My drill press will not produce spirals of metal.

richkl · Apr 30, 2012

My drill press will not produce spirals of metal. All I get is little chips of metal.

Latest example- drilling through a cheap hardware store nut with a new TiN coated 3/32" bit. The nut was held in a vise so it didn't move around. I used Tap Magic cutting oil on this.

The chart above the pulleys in my drill press suggested 2380 -2540 rpm for a bit around 3/32" dia.

I tried 1630 to 2540 rpm. All speeds produced similar chips. I thought the next speed, 3630 rpm a little extreme.

The machinists I used to see at work made it look so easy (with their expensive milling machine/drill press).

Does anyone have any suggestions? I would appreciate any advice.

Richard

.mike. · Apr 30, 2012

lower RPMS, more pressure.

You need to be in the low hundreds range, close to 200 or so. You won't damage a bit by going too slow. Use cutting oil too.

platypus20 · Apr 30, 2012

Its not the drill press, it could be your technique, the angle on the drill bit and how much you are drilling out.

larry_g · Apr 30, 2012

In my opinion you are having good luck. You do not want long spirals and good bits have a chip breaker ground in them to prevent them. To produce spirals you need a sharp bit and a constant feed. You also need a material that is not brittle. You will discover the down side of spirals when they either wad up and cause problems or cut you good.

lg
no neat sig line

Jim Johnstone · Apr 30, 2012

larry_g said:
In my opinion you are having good luck. You do not want long spirals and good bits have a chip breaker ground in them to prevent them. To produce spirals you need a sharp bit and a constant feed. You also need a material that is not brittle. You will discover the down side of spirals when they either wad up and cause problems or cut you good.

lg
no neat sig line

I agree, when drilling metal you want to be "pecking" it which will naturally break the chips. You don't want to be pulling down hard and pushing the bit through non stop, or else you will burn the bit up in a hurry.

Also, as Larry mentioned, different metals chip differently. Aluminum is gummy and stringy, some stainless chips nicely but comes off hot as the fires of hell, mild steel usually comes off in longer spirals, harder steels break off and don't spiral well.

Jack Olsen · Apr 30, 2012

Still, those RPM numbers seem very high for cutting steel.

bggrnchvy · Apr 30, 2012

For drilling low carbon steel with a 3/32 HSS bit that actually specs out a bit slow, like 60% of the suggested RPM (should be around 4k rpm). You can overcome spindle speed limitations by modifying the feed, but the likelyhood is that without a good feel for it spiraling a chip is going to be tough.

3.75 x CS / Tool OD is the formula I've been taught to use for drilling. CS for that nut I'd guess is ~100 as a low grade nut will be relatively soft (less than 40RC).

3.75 x 100 / .094

3989rpm

Of course if it's deep hole you'll slow it down a bit (15% or so).

If you go too slow with too much feed you will shear bits, especially in sizes below .100".

Mike007 · Apr 30, 2012

I just loooked at a machinists guide by Morse, 3/32" drilling mild steel it says 4479-4886 RPM.

A_Pmech · Apr 30, 2012

richkl said:
My drill press will not produce spirals of metal. All I get is little chips of metal.

Latest example- drilling through a cheap hardware store nut with a new TiN coated 3/32" bit. The nut was held in a vise so it didn't move around. I used Tap Magic cutting oil on this.

The chart above the pulleys in my drill press suggested 2380 -2540 rpm for a bit around 3/32" dia.

Sounds right to me in all respects.

tcianci · Apr 30, 2012

bggrnchvy said:
For drilling low carbon steel with a 3/32 HSS bit that actually specs out a bit slow, like 60% of the suggested RPM (should be around 4k rpm). You can overcome spindle speed limitations by modifying the feed, but the likelyhood is that without a good feel for it spiraling a chip is going to be tough.

3.75 x CS / Tool OD is the formula I've been taught to use for drilling. CS for that nut I'd guess is ~100 as a low grade nut will be relatively soft (less than 40RC).

3.75 x 100 / .094

3989rpm

Of course if it's deep hole you'll slow it down a bit (15% or so).

If you go too slow with too much feed you will shear bits, especially in sizes below .100".

