mtb_addict

hi.
i am in e. Asia, and transportation is problem. i ordered a quill stem for my commuter bike, but the corona virus really messed up logistic all over the country. the seller says he doesnt know when he can ship...the govt wont let him go to the warehouse. i am thinking of cancelling the order...because i found locally source stems.

but problem is that that local stems are either too long or too short.

so i am thinking want to find a super long one, and saw it to proper length (200mm).

but i am scared of cutting accurately...it need to be angled 45 degrees. i dont know if i have the skill to do that accurately.

if the stem is not perfectly cut (so wedge nut contact is not perfectly flat), is it still okay?

or does the angle really need to be perfectly matched to the wedge nut?




p.s. the only cutting tools i have are : a hacksaw and a flat file.

alo

I would cancel the order, because you have no idea when you might get it.

Depending on how long it is, you may just be able to slide it in further.

You can cut it. If it is not right, you can grind it to get it right. You may need a shorter bolt.

Do you have a link to a website where the super long ones can be purchased.

mtb_addict

I don't have a grinder....only a flat hand file.
the long stems are like 300mm. I think it is made out of steel...which I can live with. I can probably file aluminum stem easily enough. But, I think steel might be too hard to file.

I think I can hacksaw the bolt shorter, quite easily.

JoeTBM 

Not all bolts are fully threaded

mtb_addict

taobao stem...i need to chop at least 75mm off.

dsbrantjr

Most quill stem bolts are not fully threaded. Most of the ones I have seen appear to have rolled threads, so threading them further will not work as the shank diameter is too small.

alo

You can file it. It will just take longer.

alo

Is this to ride yourself?

Is it a problem if the handlebars are 75 mm higher?

I am tall, and am experimenting with ways to raise handlebars.

Steve B.

I'd cut it.

The purpose of the wedge is to tighten up against the inside of the steerer tube wall, preventing L/R movement. The presumption is a steel steerer, which is a fairly robust material. I cannot imagine that a wedge that is not perfectly flush with the steerer is going to do any damage, is why I would try this.

freeranger

If I was in your situation, I'd put up with riding the long stem for now. Then get the stem you really want, when the virus is under better control--which we all are hoping won't be too long. Wish you the best and stay healthy!

Russ Roth

You can get away with an imperfect cut, the smoother the cut the better so cut with a hacksaw and file smoother. What holds the stem isn't the action between the wedge and stem but the way that action pulls the wedge into the steerer and not having perfectly the same won't matter much. Like any stem check it every few months to make sure its still tight, they can loosen no matter what. The big issue is the bolt, unless you can thread it my experience is that the bolt is sized to the stem and the threads are only as long as they need to be. If you have a good die it isn't the worst thing to thread but it is one more detail to have to work out.

JohnDThompson 

You can cut the stem, then file it to get the proper angle for the wedge. But as others have noted above, the stem bolt may need to be shorter. Before you begin, measure carefully to ensure that the stem bolt will have threads at the point where the wedge will engage the bolt.

jadocs

Interested in how this turns out.

AnkleWork

Better to continue shopping until you find what you need.

dedhed

If the bolt is too short, in theory you could use a piece of all thread and a nut. Ugly, but functional.

ThermionicScott 

Considering the OP's mechanical abilities and history, it's a questionable idea, but he will probably do it anyway.

dsbrantjr

As I pointed out, many (most?) stem bolts have rolled threads which means that the remaining shank is undersized for cutting threads into it. For example, 3/8" rolled threads are made from 0.330" stock, while cut threads are made from 0.375" stock. As a result, if you try to cut threads on the smaller stock you will end up with 1/2 depth threads which will strip easily. If doesn't matter if you have a good die, there is just not enough material to thread successfully.

squirtdad

+1

WizardOfBoz

Heed what dsbrantjr says. Modern quality bolts are heat treated as blanks, then temperered. Then the thread are rolled into the bolt using super strong and hard roll thread dies. Two important things:

1) The bolt blank diameter is smaller than what you need to cut threads.
2) Even if it weren't, cut threads are weaker than rolled threads. And threads cut into a smaller-than-needed blank, like the cut off shank of the original stem bolt, will be weaker still.

If you do this, the idea above to use all-thread (threaded rod) is a good idea. I'd use permanent threadlocker to put two nuts (not/locknut) on the end. Then you'd have a strong enough bolt.

If you have a hacksaw, and take some care, you should be ok. If I were doing this, I'd use a file and not a grinder to smooth out the saw marks.

CliffordK

Any chance you can find a local machine shop with a power hacksaw.

They should be able to set the angle, then cut, and it should only take about 5 minutes.

Depending on the state of the local economy, I can't imagine it would cost more than a few dollars to do.

Actually, with aluminum, you should also be able to cut it with an ordinary woodworking miter saw/chop saw. There are, of course, also quality hand miter saws.

As above, make sure your bolt will work, or you can obtain a usable bolt before cutting.

You can also use the stem long (or short) for the next few months until the economy recovers, then replace it when you can source the proper parts.

oldbobcat

You can buy an inexpensive wooden miter box with 90 and 45 degree cutting slots at a hardware store. Use a hacksaw and work carefully, and clean the edges with sandpaper, emery cloth, or a file. It doesn't matter if the 45 degree bevel isn't perfectly aligned because the wedge nut will just follow the bevel.

dedhed

OP is in some backwater of E Asia, so no Home Depot around the corner.

mtb_addict

wel, i cannot find a shorter stem bolt locally.

i guess i just have to wait for the transportation to resume.

WizardOfBoz

If you have any access to a hardware-type store that would be great. All-thread is merely threaded rod that you can buy in any length. A meter. A half-meter. Whatever. And the threads are rolled. So buy all-thread longer than you need, put two nuts on the end (you could use threadlocker if you have it) and cut it to length with a hacksaw. Et voila, a bolt the right size. But if there aren't any hardward stores/industrial supply shops, etc, near you then you'll have to have it shipped in i guess.

dedhed

Temporarily a guy in theory could put a stack of washers or spacer on the bolt under the head to "shorten" the bolt.