EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: rozeh on December 02, 2013, 09:43:55 am
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Hi guys
I bought a WL-500A Mini Hand Drill (http://www.tmart.com/WL-500A-Mini-Hand-Drill-Nail-Manicure-Machine-Nail-220V_p171044.html). it has a problem. when I use of it for drilling the fiber(PCB) by 1.0mm "bit" it bad work. :palm: I think the "chuck" of it is lopsided. in your opinion, how can i repair it? with shorten the "bit"?
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If the chuck is bent there isn't much you can do but return it.
It will be hardened metal and will probably break if you try to bend it straight.
Check that you have the drill bit inserted correctly with the right collet
Sometimes with chucks and small drill bits the chuck can close with the bit jammed (not centered).
Also check that the drill bit itself is straight.
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I doubt that that drill can make a precise small hole, even with a perfect bit.
You need something with ball bearing like Proxxon, and a drill stand.
Maybe it's a little more expensive, but this is the cheaper price for that kind of precision holes.
http://www.proxxon.com/en/micromot/28500.php?list (http://www.proxxon.com/en/micromot/28500.php?list)
http://www.proxxon.com/en/micromot/28606.php?list (http://www.proxxon.com/en/micromot/28606.php?list)
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y 1.0mm "bit" it bad work.
define "bad work". What exactly is the problem?
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You need something with ball bearing like Proxxon, and a drill stand.
I second that! And some good drill bits, e.g. from Bungard.
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Thanks guys :)
define "bad work". What exactly is the problem?
So, it does not drilling in center.
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You always get run out with drilling machines, some have more than others, accuracy costs money. A very small amount of run out will be amplified by holding it in the hand so put it on a stand as that will help.
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Those type of drill holders are bad for small drils. I always had problems with drills smaller than 1.5mm. Drills were basically falling out of it. Solution was to wind some copper wire onto a drill so its diameter is bigger then screw into the machine, then it held and worked fine.
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So, it does not drilling in center.
Do you have a centering divot?
A drill bit will naturally wander before biting when you are holding the drill by hand. If you are etching your pcbs, ensure that there is a hole (narrower than the drill diameter) etched in the center of the pad you will drill to center the bit.
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1mm is relatively large for such a small drill.
You could try drilling a 1mm hole in 2 or more steps.
When drilling a large hole in steel you usually centerpunch, center drill, drill the hole in several steps.
This is due to drill geometry:
(http://www.anca.com/getattachment/ce908d8c-7e91-4aff-975e-a87c62824788/drills-101-2.gif.aspx?width=250&height=241)
The web of the drill doesn't actually cut material all that much. So when you start a hole the web causes the drill to wander about.
Often you can drill a small hole (larger than the web size of the large drill) first, because a small drill has a small web, which means you can sometimes get away with not drilling a centerhole first.
After this the web on the larger drill will not "cut" any material. (it will rotate in the small hole)
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I second that! And some good drill bits, e.g. from Bungard.
Also this (http://it.rs-online.com/web/p/products/666-5669/) are good drill bits
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This drill is a total shit. You can find it under 100 different brands, also a a manicure tool.
Cheapest thing I've found to be working reasonably good will be a full-sized dremel knock-off. You can buy those in most diy&hardware stores (for example MacAllister brand in Castorama). You want to check the runout before making the purchase, ideally with a clock indicator, but you can do it by eye too.
Good drill bits = carbide ones. And those are brittle. If you try to use them without a good drill and stand you will break them and they are not that cheap.
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@G7PSK
The problem is not my hand!
I think the "chuck" is not straight.
@sleemanj
divot?
@FJV
Great! Good point!
Also I think use of a pipe that has a diameter equal with the bit can be good. mean, for drilling you put the bit in pipe and turn on the drill.
@mcinque
Are you a marketer, friend? ;D
@poorchava
I agree with you completely!
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@sleemanj
divot?
Center hole.
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Do you have a centering divot?
[ok]
no.
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I second that! And some good drill bits, e.g. from Bungard.
Also this (http://it.rs-online.com/web/p/products/666-5669/) are good drill bits
They look fine too, but are a little bit exensive. The Bungard drill bits are EUR 2.50 each.
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I have similar drill to OP's and one thing that helped a lot with bit moving was to first press the drill onto the PCB, rotate the chuck a few times by hand and then turn it on. This way, the bit will make a small starter hole and not jump around.
The bad side of the story is that this procedure slows down the speed of drilling, since a short pause between each hole is needed.
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I would think that that pause wouldn't be a big deal. I have to pause between every hole I drill as I have a bit of a depth perception problem. I turn off my drill and lower the bit to the board. When I am satisfied that I am lined up correctly, I turn the drill on and make the hole. I use a dremel with the associated drill press. I fudged too many holes before I slowed down and did it right. For really small boards with only a few components, I do it by hand. I don't worry about the time factor. On my old job, we used to say that there was never enough time to do it right but there was always time to do it over.
Tom, NW0LF