Jump to content

Tungsten Carbide and screw dissolvers?

Hammer2017

By Hammer2017
in Tools & Equipment

 Share

Recommended Posts

Hammer2017 Member

Hammer2017

Posted
Posted

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

Link to comment
Share on other sites
frenchie Distinguished Member

frenchie

Posted
Posted

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...).

  • Like 1
Link to comment
Share on other sites
Sleeper Member

Sleeper

Posted
Posted

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.   

Link to comment
Share on other sites
Hammer2017 Member

Hammer2017

Posted
  • Author
Posted

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!

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Go to topic listing


  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • Randy55
      Introduction

      By Randy55 · Posted

      Welcome to the group Stirky. You can search for just about every subject in the craft here. Don't be afraid to ask if you can't find the answer that may have already been covered ( some ad nauseum LOL ). You don't have to buy Bergeon to get good quality. There are many decent mid-range tools available that will last you a lifetime. Cousins would be a good place to start . Cheers from across the pond ! Randy
    • Jon
      What are these Seitz B-Jewels?

      By Jon · Posted

      I picked up a similar amount of these jewels some years ago in a watch and clock fair. Every now and then they come in handy. This week I've got a rubbed in bombe jewel in the balance cock that is cracked and needs replacing. Very handy to have a vintage assortment of these type of jewels!
    • Stirky
      Diagram for 6497 motion works

      By Stirky · Posted

      Thanks Jon.
    • Jon
      Diagram for 6497 motion works

      By Jon · Posted

      Great diagram with the teeth and pinion count. Simple way to reduce the speed of the hour wheel by the 12:1 minute wheel. Genius and yet so simple. Always good to reinforce the principal by what you have done in your drawing. Keep doing that. I had a drawing on my wall for years showing me this which is very similar to the drawing you have done. Here's a formula to work out the beats per hour of a watch movement. The movement's BPH is dictated by the wheel teeth and pinion count and the hairspring being vibrated to the correct BPH by finding the pinning up point on the hairspring using a vibrating tool.  The reason in the formula there is X2 on the top line is because there are two pallet stones.
    • DDean
      Incabloc Lyre Spring & Low Earth Orbit

      By DDean · Posted

      So I just wanted to say "thank you" again.  The angle is the key bit it seems and yes, it did basically just fall, or float, back into position when I got it lined up just right. I had meant to add that now that I see how it goes in, I totally see how it came out in the first place, and that whomever cloned the original movement didn't pay much attention to the fine details around the setting or how it interfaces with the balance cock or the "rings" on the regulator and/or stud carrier arms.
×
×
  • Create New...