract at different rates. I have had some luck with this method.   

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Hammer2017 Member

Hammer2017

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Ok, I popped it into a warm Alum solution, and right away the cutter started to bubble, so it looks like it's not tungsten carbide after all. It's the original Bergeon model, the 30615.

That means moving on to Plan B. It's the 0.85mm cutter, so Ive got a 0.8mm drill bit to see if I can drill it out. There's not really enough of the screw sticking out to get a hold of it, so I don't know if a hot/cold approach will work. I'll keep it in the bag for if the drilling doesn't work out. Failing that, I'll replace the cutter. I got a great deal on the tool, so even replacing it will leave me at less than 25% of the cost of a new one!

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