This instructable will teach you the process of restoring machinery, and how to disassemble and assemble a drill press.
I had been looking for a drill press in about a month before I found the Knuth KB-16 (1984). Knuth a good industrial quality brand, and their cheapest belt driven drill press goes for 1200$ today, so this project was well worth the time and effort. The seller wanted 200$ for the drill press, which is a fair price, when it usually goes for 350$, in worse condition! So I told him I was 17 years old and I needed it to make some prototypes for a very unique 3D-printer I was designing and offered 100 bucks ;-) He said we had a deal, and my dad, brother and I picked it up the next day.
This was great since I have used all my money on the 3D-printer, now the only problem was its condition. Which was terrible by the way (as can be seen in the pictures). I don't have a workshop and not even something you can call a worktable, which basically meant the drill press had to be in my room. Therefore it would need to look like new of course.
Step 1: Preparation and Tools
In order to restore a drill press, you will need the tools listed below;
- A wrench (not too small)
- Socket wrench set
- Standard types of pliers
- Rubber mallet
- Allen key set
You will also need some machines if you would like to be done within the next year.
- Bench grinder (This is a must)
- Angle grinder
- A drill might also come in handy
- Assortment of bolts and nuts (not mandatory)
- Wire wheels for the bench grinder and the angle grinder (you will probably need at least two wire wheels)
- Primer (Motip have good reputation)
- Paint (I used Motip)
- Clear coat (mine is UV something something protecting)
- Softsoap and ammonia (whatever else you have for cleaning oil and grease, will probably do just fine, or perhaps better)
- Power cord (harvest one at the scrapyard)
- Safety glasses
Now that our tools are gathered, we can begin the teardown of the drill press.
Step 2: The Tear Down
Since a machine obviously consists of many parts, we will have to disassemble the whole machine, before we can begin restoring each part. Above I have included a picture that describes what comes afterward, just to give an overview ;-)
Remember to take a lot of pictures! I worked on this drill press every day all day, six days in a row and I never thought I would be needing the pictures. Next day I broke my collarbone in half and was out for two weeks. Now the pictures came in pretty handy.
Disassembly of a drill press
Disassembling a drill press is pretty straight forward. You start from the top, and then basically just screw your way down until every part is detached. You will end up having lots of different pieces everywhere, so it will be a good idea to have many different containers to contain small bits and what not. I, for example, had a bowl to contain all the screws from the head, and another one for the electronics (I ended up having 6 small bowls, and it came in very handy when it was time to assemble the drill press again).
Detaching the pulleys
A pulley is usually mounted in three ways and I was lucky enough to encounter all of them. (damn press fit!)
- Press fit
- Set screw
A press fit is when two parts is held together by friction. In order to remove a press fitted pulley, you will likely need a gear puller. You can use different methods of pulley removal, depending on how good it's stuck on there.
A gear puller is the best option out there, but not all of us have one laying around (it's kinda expensive), so you better pray that it's not stuck on as good as mine ;-) The first thing you can try, is to lift it off with two screwdrivers, if this doesn't work, try heating the pulley up. When you heat it up, the metal will expand, you should therefore only target the pulley. If you heat up the shaft, it will expand, which as a result makes the pulley harder to get off. So only target the pulley, if you decide to heat it up. If you still can't get the thing off (like me), then it's time to get creative. So I did, but it didn't work out so well, therefore I visited the local car workshop and borrowed a gear puller (should have done this after giving it a shot with the screwdrivers, instead of being "creative" for the next three hours).
A pulley mounted with a set screw will have the thread located on the side of the pulley (where the belt goes). Some pulleys have two set screws, so be on the lookout for that, if you can't get the thing off.
Some pulleys are mounted with a nut on the top so that it's pressed down. Be aware the nut mounted pulleys, have counter-clockwise threads! Since you will have to hold on to the quill's (the part that moves up and down while drilling) inner shaft, you can align the inner shaft with the outside, if you pull the quill down. Now you can use a wrench to loosen the nut.
Motor and electronics tear down
When taking out the on/off switch and detaching the wires to the motor, it is important to make a drawing of the wiring, to ensure the right connections when assembling. Pictures will also do just fine of course.
My drill press had a 1/2 hp induction motor installed, so this is the motor I will write about. An induction motor consists of a motor frame, two end bells (the "caps"), a fan blade and a fan cover (take a look at my drawing above).
