Drill press hacking

Flashlight Modding and DIY Parts
1

This is a case study in how to spend a lot of money attempting to make a cheap drill press perform about half as well as a cheap vertical mill.

In stock form this $129 'Skil' drill press had the limiter/stop on the shaft of the handle, which is the wrong way to do it. If there is any slop in the gear rack between the handle & quill (and there will be, did I mention this is a $129 import drill press with a deliberately-misspelled brand name?), the limiter will hit the stop but the quill will still be free to move around within the slack in the gear. When drilling, you pull the handle down until it hits the stop, but the quill will drop another ~1/16" before it lands on the lower face of the gear teeth. Sucks.

The limiter needs to be on the quill, not the handle. Who cares where the handle stops, the handle isn't the thing doing the cutting.

3/8"-16 stainless threaded rod (the hardware store stuff will be zinc plated/galvanized, and much too rough for this - stainless was the only thing I could find that wasn't plated). The quick release adjusters are from Grizzly - http://www.grizzly.com/products/Quick-Threaded-Stop-Collar-3-8-16-/G7317 . Press the button to slide up/down, or turn them for fine adjustment. The red anodized clamp bracket thing was a leftover, originally it was a mounting bracket for 2" CO2/nitrous bottles.

With two adjusters, the one on the bottom will set the quill in a fixed position, the upper one is used as a depth limiter. With both of them screwed together against the bracket, the quill will not move even if you yank on the handle.

To get rid of the side-slop between the quill and head, I drilled/tapped to add two 3/8" load bolts, their tips have a little brazed blob of aluminum bronze to minimize wear & tear. No more side-slop means no more chatter when using endmills, these bolts were the single biggest improvement of anything I've done so far.

Once those two things were done I could see that all the chatter and grabbing and flinging parts across the room were solved, and milling with a cheap drill press would be feasible, so I invested in a small X-Y table - http://littlemachineshop.com/products/product_view.php?ProductID=2008 .

Sill using a little toy $19.95 Bessey drill press vise, but it's now got self-made aluminum jaws, and all the surfaces have been remachined to true it up as much as possible. Out of the box, nothing on them is accurate. The base isn't flat, the ways and tops of the jaws aren't parallel to the base, the jaw faces aren't square to anything. The bottom is painted - why, I have no idea. Paint scuffs, scratches, and gets metal embedded in it. All that has been removed and the bottom cut flat, and all the other important surfaces re-cut using the newly-flat base as a reference.

After I had the X-Y table and had the ability to do semi-precision cutting, I milled 8mm slots in the base parallel to the jaws to hold 8mm wide aluminum blocks, these fit into the 8mm t-slots in the table or against the rear edge as shown here. The vise needs to go in different locations on the table depending on what's being worked on. The aluminum blocks index the vise to the table axis so that the vise jaws will be square. If the vise is skewed, the cuts you make will be too. The blocks make remounting the vise a 30 second job, if they're in the slots the vise is square.

This X-Y table is really too small for even a small 'real' milling vise; those are around 11-12" long and weigh about 30 pounds. The only smallish/lightish alternative to the generic flimsy drill press vise models is this one - http://www.ebay.com/itm/301225076081 . Note it has a round solid bar from front to back that the movable jaw slides on, opposed to the Bessey-style that has only a bolt-on plate underneath that attempts (and mostly fails) to keep the jaw from tilting.

Next to be solved was the flexi-table. There's a reason why real mills have a fixed table and move the head down to reach the work, instead of moving the table up to reach the head. That's because these things will bend and flex by several thousandths just by applying a little pressure from one finger. Pile up a X-Y table and a vise and some other crap, and the table is no longer where you thought it was.

More leftover junk, yay! 5/16"-18 threaded rod, a nut, a washer, and some kind of brass compression fitting. Unscrewing the nut makes it longer, and raises the outside edge of the table. No more flex - well, not from the table, anyway. The thing the table is mounted to (the main column), still pretty flexible...

...so that's the next problem to be solved, it needs a stiffer column. If I push up/down on the head, the chuck moves at least .005" in relation to the table. All that flex is in the column. The stock part is much thinner wall than you would expect. If I remember right from when I last had it apart wall thickness is only around .080", which is just ridiculous. Outside diameter is 2.35", height is 21". I'm considering replacing it with a 24" long piece of solid 6061 barstock (http://www.ebay.com/itm/350866407440). Would be about a billion times stiffer, and also raise the head by 3" which would not be a bad thing, now that the pile of stuff on the table seems to get bigger every few hours.

