This is quite a long instructable. It's not really a 'how to' as such because different models, sizes and ages of drill press will require different repairs, adjustments and techniques to renovate.
This is more of a 'how I did this one', and there's no way to cover everything, I can only describe what was needed to get this drill press back up and running.

My reason for doing this project was purely practical. I needed a drill press for my 'micro workshop' and I had no money to buy even a good second hand one. Cost had to be kept to the absolute minimum, whilst giving me a practical, usable tool at the end. It's a bit of a gamble because the drill could have turned out to be beyond repair and therefore a waste money.

I waited and searched for a drill that was ready for the scrap yard. It had to be quoted as 'working' but I knew that this would probably mean that it would turn when the motor was switched on. It took me two months to find one.

Step 1: The Drill on Arrival

Here's the drill as I got it. It cost me £5.00 GBP.(about $8.00)

The first thing to do is to check the drill over and try and figure out exactly what you have bought BEFORE you start working on it.
The second image shows the general arrangement of the standard drill press from 1931. Some have a lot more parts than mine, but the main areas of interest are the condition and accuracy of the base, the main pillar (column), the table, the spindle, the quill and the chuck.
This is the correct drive pulley system for the pattern of drill I purchased. Do a little research before you start work.

Everything was covered in light surface rust and the shite of a hundred years worth of use (the drill was made between 1899 and 1914). The paint work was a multitude of colours with at least three layers of paint, all poorly finished. The motor mount was a homemade item that was badly fitted and totally wrong for the drill, the drive belt pulley was the wrong type and size for the drill, the ancient key-less chuck had a broken jaw and wouldn't tighten, and most seriously, the quill rack and pinion gearing was U/S and kept jamming. The ball bearings were pitted and rusty.
The motor wiring was dubious at best and dangerous at worst, there was no on/off switch, the motor started as soon as it was plugged in.

But the drill DID spin up when the motor was turned on (although the motor stalled at start up). So not a total disaster. there was some slop or 'wobble' at the chuck (about 30 to 40 thou on my dial gauge) but the bearing cup was also a little loose so maybe that could be improved upon.

All these problems needed testing, investigating and correcting.

Step 2: Strip It All Down

Once you have established what you have, and what the problems are, you can begin to strip down the drill press. If there are a lot of small parts, make sure to mark them up and store them carefully so that you know what order, and where, they need to be re-placed when you re-assemble the drill!

The images show the main parts of the drill following the strip down. The base is not shown here, it was already soaking in paint stripper when I took these images.

The original chuck was beyond repair, so I decided to use a Jacobs chuck rescued from an old cordless drill that had died. The motor mount and belt in the top left of the first image will also be discarded since it was wrong, and was putting undue strain on the head.

I have had to do some wiping and basic cleaning just to get the parts to this stage. In the first image and second image, you can just about see a small patch I have cleaned at the base of the main column. Nice and shiny!

The third image shows the handles, bearing cups and gear assemblies for the quill movement, and the pitted quill body. The small pinion gear was a major headache (more of that later).

The fourth image shows the head, pulley and table castings. At least three different layers of paint! The main spindle showing the terrible thread for the old chuck and surface rust.

The final image shows the base of the table, again three colours in evidence, you can also see the ends of the motor wiring which was totally discarded.

Step 3: Cleaning Up

The first job is to clean everything off. It's far easier to work on the machine when it's clean and free from grease and rust. All the cast parts were soaked in Nitromors paint stripper overnight. Then I went to work with a Dremel, wire brushes, wire wool, Scotchbrite and wet and dry paper. All the old scale and rust were taken off the main castings.

When trying to remove rust from the machined and accurate parts is is important that were don't damage the running surfaces or the sizes. Use wire wool soaked in WD-40, then, rubbing alcohol followed by Scotchbrite. This should lift the rust without altering the working surfaces. It takes elbow grease. I spent a week carefully cleaning all the parts back to bare metal.

Step 4: Painting

Once the parts were all cleaned up, I tested the run on the phosphor bronze bushes. These must have been replaced at some point in the drills lifetime (professionally) and were not worn or damaged. There are only two bushes, one in the upper head arm and one in the top of the quill.
Once I was satisfied that the quill movement in the lower head casting was also correct (I used a dial gauge to test this), the castings were re-painted.

