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Hi all, 

 

Im in diré need of your recos for a great tungsten carbide drill bit I've bought all brands and they keep breaking. Before you ask, yes I've taken all the precautions and still can't find ones that do the job right. Some will work for a couple of times and then break. If you could send me the link to your favorite bits I'd owe you big time. I'm looking for 3/16 and 1/4.

 

Thanks.

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Honestly, I dont buy carbide bits for exactly that reason.  If your drilling setup is not rock solid and perfectly true (most home machines aren't), you're going to have a very hard time getting the most out of them.  Small inconsistencies lead to chips, which then lead to bit failure.  I tend to lean towards cobalt bits, drilling slowly, with plenty of lubricant.  I've been using the same 1/8" bit for two years with no issues.

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hi alex, 

i had replied but for some reason it didn't send.  thanks so much for your comment. i will try with cobalt bits to see if it will help me out, do you have a brand of choice that you can send me a link to buy, i normally use 3/16, 1/4, 1/8.  i can only find 3/16 y 1/4 in mexico,  thats where im from, and they are Makita brand. i dont personally know how good those are, but i would rather buy where you have had good experience from. would you be so kind to share your supplier? 

 

thanks so much!!!

 

 

 

Edited by Paul Checa
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I typically order my specialty bits like that through McMaster-Carr, for no other reason than it is extremely convenient for me.   Pretty much any industrial supply house, or even a good hardware store, will carry them.  

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As noted above, when using carbide drills, everything must be rigidly mounted, your workpiece clamped to the drill press table either in a vise clamped to the table or the part directly clamped. Forget about using them without breaking in a hand held drill motor so you must have a drill press.  The other cause of breakage is when the drill begins to enter the farside of the part being drilled.  The cutting edges can grab easily since there is less material being cut so feed pressure must be reduced.  It is definitely a "feel" issue. 

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3 hours ago, Gazz said:

As noted above, when using carbide drills, everything must be rigidly mounted, your workpiece clamped to the drill press table either in a vise clamped to the table or the part directly clamped. Forget about using them without breaking in a hand held drill motor so you must have a drill press.  The other cause of breakage is when the drill begins to enter the farside of the part being drilled.  The cutting edges can grab easily since there is less material being cut so feed pressure must be reduced.  It is definitely a "feel" issue. 

 

Yes that's pretty much what I do, and now I don't feel so bad that I break them in the exact same place someone else does. Hahaha. 

I'm gonna try the cobalt. And if that doesn't work I'll go back to the carbide with a lot more rigidity in the mounting and I'll be even more careful. 

 

Thanks

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I have the dual flute carbide bits in 3/32, 1/8 and 1/4 but for the most part I do all my drilling in the annealed state but I sometimes get a bar of stainless damascus for special orders and it comes heat treated to 58R so I do the drilling then with the carbide bits. One trick I found to break less of the 3/32 bits is to drill the magority of the hole with the 1/8 bit and do the break through with the 3/32 bit and this way I have been able to keep the same 3/32 bit for a lot of holes. i get all my carbide bits from USA Knifemakers with the cobalt bits by Sutton Tools through the NZ subsiduarly of the Australian Gameco Artisan Supplies.

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9 minutes ago, Garry Keown said:

I have the dual flute carbide bits in 3/32, 1/8 and 1/4 but for the most part I do all my drilling in the annealed state but I sometimes get a bar of stainless damascus for special orders and it comes heat treated to 58R so I do the drilling then with the carbide bits. One trick I found to break less of the 3/32 bits is to drill the magority of the hole with the 1/8 bit and do the break through with the 3/32 bit and this way I have been able to keep the same 3/32 bit for a lot of holes. i get all my carbide bits from USA Knifemakers with the cobalt bits by Sutton Tools through the NZ subsiduarly of the Australian Gameco Artisan Supplies.

 

Awesome. Thanks so much! Yeah I found that annealing and then drilling helped but for some reason (that I found out in this post) the instability of the mount and lack of rigidity was making me chip my bits. I actually tried to drill a 3/16 carbide and securely fastened it and made it so it was soooo rigid it wouldn't move an Inch and by calculating the force nearing the end of the hole I was successful on 4 holes! 

So for now we got a proved experiment. Next it's the cobalt test. I'll let you guys know how it went! 

 

Thanks to all! 

 

PD. I'll check those suppliers for sure! 

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I have never personally used these drill bits but when we were at an engine builders convention in Florida, we were setup right next to these guys and I watched them drill through about everything you can imagine with these. Files, bearing races, taps, dies, easyouts, ball bearings, you name it, they were drilling through it. They now sell the bits individually and not that much money. A 1/4" x 4" will run $10.50, according to their website. They did say that you need to spin them fast, so you need to have a drill or drill press that is fast. Their website probably shows minimum speeds recommended. The guy also told me that the hardest thing he ever had to drill with them was a bedframe rail. He said it took him about 5 minutes to drill through that.

https://baddogtools.com/product/z-loosesingle-multi-purpose-drill-bits/

Edited by Paul Carter
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Thanks so much! I'll take a look! I do t know if a bed frame is as hard as quenched high Carbon steel. But let me take a look and I'll let you know after testing! 

 

Thanks again Paul! 

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10 hours ago, Paul Checa said:

Thanks so much! I'll take a look! I do t know if a bed frame is as hard as quenched high Carbon steel. But let me take a look and I'll let you know after testing! 

 

Thanks again Paul! 

According to that guy, it was the hardest thing he'd seen. The guy brought him a piece at the trade show and said, let me see you drill through this. So he did, but he said it took a while. Then he asked the guy what it was. The guy grinned and said bedframe rail. Whether it really was or not, I guess we'll never know, but that's what the guy told him. I know those things are hard.

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Another thing you can do is to back the workpiece with another piece of steel.  This way when you break through you are still drilling material.  Again, rigidity is important.

Bed rail is some tough stuff.  I use it for building machine or sculpture bases and it kills drill bits immediately.  If I need a bolt hole, it is rough cut with the torch.

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ive got a nice knife made from bed frame but the frame section i tried had a cold shut or multiple cold shuts running its entire length, some bed frames can be hardened because they need to be springy but not all of them can be hardened. 

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Im sure you know this but making sure you are "pecking" as you drill and keeping it well lubed are important as well as the aforementioned rigidity.

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17 minutes ago, shane45 said:

Im sure you know this but making sure you are "pecking" as you drill and keeping it well lubed are important as well as the aforementioned rigidity.

Amen haha 

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  • 6 months later...

I have found that brands of cobalt bits are not all equal. Alpen is the best I have used so far.

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