DIY Mini PCB Table Saw

[G. Hoffman]

I'd say that the blade is a bit high if you're only cutting pcb material max 1.5mm thick. Also, I would use some kind of bearing, you can get pressfit bushings, but these will also not last very long with the threaded rod gnawing it's way in there, ideally ball bearings can be used there maybe use epoxy to tie the threaded rod to the inner ring of the ball bearing.

ABSOLUTELY!!!  The blade of a table saw should almost never be more than about a tooth's depth above the top of the workpiece.  You could improve this pretty simply by putting a piece of plywood or something like that on top to act as a scrap table, and make sure you bold it down.  This would also give you the advantage of a larger table, and you could even work up some kind of fence which would vastly improve safety.  Also, by doing this you would have a zero clearance plate, which pretty much eliminates most chipping and tear-out.

And a bearing is also very important if you want the thing to run at all true. 

I also have a slight problem with the saw blade.  If I'm not mistaken, that's a screw slitting blade.  They are wonderful things for certain purposes, but they are not intended to cut through things.  Now, that may not seem like a big deal, but the problem is they do not have any set to the teeth, which means they will tend to bind, burn, and to dull very fast. 

The band saw is infinitely safer that the table saw types.

Yup.  While it is, in theory, possible to cut off your finger with a band saw, I've never been able to figure out how.  I know that a lot of people every year do so, but it isn't NEARLY as big of an issue as table saws.  The two primary dangers with saws are self-feeding and kickback.  Radial Arm saws are self feeding, and table saws will kick-back.  Band saws don't do either - in order to cut anything off, you have to actually push it the whole way through.  I've nicked my fingers on my band saw a couple times, and while I don't recommend it, they were both Band-Aid injuries.  Your typical table saw injury costs over $60,000 in medical expenses.  (Not all band saw injuries are as minor as mine happened to be - I was very lucky.  Don't push your luck.)

A table saw is a VERY different animal.  It can grab your hand and cut things off faster than you can imagine, and running the blade at a slower speed can actually make things worse.  First of all, the blade will be MUCH more likely to catch, kickback, and to throw the work piece (including, potentially, right at your head, which can have enough kinetic energy to make you a vegetable!)  Also, somewhat counter-intuitively, you can build up more heat at slower speeds, because at higher speeds (and, more to the point, higher feed rates) the dust from the workpiece work will work as a lubricant.  It does depend on the material, and with metals that doesn't work, but with the fiberglass faster speeds tend to make the blade safer.


Gabriel

[Jarno]

I think most injuries with a band saw occur BECAUSE it seems so well mannered. "let me put my finger against the workpiece there to make that tight curve", and oh oh, there it goes.

[G. Hoffman]

I think most injuries with a band saw occur BECAUSE it seems so well mannered. "let me put my finger against the workpiece there to make that tight curve", and oh oh, there it goes.

Actually, I'm pretty sure that most serious band saw injuries happen in butcher's shops.  Certainly, no woodworker I've ever known has had one.  I know there are guys who have, but I've never met one.  Same for metal workers.


Gabriel

[markeebee]

I just watched that video that someone posted earlier - the feller that had made a saw table from a dremel and a plastic stool.  It gave me a funny feeling in my willy, and not in a nice way.

All those spinning sharp metal things scare me.  I've got a fairly well equipped metal-bashing workshop, but I try to do things using hand tools wherever possible.  If I really have to use the big dogs, I'm keen on clamping stuff down really well, and wearing more protective clothing than a tiger trainer.

I might be a fraidy cat, but I've still got my good looks.  And all my fingers.  BE CAREFUL OUT THERE! 

[BRingoC]

I have to chime in on this.  That thing is AWESOME!  That is some amazing resourcefulness for sure, it's like a pocket table saw.  I thought of something, you said you are using oil for the lubricant for the shaft.  Rollerblades use a ball bearing system that is sealed up and interchangeable, you might look into those for a better fitting and less ad hoc axl.

[Processaurus]

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90757

I use a shear as well, or a hacksaw.  PCB's are often so small your fingers will be uncomfortably close to a power tool, if something grabbed, etc.  When things happen with power tools, they happen fast.  Say your naive medieval grease only axle gets hot and dries up and seizes, the whole saw seems like it will flip up towards you, since it doesn't look like it is secured down, or very heavy...  Sorry Karl, I don't like it.

[G. Hoffman]

All those spinning sharp metal things scare me.  I've got a fairly well equipped metal-bashing workshop, but I try to do things using hand tools wherever possible.  If I really have to use the big dogs, I'm keen on clamping stuff down really well, and wearing more protective clothing than a tiger trainer.

