WC 1 - LT 0

[Steve Maskery]

Steve's Tip of the Day

When using one of those nice, small, light, easy-to-hold-in-one-hand trim routers that don't have handles on them, like the Kinzo, don't stick your left thumb through the hole in the side when the tungsten carbide bit is going round at 26000 rpm, because if you do, it will hurt.
<captainmainwaring>Stupid Boy</captainmainwaring>

 

[AES]

Like hell I'd imagine! "Gute Besserung" Steve

 

[Racers]

Ouch! Hope it’s not too bad Steve.

Photo is required, just to warn others.

Pete

 

[Steve Maskery]

Oh, it's not that bad, but it's a tiny bit of flesh that's gone rather than just a cut. Nothing to stitch up. It just looks as if I've tried to countersink it for a No.6 screw. It does throb somewhat.

I'm not taking the plaster off just to take a photo, Pete!

 

[AES]

Come to think of it, I think someone did once tell me about not sticking my fingers into little holes. :wink:

 

[banjerbill]

With some of the kit we use it's a wonder most of us still have all our digits. I think nearly everyone has had a near miss or an injury that could have been a lot worse.

"Let's be careful out there".

 

[Eric The Viking]

I really, really sympathize.

I only just stopped myself doing the same thing a couple of week-ends ago, Using my little Bosch POF600 to put a bevel round something: there's a convenient thumb-sized area on the baseplate, surrounded by some castings. They protect you from the cutter, unless you pick the thing up facing the other way round and start using it.

And if you do that, don't start feeling about for the castings that aren't there... I only just realised in time.

Hope it heals quickly.

E.

 

[Eric The Viking]

By the way, modern LED lighting is likely to strobe quite well, meaning part of the arc of a spinning cutter can go invisible.

It depends on the circuit design for the LEDs, but if they do pulse on/off, they will do it far more "effectively" than fluorescents will.

I've just replaced the bulb in the pillar drill with an LED one as an experiment. It's one issue I'm (literally) looking out for. It shouldn't be too serious on a pillar drill, so it's a "safe" place to test it.

I may be wrong, but I've a vague feeling that back around the 1950s or 1960s the HSE banned (or at least deprecated) the use of fluorescent worklights on lathes for exactly that reason - they had to be incandescent.

E.

 

[AES]

Interesting EtV. I've just fitted a small "long life saver" bulb into a small lamp on my lathe. I presume it's some sort of fluorescent as it consists of a small "coil" and takes a little while to "warm up" to full brightness (I had a teardrop-shaped incandescent bulb for a sewing machine light in there before).

I also have a small "double strip" of LEDs (also for a sewing machine) on my scroll saw.

But in neither case do I notice any stobing effect, though I must say, there's not a lot of "roundy roundy" motion to be seen on the scroll saw. (Do LEDs pulse with the mains frequency like fluoros?).

 

[Droogs]

Hi Steve,
glad it wasn't more serious, perhaps we should pass the hat round and get you some of these

Does show though, that even the most experienced of us can make a ****oo at times

 

[Doug B]

That’s not idea Steve, hope the throbbing has subsided some what this morning

 

[AES]

Yup, as said before Steve, not really "funny" at all (sorry to extract the Michael) - "Gute Besserung"!

 

[bourbon]

Hi Steve,
glad it wasn't more serious, perhaps we should pass the hat round and get you some of these

Does show though, that even the most experienced of us can make a ****oo at times

don't use these, You will blunt the cutter! lol Hope you heal ok Steve

 

[Steve Maskery]

I've had to change the dressing, so here it is in all its gory glory, 24hrs on.

It could have been much, much worse.

 

[Racers]

Yeah, it could have been in focus!

:wink:

Pete

 

[Steve Maskery]

I know but I can't hold the phone steady in one hand...

 

[Droogs]

=D>

 

[Eric The Viking]

Interesting EtV. I've just fitted a small "long life saver" bulb into a small lamp on my lathe. I presume it's some sort of fluorescent as it consists of a small "coil" and takes a little while to "warm up" to full brightness (I had a teardrop-shaped incandescent bulb for a sewing machine light in there before).

I also have a small "double strip" of LEDs (also for a sewing machine) on my scroll saw.

But in neither case do I notice any stobing effect, though I must say, there's not a lot of "roundy roundy" motion to be seen on the scroll saw. (Do LEDs pulse with the mains frequency like fluoros?).

All depends on how the LEDs are being driven. If they get rectified AC that's not smoothed they will switch on and off with the waveform, at least once per cycle (twice if full wave rectified). I have experimented with my bench power supply, and it's not as sharp an on/off as I thought with changing voltage, but there's no lag that you might get from a phosphor glow - off is instantly off.

I know too, that one way of improving battery life in portable kit is to pulse LEDs at fairly high frequencies (kHz), which fools the eye/brain, but lets them be off for a significant proportion of the overall time, and obviously that will strobe with spinning cutters - I'll try it with my drill press. It ought to be possible to work out the frequency roughly, if the press RPMs are reasonably close to what's in the speed table.

I suspect the "assistive light" LED on my Samsung phone and tablet both are strobed by the driver circuit. When you use that LED as a "flash" with the camera it seems to be brighter, and I suspect that's because it isn't strobed for that function (and the brain integrates to some extent). Similarly, my bicycle front light has three settings: flashing, continuous but dim, and full brightness. There is not enough room inside it for power-limiting circuitry, so I think the middle setting is done by strobing it.

I will do some experiments to see if any of these cause issues with the drill press and or routers.

 

[novocaine]

it's called Pulse Width Modulation (PWM) and it's very very common in LED drivers to supply different light levels. we are talking 100-1khz though, so any strobe effect is going to be pretty minimal at that rate (6000-60000 RPM equivalent), at around 70hz you will see noticeable flicker (4200 rpm), I have some unsmoothed mains LED bulbs in the living room (because the wife want's the "eddison style" bulbs), they flicker at 50 hz (3000 rpm), you can't see it until you wave your hand, then it's like being in a disco. in the workshop I have LED strips (4 off, 3 over the bench) and 2 LED panels, both have smoothing capacitors in, minimal flicker and dirt cheap. you can buy the driver separately for LEDs, buy one that has a full bridge rectumfrier and capacitative smoothing with no dimmer function.

I also use a USB led lamp plugged in to a power bank on the scroll saw (can move it around) that has no regulation and is flicker free.

Edit: oh yer, forget to say, sorry about the finger, you'll be reet, but I hope you aren't traveling to the states anytime soon, your fingerprint is going to be somewhat different for a while (I got pulled for 30% difference on a trip but it was easy enough to explain to border control once they saw the burn marks from the sanding pads)

 

[AES]

Interesting info, thanks both (all this "electrickery" is a big of a black box to me).