# Milling on the drill press



## ericc (Apr 8, 2020)

Recently, I have been revisiting this topic, and with the recent post on "safety third", I thought I would share some observations.  I don't have a vertical mill, and sometimes the thought crosses my mind about milling on the drill press.  Typically, this question is asked by a beginner, and the group answer is usually "NO", because the drill press is not designed to handle side loads.  The reason I thought of this is that drill bits wander (as the mind does), and in a sense, there are side loads associated with the wandering (else why would the bit wander).  The question is how much can one get away with before the dreaded taper disassembly and potential resulting hazard.

I am attaching three photos of my latest attempt at milling on the drill press.  In the first picture, a small spotting drill is posed to take a peck in preparation for drilling a hole for a spot weld.  Note that the shaft is proud of the surface of the puck.  That is due to a belated relief feature machined on the opposite side where the shaft is pressed in up to a collar.  Also note that the transition has been relieved near the drill point with a file.  This is necessary.  The drill is short and relatively stiff, and can withstand some side loading.  The trick is to bury the point before the drill does an appreciable amount of side loading. Finally, note the clamping arrangement.  This is necessary.  If you don't clamp this setup well, you will find out as soon as the drill hits the part.

The second and third pictures are for the main drill, which is about 5/16" in diameter.  This is also a spotting drill, and is short and relatively stiff.  This will drill the unequal heights with ease, and the point is captured in the divot made by the spotting drill.  All drilling is done at a low speed, well below the 100 ft/min recommendation for drilling steel.  The two spots are earlier successful spot welds that hold everything in place.

Now for the obvious question.  "Have I ever had an accident in which the chuck became free when I was doing something like this?"  The answer is "yes."  In my defense, first I was a beginner when it happened, and second, I thought I was drilling, not milling.  I was trying to drill a large hole, I think something like 7/8" in diameter, in a piece of 1/16" sheet metal.  But, I actually was milling it.  What happened is pretty obvious in retrospect.  As the drill broke through, one lip caught on the side of the hole.  Instantly, this converted drilling into milling as a reactive side load was imposed on the chuck taper.  The sheet metal was thin, so the point of the drill was not restrained, and it exited the part along with a now free chuck flying out of the spindle.  Fortunately, the speed was low, and there was no harm done.  After that, I drilled all sheet metal holes with a hole saw, a trepan tool, or a boring bar.  One may insist that the trepan tool creates side loads, but the pilot point is buried, so this is relatively safe, at least until the cutter breaks through.  Break through seems to be more controlled, and the point is already pretty far down.

After thinking about this, I understand the "safety third" post a little better.  It doesn't mean that safety is third.  Safety is always first.  But safety is not about rules.  It is about understanding the rules, obeying the rules when they apply, and knowing when it is safe, or safer, to break the rules.  This requires not a more cavalier attitude about safety, but rather a holistic understanding about what safety really is, and not a blind adherence to the letter but not the spirit of the rule.  The reason I said that the post was cryptic is that I did not understand the concept until I followed the links to see what Mike Rowe said about the topic.

Be safe out there!


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## Mitch Alsup (Apr 8, 2020)

I fail to see and "significant" side loading on the drill press, the cutting pressure remains axial. Thus this is something that could be done on the drill press. However chucks are not adequate when holding end mills when really milling.

Now if you were to try and mill a slot, then we would be talking about significant side loads and avoiding end mills flying off the drill press taper and laying waste to everything in sight.

Also note: the kind of drill that is proper to start a hole (divot?) pictured above is a spot drill.


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## SLK001 (Apr 8, 2020)

I am embarrassed to say that I do milling on my drill press.  I bought a HF X-Y vise that I clamp to the table.  I only have done slotting with a saw - I don't dare do any real milling with my setup.  My DP has an MT3 arbor that can be changed as needed, so I don't use a chuck to hold any tooling.