Typical metal worker!  

It's a funny thing - metal workers usually have their work piece clamped down, and either move the table or move the cutter.  Woodworkers usually do not clamp down the work piece, and keep the table and cutter stationary.  That said, if I were to cut circuit boards with a table saw, I might be tempted clamp it to a sliding table to insure my fingers were well out of the way.  I do something similar for the wood pickup rings I make.

Be careful about clothing when using power tools.  Gloves and long sleeves have a tendency to get caught in blades and such, which is REALLY dangerous.  It may be different for metal working, where your hands are usually further from the danger and the metal filings are a bigger concern, but with a table saw the safest clothing is long pants, normal shoes with good traction, a tee shirt, and no dangling jewelry.  Its best not to wear a wrist watch either.

Oh, and Norm Abram is wrong about the most important safety precaution being safety glasses - they are hugely important, but the most important safety precaution is knowing how a tool works, what will go wrong, and how to position yourself so that WHEN it goes wrong you're not in the way!  I caught a very small piece of debris (maybe 1/32"X3/4"X6" - just an off cut that fell between the blade and the throat plate, and got kicked back) in the shoulder once - and have the scars to show for it - and it drove home (quite literally) the importance of keeping out of the path of danger.  I was lucky it was small and all I got were a couple puncture wounds and a big bruise - it was small enough not to have enough kinetic energy to do any serious damage.  By the time I noticed the cut off was falling into the blade like that, it had already bounced off my shoulder.


Gabriel

[G. Hoffman]

Say your naive medieval grease only axle gets hot and dries up and seizes, the whole saw seems like it will flip up towards you, since it doesn't look like it is secured down, or very heavy...  Sorry Karl, I don't like it.

VERY serious concern. 


Gabriel

[jacobyjd]

There aren't many power tools that make me nervous--I was taught how to use most types of them properly (lol...except for the safety guards--those were always removed) from when I was little.

My grandfather's custom furniture shop still has all kinds of nice machinery sitting unused since he passed. The only one I haven't used is the raised-panel router table, because I'll never forget the day Pap wrapped his hand in his handkerchief and drove himself to the hospital while everyone else was still trying to call 911.

He lost 2 fingers to a 4" version of one of these:


I get the same feeling when I see ANY kind of makeshift table saw. I'd stay FAR away from that stool one. Woo.

[mikemaddux]

  Im scared of this thing

[R.G.]

When things happen with power tools, they happen fast. 

Yeah - and the machine doesn't stop to see why you're yelling. One thing my previous employer was persnickety about was training on power tools. No training certificate, no operation. Firing offense. I had to get "trained" to use the manually operated lever-shear and brake in the shop. The training for these two consisted entirely of "OK, you put the work in there, pull down on this lever here, and you're done. Don't put your fingers in it."

I was young then, and had been raised on the maxim "Question authority". Had a couple of T shirts that said that. So I asked why the training course was days or weeks on the power equipment and so nearly-nothing on the manual stuff. The machinist training me grinned and replied "We all figured out long ago that if you're supplying all the power by hand to a whatsit that's hurting you, you'll stop on your own before it gets worse. A power tool doesn't stop." Then he signed off on my manual-tools-only training chit and handed it to me.

[R.G.]

You know, it occurs to me that I slice and dice more than 25 PCBs a year. Before the shear, I used a hacksaw. Not pretty, perhaps, but if you clamp down the PCB in a vice or on a table, you can get nice straight edges. A little sandpaper and the PCB looks routed.

Or a coping saw. Or a jewelers/fretsaw.

I can't think of the last time I heard of someone accidentally sawing off a finger or two with a hacksaw... 

[petemoore]

When things happen with power tools, they happen fast.  
   

[petemoore]

