Strobe source for the lathe?

Re: Strobe source for the lathe?

john lucas

Hopefully Josh bowman will see this. He did a demo for our club once. It worked fine until he cranked the rpm up. Then the magnet flew off. Of course you won't be running an offcenter piece that fast. I don't remember all the particulars about the strobe unit but he bought it off ebay.

Re: Strobe source for the lathe?

John Veerkamp

the problem I foresee is that the pressure of cutting may slow the rpm enough that the strobe is no longer in sync. Any bother ideas on this?

Re: Strobe source for the lathe?

john lucas

Maybe if you take large cuts. If you slow it down only a little the piece will look like it's moving one direction or the other very slowly. As you lighten up on the cuts the piece should move back to the zero position. I haven't use one turning but have had to photograph things using strobes for stop action and that's what seems to happen.

I plan to use a magnet to trigger it. *LINK*

Keith Newton

The magnet would be positioned on the arbor, or face-plate where I want the flash, so rpm's would not matter.

I found a nice how to article, link below.


http://www.larsstole.com/Lars_A_Stole/techniques_files/notes.pdf

Don't overlook the fact that there is a..........

JamieDonaldson

..... neurological potential that strobe effects can trigger epileptic seizures in some users!

Re: Don't overlook the fact that there is a.......

Jeff Smith

we picked up a modified strobe light at Boeing surplus years ago and experimented with it in the studio. This was a commercial powerpack modified to control both output and duration for producing motion studies on film. For short bursts it was fun to play with, but as exposure started going up to 10 minutes or so, the headache it produced was debilitating. Not just me, but our other shooter and the studio assistant as well. Put it on the shelf for a few years, then we gave it away in a studio cleanup several years ago.

I can see how it could be of use turning, but I'm thinking that the potential for serious accidents makes me think it may be a mis-application of technology.

Re: Don't overlook the fact that there is a.......

Dwight Rutherford

Lars Stole had a thread on the AAW forum in 2012 about using a strobe. There were numerous issues with headaches after use. Suggest you do a search of the forum. I believe there was a link to a U-Tube clip also.

Thanks, I think I'll try something else..

Keith Newton

I've got some pretty bright spot flashlights, that I think I might be able to set up to brighten the portion where I'll be cutting, so maybe that will allow me to see it a bit better.

Re: Thanks, I think I'll try something else..

John Veerkamp

Also place a white background on the ways. paper, cloth, etc.helps a lot.

Or sometimes a black background .........

JamieDonaldson

...on the bed works better for light colored woods like maples.

Re: Strobe source for the lathe?

Josh Bowman

Keith I can help with that, if you want to pursue it. I did find the strobe somewhat irritating, at least to my eyes. It's also deceptive to those who think the lathe is stopped and try to put there hands on the piece, that actually going at 1000 rpm!! Anyway, let me know and I'll scrounge up the stuff. I never found a cheap work around for the strobe and had to buy one from Radio Shack.......if you live close to Spring City, TN, I'll make you a deal. Here's a few links the previously mentioned PDF link of Lars was great help to my build.

http://www.aawforum.org/vbforum/showthread.php?9254-Notes-for-a-synchronized-lathe-stroboscope

https://www.youtube.com/watch?v=rpIGahaKl40

https://nwwt.wildapricot.org/Resources/Newsletters/Newsletters%202012/NWWTaug12.pdf

BTW John, you weren't suppose to remember the magnet flying off !

Re: Strobe source for the lathe?

Josh Bowman

John, the strobe is actually synced to the lathe with a special sensor and magnet.

Re: Strobe source for the lathe?

Pete in Holland MI

Your strobe does not have to be pulsing the same as the RPM of the lathe. Only some interval of it it. Thus, the strobe flashing at 500 beats per minute will still "freeze" a turning object turning at 1000, 1500 & 2000 rpm.

Still, gotta be damn careful not to reach for that "still" object in front of you.

Re: Strobe source for the lathe?

john lucas

I watched a video of a table saw with a strobe. It's really tempting to touch that blade even though it's slicing throught the wood. Better be a saw stop if I do that however.

