Best Way to Repair Forks Threads?

[stuvy]

i used to be a frame builder for Bob Jackson Cycles years ago, we often fit new steerer tubes to forks when the threads were knackered.
othewise you can get inserts that wedge in like a quill stem but you then use an 'aheadset' style stem and bearing set on them.

View attachment 228189

sorry to detest of the thread title any pictures of the bikes youv made?
Was it brazing?
Iv always wanted to build my own bike it’s in the to do list

 

[wacky7791]

sorry to detest of the thread title any pictures of the bikes youv made?
Was it brazing?
Iv always wanted to build my own bike it’s in the to do list

brazing and bronze welding mate, all done freehand with a vice and a straight edge. Was almost 20 years ago when I left there lol, have a look at their website for the bikes as the designs haven't really changed in decades.

 

[VeryFEDUP]

Thanks for the ideas folks. I have had the devil's own job signing back in. Forum kept telling me I had disabled cookies but hadn't!

Forks that are at least 531 steel with a 200mm threaded steerer in 1" and with one eyelet on the dropouts seem pretty sparse! There isn't room to but a spacer in as two nuts are need to lock against each other.

I'll keep scanning the Bay of evil and specialist forums.

 

[stuvy]

Thanks for the ideas folks. I have had the devil's own job signing back in. Forum kept telling me I had disabled cookies but hadn't!

Forks that are at least 531 steel with a 200mm threaded steerer in 1" and with one eyelet on the dropouts seem pretty sparse! There isn't room to but a spacer in as two nuts are need to lock against each other.

I'll keep scanning the Bay of evil and specialist forums.

on my 24” bmx the head bolt has a grub screw to add extra security

 

[slim_boy_fat]

Stick it back together with Araldite, or the new Loctite HY 4070 two-part resin stuff.

 

[Gareth J]

Get an old nut, slit it in one place and wind it down on carefully? Can be enough to clean up gnarled threads without an expensive die

 

[Melvyn Best]

Get an old nut, slit it in one place and wind it down on carefully? Can be enough to clean up gnarled threads without an expensive die

X2 , might also help to use a jubilee clip around the nut after fitting to apply a bit more pressure

 

[Kram]

Cut the threaded section off and shrink fit and braze a threaded plug made from en16 or en19.

That way the stem does not need to go in a lathe, and the plug can be made on a small lathe easy enough.

 

[citizen kane]

Ceeway will sell you a new steerer, threaded or unthreaded if you want to go aheadset.

https://www.framebuilding.com/Forks.htm

 

[Shox Dr]

Whenever a component is to be modified, you need to take into account what would happen if it failed...

As I alluded to earlier, I was involved with end users modifying steer tubes. One person replaced a steer tube pressed into an aluminium forged crown. He had called us sometime before wanting use to replace the steer tube as he had cut it too short for a aheadset. We quoted him. It was explained an oversize tube would need to be used as the crown would have stretched. We would not supply. Only Supply and fit.
Sometime later it failed ploughing him into the ground at speed, he spent a week in ICU with his face caved in. He had taken out a tube from other set of forks and used that. For some reason that was our fault.

No2. Sent in forks for service. We refused as they were beyond repair, in fact they were rotting. Initially we refused to return the forks, as they were of no use, and to prevent further use. In the end we made him sign to say they were never to be used again and were for decoration only.

Serval months lather he refitted them and ended up in a comma for a week.

Moral of the story.
Listen to those who know more than you.
Parts are cheap.
Pain hurts
I’m not a mug.

 

[keithski122]

Somewhere that does cheap bike stuff :- https://www.bankruptbikeparts.co.uk/

 

[mtt.tr]

Whenever a component is to be modified, you need to take into account what would happen if it failed...

As I alluded to earlier, I was involved with end users modifying steer tubes. One person replaced a steer tube pressed into an aluminium forged crown. He had called us sometime before wanting use to replace the steer tube as he had cut it too short for a aheadset. We quoted him. It was explained an oversize tube would need to be used as the crown would have stretched. We would not supply. Only Supply and fit.
Sometime later it failed ploughing him into the ground at speed, he spent a week in ICU with his face caved in. He had taken out a tube from other set of forks and used that. For some reason that was our fault.

No2. Sent in forks for service. We refused as they were beyond repair, in fact they were rotting. Initially we refused to return the forks, as they were of no use, and to prevent further use. In the end we made him sign to say they were never to be used again and were for decoration only.

Serval months lather he refitted them and ended up in a comma for a week.

Moral of the story.
Listen to those who know more than you.
Parts are cheap.
Pain hurts
I’m not a mug.

And this is why im a follow the rules person to the point it can be a little limiting.

 

[citizen kane]

Clearly a lot depends on the original construction of the forks and the abilities of the OP. The OP already seems to have suggested he can braze, so if its already a brazed and lugged construction it should be faily straight forward to put in a new steerer. As long as your doing it for yourself, can do it to the required standard and you accept the risks then why not. Plenty of people on here have made there own frames.