Rock drill bit tungsten/carbide tip removal

**ironlife** · 04-21-2014, 08:47 PM

Hello everybody! New member here looking for some information on removing carbide buttons on rock drill bits and now before anybody says "use the search button" I have and although I have read that removing buttons is as easy as heating the steel up and popping the buttons out I'm looking for a bit more information if possible...

How long would it take to heat up a 10" diameter drill bit to an adequate temperature?

Once the face is hot enough that the brazed material has melted is it safe to hit the top of the button with a hammer to knock it loose in it's sleeve or will that shatter it?

Are there any other methods than an acetylene or rosebud torch followed by hitting each button out with a hammer that I could use?

Is this venture going to be worth my time, acetylene and oxygen bottle refills, gas etc...

Does anyone have experience with this and can give a rough estimate as to how many buttons per hour can be removed?

To put things in perspective I live in a very small isolated mining town where there are no scrap yards that pay for ANY metal, they will however take whatever people give them for free just so you can avoid paying to get rid of it at the dump. I have been working in the drilling and blasting field for the last few years and have my in to just about every drilling company in town (and now work for the company that supplies and sharpens all the bits for the entire town) because of this I have access to all the scrapped rock drill bits I can get my hands on and in the eyes of the company I work for would be doing them a favour since otherwise they would have to pay to get rid of them.

I would really like to take on the venture of rounding up all the bits that get scrapped in the course of a week and on my days off pulling the carbides out, I'd just really like to hear someone else's first hand accounts to if it would be worthwhile before I do!

**Mechanic688** · 04-21-2014, 10:32 PM

http://www.scrapmetalforum.com/disma...ase-metal.html

http://www.scrapmetalforum.com/intro...de-canada.html

http://www.scrapmetalforum.com/scrap...ill-teeth.html

And a whole lot more in the search feature.

**src3collector** · 04-22-2014, 08:22 AM

If you're talking about this kind of drill bit that I have pictured you can probably sell it as is on ebay for more than scrap. I don't know much about these (and someone had to tell me what it was when I found it) but this one weighed 70 pounds and wasn't in the best condition. One roller spun freely on it, one was tough to spin and the third was frozen. Sold it in that condition on ebay for $200. There's alot of people that collect things like this, and it makes for the ultimate paper weight!

**DAVECCT** · 04-22-2014, 10:43 AM

the large oxy acetylene torch and a hammer should have those off in no time, just heat them up and tap them off. We are purchasing the mining inserts at $10.50 lb (4/22/14)........so if you have a 70lb piece and knock about 30 to 40lbs of carbide off of it your gonna make 300 to 400 bucks. There are tons of guys from small mining towns that do this and bring us on average a 1000 pounds a week. Link to our buyers and sellers thread http://www.scrapmetalforum.com/scrap...-tungsten.html

**src3collector** · 04-22-2014, 12:43 PM

Originally Posted by DAVECCT

the large oxy acetylene torch and a hammer should have those off in no time, just heat them up and tap them off. We are purchasing the mining inserts at $10.50 lb (4/22/14)........so if you have a 70lb piece and knock about 30 to 40lbs of carbide off of it your gonna make 300 to 400 bucks. http://www.scrapmetalforum.com/scrap...-tungsten.html

Isn't the carbide just the small dark teeth on the rollers? Forgive me if I'm asking a dumb question but how do those make up half of the weight of this? Seemed to me that most of the weight is in the huge chunk of steel. I honestly don't know too much about this other than I got with a bunch of stuff from an oil company here in Texas.

**DAVECCT** · 04-22-2014, 01:30 PM

src3collector yes the dark spots are carbide and in your case the bits on yours might way 20 pounds but carbide is heavier than steel because of the density, just like gold it is heavier than it looks. Also have no idea what the op has because he hasn't posted a pic but mining bits come in all shapes and sizes.

