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Drills & drill bits

md21722

NAXJA Forum User
Location
TN
Anyone have good direct experience will drills and drill bits?

I'll attempt to summarize what I've read:

- Generally HSS USA drill bits are fine, or cobalt if you're cutting something really hard. The disadvantage of the cobalt is that it is hardened and can shatter

- Buy American, Chinese drill bits are generally garbage

- Use cutting oil!!

- Remember to use the appropriate drill speed (lower speeds on larger drill bits, this is why 3/8" drills turn much faster than 1/2" drill bits and why someone would have both)

- Air drills are handy for tight spaces and won't overheat

- Drill Doctor (http://www.drilldoctor.com) to sharpen your own bits

Please jump in and correct me if I'm wrong on any of this or if you have different opinions.


I've considering drill bits like this:

http://www.amazon.com/Norseman-29pc...0151&sr=8-1-spell&keywords=NORSEMEN+DRILL+BIT

Norsemen is a name that keeps coming up.

I'm also looking for an air drill because the past few times I've wanted to drill something in the Jeep, the Milwaukee electric drill I have has had clearance problems because of something I didn't really feel like disassembling to make more room.
 
You can get the 90 degree angled air drills as well. I think there might be some cordless out at this point as well.
The Blair rotabroach bits are pretty awesome too.
 
As far as the actual drill goes, I have a Dewalt 20volt ion that is brushless. I really like it. I was able to drill out all the holes for my WJ swap with one 2 amp hour battery. That was 2x 1" holes for the drag link, 2x 7/8" holes for the tie rod, and 4x whatever size the bolts were for the heims on the track bar mounts. I started with smaller bits and worked up to the final sizes and used cutting oil.
 
Norseman bits are awesome, I bought a complete set and a bunch of spares at a great discount when I worked at fastenal. I have the black and golds but i believe they also make a cheaper line domestically as well.
 
Get yourself a gear-reduction 1/2" drill. They're great for drilling though steel. I have one that's ancient but works great.

As for actual drilling go slow and use lots of lube (teehehe). If you see tiny chunks of steel flying off the bit you're going too fast. If you see nice long stringers coming off the bit you're just right.
 
So I've been having a bit a trouble drilling through steel. I figure I'm either using the wrong speed, feed, or my drills are no good (runout).

When drilling through 1/8-3/16" mild steel (air compressor tank, for example) with a 1/2" bit, what speed and how much force should I be using? I started off with a 0.6HP 700 RPM speed and it was taking forever the chips were small flakes. So I said hmm maybe this drill bit is dull and switched it out for a 31/64" and it was much faster. Chips were long strands but not spirals. The drill bound up at the end and the next hole felt like the bit was duller.

I tried another size on a faster, more powerful drill 0.9HP 850 RPM and with tons of force it was cutting. It also was unlikely to bind up. It did vibrate more during the entire cut.

I also tried on a 0.5HP 450 RPM drill. The 450 RPM drill seemed to run the smoothest of all of them. But it also seems to take forever to drill anything.

Bottom line, it seems like unless I use a brand new drill bit, I run into trouble. And new bits require significantly less force.

The bits are not getting too hot to touch and the chips just look like metal.

I was able to drill at least 10 1/4" holes in a 3200 RPM drill (using lower speed) and it seemed to cut like butter. So it seems like my problem is with the larger hole sizes.

All drill bits used were Norseman SPM-29 series (mechanic length black & gold).

How much force is needed? Just light pressure?

With a bit of guidance I'll keep trying.
 
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Once you get the hole started, make the bit hog into the material.

If you can't do anything to back up the material you are drilling, lighten up the pressure as you break through.
 
Lighting up the pressure or going at it full force doesn't always help. The two things I found that always work are (a) using a right angle drill for all or the last part. The most the right angle drill does is sway 1/2-1". And (b) Using a high speed drill. That last little bit just flies out of the whole when you hit it for a split second at 3200 RPM. My right angle and high speed drill are rated 0.9HP. I'm not sure if that matters.

I found this for additional ideas after the fact:

http://www.metalsmith.org/pub/mtlsmith/V20.4/Dholes.htm

Since the drill bit binds and the drill starts turning I do wonder if a more powerful drill would circumvent this problem or just rotate the drill itself harder. In the case of the right angle, the long body and dead handle are rigid and you get the extra leverage by having 12" of drill at a right angle. It never swings up hard where you might smash your fingers/hand on something.

On the old metal body drills I've heard of old timers using 12-18" of 1/2" pipe as the dead handle to get the same type of leverage.

It seems that if you have a long enough dead handle to provide enough leverage the problem goes away and saves broken wrists or hands.
 