Flicker sensitivity - You might do a test

John K Jordan

Keith,

You might borrow a strobe and see if you are affected by the flicker others mentioned. It doesn't bother me.

Some people are not bothered in the least. Some get headaches. In extreme cases, flicker can cause violent convulsions. I remember from my piloting days this was called "flicker vertigo." However, the most severe symptoms are seen at much lower frequencies than what we use on a lathe, typically less than 60 hertz. The much higher frequencies are more likely to cause headaches or drowsiness but only in some people - those in the flying community say this problem is "rare". Some are so sensitive they can't even watch TV or be in a room with fluorescent lights!

Some people are sensitive even to much higher frequencies. This might be interesting for people who use CFL and LED lights at their lathes:

https://vestibular.org/news/11-21-2013/lighting-flicker-health-concerns

But again, many people are not affected in the least.

I experimented with strobe lights many years ago and found they didn't bother me in the least IF there was some ambient light present. I had an industrial variable-frequency strobe and played with it a lot.

You might borrow a strobe and do some tests to see if you are one of the unlucky ones. Even if the test strobe is not perfectly synced to the lathe it should be enough to see if you are sensitive. Try mixing the strobe light with some non-flickering incandescent light or daylight. I suspect that even a small amount of strobe light in the mix will stop the movement enough for you to see what you want.

A mix of light at the lathe may actually be better for safety reasons since you will still see the shadow of rotating corners and other sections of the off-center piece.

BTW, I find certain CFLs and LED bulbs make an annoying strobe effect on turnings. Others don't. (The persistence of phosphors varies as does the frequency in different brands.) Since I have multiple lights over my lathe I use a mix of different types of lights which smooths things out where I can't see the effect. Rogue bulbs can transmit electrical noise through the air as well. I had one bulb that made one digital caliper go crazy when I brought it within two feet of the lathe!

JKJ

Re: Strobe source for the lathe?

Dale Miner

Looks like you understand that you need a trigger that keeps the stobe in sync with slight rpm changes. You will also need a way to time the flash to occur where the cutting action on the part is taking place.

I used to do vibration analysis and often used a strobe to 'look' at problems.

One thing that you will need to be careful of is a tendency to reach out and touch the apparent non-moving part. Sounds like a no brainer, but is is very easy to focus on the rotating apparent stopped part and put fingers in where emergency room visits result.

Thanks Everyone

Keith Newton

Rather than order and having to wait on it to come in, I tried something that was simple and worked pretty well. I've got a few bright flashlights and headlamps that i used. One that I know JKJ doesn't like mainly because of the switch.

My turning, is a cherry sphere about 10" D, which I hollowed out to about 2" thick through 1.75" hole. I then made a sub-faceplate from 3" thick Black Tupelo, which I cut a 20º wedge out of the face on one end. I mounted the first blank on that face, then using a laser set up to project a dot on the center of the arbor, mounted it, where the center of the opening was again located on the center axis of rotation.

When I started, I thought I'd probably use 4 different lobes inside, but after getting the first side out to about 3/8" thick, it consumed almost half of the original inside, so I rotated it 180º, and did the other side.

I was thinking about carving the outside in a seedpod shape, like some I did about 10 years ago. But there is a bird theme sneaking in there trying to nudge the pod aside. I wish I could keep going on it tonight, but I have been having a nerve thing shooting down between my neck and left shoulder, that feels like I've been stabbed with an icepick. that kinda takes the fun out of pushing on through.

Re: Thanks Everyone

John K Jordan

I'd love to see a picture of the setup if you have one - I'm too dense to understand the shape you are turning. But do you mean you made a "strobe" with a bright white light shining through a cutout in the sub faceplate? If so, that's brilliant! Automatically perfectly synchronized with no electronics and no expense.

Re: Flicker sensitivity - You might do a test

Ric Taylor

What John says is true. "Flicker vertigo" or "Flicker Syndrome" as it is known in the U.S. Air Force, has been designated as the cause for several aircraft accidents, mostly in helicopters. Sunlight passing through rotating propellers or rotor blades as just the right angle and frequency can cause a hypnotic effect on some pilots.