Threading a threadless steerer?

[maximus]

I have done a bit of reading around on this, but the advice I get here tends to lead me in the right direction more times than not.

I just picked up a cheap frame with a 1" threadless steerer tube (4130 cromo). I am wondering if I can find a machine shop to cut it down and add threads. I have a nice threaded headset and a few quill stems already.

Does anyone have experience with this? I gather that 4130 is some pretty hard stuff. I can of course throw in the towel and get some threadless gear, I just prefer threaded set ups and have no idea how much something like this would cost if it's even possible.

Thanks as always :beer:

[EricEstlund]

Assuming the steerer is of the appropriate wall thickness it can be done, but generally requires some fairly specific fixturing if done on a lathe. Threading an unbuilt steerer is a much simpler task.

It is not something I would recommend having done by hand. For that matter, it isn't something I would generally recommend at all, especially if not done by someone with a proven track record. Most of the times I've seen it attempted I have seen it not work out.

There are several very nice headsets on the market for very reasonable rates. Odds are an inexpensive stem and a mid range headset would set you back less and be much easier to predict a positive outcome.

[wallymann]

with a threaded one, cost $100. I've had this done to 3 forks.


I have done a bit of reading around on this, but the advice I get here tends to lead me in the right direction more times than not.

I just picked up a cheap frame with a 1" threadless steerer tube (4130 cromo). I am wondering if I can find a machine shop to cut it down and add threads. I have a nice threaded headset and a few quill stems already.

Does anyone have experience with this? I gather that 4130 is some pretty hard stuff. I can of course throw in the towel and get some threadless gear, I just prefer threaded set ups and have no idea how much something like this would cost if it's even possible.

Thanks as always :beer:

[guyintense]

Find a shop that has a steertube threading tool like this. I have one and have done it a few times, so it can't be that hard.

[EricEstlund]

Hand threading an unthreaded steerer with a chasing tool is not how I would want to spend my afternoon. That tool is designed to clean up existing threads or to cut small runs of extension in existing threads. It's fairly unreliable to try to get it to go on and cut straight for any length without existing threads to guide it.

As you say, it is doable, but I wouldn't recommend it.

[maximus]

Thanks for advice. I imagine Eric knows best here (I really admire your work btw).

If there is a machine shop around here that could do it, I wouldn't even know where to begin. Sounds like going threadless is the easiest option and probably about equivalent in price.

Thanks for the responses!

[Louis]

sounds like going threadless is the easiest option

+1

[guyintense]

Hand threading an unthreaded steerer with a chasing tool is not how I would want to spend my afternoon. That tool is designed to clean up existing threads or to cut small runs of extension in existing threads. It's fairly unreliable to try to get it to go on and cut straight for any length without existing threads to guide it.

As you say, it is doable, but I wouldn't recommend it.

Actually mine is the VAR and it has a guide bushing but so does the Park version above. Again, not that hard and excellent results. If it's chromed that's another matter.

[oldpotatoe]

I have done a bit of reading around on this, but the advice I get here tends to lead me in the right direction more times than not.

I just picked up a cheap frame with a 1" threadless steerer tube (4130 cromo). I am wondering if I can find a machine shop to cut it down and add threads. I have a nice threaded headset and a few quill stems already.

Does anyone have experience with this? I gather that 4130 is some pretty hard stuff. I can of course throw in the towel and get some threadless gear, I just prefer threaded set ups and have no idea how much something like this would cost if it's even possible.

Thanks as always :beer:

Possible, I have a machinist locally who has done this for me. Just needs a lathe to do it right, not with hand tools, as the threads have to be parallel to the fork crown race seat.

[guyintense]

Possible, I have a machinist locally who has done this for me. Just needs a lathe to do it right, not with hand tools, as the threads have to be parallel to the fork crown race seat.

Why would you of all people send the OP to a machinist when a well equipped bike shop will have a tool designed to that exact precedure? Are you unfamiliar with the tool?

[oldpotatoe]

Why would you of all people send the OP to a machinist when a well equipped bike shop will have a tool designed to that exact precedure? Are you unfamiliar with the tool?

It's not the cutting but the first thread. 'Me of all people', maybe because I don't want to buy the guy a new fork after installing the HS it binds or kills bearings.

