Drilling/tapping carbide questions

[AlNyhus]

I've got a piece of carbide to drill and tap. It's 90% tungsten carbide and 10% cobalt.

Tips and suggestions appreciated.

Thanks! -Al

 

[Walt Krafft]

EDM is the only way.

 

[Toolbreaker]

EDM is the only option that I'm aware of. A round electrode for burning a basic hole, then a threading electrode to burn the thread form in.

Edit to add: if the parent material and threaded hole is large enough, a soft plug can be turned and soldered/brazed in to accept the thread. Still need a sized hole in the carbide, though.

 

[LVLAaron]

Nope.

 

[AlNyhus]

I didn't think there was any option but EDM. We've got a local shop that has EDM but they really specialize in large run stuff. Will see if they'll pity me and and do a one-zie deal.

 

[Alex Wheeler]

You probably have tungsten not tungsten carbide. Drill and tap as normal. If the drill wont scratch it then you do in fact have tungsten carbide.

 

[gunsandgunsmithing]

It's 90% tungsten carbide and 10% cobalt.

If that's the case, edm is all I can suggest.
Like Alex said, pure tunsten is far from tungsten carbide. But still, even 70/30 tungsten/copper is pretty tough to tap. Much less carbide and cobalt. Because you were very specific about the alloy you have, I believe you are down to edm.

Ebay is a good place to look for copper tungsten cutoffs and they work great for weight systems but carbide and cobalt sounds like good boring bar material. IME, it will not machine with typical tooling and tapping is bad enough even in softer stuff. I'd try to get 65/35 tungsten/copper rod but 70/30 will work too. Most tungsten tods are a sintered metal and will cut better than it'll thread. Carbide is a micrograin structure and hard as woodpecker lips.

 

[AlNyhus]

The spec. sheet with the piece specifies it as 90% tungsten carbide and 10% cobalt. I ended up with it when I bought a box of surplus aluminum and Delrin/acetal round stock. This was in the box along with the rest of the stuff...still in the tube with the spec. sheet.

It's a nice piece of material but it may cost me more to have it EDM'd than buying a tungsten copper cut off piece. A local source used to refurb XRay tunes and they use tungsten copper round as the anode. He's got a bunch of stuff left over....am going to scrounge through that later today.

 

[gunsandgunsmithing]

The spec. sheet with the piece specifies it as 90% tungsten carbide and 10% cobalt. I ended up with it when I bought a box of surplus aluminum and Delrin/acetal round stock. This was in the box along with the rest of the stuff...still in the tube with the spec. sheet.

It's a nice piece of material but it may cost me more to have it EDM'd than buying a tungsten copper cut off piece. A local source used to refurb XRay tunes and they use tungsten copper round as the anode. He's got a bunch of stuff left over....am going to scrounge through that later today.

Sounds like you have the right hookup. Yes, they are commonly used as big electrodes.

 

[AlNyhus]

Talked to our local EDM guys. They suggested I drill and tap a piece of mild steel round stock and bond it to the carbide using a bonding agent that's frequently used for this. -Al

 

[gunsandgunsmithing]

Talked to our local EDM guys. They suggested I drill and tap a piece of mild steel round stock and bond it to the carbide using a bonding agent that's frequently used for this. -Al

It may work but a 30br has an impressive amount of inertia from recoil. Lots more than I would've believed until I tried something similar to what you're doing and it failed. Worth a try as long as the weight is where it can't beat the stock to pieces inside, if it fails. Brazing would probably work

 

[Road_Clam]

I've got a piece of carbide to drill and tap. It's 90% tungsten carbide and 10% cobalt.

Tips and suggestions appreciated.

Thanks! -Al

You can't . Only method other than EDM for machining carbide is diamond coated tooling or diamond abrasives.

 

[AlNyhus]

I know I should have used other terms than "drilling and tapping". Old habits....

 

[LVLAaron]

I'm itching to know what you're up to.

 

[AlNyhus]

I'm itching to know what you're up to.

It's just a weight for the butt of a BR stock.

A classic case of something simple being turned into something complicated. The 'complicated' is me trying to use this piece of material.

 

[WSnyder]

It's just a weight for the butt of a BR stock.

A classic case of something simple being turned into something complicated. The 'complicated' is me trying to use this piece of material.

Silver braze a short section of steel to the end, drill and tap. Done!

 

[Walt Krafft]

I am guessing the tapped hole is so you can pull it back out? Why not put a spring in first, the weight, then the cap that covers it. The spring will keep it from moving and pop it out when you remove the cap.

 

[AlNyhus]

Walt, my preference is for the butt plate to pull the weight rearward in recoil.

Years ago, I had one of those C&H mercury recoil reducers in a stock with a spring on both ends.

 

[Retired shooter]

hard as woodpecker lips

Get that woodpecker to do it.

Sorry couldnt resist

 

[Dusty Stevens]

Walt, my preference is for the butt plate to pull the weight rearward in recoil.

Years ago, I had one of those C&H mercury recoil reducers in a stock with a spring on both ends.

You put the spring in front and close it up with the buttplate. Pack it tight to limit its movement- you should see how big of a group i can shoot when my scarbrough weight gets loose