Viewing 16 posts - 41 through 56 (of 56 total)
  • Surely there is a cost effective way to fix this lovely frame….
  • theblackmount
    Free Member

    >if they’ve blasted that much material away (or disolved in acid before anodising) would you not ne worried about how tin the tubes have got and how likely it is to snap?<

    This…

    Doubt you could afford to lose a mil around the centre point of any of your tubes. ;-(

    Can’t see how shimming the cups will work – the bores are likely to be eccentric and they wont be concentric with each other. Best solution would be to have the HT machined then oversized cups made up / inserted. Or, bang the loctite in and align everything by nipping it up with the fork / stem.

    As I say the HT might be the least of your worries – I wouldn’t ride it myself if it’s as bad as you say it is.

    billyboulders
    Free Member

    Good points from sssimon and theblackmount – is it just the headtube thats affected or are all the tubes thinner? (From the pic the cable mounts seem to be ok and all the welds look as normal) any excessive material removed should be obvious here I would have thought. Is there any play where the two halves of the frame join? As sssimon suggests have you tried a seat-tube/clamp yet?

    remoterob
    Free Member

    How much does the frame weigh now?!

    Can’t see why anyone would shot blast the unpainted inside of a head tube that much without blowing holes in the thinner painted tubes. Could they have anodised the entire thing and then machined out the head tube?

    How did they protect the threads in the BB – if a 1mm has gone from the headset, I’d expect them to have been destroyed?

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    walleater
    Full Member

    +

    Potentially stupid thought, but was the headset loose before? Did you remove it?

    andyl
    Free Member

    Ignoring all other issues regarding pivot bearing holes, BB thread, potential weakening and just dealing with the headset problem:

    Do not shim it. If you end up slightly too thick/not round and force it you may split the head tube.

    My immediate solution was the proper loctite for setting bearings. You may need it elsewhere anyway. It is designed exactly for taking out slop in bearings. Something like Loctite 660 (high strength repair retainer for up to 0.5mm) or failing that a decent epoxy.

    Blazin-saddles
    Free Member

    I suspect that as mentioned above, if you got accurate measurements and speak nicely to Hope they ‘may’ make you some cups to fit. Their cups have replaceable bearings so in the event of one wearing out then you can leave the new cups in place and just take the bearings out.

    brant
    Free Member

    Ano process eats metal.
    Taiwan have a “frame lightening” process where you just leave a frame in ano bath for a while to lose weight.

    I found out about metal eating when I had some hubs anodised and the bearings could be ” thrown in from Barnsley” rather than being a “big hammer fit”.

    irelanst
    Free Member

    It’s a pretty common repair problem in industrial engineering, and there are a few off the shelf solutions;

    Ready made sleeves;
    http://simplybearings.co.uk/shop/Engineering+Parts-Shaft+Repair+Sleeves-Metric+Shaft+Repair+Sleeves/c4713_4847_4849/index.html

    Tolerance rings;
    http://www.wixroyd.com/en/catalog/standard-parts/transfer-rollers-and-tolerance-rings/tolerance-rings

    Or any of the suggestions above

    JCL
    Free Member

    I’d cut the head tube off and take it to frame builder and get a new one welded on -1 or 2 degrees. Then I’d polish it to few inches down the toptube and downtube. It’d look alright and it’d ride better.

    pictonroad
    Full Member

    As said above (a few times tbh) it’s not the ‘retards’ who blasted it, the person who stripped paint from an the downtube without cutting it in half didn’t then erode the inside of the headset through error or spite.

    I would Epoxy it, it’s a good solution, it’s not like it can go anywhere if it does fail to hold together.

    robinlaidlaw
    Free Member

    Get the headtube reamed to take the whole depth of the deep insert cups, that’ll give you at least some engagement that’s the proper fit to hold it central. Then add plenty of JB weld and press it in and leave it somewhere warm to set for a good long time. It’ll be completely fine, I’ve fixed a badly ovalise headtube by JB welding the bottom cup in before and that was on a bike that used to get a lot of very hard use (big drops and jumps etc), it was fine, didn’t even creak.

    YETIboyJAY
    Free Member

    Fixed it today. Thanks for all the thoughts…it was as a result of sandblasting, the guy who did it said today. Basically they said there was old Powdercoat in the tube so he thought he’d ‘clean it up’ as a result he took quite a bit of material off of it. Not overly helpful but not done on purpose…he knows now.

    My initial thought of 1mm was way to much, just seemed like it when I stuck the headset in. Infact it’s .5 if that. I had the ‘step’ taken out so upper and lower 2″ cups go all the way in and had some shims made to ensure the cups grip for their whole depth on the inside of the tube.. I also used some locktight 660 to hold it all permanently (hopefully!)

    Thanks all, he’s just happy he can ride (albeit a mile behind everyone else)

    matt_outandabout
    Full Member

    I have a brand new WTB headset that rattles in any headtube – bottom worse than top cup.
    Have you double checked the headset?
    (If anyone want’s and undersized headset, yours for a beer voucher and postage…)

    YETIboyJAY
    Free Member

    Yes I did. A used HOPE (that was in it) a new Syncros sealed one and finally the Nuke Proo SS (deep one) that’s been used to fix it.

    midlifecrashes
    Full Member

    Just looking at how much metal you have in the headset, you could probably drill through and get a couple of bolts in there too. 🙂

    chief9000
    Free Member

    Hello,

    I am a little surprised that blasting operation has increased the internal diameter of the head. I am wondering if you can see some uneven abrasion marks on the inside?

    To fix it I certainly would not do any welding to the frame. I also would avoid removing any further material.

    I’m not sure what workshop equipment you have access to but I would do the following. (you need access to a lathe)

    Take the headset cups that you have measure the OD and then the ID of the head tube. Then work out what the difference and what you need extra on the cup.

    Put some bar in the lathe and make a hole in the centre so its a super tight fit on the cup (the part that goes in the head tube). Then part of the right amount. The heat it up and insert the cup into it. Once its cool, put it all in the lathe again this time holding the headset cup and machine down the added sleeve until you have the right OD. Then bingo!

Viewing 16 posts - 41 through 56 (of 56 total)

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