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Not your average ovalized headtube

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Not your average ovalized headtube

Old 05-02-13, 08:52 PM
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seanile
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Not your average ovalized headtube

bad luck and carelessness right here...

took a frame to get repainted today, and I was carrying it in my bag as just a bare frame (no headset, nothing) and I must've laid my bag down too hard because now the bottom of the head tube is slightly ovalized and I can't get the cup back in.

suggestions on how to straighten it out?

i feel like i can approach this as if i'm making an ovalized ring circular again, like by maybe finding a steel pipe that fits snuggly through the headtube and hammering it through to reshape it.
but i don't know the internal diameter of the head tube, it's a basic 1 1/8, so if you might know a dimension that'd be great.
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Old 05-02-13, 10:04 PM
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Basic blacksmithy. First is how the HT is ovalized. front to back, side to side, a flat spot? Upper or lower, OR along a length of the HT? Is the frame repainted yet? Can one cup be pressed in?

Any prodding back into shape needs to be done with a few concerns. A shaft as close to the minor axis ID is the start. Placing the end against a portion of the HT that won't show outdenting. Holding the frame so no further damage happens. Prying the shaft to bend back out the flat/minor axis. Adding a shim to maintain the roundness as the shaft's fit gets looser. Trying to have the outward force as parallel to the HT ID as possible so to reduce the flaring out of it's end.

It's hard to be more precise without being there. It's a lot of common sense and thinking of all the forces involved. Andy.
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Old 05-02-13, 10:12 PM
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it seems as if the front of the bottom hole of the headtube (opposite side from the dt weld) was pressed inward slightly, just off center from the frame's back-to-front axis. the gap on the sides when the headset is placed against it is about .5mm.
it's painted.
top cup can be pressed in fine.

i've tried prying with a copper pipe, got a litttttle bit of progress, but not much. i'm just worried that it won't pull evenly as it's just barely off-center..but i guess that's where the shim would come in handy. i think i've got some spare steerer tube lying around..
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Old 05-02-13, 10:36 PM
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hate that. it's amazing how easily they ovalize. Actually only done it once, but it's a horrible feeling
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Old 05-03-13, 10:33 AM
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Wow that sux. I would suggest picking up a cheap steel headset, grease it up. and try to push it in. Might want to take a file to the end of it first to chamfer/coin/angle the edge that is going to meet the inside of the headtube. Then begin to carefully press it in. Half a mil isn't very much so I think the lower cup should be able to press against the metal enough to move it outward and let the cup slide in. If you can get it in, you could then use a block of nylon as a drift to tap the HT on the enlarged sides and then on the reduced sides to encourage the metal to form to the cup insert. After letting it set for a weekend, remove the cup with the proper tool and see if the HT has reformed itself a bit. Either way, then go ahead and press in your real headset lower cup in the same way and ride it. With a bit of luck you can get 10 years or more out of it.

On the lessons learned side; Also always put a seat post or something like a seat post in a frame and lightly tighten the clamp or bolt before transporting or shipping a frame as the same thing you experienced with the HT happens to the seat post clamp area and is harder to fix.

/K
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Old 05-03-13, 03:17 PM
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A conical plug, such as the alignment cone on some headset cup presses, can be driven into the head tube to reshape it round.
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Old 05-03-13, 03:56 PM
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Originally Posted by JohnDThompson View Post
A conical plug, such as the alignment cone on some headset cup presses, can be driven into the head tube to reshape it round.
Never done it but unless its a long taper cone seems like the entire ID of the ht might expand before the "ding" is out.
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Old 05-03-13, 04:20 PM
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I used a cone, it didn't get it all the way out, but it was a good start. It's really hard to stretch a tube to a bigger diameter, but turning it from a D shape to round is not so hard
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Old 05-03-13, 08:59 PM
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Being that the shops that i know of only have park tool pressers and they have the stepped plugs and not conical if i recall correctly, i'm thinking ksisler is onto somethin. turning a headset into a conical plug by filing a little bit off a cheap headset so it can settle in seems easy enough.. then hope it goes in straight haha.

