redshift1

I have a nice original chromed fork for a mid-80's Peugeot Aneto frame, perfect except for a loose crown race problem. It is definitely the fork's seat that is undersize i.e. there is no problem with the crown race. The gap involved is no more than one thou.

I have previously used Loctite 648 retaining compound ( that's the grade here in Australia ) to secure the race and upon subsequent race removal a day later ( don't ask, done for an unrelated issue... ), I found the strength of this grade to be way over the top, as judged by the effort it took to remove the race. I actually chose this grade because it had the highest shear strength of all Loctite's retaining products, as I thought that perhaps it was needed in this application.

I would like to try again with a lower strength Loctite. Does anyone have personal experience with doing this and could possibly recommend a suitable Loctite product ?

I am not sure about the forces on the crown race during actual use.

maddog34

i use the green bearing retainer grade, not sure of number... you can also use a center punch to dimple the fork crown mating surface... six to ten evenly spaced dimples, depending on how loose the fit is. there are also these cool cylindrical shims called "Easy Sleeve"... various thicknesses and diameters..... precise micrometer measurements required.

SJX426 

@redshift1 - @maddog34 has it right. you want the crown race concentric to the steerer.

Moe Zhoost

A well-equipped bike shop will have a knurling tool that will make quick work of increasing the diameter of the seat to fit your race.

FBinNY 

The first step is to build up the crown seat to properly locate and support the crown race.

This is an easy DIY job with low cost tools you may already own.

You'll need a hammer, center punch, some kind of anvil, bench vise or other support. Support the fork at the crown race and steerer with the crown and blades overhanging. Use the hammer and punch to raise a series of "volcanoes" at even 5mm or so intervals all the way around. Don't sweat size, but keep them reasonably uniform.

Now you can press the crown race home, and it'll stay tight and centered. If you wish you can apply body filler for added support, then press before it sets which will push out excess, and you're good for the next 100k miles.

redshift1

Three good options. I will investigate further.

I'll check measurements using micrometer, etc. and see if this is going to be an issue but is a good point which I had not thought of.

I did some knurling at technical class many years ago. Not sure that the bike mechanics I have spoken to would know how to use this tool. Would have to find a good one. I would even consider doing it myself if I had a lathe !

Great detailed procedure information !

Thanks to everyone for their help.

dsaul

A spring loaded center punch will do the job nicely. No need to use a hammer and all of the punches will be the same size. I've used this method for crown races and headset cups and it works great.

Dan Burkhart 

A Stein knurling tool will do the trick with no lathe required.
Certainly not worth it for a one time use but if you can find a local shop that has one it does a nice job.
Here is one of a couple of videos I have done showing the procedure.

redshift1

Good to know that if I go this way.

Dan Burkhart

Certainly not worth it for a one time use but if you can find a local shop that has one it does a nice job.
Here is one of a couple of videos I have done showing the procedure.

You video shows this very well.

If you see this question, can I ask you whether or not you need to run the fork race milling tool down over the knurled part, after the knurling is done ? ( Not asking about the actual milling of the fork far end seating surface, but only of the knurled part. )

In other words, to reduce the diameter of the raised knurled part back down to the original dimension.

FBinNY 

ABSOLUTELY NOT.

Whether you raise metal with a center punch or a knurling tool, you do not want to remove metal. Since it's only raised metal that you flowed from the valleys to the peaks, the race will have no problem flowing some of it back as it's pressed home.

FWIW - my oldest bike with the most mileage (60,000 when I stopped counting) had the crown fitted using the center punch method starting from when it was new.

redshift1

Awesome. Thanks FB.

Dan Burkhart 

Well the milling tool has to pass over the knurled part to do it’s real work which is to ensure the seat is flat and perpendicular to the shaft.
It also ensures that the cylindrical part of the seat is concentric.