Tapping threads onto a threadless steerer | Yay or Nay?

[waddelblah]

Question:

I have a cro-mo GT Bologna fork, threadless, that I am contemplating tapping threads onto for a threaded headset.

Is this feasible / safe? Or is the base metal thickness of a threadless steerer too thin to do it safely?

Anyone?

 

[Mike Muz]

ask biglev.

As you're new to the forum , click on search .
Put biglev in the author box , retro mtb > 97 in the category box and some of his posts will come up when you press the search button. At the bottom of his posts , thereis a pm box . Click on that . Send him a pm about it . Smashing bloke and helpful . Good luck with your forks

Mike

 

[waddelblah]

ta

 

[Rampage]

Only way it would work AFAIK would be to thread a 1.1/8" steerer that has an ID of 22.2mm and use a 1" stem.

 

[pete_mcc]

Only way it would work AFAIK would be to thread a 1.1/8" steerer that has an ID of 22.2mm and use a 1" stem.

Are you sure that's even possible? That would be a seriously thick steerer - steel tubed with 3.2mm walls. It would have had a previous life as a russian gas pipe.

A standard 1 1/8" steel fork will be fine to have threaded. Potentially not so with any suspension forks that might use alloy or butted steerers where you are best buying a new steerer or a high end steel fork that, again, may use butted or thinner tubing (GT forks are not in that catagory)

Don't use a 1" quill stem on a 1 1/8" fork, that would only end in disaster.

Having the threads rolled on is a different matter, while many shops will have a thread cleaner and cutter able to extend threads, they may not have a cutter able to initiate the threads and this is where you will need a frame builder or engineering shop. There is no quicker way to destroy forks that have some ham-fisted shop monkey attempt to cut the threads

 

[Rampage]

Sorry, thought he said aluminium steerer!
Ignore what I said above.

 

[waddelblah]

Thanks all. There are a couple of good local frame builders here so that is helpful . Sounds like its a slightly more tricky excercise than I had anticipated, it might be easier just to retain an ahead setup opposed to trying to backwards convert to threadless

 

[andyz]

You just need to borrow one of these:

http://s988.photobucket.com/user/36x18/ ... 9.jpg.html

It has a guide so that the die is not skewed when it starts the thread.

 

[jinjrich]

You just need to borrow one of these:

http://s988.photobucket.com/user/36x18/ ... 9.jpg.html

It has a guide so that the die is not skewed when it starts the thread.

You'll find those in all decent bike workshops (like ours) but believe me, we had a mechanic try and ruin the tool after cutting only about 1" of thread. If you want threads cutting into a steel steerer you need a proper engineering shop.

 

[WD Pro]

My back garden and black and decker workmate must be a proper engineering shop then ... ;-)

To the OP - I can't guide you if it is safe or if it will work, but if you can borrow a tool, check out my how to guide here : viewtopic.php?f=1&t=282496&hilit=thread

WD