It's pretty straight forward to detach the fan cover and fan blade, but you have to be very careful when taking the end bells off, let me explain why. Inside the motor, you will find a stator with insulated wires wrapped around. The wires are insulated for a reason, and if you make a single scratch in the wrong place, on one of the wires, then you could potentially kill the entire motor! So watch out when you take off the end bells and make sure the motor shaft doesn't scratch the stator windings.
After I had my motor disassembled I immediately covered that stator with a plastic bag, sealed with some painters tape (use duct tape).
*Warning* danger of getting cut
When taking the spring and spring cover off, it is important to remember it's under tension!
Step 3: Repairing and Replacing
On the drill press, all the spring washers had basically just become normal washers over the years, wich is to be expected when you restore a 33-year-old machine. Since the motor vibrates a bit when running, it will be a good idea to make the old washers springy again. Just simply fasten them one at a time in a vice, and hammer it, until it looks like a normal spring washer. This will ensure your bolt and nuts doesn't loosen as much over time. They will eventually loosen at some point, but it will take more time since the bolts now will be under constant tension.
Some of the bolts were either missing broken or too dirty to reuse. This is where it becomes really helpful to own an assortment of bolts, nuts, and washers. Above you can see two pictures of the drill press head, before and after. Since the screws and washers were filled with oil and dirt, I decided to replace them, because the old ones would look too bad on the newly painted drill press head.
Step 4: Paint Removal
This step covers all the parts that need to be painted.
You can remove paint in many ways I'm sure. In this instructable however, I will introduce you to the two ways I am familiar with. (If you have a sandblaster available you know what to do!)
- Using a wire wheel
- Using a chemical paint dissolver
Using a chemical paint dissolver work really great, but unfortunately, my dad recently moved and we couldn't find it, so I decided to use wire wheels instead.
Wire wheels are a great and fast way to remove paint. They come in many different shapes, both for angle grinders and machines with a chuck (my bench grinder has a chuck installed, it's very handy). When using a wire wheel it is important that you don't feed it with thick layers of oil and grease, otherwise, you will do more harm than good, if you intend to paint the surface afterward. This is because the wires will get smushed up with dirt and what not, and then drag it down into any unevenness in the surface you are preparing to paint. Therefore you must clean the surface from any dirt, oil, and grease before using the angle grinder and or bench grinder. You don't have to be too thorough though.
*Warning* getting wires from wire wheel in the eye
When using a wire wheel it is important to remember that rotating shafts easily spins 2500 rpm's, and wires therefor fly off the wire wheel with high speeds. In regards to safety, you should therefore wear safety glasses as long as the wire wheel is spinning.
Notice the toad on the first picture, it was about to attack me while I was sitting down removing the paint with the angle grinder. Holy shit it scared me when it passed by within 30 centimeters of my hand! It came out of nowhere.
Step 5: Polishing and Rust Removal
The parts metal parts that are not painted, probably need some rust removal.
There are many ways to remove rust, after surfing the internet to find the best way for rust removal, I found that electrolysis and wire wheels were commonly mentioned. Since I don't have a workshop or any space for that matter, I am only going to use wire wheels. But after removing all the rust I felt stupid for not giving electrolysis a try, even though it meant finding an old car battery or something. Look into it, it will probably save you a lot of time.
Since non-painted metal parts generally are small, it becomes really handy to own a bench grinder, because it allows you to hold the workpiece with both hands. In order to remove the rust, you simply remove the rust with a wire wheel, and then finish it up with some kind of semi polish wheel, since the wire wheel probably is dirty.
Notice the spring cover and the drill chuck on the pictures (the rust on the chuck is from inserting it in the quill, and the scratches on the spring cover are from a wrench), they have both been polished on the bench grinder using wire wheels and a semi-polish wheel.
After polishing I apply a layer of clearcoat, to protect the part from the water, aka not rusting.
*Warning* getting wires from wire wheel in the eye
When using a wire wheel it is important to remember that rotating machine easily spins 2500 rpm's, and wire therefor flies off wire wheel with high speeds. In regards to safety, you should therefore wear safety glasses as long as the wire wheel is spinning.
