This next step is a very scary one, one that has the potential to wreck the frame before I have even started the build proper - I need to press fit the headset bearing cups into the carbon headtube...
This is what the headtube looks like, I was hoping for a metal sleeve but no, nothing, no sleeve - just carbon. Placing the cups in position before the pressing, the cups rocked slightly indicating that the carbon aperture wasn't quite round....
Using this special tool you can see how it's all going to work. The tool is a simple device comprising of a length of 10mm stud iron, 2 mild steel bearing presses, a couple of washers and 3 nuts. Unfortunately I didn't take any photo's during the pressing for you to see it in action as I was much more worried about getting this right than generating material for this blog!!!
With the headtube not being perfectly round it didn't go as straight forward as it could have been so with my heart in my mouth waiting for a terminally sounding cracking noise I now start turning the nut a quarter turn at a time only to see the cups tilt slightly so a quick readjustment of the press brought the cups back in line and this was the story for the rest of the pressing - a slight tilt, reposition the press, tilts a different way, reposition the press. The whole process took around 20 minutes to press the cups in all of the required 10mm...
The above shot shows the end result, you can just see the lip of the cups at the top and bottom of the head tube in black, no 'crack' and the headtube is now perfectly round (at least at the ends)...
So with a big sigh of relief I move on to the next job of knocking the fork crown race into position on the steerer tube. Again the steerer tube is all carbon and tapers slightly to a slightly larger diameter near the fork crown. The crown race slides down easily enough until it comes to a stop against the widening taper approx 30mm from the crown - time for a bit of force...
A piece of shaped hardwood to protect the race and a lump of steel acts as a slide hammer to knock the race down onto the fork crown - simple tools but they do the job. I was thinking that it would be fairly easy to knock the race into position, that it would shave itself in as if the carbon was like hardwood but no, not that easy, it took me ages to knock it into place at least 15 minutes of hammering and no shavings either, just a few specks of carbon on the carpet. This carbon is really tough stuff and I've got the blisters to prove it...
The next picture shows the race knocked down into position flush with the crown, I wouldn't like to get that off now it's on, probably the only way that's coming off is to grind it off...
The last picture shows the assembled forks, bearings and spacers... The final job that needs doing once I'm happy with the height of the stem is to cut the fork tube to the right length. After this picture was taken I measured how much needed to come off, measured again and then again just to make sure and cut 70mm off with a mitre block and a hacksaw just letting the hacksaw cut it's way through under it's own weight and being careful not to rip through the inner wall delaminating as it does. At the moment I have left all the spacers in on top of the stem so once I've been on a few rides and I'm definitely happy with the height of the stem the remaining 30mm will be cut off...
This is what the headtube looks like, I was hoping for a metal sleeve but no, nothing, no sleeve - just carbon. Placing the cups in position before the pressing, the cups rocked slightly indicating that the carbon aperture wasn't quite round....
Using this special tool you can see how it's all going to work. The tool is a simple device comprising of a length of 10mm stud iron, 2 mild steel bearing presses, a couple of washers and 3 nuts. Unfortunately I didn't take any photo's during the pressing for you to see it in action as I was much more worried about getting this right than generating material for this blog!!!
With the headtube not being perfectly round it didn't go as straight forward as it could have been so with my heart in my mouth waiting for a terminally sounding cracking noise I now start turning the nut a quarter turn at a time only to see the cups tilt slightly so a quick readjustment of the press brought the cups back in line and this was the story for the rest of the pressing - a slight tilt, reposition the press, tilts a different way, reposition the press. The whole process took around 20 minutes to press the cups in all of the required 10mm...
The above shot shows the end result, you can just see the lip of the cups at the top and bottom of the head tube in black, no 'crack' and the headtube is now perfectly round (at least at the ends)...
So with a big sigh of relief I move on to the next job of knocking the fork crown race into position on the steerer tube. Again the steerer tube is all carbon and tapers slightly to a slightly larger diameter near the fork crown. The crown race slides down easily enough until it comes to a stop against the widening taper approx 30mm from the crown - time for a bit of force...
A piece of shaped hardwood to protect the race and a lump of steel acts as a slide hammer to knock the race down onto the fork crown - simple tools but they do the job. I was thinking that it would be fairly easy to knock the race into position, that it would shave itself in as if the carbon was like hardwood but no, not that easy, it took me ages to knock it into place at least 15 minutes of hammering and no shavings either, just a few specks of carbon on the carpet. This carbon is really tough stuff and I've got the blisters to prove it...
The next picture shows the race knocked down into position flush with the crown, I wouldn't like to get that off now it's on, probably the only way that's coming off is to grind it off...
The last picture shows the assembled forks, bearings and spacers... The final job that needs doing once I'm happy with the height of the stem is to cut the fork tube to the right length. After this picture was taken I measured how much needed to come off, measured again and then again just to make sure and cut 70mm off with a mitre block and a hacksaw just letting the hacksaw cut it's way through under it's own weight and being careful not to rip through the inner wall delaminating as it does. At the moment I have left all the spacers in on top of the stem so once I've been on a few rides and I'm definitely happy with the height of the stem the remaining 30mm will be cut off...
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