Milling with a Drill Press?

[BillyNoMates]

I'm new to this maching lark, but I was wondering if anyone has had any success with using a drill press to perform simple milling operations?

I don't have sufficient funds to buy a reasonable mill, but I was considering getting a rotary table to fit to my floor standing drill press and using that to mill circular recesses in solid stock.

I understand that this will in no way be as good as a proper mill, but it may do for now - the rotary table will be transferrable to a mill bed if I end up with one in the future.

Any advice from experienced machinists will be gladly received.

Thanks.

 

[Doh!Nut]

I think there was a thread about this recently, it was based on the fact that the Drill press bearings are not designed to accomodate a side load and the chuck is held in by a taper (?) but no draw bar to keep it there - only friction.
The impact was the chuck got levered out by the side force and flew accross the workshop
Nick

Having said that I think that you could maybe use a fly cutter to cut a groove

 

[Torque1st]

A fly cutter will "fly away" also.

Buy a small mill or have someone mill your parts for you.

 

[BillyNoMates]

Good point about the drawbar. I guess that could easily be shaken loose by the vibrations.

Looking at the length of the taper it is unlikely to come out of the machine as the cutter will be too close to the work piece (it needs several inches of clearance to remove it).

Thanks for the advice.

 

[Torque1st]

What happens is the cutter point digs into the material, then things start bending, breaking, and twisting. Pieces and parts and/or cutters can fly away.

 

[Alan B]

Years ago I tried this with a 5/8 chuck in a floor drill press, the bit was one of those wood drills/side cutting rasp designs, the material was 2x4 wood. It was quite exciting when the heavy chuck and taper dropped into the workpiece at speed. Luckily the hole it was in contained the tool so it was not too exciting.

I would not recommend trying it. A router, dremel or a real mill is required.

 

[Anglepoise]

I think there was a thread about this recently, it was based on the fact that the Drill press bearings are not designed to accomodate a side load and the chuck is held in by a taper (?) but no draw bar to keep it there - only friction.
The impact was the chuck got levered out by the side force and flew accross the workshop
Nick

Nothing more to add here. Well said.

 

[gadget_lover]

I watched my neighbor use a "circle cutter" in his drill press the other day. It was a heavy duty design, using what appeared to be a 1/4 inch lathe bit on an adjustable arm. A 7/16 bit maintained the center. Quite a nice design. Basically a boring bar with a drill to maintain the center point.

1/2 of the way through his plate of 1/4 aluminum the chuck taper came loose when the bit stalled. IT was lodged in the aluminum so it did not fly anywhere.

This was a "vertical load" so the bearings were not side loaded, but the off center forces rocked the chuck right off the jt33 taper.

Using an end mill to do plunge cuts does work, but adding a rotary table is just like using a milling table. As you rotate the table into the cutter you end up with side loads.

BTW, the concept that "it will not come off too far" is only partly true. If the endmill breaks the inertia may carry the newly free chuck further than you expect.

Last (and not least) is the fact that whatever you are milling WILL be damaged when the chuck / arbor comes loose.

When you look at the other thread, you will see reference to a set of 1930's (or was it 50s) plans for adding a quill support to keep the arbor from applying sideload to the bearings. If you make it, let me know how it worked.

Daniel

 

[precisionworks]

mill circular recesses in solid stock.

Round work is best handled on a lathe, and the mini-lathe (used by many CPF members) is a better choice than any drill press ever made. If you don't have funds for a mill or lathe, have the work done by a shop with the right equipment.

 

[mdocod]

I think the last time this question was asked was by myself.

Yes, I used a drill-press to do some milling in plastics for a few runs of parts. I dropped the arbor and chuck a few times through that, while I never got hurt, I certainly could have, and I ruined probably $20-$30 worth of end-mills in the process of trying. Looking back on it, now actually having a mill, I can't believe I even wasted my time. Even a really small mill will run circles around most drill presses as a milling machine.... Drill presses will go into severe chattering under the presence of the most minor lateral loads. The chatter is what knocks the arbor loose from the spindle, or knocks the chuck loose of it's JT taper fit. My drill press is one of those 16 speed 125lb 3/4HP harbor freight "bench-top" units and is a wonderful garage drill press to have around, but the rigidity is just not in the right places for milling. Here's a picture of the drill and mill next to each-other to give an idea of the drill press that couldn't hack it.

