Lathe Question

[Tristan]

This is all nice to know, I was a little bummed at first by some of the responses, but it looks like the little lathe in the right hands can do at least what I was hoping. Anyone ever make a hub? That seems like a neat project, maybe not practical...but that's not always fun.

I've never made a shell but I regularly make axles, endcaps, preload spacers and modify freehub bodies with my ML7. It's a great sized machine for this type of work, although I wish it were metric.

[Jacques]

WTF? Are you trying to kill yourself?

[Jake Rosenfeld]

My 97 year old friend Russel says you can do little things on a big lathe but you can't do big things on a little lathe.

I tend to agree.

5 minutes ago I installed an oil lite bushing I turned from imperial into metric 10 minutes ago on my south bend.........

[Clockwork]

WTF? Are you trying to kill yourself?

The fork was surprisingly balanced and at fairly low RPM.

[NBC]

what RPM do you use for fork crowns ?

NBC

[Jacques]

The fork was surprisingly balanced and at fairly low RPM.

You're an adult and you can make your own decisions about the risks you're willing to take, but it's worth mentioning that this kind of setup would have a person fired imediately at any of the machine shops I've ever set foot in. Maybe nothing will go wrong a hundred times, or even a thousand, but when it does people might die. It happens all the time, guy has two feet of bar stock sticking through the bore unsupported but "don't worry about it", he does it all the time. Start the spindle in the wrong gear and that unsupported bar bends 90* and gets thrown through a cinder block wall.

[Curt Goodrich]

Equally worth mentioning this is a standard practice in many frame shops that I've been in including some rather largish manufacturers.

[Clockwork]

You're an adult and you can make your own decisions about the risks you're willing to take, but it's worth mentioning that this kind of setup would have a person fired imediately at any of the machine shops I've ever set foot in. Maybe nothing will go wrong a hundred times, or even a thousand, but when it does people might die. It happens all the time, guy has two feet of bar stock sticking through the bore unsupported but "don't worry about it", he does it all the time. Start the spindle in the wrong gear and that unsupported bar bends 90* and gets thrown through a cinder block wall.

This is a 1956 lathe. I can't throw a lever and accidentally turn it at 5,000 RPM. It's at 300 RPM and if it were to spin faster I would have to turn a knob many times to even get it twice that. I'm also the only person that uses my shop.

I normally do this before the legs go in but this fork didn't allow for that.

[NBC]

jaques...

stop being a **** and just accept it's common and pretty safe practice doing it this way, people have been doing that for certainly 40 years if not longer

you'd have to be an idiot to stick anything near anything your turning in a lathe ! just use your head.....

NBC

[Jacques]

I don't doubt that plenty of people have done it.

But, I'm unfortunately too familiar with the Google image results for "lathe accident" to ever consider doing this myself.

[Jacques]

jaques...

stop being a **** and just accept it's common and pretty safe practice doing it this way, people have been doing that for certainly 40 years if not longer

you'd have to be an idiot to stick anything near anything your turning in a lathe ! just use your head.....

NBC

I don't know why you'd think I'm being an ****. For showing concern for someone's safety?

I could tell you a lot of stories of people who've died in industrial accidents, none of whom were idiots, doing things the same way they'd always been done. If you want to take risks, that's your choice.

[bencooper]

RPM is critical here - what would be lethal at one speed can be perfectly safe at another. If anyone's bored, they can work it out - get the offset mass of the fork, work out the bending moment on the crown, compare that to the force required to break the steerer.

[edoz]

Keep in mind, past a couple hundred rpm the shutter speed of most phones and digital point and shoots will make it look like it's spinning 10,000.
The slickest lathe/crown race setup I've seen is Curtis Inglis using an expanding collet inside a fork crown before anything is brazed to it.

[Rody]

If you make your own fork crown race seats you don't have to worry about spinning a whole fork in the lathe...

crown race seat small.jpg

crown race seat small parted.jpg

viva la lathe!

[acorn]

I don't doubt that plenty of people have done it.

But, I'm unfortunately too familiar with the Google image results for "lathe accident" to ever consider doing this myself.

Holy crap! I just did what Jacques suggested and typed "lathe accident" into Google and checked out the images. Horrific! I agree that safe practices should take precedence over traditional work methods. You can be safe for 99 times, but that one time that something goes wrong and you die. That's 1 out of 100 that can and should be prevented.

Here is the problem. It's far easier to use hand tools for facing, chasing threads, etc. Yes, it isn't as good and as precise as doing it on a lathe, but you have to take a machining course just to be able to use a lathe safely. So, you either wing it and do it on your own, or you just do it with hand tools.

[Dave Anderson]

It's always a little surprising to me (although it shouldn't be, I guess), that pretty much every time someone posts a technique or something on this or other forums that's been standard practice in the bike industry for a half a century or more, there's always folks that pipe up and tell us how terrible of an idea or practice it is. Sometimes I think that we should all keep this stuff to ourselves and let others figure it out on their own. I am not trying to be a smart aleck or argumentative or etc. I am just being pragmatic. Should every post have a disclaimer, or "don't try this at home" statement, or a dissertation explaining all of the nuances involved that make the practice practical, effective, and not all that dangerous if done properly? IDK...I am starting to think that for many of us its a whole lot easier, and less of a headache, to just go to work, build frames, and keep quiet.

Dave

[Mike Mcdermid]

.I am starting to think that for many of us its a whole lot easier, and less of a headache, to just go to work, build frames, and keep quiet.

Dave

i think a lot of folks are on this wavelength too

[Tristan]

I am starting to think that for many of us its a whole lot easier, and less of a headache, to just go to work, build frames, and keep quiet.

This is the double-edged sward of the VSalon....look back to the early threads and see how much information builders / businessmen were willing to talk about but as the audience has grown these discussions have either stopped or been taken offline.

I generally stay out of the wheelbuilding threads because some guy that's built 3 wheels will tell me I'm wrong about something.

[bencooper]

I do find myself double-guessing whether to post on here sometimes, for that reason. Though people telling me my way of mitring tubes wouldn't work, when it's been working for years, was funny.

[Gattonero]

It's always a little surprising to me (although it shouldn't be, I guess), that pretty much every time someone posts a technique or something on this or other forums that's been standard practice in the bike industry for a half a century or more, there's always folks that pipe up and tell us how terrible of an idea or practice it is. Sometimes I think that we should all keep this stuff to ourselves and let others figure it out on their own. I am not trying to be a smart aleck or argumentative or etc. I am just being pragmatic. Should every post have a disclaimer, or "don't try this at home" statement, or a dissertation explaining all of the nuances involved that make the practice practical, effective, and not all that dangerous if done properly? IDK...I am starting to think that for many of us its a whole lot easier, and less of a headache, to just go to work, build frames, and keep quiet.

Dave

See what happened talking about a steerer replacement

Back to the forks on the lathe, I assume they weren't put to any high RPM, is it?