LED worklight conversion for Bench Grinder.

[VanIsleDSM]

I bought this 8" bench grinder for grinding tool bits for my mini lathe.

I made the heatsinks for the high power LEDs on my lathe.. 2 left over ebay 3watt LEDs. They differ in colour output so I thought this would be a fine spot for them.. where it won't matter. Power to the original lights from the grinder was 12VAC, I put in a full bridge rectifier with some diodes and drove the LEDs with an LM317 constant current mode, plus a 920uF cap to smooth the out the AC. You can see the LM317 and it's resistor under the heatsink that's mounted on top of the old bulb socket... I did everything so it could be reversible should I need to return the grinder under warranty.
I started a discussion talking about the rectified current through the LEDs with different capacitors and such here:
http://www.candlepowerforums.com/vb/showthread.php?p=2417501#post2417501

Original bulbs were 10watt each.. and were absolutely useless.. they weren't placed out far enough so the wheel just casts a huge shadow over the work area.

The 3watt LEDs could be placed much nearer to the ends of the plastic shrouds.. reducing the shadow a lot.. but there's still some left.. what a bad design, still, much brighter though for a fraction of the power.

I thought about moving the LEDs outside of the shroud to get a better angle to project the light from, but decided not to because I wanted to keep the LEDs in the protected shroud behind the clear plastic.. and a more original look, so I devised some reflectors.

I'm very pleased.. and I can see now! The reflectors are just some thin aluminum with mirrored mylar laminated onto the business side... I may end up painting the backs of them black to match the grinder better.

Well that's it, hope you enjoy the pics, they were taken on manual with the same settings for a consistent comparison.

Now I need to modify the tool support on the left wheel so I can actually change the angle on it.. the original is just stuck where it is.. you can move it in to compensate for wear on the wheel.. but no angle adjustment.. I've just been grinding tools freehand since I got my lathe... I'll do something about this soon.

 

[jrminky]

Very nice. Maybe it's time to make a similar LED modification to my router!

 

[VanIsleDSM]

Thanks.. it really does help a lot.. I hate it when I can't see perfectly what I'm doing.. especially with small precise things.

I just did the sander too.. and I'll be making a 4xCREE work light for my lathe soon as well.

For the sander I just used a 4.8v 350mA old motorola cell phone charger with a 3.6ohm resistor.. makes for 310mA through the LED.. I took it apart (that was a struggle, as you can see by the casing, but I eventually won) to get rid of the prongs and feed some wires in.. it then just barely fit into the electrical box on the sander.. Hooked it up to come on with the sander switch..

The reflector is some old flashlight reflector I found laying around, originally I had this LED under the palm tree outside but decided to replace it with a much brighter CREE.. this one is an ebay china edition of a luxeon III.. could be authentic even, looks like it.. but I dunno, same type as the grinder. I wanted to eliminate some side light while it was under the tree..hence the reflector.. it ends up making a little hotspot in the middle... well, here's the pics.

 

[carmatic]

wow, comparing the before and after pics of the grinder with the lights on, i must say it looks alot sexier with the led's !