Having said that, there are some drill presses out there that would be more suitable than others as make-shift mills. The larger the better. When you get up to spindle taper sizes of ~MT4 the machines are usually rated for face mill and end-mill capacities for plunge cuts, and they would, if properly setup, probably handle some lateral loads of light cuts reasonably well.

First I'll recommend just not doing it as it's dangerous, second, if you are hell bent on trying I'll offer some tips based on my experience and where I probably went wrong in trying to make a drill do milling.

Get the cutting tool face as close to the base of the spindle as possible! I made the mistake of trying to hold end-mills in the large heavy drill chuck, the problem with doing this is multi-fold. A: it increase the leverage that the cutting tool has against the weak spindle design in the drill, which increases the likelihood of chatter which almost always leads to a dropped tool. B: when the tool drops, it's not just a small tool dropping, it's going to be the entire weight of the chuck and possibly the arbor attached to it all dropped while still spinning ~3000RPM, this makes a tool-drop more dangerous as their is a lot more mass that is spinning wildly that has just dropped. C: A chuck isn't the best tool-holder around and is going to introduce more run-out in most cases, which will further increase the likelihood of chatter.

One of the biggest hurdles in trying to find solutions to doing a drill to mill type setup is getting over the language barrier of the machining world, now that I have had a machine and had to buy tooling I've finally got over the hump, (I think ), which means that looking back on it, I probably could have made a better effort to make the drill do milling more reliably, but at this point I wouldn't bother... Anyways....

Firstly, this will only work if you have a machine with a morse taper #2 spindle or larger. Make sure you have a wedge drift for your machine handy to remove the tooling after the fact.

What you'll probably want to use is something called a tang style morse taper tool holder. And you'll need to use end-mills with the "flat" on the shank for use with tool-holders like this. Here's a link to the tool-holder I'm talking about:
https://www.wttool.com/category-exe...Taper_Tang_Style_End_Mill_Holders_/page_num/1

The idea here is that you are removing the larger length of the drill chuck, and at the same time, eliminating the JT taper fit (the most likely failure point for "milling").

You'll want to really drive that tool-holder home good before use, I'd beat it in there pretty good with a soft face hammer.

I'm not sure what size slot you had in mind, but you'll probably be well served with a 3/8" diameter tool holder as most sizes from ~1/8" up to ~7/16" single-end-mills are available on a 3/8" shank. I would suggest the use of a 4 flute center-cutting end-mill in a the shortest length you can find if you can get away with it, medium to high rpm, and very slow feed rate. The 4 flute end-mill will balance the cutting load more evenly by taking smaller "bites" which will help increase your chances of success. Aim for smaller size cutters to reduce the lateral loading on the machine. I would suggest no larger than a 3/16" cutter. Here's an example:
http://www.use-enco.com/CGI/INSRIT?PMAKA=240-4234&PMPXNO=4843158&PARTPG=INLMK32

Take any precautions you can think of to protect yourself, like maybe some body armor or something, lol....

More layers of clothing will absorb a flying piece better, nothing loose though, getting sucked into a machine would be bad. safety goggles are going to be a must here, if the tool holder drops loose of the spindle, the end-mill will crash and send small pieces of sharpened High-Speed-Steel flying.

Position the work piece up close to the face of the cutter with the quill fully retracted, so that you are dropping the quill only a small amount to meet the work piece, however, make sure to leave enough clearance so that if the tool-holder does drop, the tang on the end of the tool-holder has room to fall out of it's "slot" up in the machine, so leave at least ~3/4" or so between the work piece and the face of the tool. By doing this, if the toolholder does work loose the spindle and drop, you can quickly lift the quill, and the toolholder will generally crash the end-mill into the work piece and come to a halt very quickly. Without that proper clearance, the machine will continue to rotate the loose tool-holder which can escalate the danger rapidly. The machine will likely suffer some minor scuffing on the inside of the spindle taper. By having this proper balance of distance to work-piece, you also increase safety by eliminating the likelihood of the toolholder itself going for a dance around the garage as it won't be able escape the "trap" created by the spindle-taper and work-piece below.

If I think of anything else I'll try to check back in here and throw in a few more pennies of thought.