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## Maddogmech1 (Apr 8, 2020)

I briefly dabbled in this when I first started playing with machining. My machine at the time was a small craftsman bench top drill press. MT2 spindle to which I purchased an ER16 collet chuck and slapped it in above a harbor freight X-Y table. I then drilled and tapped in the tang of the collet chuck taper, and used a socket head cap screw to wedge into the taper eject slot in the spindle to hold the chuck in. Very light cuts were somewhat successful but I rapidly trashed the spindle bearings as the side loads were enormous for those tiny bearings. 

Needless to say, a milling machine was purchased shortly after that


Sent from my iPhone using Tapatalk


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## Nutfarmer (Apr 9, 2020)

The side loading of milling on a drill press can destroy the bearings. Don't ask why I found this out . I will never admit it.


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## ericc (Apr 9, 2020)

A small amount of side loading seems to be tolerated.  Sticking to short bits helps, since the lever arm is shorter.  Cutting a slot is pretty much out of the question, but drilling against a step, wallowing out a hole, or even moving a hole location slightly is possible.  Also, things like jigs like for 80% lower work and clamped drill bushings help stabilize things a lot.  Those Harbor Freight X-Y tables are pretty useless, since the slides are so rough.  They don't work for even light milling, even with a dedicated spindle.  The gib screws are either too loose and sloppy, or too tight for the slide to move.  There isn't much middle ground.

There is some side load in the job mentioned above.  That is the reason for the two clamps.  The point of the drill keeps the taper in, though.  If you did this with a longer drill, the bit would bend and goof things up.


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## matthewsx (Apr 9, 2020)

Safety third guy here.

So, we do whatever it takes to complete our projects, sometimes we ruin stuff along the way.

As for milling in a drill press, yes I have done it. I actually changed the bearings in my Central Machinery DP to ones that were rated for axial loads. It still wasn't very  satisfying so I went on to milling in my lathe and finally decided to build my own mill/drill out of bits and pieces I could get cheap. 









						Homemade vertical mill drill
					

Well, I guess I'm gonna try to make myself a mill for cheap.  I found this column on Craigslist for $80.    And I ordered this spindle I can power with a VFD I already have.    And I'm going to get one of these cheap x-y milling tables.    And probably look for a really flat piece of C channel...




					www.hobby-machinist.com
				




As it turns out you can break the laws of man pretty easily but if you try and break the laws of physics you will very soon run up against a hard stop. There's a very good reason mills are made from literally tons of cast iron. It's so they can do the jobs expected of them. Small machine tools are nice and fun to play with but if you push them hard you will end up with broken s***









						Just added a 101.21200 to my shop out west
					

OK.  And what I can see of the spindle under where the cone pulley and small gear go loos much better than most.  But I wonder why the Timken Cup came out with it?  The cone should have come out but not the cup.  Something hinky there.




					www.hobby-machinist.com
				




If you just need to make a few small slots in relatively soft material you may be able to use a drill press with an X-Y table. But, I'm always reminded of a quote from the Gorton Mill yahoo group back when I had my 10-22 "those Gortons make a Bridgeport look like Silly Putty".

So, watch carefully what Mr. Whoppee posts and be ready with fresh Benjamin's cause if you want to be milling it's iron you'll need.

John


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## ericc (Apr 9, 2020)

matthewsx said:


> ...
> 
> As it turns out you can break the laws of man pretty easily but if you try and break the laws of physics you will very soon run up against a hard stop. There's a very good reason mills are made from literally tons of cast iron. It's so they can do the jobs expected of them. Small machine tools are nice and fun to play with but if you push them hard you will end up with broken s***
> ...
> ...



True, you can't break the rules, but you can bend them.  The clamp in the foreground has a slot cut in it.  This slot was not cut on the drill press.  Not the right tool.  It wasn't cut on a Bridgeport either.  It was cut with an 8 ounce piece of 4130 forged into a slot punch and heat treated.  It sails through mild steel heated to high forging temperature.  One or two heats, which are relatively fast with a coke fire.  And as for mass, 100 pounds will work just fine.

Thanks for stopping by to comment.  I appreciated your post on safety.


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