The custom stem thread

Made a high riser stem as well . Used a unicrown fork blade ( that I messed up)

And a regular 7• stem




12 Likes


Quite standard of a stem. Brazed in the top cap, made out of two washers and a short section of tubing. Welded the nut onto the bottom wedge as well. The bar clamp is tig welded, then fillet brazed over that because I trust my welding more than my brazing. Luckily, I found a set of 26.0 bars in my parts bin, though I was looking for an excuse to build a 1" quill with a 31.8 clamp.

2 Likes

Hello there.

For now I made only two stems but I have to make more. I use 1.5mm wall thichness tubing for pivot and bars clamps wich I think is okay. If it helps it is 35x32mm for bar clamp and 32x1,84mm I turn down to 28,6id for steerer clamp. All 25cd4s from ulm techno. I have some 28x0.9mm tubing for the body. Is it good for you or should I go for 1.4mm wall wich is the second option from ulm techno ?

Plus what do you think about steel frame and carbon fork (with carbon steerer ofc).
I’m thinking about building a bike with the allygn mud fork.

Thanks !

1 Like

Do you use an adjustable reamer after brazing? Trying to get ideas on post braze reaming for these setups. Thanks Em!

Well I converted a quill stem to threadless once :slight_smile:

The new bit is just some black iron pipe that I got to the right ID on the minilathe, and then cut along where it was already welded.

It’s done quite a few miles now with no issues.

4 Likes

A few months ago I made myself a mini bullmoose,
I used scraps of the top part of fork blades as main tubes for the triangle.
I’ve build it with a fork





for a Cannondale Beast of the East I rebuild as a bikepacking rig.


20 Likes

Just finished one of my MX/Cook Bros themed stems. I wanted the same width as a normal MX triple tree as I plan to use moto bars to keep with the look. The risers are actual 7/8" moto clamps and the stem clamps are 1-1/8" collar clamps. I had aluminum plate cut out to see the weight difference. The steel plate is 3/16 and the aluminum is 1/4". Both have under braces for extra support. I’m happy with it and exactly the look i was going for. The next version will he more compact and maybe use a 31.8 clamp.

4 Likes

Here’s the last stem I’ve build, it’s nothing crazy, besides that it was my first time using PMW stem plates (love their look).

10 Likes

We love the look, too! Great job! - Coco

4 Likes

Went with a piece of 31.8mm x 0.9mm 853 downtube. Analysis shows that it should be stronger and stiffer than a piece of 25.4mm x 1.6mm 4130 that I was going to use, and a bit lighter. Initial reaction from mounting it on a bike is that it feels a bit flexy. We’ll see once I get it back from paint and actually on a bike to ride.

1 Like

By my calculations, it will be less than 2% difference in flex between a 25.4 x 1.6 and 31.8 x 0.9.

My guess is you used .058” walled tubing for the steerer clamp. You can save this by slotting all the way up and then adding a 2nd binder.

1 Like

I make the 31.8 x 0.9 tube 22% more stiff than the 25.4 x 1.6

That makes the OPs feeling of being more flexible even more curious. I think it’s the clamp.

1 Like

It was my imagination. Got it all mounted up and it feels fine. It might have been that the headset wasn’t tight because I hadn’t cut down the fork yet.

3 Likes

Nice job! I still worry that there is play at the top and it’s clamped tightly at the bottom. watch for cracks at the top of the slot. I use .065” walled tubing for clamps and then ream to size to avoid the extra .009” of difference in clamp ID vs steerer OD. The top cap might support it well enough.

1 Like