Thread: Getting better knurling visibility

I once made an electric fence energizer with a 240 to 12v AC power supply and a car coil, it made my son turn white and he made a funny noise like a girl so I knew it worked

The cattle didn't want anything to do with that fence either.

It was only a temporary device so the dog could have a rest till I got into town to get another fence energizer.

something like that would run a timing light, have fun

john

Varied what I did with the magnet but may not have been fast enough. Will give it another go sometime. I know there's a better magnet around here somewhere. Maybe use a magnetic base?

Nev

Varied what I did with the magnet but may not have been fast enough.

If you insist wasting your time with the hall-sensor route:
Hold the "sensor" near a flashlight and switch it on/off. Hall sensors's signal is proportional to the magnetic field (-> current).

The orientation of the sensor has to be right!


Nick

If you have an iPhone or Android phone there are numerous strobe apps available. Some strobe the screen which doesn't seem very useful. Others strobe the LED camera flash. I just installed one on my Android phone and tried it on my lathe chuck at around 500RPM. It was useless because the strobe speed isn't constant. Maybe the iPhone is better? Might be worth a try.
Chris

Originally Posted by shedhappens

Micheal I think that the pick up clip/clamp on a timing light is just a Hall effect sensor, and that sense's the high voltage magnetic field that is produced around the coil lead each time that it is that cylinders time to go bang, so in theory you could glue a magnet to the back of the chuck and mount the high tension lead pick up as close as practical to the magnet and it should work.

I don't think you would need to disassemble the clip on the timing light as the magnet you use will be stronger than the magnetic forces from the high voltage discharge from the H T lead.

Also the the timing light would have to be a powered one that you clip onto the car battery, not one of those useless non powered neon tube pieces of sh#t .

john

disclaimer : I could also be talking total crap because I have not done this, but nothing ventured nothing gained

I think the hall effect pickup on the timing light would need a HT pulse to trigger. The coil in the flywheel of an old lawnmower or stationary engine would work but it would how do you attach that to anything on the lathe?

Better to have a small magnet and a reed switch (not sure how fast they can switch though) connected to some electronics and then connected to the pickup on the timing gun.

Other option is to take apart the timing gun and where the trigger input signal goes (assume its a simple square wave) that activates a discharge on the xenon globe, attach a variable square wave. Can be a PIC generated variable square wave. Then just adjust the pot until the workpiece becomes stationary. You get several bites of the cherry with that because it will work at any multiple of the frequency. Example if it's doing 1000rpm then 16.66 Hz, 33.3Hz, etc will show it as stationary.....

Or, you could just turn the lathe off and have a gander!

Simon

Is this in depth attempt to see how well your knurls are turning out for a production run of knurling to a tollerance or just Joe Blow working in his shed.

Originally Posted by simonl

Example if it's doing 1000rpm then 16.66 Hz, 33.3Hz, etc will show it as stationary.....

Hi Simon,
I don't think so. 16.66 and 8.33, 4.165etc would, but 33.3 would show you 0 and 180 at 1000rpm(not the end of the world as long as you have a even number of points.
I think in this case you'll more likely be doing 300rpm and flashing at 10Hz(which could be a bad thing), so lets say 40Hz which means you need at least 8 points on the dia. Fine for even numbers of knurls, you'll need a tweak for odd numbers though lol. Which might have been what you were saying in the first place

Hi PC,
Does it matter?

Stuart

I suppose it stops you from being over productive.

Being productive is just about the last thing on my mind.
Even then I'm more productive than playing golf.

Stuart

Originally Posted by pipeclay

I suppose it stops you from being over productive.

Hi PC,

Don't know about the others but I'm just spit balling..... It's not all gunna gold either!

Simon

Originally Posted by Stustoys

Hi Simon,
I don't think so. 16.66 and 8.33, 4.165etc would, but 33.3 would show you 0 and 180 at 1000rpm(not the end of the world as long as you have a even number of points.
I think in this case you'll more likely be doing 300rpm and flashing at 10Hz(which could be a bad thing), so lets say 40Hz which means you need at least 8 points on the dia. Fine for even numbers of knurls, you'll need a tweak for odd numbers though lol. Which might have been what you were saying in the first place

Hi PC,
Does it matter?

Stuart

Ha your right, I should have halved the freqs, not doubled!

For those saying why bother, I raised the idea because I wondered if it was possible and if anyone had done it. I haven't because I haven't the equipment but someone may have the necessary gear in their shed to experiment and report. I think it's interesting to throw the occasional odd idea up. Certainly from this thread there has been a bit of thinking going on and discussions on how it could be done. Stopping the lathe is an option (and what I do now) but who knows there might be a better way out there for looking at knurls or other things.
I'll be interested to see what the timing light crew come up with but if all else fails, there's always plan B -

Light Emotion Mini Strobe, Black, 20w | eBay

As for health concerns, there is no reason a strobe can't be run at half speed (or third or quarter etc) as I doubt the knurl will change that much in a revolution.

Michael

Originally Posted by Michael G

As for health concerns, there is no reason a strobe can't be run at half speed (or third or quarter etc) as I doubt the knurl will change that much in a revolution.

Yes there is, if the flash is to slow you wont get what you are after. At 300rpm its turning 5 times a second. 5 frames a second is(I would think, its been a long time. tv is 25fps) a little on the slow side(after all you are trying to do more than line up a white line with a black line. i.e. car timing). 2.5 times you could do by hand . So that leaves you with multi flashes per rev. Now depending where you get your figures, you might want to stay out of the 5 to 30 Hz range.
Does timing become more or less critical when the flashers are closer together? less I would think?

Stuart



Strobe Light Induced Epilepsy | WindWorks Design/Blog

OK, after (or during) this discussion, here's a cool video taken with a strobe light. Of course, it's absolutely metal-working-related. Even is running on a lathe.
Sorry, no knurls were raised.

[ame="http://www.youtube.com/watch?v=q2PP9P-p79w"]Video on YT[/ame]


Nick