drill press help?

[Bugman]

For some reason, the drill press and I can't seem to get along. I was drilling some 5/16th holes in 3/8" steel plate the other day(with 1/8" pilot hole), and i could not get them to drill correctly. . The first hole went great. quiet and smooth. the rest I barly got drilled. The bit screeched, and would not cut. I tried another bit with similar results...lots of noise, very little drilling. I tried cutting oil...didnt help. Ii tried speeding up and slowing down the spindle speed, and that didnt help either. Any suggestions? Thanks.

[Unkl Ian]

The drill bits need to be shapened CORRECTLY,as necessary.
Once they get dull,they don't fix themselves.

Run around 650 rpm,add coolant as necessary.


Most people run them too fast,and burn the edge off,
or too slow and snap them.

2 minutes sharpening will save 10x that in one job.Easy.

Originally Posted by Bugman

For some reason, the drill press and I can't seem to get along. I was drilling some 5/16th holes in 3/8" steel plate the other day(with 1/8" pilot hole), and i could not get them to drill correctly. . The first hole went great. quiet and smooth. the rest I barly got drilled. The bit screeched, and would not cut. I tried another bit with similar results...lots of noise, very little drilling. I tried cutting oil...didnt help. Ii tried speeding up and slowing down the spindle speed, and that didnt help either. Any suggestions? Thanks.

[19Fordy]

Originally Posted by Bugman

For some reason, the drill press and I can't seem to get along. I was drilling some 5/16th holes in 3/8" steel plate the other day(with 1/8" pilot hole), and i could not get them to drill correctly. . The first hole went great. quiet and smooth. the rest I barly got drilled. The bit screeched, and would not cut. I tried another bit with similar results...lots of noise, very little drilling. I tried cutting oil...didnt help. Ii tried speeding up and slowing down the spindle speed, and that didnt help either. Any suggestions? Thanks.

Man, that should be a breeze. What kind of drill bits are you using? I always use HSS (high speed steel) drill bits at the correct RPM with oil. The HSS speed bits with the titanium (gold looking) color are great too. Make sure they are sharpened correctly with 180 degree included angle. Carbon steel drill bits dull rapidly. Work on wood, but not on steel.Not trying to be a smarty pants, but I assume you are not using left handed drill bits. It's been known to happen. Are you sure the steel you are drilling is mild steel?

[ol fueler]

Originally Posted by Bugman

For some reason, the drill press and I can't seem to get along. I was drilling some 5/16th holes in 3/8" steel plate the other day(with 1/8" pilot hole), and i could not get them to drill correctly. . The first hole went great. quiet and smooth. the rest I barly got drilled. The bit screeched, and would not cut. I tried another bit with similar results...lots of noise, very little drilling. I tried cutting oil...didnt help. Ii tried speeding up and slowing down the spindle speed, and that didnt help either. Any suggestions? Thanks.

Your 1/8 pilot hole was too big. you would have been better off with no pilot hole than one too large. a pilot hole should be no bigger than the very point of your drill bit. If it is any wider than the very tip of the drill bit , what happens is the cutting edge of the bit is only touching at the edge of the hole on a razor sharp edge , this extremly small contact surface will cause the pressure on the cutting edge to be literaly hundreds of thousands of pounds per square inch & will instantly overheat & ruin the bit.

[Deuce Rails]

You might also want to try a 5/16 end cutting mill tool. They're meant for milling machines, but they do wonders in drill presses. You can find them at either www.mcmaster.com or mscdirect.com.

[19Fordy]

Originally Posted by ol fueler

Your 1/8 pilot hole was too big. you would have been better off with no pilot hole than one too large. a pilot hole should be no bigger than the very point of your drill bit. If it is any wider than the very tip of the drill bit , what happens is the cutting edge of the bit is only touching at the edge of the hole on a razor sharp edge , this extremly small contact surface will cause the pressure on the cutting edge to be literaly hundreds of thousands of pounds per square inch & will instantly overheat & ruin the bit.