great ideas everyone, i'll pick up a headset this weekend and see what happens!

if anyone else has any further suggestions, keep em comin!
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Old 05-03-13, 09:07 PM
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try putting a hose clamp around it ?
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Old 05-03-13, 10:09 PM
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Originally Posted by seanile View Post
Being that the shops that i know of only have park tool pressers and they have the stepped plugs and not conical if i recall correctly, i'm thinking ksisler is onto somethin.
The Campagnolo headset press uses a conical plug.
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Old 05-04-13, 02:43 PM
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Here's a link to a motorcycle forum where the poster made a tool to reshape a round suspension tube. http://45537.activeboard.com/t525002...k-tube-repair/ A brilliant idea IMO.
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Old 05-04-13, 06:11 PM
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Originally Posted by Crankycrank View Post
Here's a link to a motorcycle forum where the poster made a tool to reshape a round suspension tube. http://45537.activeboard.com/t525002...k-tube-repair/ A brilliant idea IMO.
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Old 05-04-13, 06:32 PM
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Originally Posted by Homebrew01 View Post
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Oh hell. Well, this shows a fork tube with the opening slightly flattened. The poster made a round slug with the same diameter as the I.D. of the tube but ground off a flat notch on the slug which allows you to insert it into the tube and able to clear the flattened area. After it's inserted just rotate the slug slowly back and forth which eventually returns the tube to a perfectly round shape without any galling or distortion to the metal. Should work for your situation and having a metal lathe would sure make it easier to make the tool. The thread that this came from had photos with it if you don't mind joining the forum.
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Old 05-04-13, 07:28 PM
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that's awesome, i'll definitely look into that!
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Old 05-08-13, 04:04 PM
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got it fixed.
it seems chris king headsets are ever so slightly wider than some other janky, no-name headset cups.
i was able to press/remove/repress a beat up cup a few times without filing it down at all, and then the ck hs went in with a bit of careful alignment and attention.

thanks for the help!
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Old 05-09-13, 09:12 AM
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OP: Be sure to very closely inspect the entire joint area with a strong light to ensure that no cracks have developed.

A few years back I was asked to repair a frame that had cracked due to a DIY install of a apparently oversized headset--I don't remember if was a C-K also. Anyway the lower band on the HT/DT lug showed a small crack right at the front. I pushed the lower cup half way out to get a look at the bottom edge of the HT while it was under stress. Found that the crack did continue all the way through the HT itself and ran up a total of about a 1/2". After fully removing the cup, the crack was almost impossible to see. There is a lesson there!

I recommended fully replacing the HT, but customer wanted a less invasive repair due to the customized lugs and branded paint scheme on the top tube. He eventually agreed with my fallback approach of removing the bottom third of the HT. I added a 2 inch internal sleeve of 1mm wall chromo to support the join of a replacement bit of HT and then redid the lower lug with the best silver braze followed by reaming the HT properly to fit the headset. Left it to him to takes the repaired frame in for a touch up by his original painter.

Never figured out what tool the original builder had used to reem the lower end of the HT but it and the headset diameter were both wrong. Maybe he used some ST tool or something generic. Who knows.

I left the frame owner with a lesson about not DIY'ing things if he isn't going to measure first and doesn't have the correct tools and skills to pull off the job. Wouldn't bet much on him following the advice though...its really not his way. Geez, hisses the exasperated teacher!

/K

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Old 05-09-13, 10:25 PM
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aha, great advice. love learning about things like that. as far as i could tell, no cracks.
if it helps, i've been a mechanic in my past time and hang around with some builders in boston, so i like to think of myself as an informed/half-assedly skilled amateur hahah.
but either way, thank you, warnings heeded, and i'll be sure to do close inspections over time!
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