Re: Metal drill bit

Hey kevlar,

What size of drill bits are you using ? If they are the smaller ones like the 1/8", 5/32", or 3/16" , better have some extra spare always, para hindi na aantala ang trabaho mo. I suppose sa mga C-Purlins or angle bars mo ginagamit yan to attach your fiberglass roofing.

Bro, may I suggest using the BOSCH multi-purpose drill bits or the Black&Decker Bullet Pilot Point drill bits. Check them out sa Home Depots, Panda, HANS Tools or some known mall hardware stores. 😉

Hope this helps !!

Re: Metal drill bit

Hi,

It's my first time to drill metal and it seems my drill bit always gets dull. I tried black and decker HSS (broken), common metal drill bit and my last one is a cobalt coated drill bit and they all got dull.

I'm doing some fiberglass roofing and I didn't finished last week because of the drill bit. Any tips or type of drill bit I need to use?

Appreciate the assistance. Thank you.

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I had the same experience, in our area the best that I can get is the cobalt coated Lotus drill bit, I think the key is the drill speed (drill at low speed), as much as you can, do not overheat the drill bit when doing work.

@rosy. Yeah, some part of the angle bar are ok, some are way too hard. I'll chk out your recommendation while waiting for my titanium coated bits...
@quarkzdmz. Yeah, the person who sold me the cobalt coated told me to do slow drilling but it takes so much time.. Now I know.. Hehe

Thanks for advice, need to get a new bit and finish the mini project. 😀

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Re: Metal drill bit

I tried also Nicholson Titanium coated bit, and it snapped off. Maybe I did something wrong, pero I'd rather stay away from that brand, I did try some Japanese sounding titanium-coated bit, and it also failed.

Re: Metal drill bit

drill bits fail on metal if the bit isn't pushed straight into the metal ie, wobbling left/right or material being drilled isn't stable. also incorrect combination of speed/pressure will also prematurely fail a bit.

nevertheless, i'd also stay away from b&d hss. it's cheap but doesn't last long.

Re: Metal drill bit

@spyghost, thanks for the brand info. I hope others can recommend brands too so we will not do trial and errors.:no1:

Re: Metal drill bit

I suppose most of us who have drilled some holes on metal have experienced breakage or fast dulling of bits specially the smaller bits. If we are breaking it fast maybe there's really something wrong with the way drilling is done. With wood we won't be experiencing these hassles since its softer, we can drill holes immediately in high speed and the bits would immediately embed itself to the surface.

Basically its the reverse with drilling holes on metals, whether flat bars, angle bars, tubings or pipes.
It has to be done slowly with only a certain speed letting the tip shave off that metal little by little and certain pressure specially for the smaller bits so not to break the drill bit. 😉

Some good suggestions, is to have a drill bit sharpener around or a drill doctor which will serve us a lot of time and money by extending the usage of our bits. Another one is to have a good drill with variable speed adjustments, if we can't afford yet a portable drill press. And another one if possible is to have a drill guide for our drills, it makes drilling more accurate and straight, probably a Portalign drill guide, as discussed by one member here in the forum. I think this is very useful and very practical. :no1:

Just my thoughts !! :trampoline:

Thanks Rosy for the tip.... Appreciate it!

Need to get a new one and practice proper use..

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Re: Metal drill bit

If hand drilling without a punched marker then I'd look for 135 degree split point bits. These have more aggressive starting bite than the 118 degree bits. It will prevent bit walking too.

I myself prefer Norseman Drill Bits ( USA ). Dormer ( England ), Somta ( South Africa ) and Alpen ( Austria ) comes in tied at a distant second place. High speed steel will just be fine unless I'm drilling hardened metals like stainless steel.

If drilling a lot of holes then I'd also dip my bit on cutting oil once in a while.

As other members had pointed out drilling speed, angle and pressure feed are important. As a general rule smaller drill bits like higher speed while the larger ones prefer slower speed.

Hi jayL, so it's high speed for small holes? Did I get it right? Thanks.

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Re: Metal drill bit

Hi jayL, so it's high speed for small holes? Did I get it right? Thanks.

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Yes something like that ... smaller bits like to turn at higher speed.