Excellent answer. That makes good sense. The pilot hole needs to be only the size of the drill bit dead center, which doesn't cut. Wish I had thought of it.

[Unkl Ian]

Jobbers bits are 118 degrees,not 180.

Originally Posted by 19Fordy

Make sure they are sharpened correctly with 180 degree included angle.

[Django]

Can I poke my nose in here?

My chuck is wobbly at the teeth, but straight at the shaft. I sprayed some WD40 up in the teeth and worked it open and closed several times, but it is still wobbly. Any suggestions?

[jerry]

If you have a dial indicator clamp it to the table and chuck a piece of round stock in the chuk. Spin the chuck by hand slowly and tap the chuck with a small hammer to realign it.


jerry

[HemiRambler]

I am gonna have to respectfully disagree here. I believe this process is called STEP DRILLING and I do agree IF NOT CAREFUL you can overheat the edge of your bit since the required force is so much less with the large "pilots" but it doesn't mean you cannot do it. Matter of fact when drilling holes LARGER than my machine's capacity I have often resorted to step drilling to achieve the desired hole size. There is a balance between DOC (depth of cut), FEED and SPEED. Keeping those happy will let your bit LIVE. A drill bit is nothing more than a cutting tool - not alot different than a boring bar - in some respects. Pushing for all it's worth while trying to drill a little step is gonna likely overheat just as you said, but keeping the surface speed in mind (bigger bits need LESS speed) you often get by with LESSER equipment to do BIGGER jobs.I have literally drilled hundreds if not thousands of STEPPED holes on my lathes and drill presses - if done properly the bits don't suffer at all. Matter of fact at times it is a preferred method.Granted drilling a pilot the size of the "chisel point" is good manufacturing practice for exactly the reasons you stated, but there's ALWAYS more than one way to skin a cat.That's my story and I am sticking to it.

Originally Posted by ol fueler

Your 1/8 pilot hole was too big. you would have been better off with no pilot hole than one too large. a pilot hole should be no bigger than the very point of your drill bit. If it is any wider than the very tip of the drill bit , what happens is the cutting edge of the bit is only touching at the edge of the hole on a razor sharp edge , this extremly small contact surface will cause the pressure on the cutting edge to be literaly hundreds of thousands of pounds per square inch & will instantly overheat & ruin the bit.

[fatassbuick]

Me:

758 RPM (easy and dirty formula for steel spindle speed is 240/diameter of tool. Let's not play the chip load per tooth game right now...just a quick reference..)

Pull solidly and fearlessly, ,chip should roll off like Annie's hair curls (straw colored ships are a good sign of feed and speed superiority!) Avoid purple chips.

Coolant, as in motor oil or something a little more modern and environmentally safe is a good idea.

Pilot drilled holes tend to make noise. Get used to it.

If the tool chips or breaks, your feeding too fast. If the tool burns or turns black, your spindle speed is too high.

[19Fordy]

Originally Posted by Unkl Ian

Jobbers bits are 118 degrees,not 180.

Thanks. 59 x 2 don't equal 180. Don't know why I thought it did.

[Morrisman]

Originally Posted by ol fueler

Your 1/8 pilot hole was too big. you would have been better off with no pilot hole than one too large. a pilot hole should be no bigger than the very point of your drill bit. If it is any wider than the very tip of the drill bit , what happens is the cutting edge of the bit is only touching at the edge of the hole on a razor sharp edge , this extremly small contact surface will cause the pressure on the cutting edge to be literaly hundreds of thousands of pounds per square inch & will instantly overheat & ruin the bit.

Jeez, this is a guy drilling holes in a garage, not a NASA workshop. LOL.

