My drill press will not produce spirals of metal.

[taumac]

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]

Originally Posted by bobadame

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.

Originally Posted by tcianci

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.

Originally Posted by Jim Johnstone

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.

Originally Posted by Kevin54

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]

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]

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 crap. Bet the cheap store nut is crap too.

[gorilla]

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]

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]

Originally Posted by Primered Thunder

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]

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]

Originally Posted by gorilla

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]

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]

Originally Posted by larry_g

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]

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]

Originally Posted by Primered Thunder

Not really.

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

[Tbucit]

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]

Originally Posted by OccupantRJ

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]

Originally Posted by Primered Thunder

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/...d=JBpaAAAAYAAJ

Another link

http://babel.hathitrust.org/cgi/pt?i...age/8/mode/2up

[Primered Thunder]

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

[bobadame]

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]

Originally Posted by Primered Thunder

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]

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