Step 6: Color Design
I couldn't decide which color I should paint the drill press, so I fired up Photoshop and had some fun. I thought you guys might like to see them ;-)
I ended up painting the machine the way Knuth paints their drill presses today (which was the plan from the start). I like tech, and no color scheme comes closer to that than painting a machine blue and white. I couldn't decide whether or not I should make it look like today's machines from Knuth (tech like), or just make it look like the original. But I'm hopefully going to keep this drill press for the rest of my life, so I might as well make it 100% my own ;-)
In case you would like to see Knuth's color scheme: http://www.knuth-machinetools.com/
Step 7: Painting
When painting it is important to make sure the surface is as clean as possible. Depending on the way the old paint was removed, you might have small amounts of oil and grease on the surface. You will not be able to see this with the eye, just make sure every part is wiped clean before you begin painting. This also removes dust particles.
For those of you who don't know, a primer is a layer that makes the paint stick better, you can think of it as glue. I use a spray can primer made for metal only. Spray cans and paint guns will give a better finish than using a brush. I think using a brush, gives access to choose some heavy duty metal paint, but I'm not sure. However, I'm just gonna use spray cans for this project.
I painted most of the parts on a piece of cardboard, but this meant I had to turn the parts around, in order to paint the other side. Instead, I finally began hanging the parts up. I just used some steel wire to hang the parts. On the blue part of the pulley housing, I didn't have a good place to wrap the wire around, so I used a bottle cap bigger than one of the holes in the pulley housing, instead of having a little wire wrapped around half of the part.
When painting, it is important that you don't make a puddle a paint in one spot, since it looks really bad. Increase the painting distance and spray in light layers in order to avoid this. Another thing to remember is light, it's very important to have good lighting when painting, otherwise, you might just end up with some under painted spots (like me). When painting and using a uv something something clearcoat it is very important to wear a proper respirator. I used a dust mask since I didn't have one, but I ended up having a headache afterward, even though I was VERY careful not to breathe any. Not worth it, just get a respirator.
- Spray in smooth motions
- Use correct spray distance (can be found on the spray can)
- Spray in light layers
- Paint in lighted area
- Use a respirator
After painting, it is a good idea to apply a layer of clearcoat to seal the surface 100% and protect the paint.
I ended up using a little under two 500 ml spray cans of primer.
Step 8: Assembly
Assembling the machine should be easy since you took a lot of pictures, right? In this step, I will therefore only cover how not to press fit a pulley, and the wiring of the electronics (and include pictures of the motor assembly, as can be seen above, obviously).
Press fitting a pulley
When you need to press fit a pulley, you cannot use a hammer with a small tip surface on cast aluminum. I have tried, and yes, it will break. I was very careful with not hammering on side of the pulley, and I used four layers of cardboard to hammer on, in order to distribute the load, but it didn't end up so well. Instead, use a rubber mallet and a hard flat piece of material to distribute the load while hammering.
As you can see in the picture above, I have made a little schematic of the wiring. The blue and brown wire is connected to the AC motor. There's a switch on the brown wire to turn the machine on and off. Here in Denmark, we ground everything, and my drill press wasn't an exception, there were two mounting points for ground (green wire). It first connects inside the drill press head with a screw, and then afterward lead down to the motor, where another grounding point is located.
Brown wire --> switch --> motor
Blue wire --> motor
Green wire (ground) --> drill press head --> motor chassis
If you're in doubt about anything electrical It's important to get help from a professional!
Step 9: Conclusion
The drill press works like a charm, and there's no wobble in the quill. Drilling with a 13,1mm drill bit results in a 13,12mm hole, which is why I love this brand (Knuth). I am looking forward to using this machine in the future ;-)
If you decide to restore a machine, you should expect it to take a lot of time. You should also consider getting access to a sandblaster if you would like to speed up the process. If you don't have access to a sandblaster, you better make sure your mom is okay with the fact that wire wheels are spinning with 2500 rpm's inside the house, otherwise, you might get in some trouble when your little brother gets a steel wire up in the foot.
I ended up using 9 days on this project, but don't forget that fact that I do not have a workshop. Also, all the paint removal was done outside, whilst sitting on the ground. A worktable and a workshop would defiantly have decreased the time it took to restore the drill press. Another time I would consider paying better attention to the paint job, since it was only the blue parts that turned out great (probably because I painted them last, and then had a bit more experience than before). All things said it was a really fun project, and also a bit educational if you decide to understand the inner workings of an induction motor ;-)
Be aware, the end result might be extremely satisfying!
P.S tell me if you find a spelling mistake lurking around.
Ohh and feel free to ask questions!
Second Prize in the
Before and After Contest 2017