I'm not sure where you got that formula but I spent several years working in machine shops and never have we ever used speeds like that to drill mild steel.
Even with a bit size of .100 or so, the rpm should be about 400 to 600 tops.
Stainless is another animal alltogether and requires even slower speeds or you will just work harden the stock and burn up a bit in no time flat.

larry_g · Apr 30, 2012

tcianci said:
I'm not sure where you got that formula but I spent several years working in machine shops and never have we ever used speeds like that to drill mild steel.
Even with a bit size of .100 or so, the rpm should be about 400 to 600 tops.
Stainless is another animal alltogether and requires even slower speeds or you will just work harden the stock and burn up a bit in no time flat.

So where did you get your speed from? That formula is in most any machining book you pick up.

lg
no neat sig line

bobadame · Apr 30, 2012

For mild steel you want about 100 surface feet per minute. That's around 4000 rpm. It's ok to go slower in fact you could drill a hole at 1 rpm. The chip load should be around .001"per cutting edge. Use a few drops of oil. The faster you turn the drill the more important the oil.

tcianci · Apr 30, 2012

Well if the books say I'm wrong, I'm wrong but, I've never had any issues doing it at the slower speeds, bits stay cool and last longer. I can always learn new tricks, but I'll pass on this one.

mtnwalton · Apr 30, 2012

larry_g said:
In my opinion you are having good luck. You do not want long spirals and good bits have a chip breaker ground in them to prevent them. To produce spirals you need a sharp bit and a constant feed. You also need a material that is not brittle. You will discover the down side of spirals when they either wad up and cause problems or cut you good.

lg
no neat sig line

agree; long chips are not desirable. Causes usually are the grind on the bit. On a lathe it's because the tool has no chip breaker or excessive feed. I was in the craft for 35 years and never used charts for feed/speeds since my apprenticeship. It's something you get a feel for.

Zeke · Apr 30, 2012

Man, I get long spirals all the time. Some of them whip around and are not fun at all. Maybe you have a good thing going.

gorilla · Apr 30, 2012

We drilled .010 holes in SS'T tubing for gas distribution manifolds with a special high speed drill press. I think it used to run about 10,000 RPM. The drill bits didn't last long and if you broke the drill you scrapped the piece.

Jack Olsen · Apr 30, 2012

I'm wrong, too. I keep my drill press at the lowest speed pretty much all the time.

Jim Johnstone · Apr 30, 2012

3/32" in mild steel, I'd be spinning it around 2000 RPM. Slower certainly won't hurt though.

lilscorpion · Apr 30, 2012

I have a drill press, a knee mill, and a CNC knee mill. What I can tell you is consistent speed, feed, and heat removal are all keys to drilling. To much heat, no matter what the feed and speed, dulls the bit and things start to fall apart quickly and you have to adjust one or all of the three on the fly.

I also think rigidity of the machine has an impact on a consistent cut. Most drill presses I see in garage shops aren't what I would consider rigid. Most drill presses don't have good vises holding the material firmly in place.

A CNC Knee with a machinists vise Gives you control over all components. A drill press with a material clamp is probably the opposite. Doesn't mean you can't cut a good hole on a drill press but you have to be patient. I've destroyed more drill bits on my drill press and drilled hundreds I'd holes on the CNC with a single bit...only because the CNC is my patience because it removes me from the equation.

Kevin54 · May 1, 2012

Some of you guys are running too high of a speed. Material also dictates whether you will get a chip or a spiral out of it. Never start out high then slow down, always start out slow then speed up. I hardly ever go up past 1000rpm's in drilling aluminum let alone 2000 or higher for steel. And for stainless steel, you want to go slow rpm's. I wouldn't go 10,000 rpm's in stainless no matter what size the hole. You can go faster if you would have a flood of coolant on it, but I'd slow it up and peck drill it a few thou at a time. It easier to take your time than to hurry up and scrap it.

taumac · May 1, 2012

I moslyt use 500/ 890 and tops maybe 1425 rpm on mine drill press. I never used any forumla for it, it just seems to work drilling the old bed frames and other metal I use. I dont have exspensive bits and even through they say high speed drll bits Ive use oil and very slow speed on drilling anything steal these days. I probably wrong but it seems to work for me.

bggrnchvy · May 1, 2012

bobadame said:
For mild steel you want about 100 surface feet per minute. That's around 4000 rpm. It's ok to go slower in fact you could drill a hole at 1 rpm. The chip load should be around .001"per cutting edge. Use a few drops of oil. The faster you turn the drill the more important the oil.