I did some research and found that at the turn of the last century (1900) most cast iron machines were painted with a crinkle finish in black. I decided to try and get a similar look using a modern 'wrinkle finish' variant. It was a pain, but after masking and spraying with red oxide primer, on went the black.

The base of the table and the pulley wheel undersides were finished in red since the reference material i had showed the old ones done in this manner.

Step 5: Partial Re-assembly

Once the castings and the main column were finished I partially re-assembled them and tested for squareness using the dial gauge and an engineers square. the small brass actuating lever for the table was polished up as well.

You can clearly see that the bracket at the rear of the head casting was never designed to have the motor attached to it.

Step 6: Mechanical Repairs

Next I worked on the spindle and quill. The spindle was in pretty good shape, but all the ball bearings were pitted and rusty. I measured them with a micrometer and found them to be 1/8" which is a standard size. I got a set of replacement balls and cleaned up both the bearing cups which seemed in good condition.

The spindle nose was turned down to 3/8" on a lathe and then I cut a 24 TPI (teeth per inch) thread to fit the Jacobs chuck which I had polished up a bit.
The original bearing nut was discarded, and a new 1" nut added which fitted the new thread. All the surface rust was cleaned from the quill and the quill re-assembled.

The rack and pinion was next. What a nightmare! The small pinion gear is secured to the operating handles via a small shaft. The pinion is held on this shaft with a standard taper pin, or so it should be. It took me 4 HOURS to extract the lump of old Allen key that had been forced into the tapered hole!
This had subsequently damaged EVERY tooth on the rack gear and was the reason for the quill jamming. Each and every tooth on the rack was cleaned up by hand using needle files and the Dremel.

I reamed out the pinion and the shaft using a 1/8" hand taper reamer and turned a new aluminium taper pin on the Unimat. Once reassembled the taper pin was profiled by hand using needle files. the quill action was now smooth and correct.

I re-assembled the quill into the castings for a test run. the brass depth stop at the top of the spindle was also cleaned and straightened. The new spindle and quill assembly now gave a 'runout' reading of 0.002" compared with the 0.040" when first tested on arrival.

Step 7: The Idler Wheels

Unfortunately I couldn't find a good quality reference drawing for the idler assemblies. I think the wheels should be 1 1/2" in diameter but I only had some 16mm brass bar so they had to be made that size for now.

The clamp and adjuster bracket was made from two pieces of brass earth rod fittings and a bit of aluminium from an antenna mounting bracket in the scrap box. The adjuster arm and the two axles were made from an aluminium bar recovered from an old HP printer and a piece of scrap aluminium from the local tip.

I turn the centre hub, drilled and tapped for the locking nut and the two axles. These were also turned on the Unimat. A few test assembly sessions and the addition of two steel spacers and we were getting somewhere.

I got the drill on the bench and hooked the motor up temporarily using some shock cord as a belt to check for size and operation. Blow me it actually turned the drill!

Step 8: The Motor

Next job was to strip down, clean and test the motor. The bearings were in good condition, but the oiling felts were bone dry.

All the old paint was stripped off, and the body sprayed in red oxide primer then satin black.

The windings were all cleaned, the felts re-oiled and the wiring corrected and replaced. The motor was then re-assembled.
A metal clad switch was added. the motor ran much quieter after this and it starts every time.

Step 9: Completing the Project

The drill and motor were mounted to a stout board and aligned. The switch was screwed down and the basic machine was ready for final testing.

Some new drive belting was ordered and fitted, but I felt that a vintage drill like this deserved some finishing touches. A visit to the tip provided three red snooker balls from a kids set. they are 1 1/8" in diameter. Perfect.

The operating handles were polished, placed in the Unimat and then ends turned down. The ends had a thread cut in them to take the balls

Then the balls were placed in a machine vice. A small flat was filed into one edge and centre punched. The balls were the very first holes that the drill was used for, quite fitting really. It cut square and true, what a joy!

The balls were fitted to the handles and the drill project was compete!