Halfrauds laughable

[Yellow Saddle]

Out of interest, is a machine necessary to cut the occasional spoke thread? Can't it be done simply just using a die?

That's a good question and the answer is no. A die cuts material away, a rolling head like the one Midlife shows, rolls the threads without removing material. If you cut material, the weakest place on the spoke is where the first thread starts and that's where the spoke will break in time. Not if, but when. By rolling the thread, material is moved around, rather than removed. The first thread is then actually preceded by a small hump of material, which strengthens that area.

Therefore all good spokes have threads rolled on, not cut into.

A machine like the one in Midlife's picture takes about a minute to roll a spoke. A professional machine will do it in one stroke of a lever, which makes a difference if you have to do lots of spokes. For the odd spoke, a rolling die machine like that is just fine.

Should you cut your spoke thread, you'll get a spoke life of less than 1000 kms on a back wheel. With a rolled thread and good building practice, the spoke will never break at the thread, even after 200 000 kms.

This illustration isn't very accurate either, but it makes the point wrt the first thread. A real-life spoke's thread doesn't look like either. It resembles the bottom one but the thread valleys (insides of the V) are rounded. This is to eliminate stress risers.

Here's a photo of a spoke threaded on my Morizumi spoke threader. Notice the rounded valleys and peaks of the thread and the raised bulge where the first thread starts. The scale on the ruler is in millimeters.

The Morizumi spoke cutter and threader.

 

[SkipdiverJohn]

Fifty years ago when I was a fledgling apprentice engineer I can remember buying stuff like axles and bearing cups and commenting to my old man that if I machined anything like that at work I'd get a bollocking. And a lot of the hand built frames we wax lyrical about now were not up to much either. Any fool with welding or brazing experience can knock a few tubes and lugs into shape, and unfortunately many fools did.

CNC machining has reduced the cost and variability of small mass-produced parts, and so long as the tooling is maintained without doubt the consistency can be better for a given unit cost. What you may be forgetting though is that stuff from 50 years ago made on a mass production basis could well have been produced on clapped-out leftover wartime machine tools that had been run into the ground 24 hours a day for years and were nowhere near accurate.
Whilst it's also true to say that any fool with a gas torch can knock up some sort of frame, it's also true to say that a badly built one is likely to have already failed and been scrapped years ago. Anything that has survived the rigours of several decades of riding obviously wasn't that badly built! I see more evidence of poor fabrication in modern welded frames, especially failed aluminium ones, than I have ever seen on brazed work.

 

[SkipdiverJohn]

That's a good question and the answer is no. A die cuts material away, a rolling head like the one Midlife shows, rolls the threads without removing material. If you cut material, the weakest place on the spoke is where the first thread starts and that's where the spoke will break in time. Not if, but when. By rolling the thread, material is moved around, rather than removed. The first thread is then actually preceded by a small hump of material, which strengthens that area..

Rolled threads tend to have a better fatigue life as the process puts the surface of the thread in compression, which discourages fatigue cracks from propagating. Engine crankshaft bolts are normally rolled for the same reason as they are highly stressed components. Rolling threads is also cheaper than die-cutting them if done on an industrial scale.

 

[Yellow Saddle]

Rolled threads tend to have a better fatigue life as the process puts the surface of the thread in compression, which discourages fatigue cracks from propagating. Engine crankshaft bolts are normally rolled for the same reason as they are highly stressed components. Rolling threads is also cheaper than die-cutting them if done on an industrial scale.

Nice explanation.

 

[MrPie]

Hardly warrants calling the company fraudulent tho, or indeed laughable. Someone steal the jam from your donut?

 

[Ming the Merciless]

Hardly warrants calling the company fraudulent tho, or indeed laughable. Someone steal the jam from your donut?

I went into Halfrauds and they did not even have doughnuts, the bloody cheek!

 

[Kempstonian]

I went into Halfrauds and they did not even have doughnuts, the bloody cheek!

Just shows how standards are slipping in this country.

 

[Levo-Lon]

There would have been damage you could not see.

Let us not forget cars have a lot of useful safety features, the crumple zone being one of them.

Airbag £700 + fitting they were quoted a grand just to do that..
Shame as it was a super clean low miler,no wonder cars get nicked to order..

 

[screenman]

Airbag £700 + fitting they were quoted a grand just to do that..
Shame as it was a super clean low miler,no wonder cars get nicked to order..

That was a bit of a bang in the wrong place for the airbag to deploy, normally rips the dash to bits which is where a big cost is. Cars are certainly a safer place to be if you are in a collision than they were back in say the sixties.