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Amateur replacing a lugged headtube?

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Amateur replacing a lugged headtube?

Old 05-29-20, 04:43 AM
  #26  
bark_eater 
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I was wondering a bout the what ID the cutters should create, but figured if they had been sharpened to many times they would be making the fit tighter so carried on. I was running on sleep deprivation yesterday and ended up using motor oil as a cutting fluid, and it felt like only one tooth on the face-er was cutting so I only went as far as faceing both ends of the head tube. I don't have the new headset in hand yet, but if its skirts are 9mm I will need to take another 3mm off the top and bottom to get any kind of referencing. Further inspection and cleanup indicates that both top and bottom cups are loose and where previously glued in with something. It could be JB Weld from the color, but its coming off with a brass brush. Now I'm thinking some one stuck a flex hone or some sort of rotating abrasive in there and had at it. Hopefully this will end with up with me "leaving it better than I found it"...

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Old 05-29-20, 06:21 AM
  #27  
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You'll still need to clean the area very well to get the epoxy to stick to bare metal.. That will also require scoring the surface somewhat. I'll repeat what I said about waxing the headset cup before you press it in.. There is no need to bond it in place permanently..
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Old 05-29-20, 07:11 AM
  #28  
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Well, the surface certainly is scored. I figured I'd use carefully use brake cleaner to degrease. The gaps I have seem to be with in the specs of Loc-tite 609, so I thinking I would use that. the problem I see with useing epoxy and a release agent, is that when inserting the cup the release agent will contaminate the epoxy and head tube surfaces.
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Old 05-29-20, 07:27 AM
  #29  
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Originally Posted by bark_eater View Post
Well, the surface certainly is scored. I figured I'd use carefully use brake cleaner to degrease. The gaps I have seem to be with in the specs of Loc-tite 609, so I thinking I would use that. the problem I see with useing epoxy and a release agent, is that when inserting the cup the release agent will contaminate the epoxy and head tube surfaces.
It won't if the tolerance is as sloppy as you say and you use a harder wax as a release agent. Remember molds are coated with wax before composites are laid in them and the epoxy does not get contaminated. You're not mixing it in.

Pressing the cup in will force the epoxy to go exactly where it is needed. If it all gets forced out in spots that is fine. I have done this several times and removed the cup after curing and you can see how it works.
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Old 05-29-20, 08:26 AM
  #30  
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Though my universe may well be different than your universe, I'll consider the possibility that the contamination would be insignificant. Which Epoxy are you using?
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Old 05-29-20, 02:56 PM
  #31  
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Facing the shell won't make a significant difference to the head angle. Headsets often differ in their lower stack height by quite a bit anyway. A 10mm difference (which is a lot) might be half a degree or so, which I know I wouldn't notice in the handling although some people might be better at detecting that kind of thing.

I always use transmission fluid as cutting oil as I happen to have a bottle of it from when I thought I had a power steering fluid leak one time which it turned out I didn't. I think anything oily is fine.
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Old 05-29-20, 03:52 PM
  #32  
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I have some real cutting fluid comeing, sf o i'll have another pass at it. From what I gather and half remember, useing a thick oil prevents the cutters from digging in. I may have not put enough pressure on the spring and just been burnishing the surface. I found a shop on line that will sharpen a cutter for $30 so if did mess things up its not too expensive of a lesson.
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