A 1/8 pilot hole, or no pilot hole, it won't make hardly a bit of difference to a basic hole being drilled in mild steel, as long as the drill bit is correctly sharpened and somewhere near the right speed. The usual problem with badly sharpened drill bits is they never have any clearance. It's not difficult to do, if you know how to do it, but get it wrong and you can spend all day chattering and burning away your hole.

Deuce Rails, a slot drill (as we call them in the UK) will wander and chatter all over when you start drilling, unless you have a good and solid bench drill. A properly sharpened twist bit will do a far superior job.

[corncobcoupe]

Some things to think about.
Steel plate ? What kind ?
If it's a junk boiler plate - I've seen sections that have high nickle crusties or ball bearing/razor blade material in them.
First drill always runs great, except the work hardening process.

Speeds and feeds are important to drill life.

As stated in an earlier post, wheat colored chips are ideal, purple and you are running too fast.

Also - get a Drill Doctor sharpener (great for garages and home shops).
They pretty much will sharpen the drills correctley 99% of the time.

With a step drill - the biggest problem is a lot of times when the larger diameter hits the hole, the drilling takes place more on the web of the drill cutting surface - thus the singing.

I wouldn't even use a step drill.
Just a standard jobbers 118.
If your drill press is older and has spindle slop, you might want to go to
135 degree split point drills. They start a bit quicker and drill a bit straighter.

You can buy a drill doctor and drills at www.mscdirect.com

Hope this helps.

Cob
Forum Moderator

[29RAT]

Originally Posted by Morrisman

Jeez, this is a guy drilling holes in a garage, not a NASA workshop. LOL.

A 1/8 pilot hole, or no pilot hole, it won't make hardly a bit of difference to a basic hole being drilled in mild steel, as long as the drill bit is correctly sharpened and somewhere near the right speed. The usual problem with badly sharpened drill bits is they never have any clearance. It's not difficult to do, if you know how to do it, but get it wrong and you can spend all day chattering and burning away your hole.

Deuce Rails, a slot drill (as we call them in the UK) will wander and chatter all over when you start drilling, unless you have a good and solid bench drill. A properly sharpened twist bit will do a far superior job.

I totally agree, I frequently step drill to help keep the holes closer to size when needed, plus for those without any machining knowledge (ie having a feel for what the tool is doing) a pilot hole will help eliminate wandering, especially when the bits do start to dull. My 2 cents with .0199999 change back.

[HemiRambler]

Originally Posted by corncobcoupe

With a step drill - the biggest problem is a lot of times when the larger diameter hits the hole, the drilling takes place more on the web of the drill cutting surface - thus the singing.

I wouldn't even use a step drill.
Just a standard jobbers 118.
If your drill press is older and has spindle slop, you might want to go to
135 degree split point drills. They start a bit quicker and drill a bit straighter.

You can buy a drill doctor and drills at www.mscdirect.com

Hope this helps.

Cob
Forum Moderator

Cob, just to make certain we are on the same page - the process I was referring to was STEP DRILLING - not using a STEP DRILL. The STEP DRILL most common I think is the Unibit type- which would probably be great for sheet metal but not too good for going through 3/8" plate steel. Of course there are Stepped Drills that have their uses as well but I don't want to cloud the discussion with those. STEP DRILLING is a process where you incrementally increase the size of your drill bit sometimes using several sucessive sizes to get to your final size. The "problem" with this process is that if you are going from a 3/4" dia hole to a 1" dia and treat that 1" bit like "normal" then you're likely gonna overheat that bit and anneal the cutting edge. In tis case you are only cutting a 1/4" (total) of material and your PRESSURE ought to be closer to what you'd put on a 1/4" drill bit not a 1" one - the kicker is that you also NEED to SLOW that 1" bit down!!!!! Chatter is the first hint that you've got something wrong - usually the SPEED is TOO FAST - next might be your FEED (or pressure) is too LOW - this is where step drilling can cause problems - it is RELATIVELY easy to give it TOO MUCH FEED (PRESSURE) and cause problems - as suggested watching the chips color is key but when in doubt run SLOW and WORK UP on it.