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On another note, the Norseman set I had seemed "soft". They were likely to chip on the cutting edge. I ran out of larger sizes so I picked up a set of DeWalt's from Home Depot today and I honestly can't say the DeWalt's are worse. They may even be good. The only thing I don't like about them is the that they are Made in China with some horrific drill bit box. :gee:
 
So I've been having a bit a trouble drilling through steel. I figure I'm either using the wrong speed, feed, or my drills are no good (runout).

When drilling through 1/8-3/16" mild steel (air compressor tank, for example) with a 1/2" bit, what speed and how much force should I be using? I started off with a 0.6HP 700 RPM speed and it was taking forever the chips were small flakes. So I said hmm maybe this drill bit is dull and switched it out for a 31/64" and it was much faster. Chips were long strands but not spirals. The drill bound up at the end and the next hole felt like the bit was duller.

I tried another size on a faster, more powerful drill 0.9HP 850 RPM and with tons of force it was cutting. It also was unlikely to bind up. It did vibrate more during the entire cut.

I also tried on a 0.5HP 450 RPM drill. The 450 RPM drill seemed to run the smoothest of all of them. But it also seems to take forever to drill anything.

Bottom line, it seems like unless I use a brand new drill bit, I run into trouble. And new bits require significantly less force.

The bits are not getting too hot to touch and the chips just look like metal.

I was able to drill at least 10 1/4" holes in a 3200 RPM drill (using lower speed) and it seemed to cut like butter. So it seems like my problem is with the larger hole sizes.

All drill bits used were Norseman SPM-29 series (mechanic length black & gold).

How much force is needed? Just light pressure?

With a bit of guidance I'll keep trying.

The speed in rpm's needs to be a function of a bunch of things. First off, machinists talk about cutter speed. That means how fast the cutting edge is going through the metal. As the bit gets larger you have to slow down. With a small bit, you need to speed up. Secondly, you need to know how hard the metal you are trying to drill through. If it is soft, you can handle a faster speed. If it is hard, you may need to slow way down.

The single biggest problem I find with drilling problems is turning the bit too fast. It causes it to heat up and in just a couple of seconds you can dull a bit.

The second biggest problem is keeping the bit lubricated. The same lubricant isn't for every type of metal. For instance, on cast or forged steel, you want to use a thick Sulphur based lube. With aluminum, you can get by with a much thinner lube. Some machinists will use WD40.

The third biggest problem is the type of bit you are using. There are a ton of variations here. Don't use the TIN (gold) drill bits in aluminum. The aluminum tends to stick to the drill and gum up everything. In iron and steel, the angle of the bit can impact the quality of the hole. Some bits are not designed to drill a blind hole where there was no predrilling.

My favorite all around bits are sometimes called step bits, not the ones that look like Christmas trees. There is another name for them but I can't remember it at the moment. DeWalt has them and they tend to drill a ton faster and cleaner. They look like a normal drill but if you are drilling a .5" hole, when you look at the bit, it has what appears to be a smaller diameter bit at the end, then it jumps up to the .5" diameter.
 
The speed in rpm's needs to be a function of a bunch of things. First off, machinists talk about cutter speed. That means how fast the cutting edge is going through the metal. As the bit gets larger you have to slow down. With a small bit, you need to speed up. Secondly, you need to know how hard the metal you are trying to drill through. If it is soft, you can handle a faster speed. If it is hard, you may need to slow way down.

The single biggest problem I find with drilling problems is turning the bit too fast. It causes it to heat up and in just a couple of seconds you can dull a bit.

The second biggest problem is keeping the bit lubricated. The same lubricant isn't for every type of metal. For instance, on cast or forged steel, you want to use a thick Sulphur based lube. With aluminum, you can get by with a much thinner lube. Some machinists will use WD40.

The third biggest problem is the type of bit you are using. There are a ton of variations here. Don't use the TIN (gold) drill bits in aluminum. The aluminum tends to stick to the drill and gum up everything. In iron and steel, the angle of the bit can impact the quality of the hole. Some bits are not designed to drill a blind hole where there was no predrilling.

My favorite all around bits are sometimes called step bits, not the ones that look like Christmas trees. There is another name for them but I can't remember it at the moment. DeWalt has them and they tend to drill a ton faster and cleaner. They look like a normal drill but if you are drilling a .5" hole, when you look at the bit, it has what appears to be a smaller diameter bit at the end, then it jumps up to the .5" diameter.

Do you have a link to these DeWalt bits?

I believe I'm on par with everything else. I was trying both the high sulphur & thinner CRC cutting oil with no big differences observed. Drills are slow speed. Pistol grip drills are 500 & 700 RPM. Right angle is 850.

I bought a Milwaukee #1 Step Drill (drills up to 1/2"). It's what HD had. Trying on holes that I had already drilled to 5/16" with a regular twist drill bit it opened them up to 1/2" in seconds. I think I did 5-6 in about 30 seconds. Never seen anything like it.
 