  While looking for a mellow saw in the Dewalt, Ryobi, B&D etc. catalog at Lowes, we discussed saws and bigger trucks with more towing capacity, noting a likeness, except where lower powered saws are concerned.
  I turned on a circular saw:
  The Lights Dimmed.
  The saw tried to jump out of my had.
  The overstressed side-bearing and general fierce chatter is enough to make you want to find a different cutting method alone. The numerous test cuts were each total failures. New blade/straight edge, depth set etc.,
  The grain is blown to splinters on both but severely on the deep face grain.
  The clamped straight edge line is shown as a wavy line where the blade cut.
  The squareness of depth cut is wavy too.
  Plumes of smoke, fried blades, burnt bearings...
  The other circular saw had a little bit better looking body, aesthetically speaking.
  I designed the Rail Saw. It doesn't have enough current to start wood smoking or heat a blade,
  The ''Twin Rail Guide'' [modded radial arm saw arm, just the ''arm'' thank you] gets clamped 2'' from where the cut line, and controls the slow RPM blades teeth, keeping them in a more perfectly straight, square line, instead of reaching all the way around the back of the workpiece, up the pole, back out the arm.
  The Auto-Super-Slow Drive system [allows the blade to nibble on a few fibers each pass] is a simple slip-clutch driven Rail Guide Screw, it advances the blade [specially designed so it can't take large bites] at a snails pace.
  Very slow, very limited cutting depth, ability to go back in it's bag and hang in the closet after making perfect rips, crosscuts, dado's...all the stuff the amazing powertools just can do [if you like super-high-speed 3-blade-pack prices, radial saw footprint and price].
  I've got time to take breaks while the wood glue dries...and there are many extremely important safety issues which require time to contemplate, while the snail-rail-cutter does it's fine workpiece preparations, you'll have time to do these contemplations.
  Necessity is the mother of invention, seems like such an obvious thing...oh yea...almost forgot the slide/clamps on the bottome of the Snails Rail Saw.
   
   

[G. Hoffman]

You know, it occurs to me that I slice and dice more than 25 PCBs a year. Before the shear, I used a hacksaw. Not pretty, perhaps, but if you clamp down the PCB in a vice or on a table, you can get nice straight edges. A little sandpaper and the PCB looks routed.

I'm using the score and snap method, and then I finish the edges with a tile dressing stone.  It takes longer than I like, but the edges are perfect, and I can be extremely precise with where I cut it, which I like.  I've gotten to the point now where it takes me maybe a minute for each edge.  Occasionally, when I need a weird shape, I'll use a coping saw, but I still finish it with the dressing stone, as it leaves a really nice finish very fast.

Still, there is a part of me that wants to get a little band saw for my house, which is where I do all my electronics tinkering.  I'd use the one at the shop, but it takes me less time to do it here at home (because I don't have to go down there), and I neither want to dull our woodworking blades nor to have to constantly change them (which is a PITA).  Its just hard to find the space for a band saw here in the house.


Gabriel

[bluelang]

http://www.probotix.com/FireBall_v90_cnc_router_kit/

[MoltenVoltage]

Well, I certainly wouldn't want anyone to get hurt copying this idea, so do so at your own risk!

Will post severed finger photos as they become available...

[foxfire]

well i like it...if you loose a finger with that thing you deserve to loose a finger. i'm not saying that to be a jerk...if you don't have the commonsense to know how to use a tool like that then you probably don't have the common sense to know that you shouldn't use a tool like that and it might be better to learn your lesson and hurt yourself on a this little guy than a unisaw.  i'll bet a dollar that that drill doesn't have any where near high enough rpm to over heat the grease and if your running it for that long then you should be looking for a better way to do it. with that said a set of bearings would probably be worth it in the long run. and yes mounting it would not only make it safer but easier to use.

i've been a wood worker for 20 years now and i can easily say that i've cut myself more times with a utility/exacto knife than i have with a table saw and i've been a cabinet guy for the last 8-10 years...
 
i will say that the dremel footstool saw scares the crap out of me...

[petemoore]

  Jaco, my older brother [the Real Guitarist of the famm], was making the rounds at a joiner [I think it's called] running a whole lot of 3/4'' mahogany through there.
  He lost a couple fingertips in his left hand, while looking for them they realized [with all the blood everywhere, kinda hard to see] they were still barely attached and swingin'.
  The surgeon in Bitburg was very very good, very very nice fellow, he managed to put some of the pieces he had left to work with back in there, it didn't infect...
  Lucky is Jeff's middle name...he plays amazing guitar techniques, I mean development way beyond 'normal' guitar...and uses his 1rst and second fingers of left hand which have no 3rd joint articulation to do it.
  I said lucky...yepp, dern lucky !
  Lookin' all over for those fingertips...all but about 1/8'' was completely separated, crushed/bruised/missing pieces...that Dr. was very very good...I think I said good 'n lucky like 8 times...

[foxfire]

a few years back i dipped a finger into a jointer and all i got was 3 little cuts on the side of my finger. i couldn't believe how lucky i was. they looked like shark gills. the jointer came from a navy shipyard (if i remember correctly) and it seemed as though no one ever thought to sharpen the knives which i think was in my favor...