This is it. The basic formula tells you how fast you can run the tool and how much you need to feed it. Run it slower, you feed less. It's a give and take, but the faster you remove the material the faster that tool is doing other things. If you have heat management down, the tool life doesn't suffer.

tcianci said:
Well if the books say I'm wrong, I'm wrong but, I've never had any issues doing it at the slower speeds, bits stay cool and last longer. I can always learn new tricks, but I'll pass on this one.

The only reason I presented a 4k rpm speed is several were suggesting running a 2-600rpm speed for a 3/32 hole which is a bit funny. Very few people would run a hobbyist drill press at 4k rpm for steel, the rigidity lacks for the feed to match. It's not like the time saved running at 4k rpm compared to 2500rpm is going for one hole is going to matter anyways.

Jim Johnstone said:
3/32" in mild steel, I'd be spinning it around 2000 RPM. Slower certainly won't hurt though.

When I was younger and poorly trained I managed to go through ten .018 drill bits trying to make 6 holes in billet of 6061-T6. I was going way too slow in speed and with the lack of speed my feed had to be so slow and well managed I couldn't get it on a manual drill press. Bumping up to 2700rpm made it forgiving enough I could do it manually.

So again, slower can be a problem.

Kevin54 said:
Some of you guys are running too high of a speed. Material also dictates whether you will get a chip or a spiral out of it. Never start out high then slow down, always start out slow then speed up. I hardly ever go up past 1000rpm's in drilling aluminum let alone 2000 or higher for steel. And for stainless steel, you want to go slow rpm's. I wouldn't go 10,000 rpm's in stainless no matter what size the hole. You can go faster if you would have a flood of coolant on it, but I'd slow it up and peck drill it a few thou at a time. It easier to take your time than to hurry up and scrap it.

It depends on the nature of business. A .010 hole is small and by the sound of it was production work. Running a machine and tooling at 1/4 its capability to feel safer just robs them of revenue in the long run.

If it's a one off R&D part, obviously caution takes precedence and a less aggressive approach would be called for as each scrapped part makes up 50 or 100% of the run yield.

The formulas exist so you don't have to do trial and error to make a hole, mill a slot or hog out the entire interior of a vacuum chamber. You can run some rough numbers in your head to understand what the upper limit of the tool is for the part you're working on and then modify it for the application from there.

I'm not a machinist, I do some simple rework when my parts don't fit right or don't come in as requested, and I know it. I just regurgitate and practice what quite a few well practiced men have instilled from school and industry.

Primered Thunder · May 1, 2012

i'm glad you guys don't do machine work for a living. job security for those of us that do.

3.82 * CS / Dia. of drill = RPM

3.82 * 100 (mild steel) / .09375 = 4075

you can run it slower if you want to, it will only take longer and cost you more drills.

Falcon67 · May 1, 2012

I'd bet on the material as the issue, not the speed. Not a machinist but I play one sometimes in the shop because I bought some tools, jumped up on a stool, pointed my calipers at the sky and shouted I AM A MACHINIST. Put a piece of 1/2" "mild steel" they sell in Lowes or HD on the lathe and try for a surface finish or maybe a smooth cut. It's ****. Bet the cheap store nut is **** too.

gorilla · May 1, 2012

Surface speed is the most important factor in drilling holes followed by feed speed. If you are drilling small holes too slow you will break bits and waste your time. One other thing never drill a hole in any metal without some lube/coolant. Cast iron is an exception.

Primered Thunder · May 1, 2012

If you know how to calculate RPM, SFM and/or chip load per tooth then you can get a great finish on ANY metal, regardless of where it's purchased.

larry_g · May 1, 2012

Primered Thunder said:
If you know how to calculate RPM, SFM and/or chip load per tooth then you can get a great finish on ANY metal, regardless of where it's purchased.

Well I can do all the math but that is only a small bit of what it takes.

lg
no neat sig line

OccupantRJ · May 1, 2012

We don't need no steenken' speed charts! Seriously, I drill by observation, intuition, and feel, and rarely do I need to go above about 3,000 rpm, and drill holes as small as .005 (gas jets), and as large as 1 inch daily in my work, in copper, brass, steel, bronze, stainless, and aluminum. The more you drill, the more you will get a feel for it. I do not use a quill return spring on my work Bridgeport, as it reduces the "feel" too much to suit me. A sensitive drill chuck is a good device to use for really small holes.

OccupantRJ · May 1, 2012

gorilla said:
Surface speed is the most important factor in drilling holes followed by feed speed. If you are drilling small holes too slow you will break bits and waste your time. One other thing never drill a hole in any metal without some lube/coolant. Cast iron is an exception.