You didn't say but how big of a pilot do you drill first?

I used a 1/16" at first.

I tried today mimicking the step bit. 1/8", 3/16", 5/16", 7/16" all went fine. At 1/2" it bound up on me. The reason isn't clear. I was bound to other commitments and had limited time to try again. I will try again. If there are other suggestions I will try them. I really want to get the knack of this. I have a piece of scrap steel that probably had 50 holes in it. LOL.
 
slow your speed and pressure down.

for anything I can drill with a drill press I use the slowest setting possible (250 rpm) and

most importantly

let the tool do the cutting.

I have had great results. I don't dull bits.

anything I have to hand drill I use my 1/2" drive 20v dewalt. fast speed for anything thinner than 1/8" anything thicker and I go slow.

on really heavy stuff that I have to hand drill I use a makita 1/2" drive corded variable speed. slow and steady.


I go back and forth with lubrication. I started using gear oil, which worked well, but was extremely messy. I have some cans of aerosol cutting oil that also work well.

someone recommended to me to just use straight water; the idea is you're not really trying to lubricate the bit, you're just trying to keep it cool. so I grabbed a spray bottle and started using that. it doesn't seem to perform any worse than the oils, but cleanup is much easier.

now I pretty much only use oil on hole saws.

the bits I normally use are a set just like this (not sure on actual brand) they seem to hold up really well, I can't say I have dulled any of them.

http://www.northerntool.com/shop/to..._B2Nx7Q8LneGMNHcQTrLV6wwBBH9GC_OtMaApY_8P8HAQ


I also have a pile of the stepped and stepless unibits from HF.
I will put them in my 20v 1/4" drive impact when I need to drill holes in anything thinner than 1/4" anywhere uncomfortable. it destroys the bits after a few holes, but its way faster and easier than anything else.
 
https://www.zoro.com/dewalt-drill-b...gclid=CJzTp_Le88wCFQQEaQodfukJFQ&gclsrc=aw.ds

Look at the tips. There are other manufacturers of this type of bit as well. They are commonly called pilot point.

I got a set of these, they do seem to work better than a standard 118/135 point drill bit.

slow your speed and pressure down.

for anything I can drill with a drill press I use the slowest setting possible (250 rpm) and

most importantly

let the tool do the cutting.

I have had great results. I don't dull bits.

anything I have to hand drill I use my 1/2" drive 20v dewalt. fast speed for anything thinner than 1/8" anything thicker and I go slow.

on really heavy stuff that I have to hand drill I use a makita 1/2" drive corded variable speed. slow and steady.


I go back and forth with lubrication. I started using gear oil, which worked well, but was extremely messy. I have some cans of aerosol cutting oil that also work well.

someone recommended to me to just use straight water; the idea is you're not really trying to lubricate the bit, you're just trying to keep it cool. so I grabbed a spray bottle and started using that. it doesn't seem to perform any worse than the oils, but cleanup is much easier.

now I pretty much only use oil on hole saws.

the bits I normally use are a set just like this (not sure on actual brand) they seem to hold up really well, I can't say I have dulled any of them.

http://www.northerntool.com/shop/to..._B2Nx7Q8LneGMNHcQTrLV6wwBBH9GC_OtMaApY_8P8HAQ


I also have a pile of the stepped and stepless unibits from HF.
I will put them in my 20v 1/4" drive impact when I need to drill holes in anything thinner than 1/4" anywhere uncomfortable. it destroys the bits after a few holes, but its way faster and easier than anything else.

250 RPM is really slow! I couldn't imagine drilling a 1/2" hole at 250 RPM by hand. I'm sure you don't dull bits at that speed. The speed tables I have suggest 600-850 for 1/2" through low carbon steel and I am using a 700 RPM drill.
 
I got a set of these, they do seem to work better than a standard 118/135 point drill bit.



250 RPM is really slow! I couldn't imagine drilling a 1/2" hole at 250 RPM by hand. I'm sure you don't dull bits at that speed. The speed tables I have suggest 600-850 for 1/2" through low carbon steel and I am using a 700 RPM drill.

you will continue to dull bits.

unless you pony up for really high end stuff, and even then, with the inconsitency of a hand drill, you'll probably ruin those as well.
 
:dunno:

More times than I can count, I have been in the field with a Lawson Split-Point bit and a "Good grade of 30 Wt Oil" (per AAR S-486 and MSRP Section H-Lubrication Manual), and bored a half-inch hole through some 3/8" A-36, at the lowest speed the drill motor could turn.

Was it machine shop perfect? Probably not. Was it within industry tolerance? Absolutely!

That Lawson bit has been in my kit for awhile now, making steel curls, every time I need to make that bracket...
 
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