Ideally - you want to drill a pilot that is the size of the Chisel Point - but if you machine lacks the stones to do it in one shot then you have litle other choice than to step drill.

The metal has no idea what is cutting it - meaning that having a "pilot" that is TOO BIG is NOT a PROBLEM - if you proceed with the appropriate SPEED and FEED. This gets to be a real challenge on SOFTER material where they have a tendancy to grab and SELF FEED - this can be a problem - snap!!

If your material is WORK HARDENING (alloy steel) then you are drilling with a DULL drill that will definitely not get better as you proceed. Low carbon isn't gonna be much of a problem here - just sharpen your bit - make sure it has some CLEARANCE and drill away.

Stainless is a GREAT material for illustrating the effects of Work Hardening - if you "dilly dally" you can get it to work harden even with a moderately sharp bit - it needs a certain amount of aggressiveness from the user to ensure you are cutting - sulfur based oil can be a useful lube when drilling - some materials, but it stinks when you get it too hot (clue that you are too fast) and unless it's a difficult material or I am cutting very SLOWLY- normally I just use plain old motor oil - not ideal but adequate for many jobs. It starts to sizzle when things are getting too hot!!


Bugman - how FAST was your 5/16" drill bit going?????? Try slowing it down and see how that goes. Use lube if you can - but that wouldn't be near as critical IF your speed was lower.

There was also a good point made about drilling to size. Just a few things I have noticed - just because you grab a 1/4" bit does NOT ensure you drill a 1/4" hole - noramlly the hole size can go BIGGER than you want because of various factors. If your bit isn't sharpened properly (flank lengths the same - for instance) if one cutting edge is longer than the other - the bit WILL have a tendancy to cut oversize. If you use a bunch of feed again it will tend to cut oversize. When drilling holes that I need to be more accurate and I don't have a reamer I will often grab a bit a '64th under drill with that and then go back and drill with the final size - there are times where the final size never even cuts - cheap bits are also a common offender of drilling LARGER than marked. At least the CHEAPIES I have used are!

Another excellent point made was the type of drill bit used - Carbon Steel is definietly JUNK for steel drilling - they are strictly wod grade stuff. Stick with HSS (High Speed Steel) bits - you'll be a lot happier. Coated ones are good too, but not necessary for home use - IMHO.

Drilling who'd of thought there was so much BS involved!!!

[Fossil]

I drill a lot of holes using a "center cutting" type mill. They'll put a nice clean hole in your work. Instead of a drill press I'm using a Bridgeport, but I don't see why it wouldn't work in a drill press. The only problem might be locating the hole precisely on a drill press-but you could locate by chucking an indicator into your press, or using a drill bit to locate into the pilot hole, and then switching to the end mill after you've locked everything into place. Just like with a bit...use a cutting lubricant, watch your speed and feed, etc.

-Scott

[29RAT]

Originally Posted by HemiRambler

Cob, just to make certain we are on the same page - the process I was referring to was STEP DRILLING - not using a STEP DRILL. The STEP DRILL most common I think is the Unibit type- which would probably be great for sheet metal but not too good for going through 3/8" plate steel. Of course there are Stepped Drills that have their uses as well but I don't want to cloud the discussion with those. STEP DRILLING is a process where you incrementally increase the size of your drill bit sometimes using several sucessive sizes to get to your final size. The "problem" with this process is that if you are going from a 3/4" dia hole to a 1" dia and treat that 1" bit like "normal" then you're likely gonna overheat that bit and anneal the cutting edge. In tis case you are only cutting a 1/4" (total) of material and your PRESSURE ought to be closer to what you'd put on a 1/4" drill bit not a 1" one - the kicker is that you also NEED to SLOW that 1" bit down!!!!! Chatter is the first hint that you've got something wrong - usually the SPEED is TOO FAST - next might be your FEED (or pressure) is too LOW - this is where step drilling can cause problems - it is RELATIVELY easy to give it TOO MUCH FEED (PRESSURE) and cause problems - as suggested watching the chips color is key but when in doubt run SLOW and WORK UP on it.