**ironlife** · 04-22-2014, 03:42 PM

Originally Posted by src3collector

those are known as rotary drill bits they operate on electric rock drills and cut in to rock by turning at a very high velocity, typically 15" wide and entirely disposable...once the carbide buttons are flat they are thrown out (and i can get my hands on them as well, for free)

also although only a tiny bit of the carbide protrudes through the face they are buried in pretty deep, if they werent they would break out of the steel too easily while drilling (bits get scrapped according to how many buttons have broken off, and typically once one button breaks in the hole while drilling the shard of carbide will knock out several other buttons before getting blown out of the hole, a lot of the times causing nearly brand new drill bits to be scrapped)

however the bits i deal with directly at work are on diesel powered rock drills and use a pneumatic cylinder with a piston that pounds up and down while only spinning at a very slow speed, the pounding from the hammer is what breaks the rock apart in these, not the speed at which it is turning

i had some spare time at work today so decided to see what it would take to simply use a hand grinder with a 5"x5/16" disk, took me roughly 45 minutes and 1 grinding disk, im holding on to 3lbs of carbide (with no brass braze still attached)

those 3 crates are the amount of scrap we go through in 1-2 weeks

**DAVECCT** · 04-22-2014, 06:22 PM

Even though you have removed the braze from them the damage has been done to the carbide did you try heating it up and popping them off or is grinding them the only thing that's working. We are paying $10.50 a lb for those and even though it is a lot of work that weight will add up quick you definetly can make a lot I you get a good system down... Where are you located by the way

**ironlife** · 04-22-2014, 06:33 PM

So even with absolutely no trace of braze left on the carbide it is sold as brazed scrap? Does the braze change the quality of the carbide once it has been cured to it, even though it had been removed?

And I have yet to try and heat it up, today was my first go at trying to remove the buttons and I only did it because I had an hour or so of free time at work waiting for more bits to come in

**DAVECCT** · 04-22-2014, 08:31 PM

yes brazing messes up the tungsten in the carbide….even if you remove it the damage is done. Heat is the way to go. I would say give us a call and we could give you a higher price since you would have a consistent amount of scrap

**ironlife** · 04-24-2014, 07:42 PM

Originally Posted by DAVECCT

yes brazing messes up the tungsten in the carbide….even if you remove it the damage is done. Heat is the way to go. I would say give us a call and we could give you a higher price since you would have a consistent amount of scrap

tried using heat today, at first i heated the steel around 1 carbide button until it was red hot than smacked it with a sledge but that didnt work. than i tried using a cutting torch to cut the steel around a carbide, this worked but when the carbide broke free it was discoloured and had a lot of steel bits and pieces melted on to it. lastly i decided to cut the entire end of the bit off with the torch cutter (maybe 3-4" back from the face of the bit), put this 3-4" thick piece in a vice with the face of the bit and the carbide buttons facing down, than heated the steel left in behind the buttons and smacked the top with a mallet, this method finally allowed them to slide out and look just as clean as the ones i grinded out before. this process from the start to having every carbide out took maybe 30-40 minutes, but that was with trial and error, im sure with practise you could maybe process one of these 6 1/2" bits in maybe 10-15 minutes, yielding approximately 15 carbide buttons weighing a total of around 3-4lbs

let me know if you have any other method for me to try, or can let me know anything about the quality of the carbides that have been discoloured as well as the ones that appear to have steal melted on to them.

thanks

**ironlife** · 04-24-2014, 08:34 PM

what im thinking DAVECCT (and please feel free to suggest anything) is i find a means of making as accurate a cut as possible with a metal saw (abbrasive blade only, no diamond tip blades) BEHIND the carbide buttons, than with a hand grinder expose the back of the buttons, clamp it, heat up the steal and use a center punch and mallet to knock the buttons out...yay or nay?

**DAVECCT** · 04-24-2014, 10:09 PM

Cutting the head about 3-4" away from the buttons is probably best I would say try to cut closer to the buttons and they might pop out while your cutting it. People we buy them from will never ever tell us how they do it. You might be getting it too hot also, it only takes a little heat to release the braze. Simple plumbing mapp gas torch will release it.