Okay folks, let’s talk about modern products. Unfortunately, nowadays, I feel that both the well branded and low-end products are awful. To avoid frustration with the poorly designed products, I have adopted the mentality that the customer is the final step in the production line. A customer has to find the shortcomings in the “almost-finished products” and fix them. Otherwise, the customer has to struggle with the awful quality, or soon throw the broken product into the garbage bin. With many cases, I feel the products are badly designed in purpose. They last only for so long that the customers are hooked into the features the products offer. But once the products fail, customers are forced to buy new. The money might temporarily go to the competitors, but if the whole industries are flooded with these problematic products, then the markets become more dynamic. Cash is frequently spent for various reasons, and the customers are adapted to accept the hassle. The likelihood increases that a product is being bought and more regularly. Decreasing the production costs is not an explanation in all cases. I have seen extra efforts done with weak designs instead of using rough, but more straightforward and robust parts that would more logically suit for the low-end products. This is unacceptable and unecological.
Today I show you how I enhanced my low-end drill press with a couple of tricks. I simultaneously fixed a problem and added a feature. The problem was the huge play in the wrong-type factory bearings and the play between the quill housing and quill itself. The new feature is the added tolerancy to various load types. More detail below. Taking into account the above reasoning, I don’t want to disclose the brand and model of the drill press specifically. As said, these problems cover whole industries, why I don’t want to point and blame a specific manufacturer. The principles described here are more important, and I believe they can be applied on various brands and models. And once again, if you decide to follow these principles and fix your drill press, I don’t take any responsibility for your acts and the outcome. I cannot guarantee the proper and safe functionality of the drill press after these modifications. That out of the way, let’s start!
THE FIRST SOLUTION! The factory-assembled spindle bearings were standard single-row ball bearings. Everybody familiar with the bearings knows that these standard bearings are not suitable for axial loads, they are designed to tolerate moderate radial loads. No wonder the bearings had a lot of play after a while of usage. I bought two double-row angular-contact bearings to handle all kinds of loads, axial, radial, and momentum load. The increased tolerance against axial loads is crucial for the default usage of the drill press – drilling. But I also tend to use my drill press for other purposes. Sometimes I insert a brush in the chuck and feed the part I want to clean from the side. This causes both radial and momentum loads. Now with the better bearings, I’m also considering to try careful milling. But I don’t have any experience of milling yet, and I don’t even own a proper chuck for the job. So take these milling considerations with caution! The bearings I used were 3201 2RS, NACHI (upper) and 5204 2RS, KOYO (lower). Notice that they are taller than the single-row factory bearings, why I needed to verify they fit into the device without problems! More details below.
THE SECOND SOLUTION! The better bearings do not solve the play between the quill housing and the quill. To fix that issue, I found this handy tutorial on how to tighten the quill housing to get rid of the play. Many thanks for the Steve Vine who invented this clever solution! I will extend the approach a little to cover quill housings through which threaded rods cannot be inserted without collision with the quill. I made external S-pieces that can be used to pull the sides of the quill housing closer together by tightening an external bolt.
In the following series of photos, I show roughly the steps I did. Enjoy!
I first removed the control unit. A screw was hidden behind the ON/OFF switch. Remember to disconnect the power before opening the enclosure; there are a lot of wires in a small space!
With my dial indicator, I measured that the play between the quill housing and quill was about 180um. After the operation, it was absolutely zero.
The play between the chuck and the quill was about 160um, caused by the damaged bearings. After the fix, it was zero.
Then I opened the spring housing. Be very careful, when the tension reliefs, the parts can snap on your fingers badly! And do not remove the nuts before the spring tension is relieved so that the parts do not jump to your face! Wear gloves and protective glasses, and with a screwdriver, carefully wedge the spring housing away from the quill housing. Try to remember how the spring assembly was assembled so that you can later put it back together.
After the spring is relieved, the spring might be stuck into the slot of the bolt. Relieve the gap carefully with a flat screwdriver.
Here is the spring assembly.
I pulled the crank out from the other side. Be careful not to drop the quill.
The above bolt might need to be opened a little. During the assembly, the flat tip of the bolt needs to be properly realigned with the groove on the quill.
Removal of the upper spindle-bearing retaining washer.
With a nylon hammer, I removed the spindle from the quill.
Using the wise as support, I removed the lower bearing.
Here are the spindle next to the new (left) and old (right) bearings. As you can see, the new double-row bearings are taller. It is essential to verify that the new dimensions do not cause problems.
As the old upper bearing was still in its place, using a stack of washers, I simulated the new taller bearing. I installed the quill-spindle assembly into the drill press and didn’t notice any obvious problems or collisions of the parts. I also verified that in the lowest position of the quill with the new taller lower bearing, the upper tooth of the spindle had good contact with the rotation feed. The taller lower bearing pulls the spindle to a lower position.
Nice package design with the hologram.
To install the new bearings without damaging them, I used wood pieces with small holes. When hammering the bearings, the softwood distributes the forces evenly on the inner and outer races of the bearings. Force concentrations could damage the new bearings.
Smashing the new lower bearing to its place.
After the installation, this much the new lower bearing protrudes downwards from the quill, but it doesn’t bother me.
I made a new groove for the retaining washer on the spindle due to the new positioning. And notice that because the taller lower bearing positioned the spindle into a new lower position, the contact area between the upper bearing and the spindle decreased a little. That is why I carefully cleaned the inner race of the upper bearing and the contact surface of the spindle, and applied a little bit of strong thread locker.
So, the bearing change is ready. Next, I took the head of the drill press outside and used an angle grinder to cut it. The cut is not as straight as the one Steve did with his slitting saw, but it will do its job. After cutting, I tried to get rid off the grinding dust as much as possible.
Then I made holes with threads on each side of the quill housing. I verified that the bolts will not collide with the quill and that there was enough supportive material around the bolts. The space was tight!
With my steel bender, I made a couple of S-pieces.
Here is the new tightening assembly.
I cleaned the threaded holes and used normal thread locker with the housing bolts.
Ready to tighten the quill housing.
I pre-tensioned the quill housing with a clamp. I used a caliper to verify that the quill housing indeed became tightened.
Some tacky grease in before the quill.
I tightened the front bolt until the quill didn’t move, then loosened a little. Now the quill moves quite easily but is firmly held in place by the quill housing. The play is zero.
I cut the enclosure of the control unit to fit nicely. The laser toggle protrudes a little, but it doesn’t bother me. I protected some of the wires with heat-shrink tubing and gorilla tape so that the new pieces do not abrade the electrical insulations so easily when the drill press resonates.
Done, looking good! I managed to broke the enclosure of the control unit a little, why I needed to use a new longer lower screw with washer shining in the photo.
The total runout between the table and the drill bit is now about 80um, and the play is 0.
Oh yeah, so smooth drilling! Usually, almost the whole workshop shaked while drilling. Now the drill bit sinks into the metal like a hot knife in butter 🙂 The holes are also smooth looking.
With my FLIR camera, I verified no parts heated up too much. The maximum RPM of the bearings were much higher than the maximum RPM of my drill press.
