BACKGROUND: I recently needed to replace the fork on my bicycle. I could have taken it to a bicycle shop, but wanted to take this one on for myself as a skill-builder. In the process of replacing the fork, it turned out that I also needed to replace the headset cups, which are two pieces that hold the bearings for the fork's teering tube. The cups are press-fitted into the frame, and typically require a special tool to hammer them out. I didn't want to wait to shop for a new tool, or to pay for one. So, I made one out of a piece of 3/4" rigid electrical conduit that I had around my workshop.
OBJECTIVE: This Instructable shows how to make and use a simple tool to remove the headset cups from a bicycle frame.
Step 1: Measure the Steering Tube
First, get a rough idea of how long the steering tube is on the frame. The removal tool will be several inches longer. So, an exact measurement is not necessary. The steering tube on my bike is about 5 inches long.
Step 2: Pick the Material and Mark Where to Cut.
I used a piece of rigid electrical conduit, but any sort of metal pipe with a relatively thin wall will do. For example, after finishing this project I found a broom which has a handle made of a metal tube that would probably have worked just as well. Look for the biggest pipe you can that easily fits through the headset cups. If you can't find anything, rigid electrical conduit is readily available at home improvement stores, and is relatively cheap.
I decided to cut at a length of 9 inches, which is about 4 inches longer than my bicycle's steering tube. The extra length is long enough for me to hold onto when using the tool. Pick a length that works best for you.
Step 3: Cut the Tube
I have a pipe cutter (shown) which does a great job of cutting the conduit. If you don't have a pipe cutter, use any other metal cutting method you can like a hacksaw, band-saw or cutting wheel. If you're not used to cutting metal like this, remember to use a file or sandpaper to remove sharp edges or burrs left after cutting.
Step 4: Mark-off Thirds Around the Diameter.
This tool has three cuts along the length of the tube which are evenly spaced around the tube's circumference. I used a hex nut as a reference to mark-off where to make those cuts. just make a mark on every other corner of the nut.
Then, I used a straight edge to draw a line along the length at each mark.
You can also mark off how long to make each cut. I made 2-inch long cuts, which made it easy enough to flare the ends of the tool.
Step 5: Cut the Tube
I used the cutting wheel on my Dremmel tool to cut the tube.
If you're not familiar with that kind of cutting, here are some tips: Remember to clamp the tube down and use safety goggles for safety. Also, I recommend starting the cut at the open end of the tube by gently tracing along the line you marked with the cutting wheel. Gradually, make the cut deeper until you cut all the way through the wall of the tube. Continue the same method as you move along the line you made. Don't use too much force or place the wheel too deeply in the cut. That will increase the chances of breaking off the wheel or causing the Dremmel to slip.
When you're done cutting, it's important to use a file or sandpaper to remove sharp edges or burrs. Not only does this go easier on your hands when using the tool, it helps avoid scratching the paint on your bicycle's components during use.
Step 6: Flare the End of the Tool.
Bend each of the three pieces of the tube to flare them out. Do what you can to grab the full length of each piece to keep it mostly straight during bending. In my case, I used a needle-nose style, vice-grip pliers (as shown). Also, bend each piece an equal amount. The flared end should be just a little bit bigger than the inside diameter of the head set cups.
Step 7: Insert the Tool Into the Steering Tube.
To remove the headset cups, insert the tool into the steering tube small end first. Pull the flared end of the tool through the headset cup until it snaps open inside. Check inside the tube to see that the flared end catches the end of the head set cup.
Step 8: Remove the Headset Cups
Use a mallet or hammer to tap on the end of the tool to knock out the head set cup. Be patient as the cup loosens gradually. If the flared end is a little loose inside the tube, you might end up knocking it out crooked. It will help to move the tool around the circumference of the cup evenly while knocking out the cup.
When the first cup is removed, use the tool to knock out the other cup from the other direction.