-Eric

 

[Torque1st]

Thanks for all of that information Eric. We can all re-iterate that it is dangerous but until someone comes here with nice bloody pictures of loosing an eye or other body part people will continue to try it. It seems that is the price we pay to get people to use most safety measures. As an example most cities etc won't put in a traffic signal anywhere until a person or two is maimed or killed at an intersection. People still don't wear safety glasses or face shields while grinding, -until they see the pics of that operation where they are removing a big chunk of grinding wheel out of a person's eye. Even then, how many times have we all stepped up to the grinder for a quick pass without safety equipment etc... Unfortunately using a drill press as a mill requires that someone actually think about it and then do it, -which is plumb crazy. We all do crazy things tho and most of the time we get away with it until...

-Eric

 

[precisionworks]

until someone comes here with nice bloody pictures of loosing an eye or other body part people will continue to try it.

Way back when, the smallest mill for home shop use was the Bridgeport Series 1. No body would ever mistake a Bpt for a drill press, as the two are as different as night and day. Those few who had to try axial loading of drill press components got a quick lesson in what not to do:mecry:

During the period from 1970 - 1980, the American machine tool industry had almost died. Japanese machine tools were not an option for many shops, as Japanese prices were almost as high as American prices had been. The Taiwanese entered the machine tool market, making mostly identical copies of classic American tools. Someone saw a need for a table top milling machine and modified a drill press into a mill-drill. Which created a problem, as a drill press looks almost like a mill-drill ... so a drill press should almost be able to do the same work:sigh:

You'll want to really drive that tool-holder home good before use

The most common method for seating Morse Taper tooling in a spindle is to bring the MT tooling down sharply against a hardwood block. Hard maple is an ideal wood for this, and you want to bring the spindle down as fast & as hard as possible.

 

[BillyNoMates]

A big thankyou to everyone who offered advice - especially those messages regarding safety - I hear you, I really do. With the information provided by mdocod, I decided to give it a go to see how I got on.

Armed with a couple of two fluted slot drills, I set to work. Concerned about the possibility of the taper coming loose, I decided to opt for a slow cutting speed (about 500rpm) although far from ideal, it looked a lot less scary than spinning round at 2000rpm or so.

True to everyone's predictions, the taper came loose after about 2 minutes. It didn't break or fly out, it just started cutting deeper and deeper as the taper started dropping out of the collar.

For the second attempt, I used rubber mallet to seat the taper - hitting it pretty hard seemed to do the trick and I was able to press on and finish the piece without any more problems. There was some slack in the bearings which limited the accuracy, but this was manageable provided I didn't try to remove too much material too quickly. Anyway, here is a picture of the finished item...

I know it's is not a particularly fine finish, but it is good enough for my purposes. The lens and o-ring sit nicely on the shoulder half way down the recess and line up perfectly with the LED PCB screwed in place. The slot is for the connections to the driver circuit which sits in a second recess on the reverse side.

So, would I buy I mill or lathe to do this again? - yes absolutely (once I get sufficient money). Actually trying it, makes it perfectly clear how unsuitable the drill-press is for this application.
Will I use the drill press as a makeshift mill again? - possibly, as long as the part I'm trying to make is not too complicated, the whole process is slow and the tolerances are a bit rubbish, but it can be made to work.

 

[choffman]

FYI, hf has their micro mill on sale right now. 300 smackers. with the 20% coupon you're looking at 240. I saw it in the in-store flier yesterday. The 8x14 is also back on-sale as well.

FWIW

 

[Torque1st]

The "pucker factor" when attempting to mill with a drill press makes spending a few bucks on even a mini mill worth it. It got real old fast.

I bought a used benchtop mill off ebay a couple years ago for $700 with tooling. It was a very good deal. It came with two Kennedy tool boxes full of odds and ends etc. I went thru the tool boxes and found they contained over $3000 worth of tools like mikes, wigglers, V-blocks, etc at used prices and I did not even go thru the smaller stuff or add up cutters, collets, chucks, files, tin snips (4 pairs) etc. The mill and tool boxes are in fine shape also and are not included in the above $$ figure.

 

[Alan B]

...
Will I use the drill press as a makeshift mill again? - possibly, as long as the part I'm trying to make is not too complicated, the whole process is slow and the tolerances are a bit rubbish, but it can be made to work.

Milling with a drill press is like driving an old beat-up truck at 100 miles an hour. It may work, but if anything goes wrong the results can be really really ugly. Glad you did not have an incident. This time.