Besides, I doubt many shops have this tool. I don't, 'me of all people'...oh no.

Even with the Var tool, that first thread just 'may' be 'perfect'...but Frank will always make them perfect. Ya know, I don't repair frames either, I let somebody else do that also.

[lovebird]

I've threaded an threadless steerer twice using a Park tool (with the guide bushing). Sure, it's time consuming and does wear the tool a bit, but in my experience not that hard.

The initial threads are of course the toughest part. But when you think about it you've got some "wiggle room" here, in that the threaded steerer is ultimately going to be a lot shorter than the threadless one. So, if you really screw up, you'll know it within the first 0.5-1cm, and you can stop, just cut that part off, and try again.

The park tool has sort of an adjustable threading die - I ran that fairly "loose" so the initial cut was very light. That seemed to help get the tool started straight. Later you can tighten up the die a bit and get a somewhat deeper cut.

Anyway, just thought I'd throw that in there, of course YMMV. BTW, the first fork I threaded was on a nice Zanconato, and no headset binding or any other problems I can tell in well over 2000 miles since, and at about 210, I'm no lightweight!

[maximus]

Sounds like its possible - but the cost of the tool/machining likely outweighs the cost of just getting a threadless HS/stem.

I may give Velo Classique here in VA a call since they deal VAR tools. Not many shops these days deal with steel (least not around these parts).

[vqdriver]

i've had this done at my lbs without issue. it was very tedious to make sure it started straight. and my shop didn't cut first. they started with the longer steerer so if they were off, they could cut off the top and have enough to do it right. they ended up starting off wrong once and the second time it was perfect. they continued those threads down to the correct length and ultimately cut off about an inch of steerer that they had threaded.

fyi, this was to a fork that, at the time was available in both 1" threaded and 1" threadless and was known to use the same steerer for both forks so wall thickness wasn't an issue.

i don't remember the cost but it wasn't a lot, maybe something like $50 or so since they charged me by time.

[stuckey]

Threading something with a thread chaser is possible, but it is about as smart as wiping your ass with your bare hand.:banana:

[rustychisel]

Threading something with a thread chaser is possible, but it is about as smart as wiping your ass with your bare hand.:banana:

I'm struggling with this as a reasonable analogy.

What, you've never had an 'oh oh' moment when you ripped through the tissue? C'mon..? :mad:

[stuckey]

The way these threads are going lately... There is no reason to be reasonable, ha, ha.:eek:

[Shiversolitude]

Theres certain things that can be done, but maybe shouldnt. Im thinking you should probably not thread a threadless tube.

I would question how much material are you removing to make the threads, and does this threaten the integrity of the tube.

[Germany_chris]

I can't believe this innocuous thread turned contentious.

@OP I wouldn't do it by hand the issues with the hand tool is your making an assumption the the original cut on the tube was right. I got a surly 1" threadless fork not to long ago that was not flush, on threadless it's not as important because you tighten on the stem and spacers not the steerer tube itself.

[Fixed]

Possible, I have a machinist locally who has done this for me. Just needs a lathe to do it right, not with hand tools, as the threads have to be parallel to the fork crown race seat.

It is easy for a machinist to do . But would it not be easier to buy another fork?
The graceful beauty of a threaded stem/fork combo is underrated these days IMHO
Cheers :)

[Dave Wages]

Not sure if this has been mentioned, but you'll want to make sure that the ID (inside diameter) of the steerer is correct for a quill stem before you start cutting threads. If not, then you've got two issues to deal with instead of one.

Also, if it's a smaller bike, (not sure if you mentioned the size?), then you'll want to make sure that the quill is not going to be impeded by the thicker butting at the bottom of most steel steerer tubes. What I mean is this, you may have plenty of insertion with the long threadless steerer, but once you cut it down and put threads on it, you're going to be inserting the stem much farther down into the steerer and this can lead to interference with the butting.

[maximus]

Lots of good advice from very knowledgable folks.

I know for certain this frame was offered with a threaded steerer and recently changed over to a threadless. Going to get one reputable shop's opinion on it otherwise buying a new headset and stem is no big deal.

Many thanks for all the replies.

[Louis]

Many thanks for all the replies.

Hey, don't try to stop the discussion - we want to continue arguing about this! ;)