Thread: Getting better knurling visibility

My knurling has been done on a suck it and see basis. I know some suggest working out the suitable work piece diameter based on knurl pitch but I ain't a mathmetician nor a fitter and turner. If I mangle the knurling I cut it off and have another go. A good thing sometimes not working to a drawing.

I stop and toothbrush off the swarf then repeat the process until I end up with sharp points on the knurl. The strobe idea sounds neat but I wonder how visibility would be affected by oily swarf.

B rough and ready T

Hi Michael,
Some time ago, before I got into metalwork, I remember a couple of mates talking about fitting a timing light to a lathe. I had no idea what they were talking about back then but it makes sense now. Not sure how easy it would be to get the timing right though, I have no idea how a timing light works........

Hi Michael,
I cant see why it wouldnt work, though some sort of optics to keep you away from the moving parts would be handy. I was thinking with would be pretty costly to try but a clever fella could add a timing circuit to the trigger of a car timing light(remember those? lol).

Hi BT,
I was taught either use flood coolant so swarf is washed away or everything clean and dry so there is no oil to stick the swarf to anything. Still, your way seems to work just fine.

Stuart

Originally Posted by Ueee

Hi Michael,
Some time ago, before I got into metalwork, I remember a couple of mates talking about fitting a timing light to a lathe. I had no idea what they were talking about back then but it makes sense now. Not sure how easy it would be to get the timing right though, I have no idea how a timing light works........

Regarding the discussion this morning about timing lights.
The only timing light I have, is one that is connected to the spark plug of an internal combustion engine & checks the timing of the ignition by flashing a strobe light onto the flywheel of the engine so as to be able to see the mark on the flywheel at top dead centre of ignition.
The timing is then adjusted by rotating the distributor.
Needless to say I do not use it these days, & dont think it would have application on a lathe.
Its a quality piece of equipment
regards
Bruce
ps After reading about Bobs knurling from the rear toolpost, I have just made up a new packing piece to do the same with my scissor knurl.
Great idea again Bob, thanks.

I've just realised that a strobe wouldn't have to be adjustable - all you would need is a switch & cam (or similar) arrangement so that it fired as the chuck rotated but always in the same spot. Possibly that auto timing light would do the trick after all?

Michael

Hi Michael,
How fast do you knurl? Likely to slow for one flash per rev to be much use. I'd think you'd need something around 900rpm? But then switching would become a problem.

Stuart

Stuart, I've actually been waiting for one of the more electron-ically minded members to jump in at and explain how all this is so easy because they can just link up a xyz module to a dooverflicky and it will be done.
Usually I don't knurl much faster than 300 to 500rpm but you are right - thinking about it, I'm likely to get switch bounce if I go mechanical.
Technical issues aside, I still think that it would be a useful thing to have - I tend to either 'underknurl' or 'overknurl' and it would speed up the process if I could see how I was going on the fly.

Michael

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

The pick up of a timing light (from those early days) is a capacitive coupler.

I simply stop and have a look at the knurl. That doesn't hurt the knurl.


Nick

Hi Micheal,
500rpm might, do it(?). Thats almost 10fps but I'm not sure you should be running a strobe light around that speed. Though I guess you would know by now if you had Photosensitive epilepsy.

Hi John,
I'm not sure your idea will work as the ferrite core in the leads I have seen closes around the lead...... still wouldnt hurt to try. I would if I had one .
One idea that crossed my mind was to clip it around one phase on a VSD. Not sure if that would work either.

Stuart

Originally Posted by Stustoys

I'm not sure your idea will work as the ferrite core in the leads I have seen closes around the lead...... still wouldnt hurt to try. I would if I had one .
Stuart

Just tried this with my timing light. Didn't work with a magnet. Only had a small fairly strong magnet from a broken pickup tool.

Nev

Originally Posted by Stustoys

Hi Micheal,
500rpm might, do it(?). Thats almost 10fps but I'm not sure you should be running a strobe light around that speed. Though I guess you would know by now if you had Photosensitive epilepsy.

Stuart

Impressive Stu. Your interest in amateur medicine is paying dividends.

Hi Nick,
How does one going about fooling a capacitive coupler?

Hi Nev,
Pitty. Were you moving me magnet fast?

Hi BT,
Dont you start............I've been shopping again but you'll have to wait until later tonight to see. lol

Stuart

It seems the the clip on the timing light is called an "inductive pick-up module", and that appears to be a variation of a hall effect sensor,

RayG would have the smarts on this.

Don't forget also that the timing light on a car only strobes every 2nd revolution as it is running off the camshaft eg 2:1, so at 200 rpm on a lathe you get 200 strobes/min

Surfin Nev, what speed did you try it at ? I'm wondering if it has something to do with the rise and fall time of the magnetic field ?

john

ps, yeah I know I haven't a clue