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-   -   Mouting bearing cup on a newly painted steel fork (https://www.bikeforums.net/framebuilders/886784-mouting-bearing-cup-newly-painted-steel-fork.html)

Meper 04-29-13 11:36 AM

Mouting bearing cup on a newly painted steel fork
 
I have just got a 1" steel fork back from painting and I am going to mount the bearing cup for the head set on the fork (Stronglight A9). I have the tool to do it but no tools (jaws) to hold the fork. So I must hold the fork in my hands and use the carpet to place the drop outs on. I did not succeed on hammer down the bearing cup. There is a layer of paint on the fork where the cup goes. Do you normally remove the paint from this area so it is metal against metal? ...if I remove the paint it may be a bit easier to hammer down the cup without being able to fix the fork in some jaws. I use grease on the cup.

To press the cups in the frame with a press tool was very easy.......

JohnDThompson 04-29-13 03:27 PM

Has the race seat on the fork been milled to the proper diameter? If you're perhaps trying to install an ISO diameter (26.4mm) race onto a JIS (27.0mm) race seat, it ain't gonna work until you mill it down to the proper size.

busdriver1959 04-29-13 03:35 PM

The cutters for 1 inch forks come in two different diameters, 26.4 and 27.0 mm. First determine which diameter your bearing race is. The letters JIS would indicate a diameter but I can't remember which one. Somebody will have to chime in here. The paint should be removed first in either case but if the fork is 27.0 and the bearing race is 26.4, all the pounding in the world won't help. Ask me how I know. I think you are dealing with two different sizes too. A halfway decent bike shop should be able to help, just make sure they are measuring or finding markings that say for sure which size your bearing race is. Edit: looks like John D Thompson beat me to it.

Meper 04-29-13 04:27 PM

It is a 26.4 diameter and a "similar" steel head set was mounted before the painting (the new one is alu). It may be the first layer paint that causes the troubles so it is difficult to mount the cup especially if I am not able to fix the fork. when I now use a hammer on the "crown race fitting tool" much of the energy is absorbed by the carpet I use to protect the drop outs. It may be a good idea to go to a bike repair shop in any case. I could try to remove the paint using sandpaper and see if this does the trick.

Andrew R Stewart 04-29-13 05:09 PM

Before I do any race seat paint removal of facing, after a paint job, i first cut the edge of the race seat with a needle file. This prevents any paint chipping from "turning the corner" from the race seat and onto the crown. I will lightly file the seat, crown and steerer surfaces, of the color but leave some of the primer to act as a slight and further removable shim. I have had some cutters cut a touch small and having a thin but sacrificial layer for the headset race to press onto has sometimes been needed. Andy.

Andrew R Stewart 04-29-13 05:13 PM


Originally Posted by Meper (Post 15567235)
It is a 26.4 diameter and a "similar" steel head set was mounted before the painting (the new one is alu). It may be the first layer paint that causes the troubles so it is difficult to mount the cup especially if I am not able to fix the fork. when I now use a hammer on the "crown race fitting tool" much of the energy is absorbed by the carpet I use to protect the drop outs. It may be a good idea to go to a bike repair shop in any case. I could try to remove the paint using sandpaper and see if this does the trick.

Never place a fork on the floor or bench top while hammering on the race! If you need more support then your hands can do (and you shouldn't) make sure to support the fork by an axle placed in the drops. I have seen the drops close up from the force of race seating. Andy.

himespau 04-29-13 05:29 PM


Originally Posted by Andrew R Stewart (Post 15567394)
Never place a fork on the floor or bench top while hammering on the race! If you need more support then your hands can do (and you shouldn't) make sure to support the fork by an axle placed in the drops. I have seen the drops close up from the force of race seating. Andy.

Ooh, that's a good tip and one I never thought of. Will have to keep that in mind.

Meper 04-30-13 02:40 AM


Originally Posted by Andrew R Stewart (Post 15567380)
Before I do any race seat paint removal of facing, after a paint job, i first cut the edge of the race seat with a needle file. This prevents any paint chipping from "turning the corner" from the race seat and onto the crown. I will lightly file the seat, crown and steerer surfaces, of the color but leave some of the primer to act as a slight and further removable shim. I have had some cutters cut a touch small and having a thin but sacrificial layer for the headset race to press onto has sometimes been needed. Andy.

Thank you for the advices. I will remove the paint and give it one more try. Then I have to find a support for the drop outs. It would have been good if the "paint shop" as covered the crown before painting. I also had some troubles with the seat post. It was necessary to using sandpaper inside the seat post to be able to insert the post. It seems always a very tight fit on steel frames.

Meper 04-30-13 05:38 AM

It made a big difference to remove the paint from the crown. The cup went relative easy no. Compared to the old head set of steel the A9 is just a bit "longer" so I have just enough "space" on the top to get the locking nut on. For a first time bike building there are a lot of small surprises :-)


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