I have heard of people filling the hollow columns with cement to add stiffness, but how much does that help? Any other solutions that are known to work? I'd rather use thick wall tubing (1/4" or more) instead of a 12 pound piece of solid barstock, but I can't find tube/pipe close enough to the right OD, in either aluminum or steel.

(and it's at this point in the story where you add up what you've spent, and realize you could have just bought a damn mini-mill and not only spent less money but also ended up with something that works better - xD)

2

Thank you for posting your experiment and lessons learned. A lot of food for thought.

3

Nice and yes it is no different to modding a light for more than something better would cost. You have a better set up than I have. Be around soon with a barrow fool of parts to machine.

4

I have a grizzly drill press. I will send it to you for modifications.Wink

I really just want this.

5

Whoah daggum

Question, the bushing screws, could you just use brass screws instead of soldering a blob of aluminum bronze on the end like the ends of a steady rest (that use bronze inserts I believe), or are the screws metal for strenth and the brass for soft metal on hard metal bushing effect?

(P.S. any/all machining knowledge I have is from watching Abom79 and tubalcain · mrpete222 on youtube)

6

Yeah I looked for and found some brass bolts on ebay, but they're damn expensive for what they are and I already had the brazing rod and plain bolts here, so it was free to do it this way.

7

Nice to see someone else build a mini-mill from a Drill press!
I did a similar modification and build roughly 8 years ago before i managed to invest in a full size mill. Below i used a 12” Delta and did some major modifications to it, including adding digital scales made from a couple $ 20 Digital Verniers on the cross-slide table.

8

Be aware that drill presses have bearings prepared to handle vertical forces but not prepared for lateral forces (hope english terms are correct).

9

I remember some of the smaller drills had only single-race ball bearings, the Delta i had above had double taper bearings, (similar to a wheel bearing on a car) which could handle the X, Y and Z axis forces much better.

10

I have been (mis)using it like this for nearly a year now, bearings still tight. I can't measure any play in them at all. The only issue left to address now is the column flex.

11

nice cutting. :slight_smile: its likely the bearing would last years as long as they are well oiled.

12

that Harbor Freight mill looks very nice

But you would not have had the knowledge and skills you have gained with rebuilding the drill press :-)

Thanks for sharing this!

13

Oh don't be fooled, the import lathes & mills can benefit from a lot of the same tweaks too. Stuff flexes that shouldn't, parts aren't aligned like they should be, cheap plastic parts can be upgraded with metal, etc.

14

I did similar thing a few months back. My brother bought a drill press that he kept at work. It’s been there a year or two. I bought the table for it a few months back. I used it to do a few tritium slots in titanium. Shortly after that my brother finished building his house and took the drill press to his shed :_(

15

I’ve just got a drill press and I’m finding this thread most interesting.
I’m intending to use it for G10, Kirinite, and wood knife scales and I’m thinking that the forces involved in milling and sanding these materials would be within the limits for a cheapie drill press, I’m still buying the safety stuff like a vice and bolts, dust masks, safety glasses etc. so the milling vice is a bit in the future.
I’ve been looking at this one though, any good for light-weight work?
3 inch vice

16

Those all-in-1 cross slide vises are, frankly, crap. Too much backlash, too bulky except for very large machines, and the biggest drawback is that the vise jaws are fixed and sometimes you need the jaws turned 90* one way or the other to do certain jobs. I know a real X-Y table is more money, but it's worth it. Is it really saving money if you buy something that doesn't work? (trust me on this, I wasted $50 on one so you wouldn't have to)

17

Thank you, noted, and saved me money. :slight_smile:

18

Hi Confy. Great documentation/tutorial :-)

Before you buy some solid bar you should try the concrete pour into the tube. But before you do that you should fit some reinfocement steel in there. Makes a world of difference on the finished product. You can use almost anything. I've used olde water pipes and chichen wire/fence to reinforce small pours and steps and it does make it a LOT more stiff and less prone to cracking.

It wont cost you much and it is fast work so I thought you might try it before buying that big old expensive piece of bar stock :-)

19

Two years ago this thread below was the beginning of another addiction that replaced my flashlight obsession. Although BLF was not totally abandoned all extra time when into these projects.

Took me about 9 months but a total rebuild was done on this mill. Then a lathe found me. Trust me it is NEVER possible to have enough tooling for these machines. Being a “Flashoholic” was just a gateway drug to the hard stuff. You have been warned. >)

20

I know a bit about the heavy stuff, I used to build race engines for a living (not my own shop though, working for someone else). Just like then, it seems I spend as much time making fixtures and tooling as I do working on the actual object.

The reason I'm leaning towards replacing the column instead of concrete, well, wouldn't you pay $50 for another 3 inches? (you there, in the back, stop that snickering right now! last warning)