Ideally - you want to drill a pilot that is the size of the Chisel Point - but if you machine lacks the stones to do it in one shot then you have litle other choice than to step drill.

The metal has no idea what is cutting it - meaning that having a "pilot" that is TOO BIG is NOT a PROBLEM - if you proceed with the appropriate SPEED and FEED. This gets to be a real challenge on SOFTER material where they have a tendancy to grab and SELF FEED - this can be a problem - snap!!

If your material is WORK HARDENING (alloy steel) then you are drilling with a DULL drill that will definitely not get better as you proceed. Low carbon isn't gonna be much of a problem here - just sharpen your bit - make sure it has some CLEARANCE and drill away.

Stainless is a GREAT material for illustrating the effects of Work Hardening - if you "dilly dally" you can get it to work harden even with a moderately sharp bit - it needs a certain amount of aggressiveness from the user to ensure you are cutting - sulfur based oil can be a useful lube when drilling - some materials, but it stinks when you get it too hot (clue that you are too fast) and unless it's a difficult material or I am cutting very SLOWLY- normally I just use plain old motor oil - not ideal but adequate for many jobs. It starts to sizzle when things are getting too hot!!


Bugman - how FAST was your 5/16" drill bit going?????? Try slowing it down and see how that goes. Use lube if you can - but that wouldn't be near as critical IF your speed was lower.

There was also a good point made about drilling to size. Just a few things I have noticed - just because you grab a 1/4" bit does NOT ensure you drill a 1/4" hole - noramlly the hole size can go BIGGER than you want because of various factors. If your bit isn't sharpened properly (flank lengths the same - for instance) if one cutting edge is longer than the other - the bit WILL have a tendancy to cut oversize. If you use a bunch of feed again it will tend to cut oversize. When drilling holes that I need to be more accurate and I don't have a reamer I will often grab a bit a '64th under drill with that and then go back and drill with the final size - there are times where the final size never even cuts - cheap bits are also a common offender of drilling LARGER than marked. At least the CHEAPIES I have used are!

Another excellent point made was the type of drill bit used - Carbon Steel is definietly JUNK for steel drilling - they are strictly wod grade stuff. Stick with HSS (High Speed Steel) bits - you'll be a lot happier. Coated ones are good too, but not necessary for home use - IMHO.

Drilling who'd of thought there was so much BS involved!!!

That pretty much settles it and End mills in a drill press are sketchy at best

[23 bucket-t]

a step drill { pilot drill } is when you want to to keep two holes concentric with each other . lets say you want to drill a hole .500 2 in. dp, and a .375 thru. you will want to drill the .500 drill to depth, then you will need to use a .4995 / .3755 step drill, then you will drill about 1/4 inch deep, that depending on the length of the pilot { just keep it back about .050 } then you can drill the .375 thru ****** but what this guy is refusing I believe to is a center drill. it is so you can center the hole where you need to put it. why -- because if you do not center drill first the twist drill tends to wobble and it will be off location by a few R.C.H.s also you can get bell mouth., which you my not want. When using a center drill you use the correct size drill, down to about the same size of the twist drill. which should be no more than about 1/4 inch dp. then you will be able to drill your hole. But if you have a dull drill or an incorrect drill point you will not be able to drill it, then again if you have cheep steel, which my have hard and soft spot in it and it can dull the drill very quickly . so what you will want to do is center drill first, then twist drill about 750 rpm. use a light grade oil, and light presser, using the waight of your hand push down. take it slow.

[Bugman]

Thanks for all the info. It did help. I think I setteld on my problem being shoddily sharpened bits. I used to be able to hand sharpen a mean bit, but I've lost my touch. Drill Doctor here I come