DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Tools (
-   -   I need some help drilling into a metal bolt (

amodoko 08-06-2012 09:18 PM

I need some help drilling into a metal bolt
Hey guys, I'm a just a basic DIY guy, just started working on basic stuff around the house a few years back and basically I just try to fix whatever I can. Over the years I have run into a few situations where I've needed to drill into metal, and generally I've had luck with it but it always takes REALLY long. All I'm using is a Black and Decker cordless drill, some High Speed Steel (HSS) drill bits, and various oils (such as used motor oil) for lubrication and cooling of the drill bit. I've been able to drill into metal using these tools, but it takes very long and I believe my drill bits are still sharp.

Now I need to drill into a bolt, and I want to completely drill all the way into it. However, it is taking WAY too long for me. At the rate it is going I wouldn't be surprised if it took me several hours.

What do the pros use to drill into bolts fast? I am willing to go out and buy whatever I need, and from watching videos online the pros always seem to drill into various metals super fast, with metal shavings going everywhere.

Maybe the bolt I'm drilling into is a harder metal, but I figured there are drill bits even for that purpose.

So if you have any suggestions for what I need to buy or what I may be doing wrong, please tell me:) From what I read online, I shouldn't be having this much trouble.

Eds_tls 08-06-2012 09:53 PM

Theres a wide range of bolt hardness. Everythng from unhardened mild steel that is super soft up to a high strength alloy steel hardened socket head cap screws...and everything in between.

We use carbide drill bits sometimes, but theyre expensive and break easily if youre not careful. Or you could take it to a machine shop and they can EDM a hole in it for you. But that will cost some $$$

ddawg16 08-06-2012 09:53 PM

Is it a grade 5 or grade 8 bolt? If you have 5 lines on the head....that is a grade 8....if only 3....grade 5. A grade 8 is going to be hard to drill into.

I guess most of us would use a drill press. Slap that bolt into a drill press vice and start drilling.....

jbfan 08-06-2012 09:56 PM

What kind of bolt?

Some bolts are hard to drill into.

md2lgyk 08-07-2012 05:00 AM

Drilling into metal works better if you don't turn the bit too fast.

user1007 08-07-2012 06:04 AM

Speed does make a difference but unfortunately you do not have speed control on your drill. Most drill presses do. Generally, the bit should be stronger than the material you are trying to drill so you might try a carbide bit but heed the warning in the post about them being brittle.

What are you trying to accomplish? If the bolt head is broken you might try using an extractor. You will still have to drill a hole for it but you won't, if it works, have to drill out the whole bolt.

toolaholic 08-07-2012 06:46 AM

Get blu moil or dewalt cobalt drill bits. Cobalt is very hard and doesn't dull easily.

wkearney99 08-07-2012 09:04 AM

A drill press is among the best tools to have. Even a bench-mounted one would be better for the purpose than a handheld, let alone cordless, drill. With a drill press you get control over speed and pressure, while keeping things straight. Pickup one secondhand, you'll be staggered that you didn't buy one a long time ago.

amodoko 08-07-2012 02:16 PM

4 Attachment(s)
Thanks for the replies and suggestions everyone, I appreciate it. To answer some of the above questions above I am attaching some pictures to this post of what I have done so far. I'm not sure what type of bolt it is since I have already drilled a bit into the head and can't see the 3/5 line markings. Also, the reason I am drilling into this bolt was so I could drill out the bolt completely to access the rubber washer in a frost proof faucet so I could replace it (the faucet was leaky). The bolt is over 30 years old and it had rusted so bad that it was stuck. I had tried penetrating oils, tapping it with a hammer, using screwdrivers and socket wrenches and it wouldn't budge. I can't use a drill press in this case since the bolt is attached to an immovable object, thus the job is out in "the field" as some pros would say. It is broken off, but just impossible to pull off without damaging the faucet itself. It's one of those situations where you need all the force you can get to get it off, but if you use too much force it will break the inner workings of the faucet I believe (and that is even when I stabilize the copper piping).

At this point, I am actually just going to replace the faucet completely and solder a new one in, so drilling into the bolt is no longer necessary. But I am going to continue to drill into the bolt anyways because I really want to learn how to do this so if I run into this issue some day down the line (and I'm sure I will), I will know exactly what to do.

Even though HSS drill bits should be sufficient, I think I am going to buy myself some cobalt bits too. If I understand correctly, cobalt can be used for the hardest of drilling jobs, and the bits are cobalt through and through vs the other harder bits which are just coated, correct? If you think I should get another type of bit let me know, I'm open to suggestions.

With the attached pictures, you can see my attempt at trying to drill through the bolt. The little work shown there literally took me about 15 to 20 minutes, and it barely did anything to that bolt.

I really do want to learn how to do this properly now, so when this happens again in the future I'll know exactly what to do.

toolaholic 08-07-2012 02:28 PM

Where you going to drill it out completely or use a screw/ bolt extractor? Looks like maybe after some more drilling you could try a extractor. Cobalt bits rule when it comes to hard steel/ stainless steel/ cast iron etc.

ddawg16 08-07-2012 02:31 PM

Looks like your using too big of a bit....

Start small.....say like a #25 or even smaller...then work your way up.....

BTW.....just how old is that faucet?

amodoko 08-07-2012 02:33 PM

I was planning on drilling it out completely, I didn't really want to do the screw extractor method on this one... but I'll probably try that the next time I need to remove a bolt for fun:) At this point I want to find a method that works well enough for drilling out a bolt completely though.

I was thinking about starting smaller as well with the bits. I will try that too, to see if that helps much. The faucet itself is roughly 30 years old.

DangerMouse 08-07-2012 03:23 PM

Why can't you use a pipe wrench and pull the entire faucet off? Then just put on a new one.


amodoko 08-07-2012 03:36 PM

Hey DM:) Yep, I'm replacing the faucet completely, but I made this thread mostly to learn how to drill through a hard bolt. So yes, I'm replacing the faucet, but I still want to learn how to drill through a bolt so when i have to do it again one day it won't be such a hassle.

But you did mention something that got me thinking, I thought you couldn't remove these faucets with a pipe wrench since that would cause the copper piping to twist inside the house causing a possible break/leak in a soldered joint. I thought these had to be cut out with a pipe cutter since they are soldered in, right?

DangerMouse 08-07-2012 05:00 PM

That would depend of course if it's screwed on or soldered, yes.
Mine is a screw on type, easy to pop off and replace if it ever fails. :)


All times are GMT -5. The time now is 10:18 AM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1