Hey do any threadless to threaded stem adaptors exist? I have a bike which rides nice but I hate the look of modern stems are there any converters that would allow me to put a quill stem into my bike that takes a 1 1/8 threadless stem.

Can't think of an easy way to do this. You could get a 1 1/8 threaded fork and then fit a quill to that?

Because a threadless stem also functions as the topmost piece of the headset, setting bearing preload (or just eliminating play), it's not just a matter of sticking a quill stem into the steerer tube. Plus, a threadless fork's steerer might not be built for the stresses a quill stem wedge or expander plug might exert.

One thing that should work, if you find it aesthetically pleasing enough, is a "classic style" threadless stem like the ones Velo Orange carries:
VO Tall-Stack Stem 31.8, 1-1/8" - Threadless Stems - Stems - Components

Similar thought. Threadless stem are designed for compression...the stem squeezing it. A quill stem does the opposite, pushing out from the inside (tension). You will break/crack your steerer tube.

This is easy. Time to buy another bike!

Here's what I did, OP: I got used to the look of threadless stems and stopped worrying about it. I feel the same way - not too crazy about the way most threadless stems look, but there's just not much to be done about it.

On a side note, why do almost all threadless stems have a rise?

Apparently you don't know the stems can be flipped.

Wow - how clever! Thanks for pointing that out to me.

No problem. You'll learn a lot from this forum

1 1/8" metal steerers are generally considered OK for quill type steerer tube extenders, which should make them OK for quill stems.
All you need is a way to lock and preload the headset.
Lock can be achieved with a suitably sized seat post clamp.
Preload can be set with some threaded rod, large washers and a piece of tubing.
Or a big c-clamp and a piece of tubing.

I've been surprised that over the years that no manufacturer has really come out with a line of slim, elegant looking threadless stems. You'd think there'd be a market for it with most threadless stems looking so squarish and clunky. I think someone posted a pic of a pretty nice on these forums a while back, but it was certainly the only one I'd ever seen.

New to the forum, and was wondering, is it much of a hassle to convert your Threadless stem to a Quill stem? I'm partial to a more classic look. And the conversion would be taking place on a 2009 Mercier Kilo TT. Any info would be appreciate

I never thought I'd need to pass on this bit of information I once stumbled across but apparently there is a market for it. I present the 'Quillinator':

Quill-inator | SOMA Fabrications

Convert your threadless stem to the inferior in almost every way quill stem. Enjoy!

Wow, that is elegant! lol.

Uhm.. maybe read the very posts in this thread.