I may be the exception to the rule. Most of my drilling is done dry. Compressed air works most excellent for drilling and hole saws in cast iron. Low pressure compressed air also works well for drilling and turning on the lathe. I find that chips evacuate better without oil gumming them in the drill flutes in deep hole drilling. Dry machining is somewhat of a developed technique. I deal with a lot of heated tool prototyping, and the oils cooking out of the metals later is not desirable.

Larwyn · May 1, 2012

The drill press in my garage, which is the one I normally use for drilling holes in steel/aluminum has been set on the lowest speed ever since I got a different drill press in the wood shop. I change the speed on the one in the wood shop more often to help preserve the expensive forstner bits and to avoid burning expensive hardwoods.

Primered Thunder · May 2, 2012

larry_g said:
Well I can do all the math but that is only a small bit of what it takes.

lg
no neat sig line

Not really.

richkl · May 2, 2012

Thanks guys,
I appreciate the advice everyone has given.

It seems that the answers break down to real high speed and low speed.

My drill press is a real P.O.S. At maximum speed, 3630, it sounds like it is about to take off for the ceiling so I haven't tried that yet. I'll get busy on trying a bigger range of speeds.

I am somewhat surprised by the comments on tiny metal chips vs. spirals. It's tough being an amateur in any field.

Richard

OccupantRJ · May 3, 2012

Primered Thunder said:
Not really.

And there I have been all this time thinking that cutting tool geometry had something to do with it, also.

Tbucit · May 3, 2012

Just had to post my 2 cents worth on this subject. I am a machinist and have been for about 40 years so the guys saying that you can drill at a high speed are mostly right. Meaning that there are always exceptions. Most people would be amazed at the speeds that the charts and formulas allow. However as pointed out the machine itself can be just as big of a problem as the speed or material and any lube you decide to use. Another thing is that is misunderstood is coolant use. While a lot of machining is done with flood cooling it is not necessary to cover a part in oil to cool it properly. If a tool is sharpened correctly it should remove the heat with the chip thus making the part cooler. I recently rediscovered this as a lot of shops are now using inserts and the art of sharpening tools appears to me to be dying. And like a few of the others have said I rarely use charts myself but after removing a lot of metal in my time you do get a "feel" for what the tool will take. And you should if your drill is sharpened properly get a spiral chip which would be broken by backing up and clearing the chips from the hole. I may be wrong on this but I don't think I have ever seen a chip breaker on a twist drill.
Randall

Primered Thunder · May 3, 2012

OccupantRJ said:
And there I have been all this time thinking that cutting tool geometry had something to do with it, also.

Considering the topic of the thread is Speeds & Feeds, that' is what I based my reply.

OccupantRJ · May 3, 2012

Primered Thunder said:
Considering the topic of the thread is Speeds & Feeds, that' is what I based my reply.

The topic of the thread is " My drill press will not produce spirals of metal". Tool geometry has EVERYTHING to do with the topic, even more so than speeds and feeds, as a drill can be sharpened to pull spirals when it has been producing chips, without ever changing speeds or feeds. For those interested in learning about cutting tools, this link is to a free ebook on the subject. I inherited an original hard copy when I started removing metal in my 20's.

http://books.google.com/books/about/Metal_cutting_tools_their_principles_act.html?id=JBpaAAAAYAAJ

Another link

http://babel.hathitrust.org/cgi/pt?id=wu.89089662639;skin=mobile#page/8/mode/2up

Primered Thunder · May 5, 2012

OK, so tell us how to sharpen a drill to pull spirals.

bobadame · May 5, 2012

I think that the drill is producing little flakes instead of long continuous spirals because the bit is chattering as it is being forced into the steel. Try using heavier pressure on the handle to make the drill bite into the metal. Use constant, firm pressure and a few drops of oil. If the bit is sharp, this will work. Drill in stages about 2X the diameter. Pull the bit out of the hole, re-oil the bit and start again.

drmarkr · May 5, 2012

Primered Thunder said:
If you know how to calculate RPM, SFM and/or chip load per tooth then you can get a great finish on ANY metal, regardless of where it's purchased.

And have a proper, sharp tool....

Primered Thunder · May 5, 2012

I would assume a NEW drill was ground with the proper geometry. That is, after all, what the original poster stated he was using.

My drill press will not produce spirals of metal.

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