Instructables
Picture of PCB cutter tool
IMG_1007.jpg
I wish to have a mini circular saw to cut my pcb, but sometimes it's enough to have a modified cutter and a proper frame to drive cutter into a straight line. I've designed one in this instructable, it's very cheap and it cames from ordinary objects.
Because you can't simply "cut" the pcb with an ordinary blade, you have to modify it to scratch the two surfaces of the pcb, so to snap it.
This method works well if you draw on pcb two lines on the upper and underneath surfaces, and check that they're exactly aligned. Then slide the pcb into the frame and scrath more and more times the surface until you have a rut which runs over all the lenght, then turn upside down the pcb and make the same on the other side. Now take out pcb and make a little force by hand to break it into two pieces. Round off the pieces with some sandpaper.

Step 1: The cutter

Picture of the cutter
Let's begin with the cutter. You need a strong one, better with some additional blades. I've bought this aluminium one, it came with 10 blades for about 4$. You can extract the blade acting on the little lever, and when blade is in position it's very tough, also if you pull hardly.

Step 2: The blade

You need to modify the blade so it will form an hook shape, with a spiky point. You can easily make it with a grinding wheel and refine it with a dremel mini drill. Insert back the blade into the cutter and you'll have a perfect tool to scratch the pcb. Maybe you want to make the same modification to other blades to have the ready when this one will be consumed.
[UPDATE: I discovered that you can buy these blades]
 
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Dave543211 year ago
I was looking for a way to engrave a circuit board to cut lands on the top to solder ic's. There isn't any instructables out there on this topic. I have made plenty of etched boards and drilled holes and soldered the IC's on the bottom, but it is confusing and you have a lot of holes to drill. I came across a gun stock diamond pattern video where once you have a straight line they have a tool that rides in that groove and cuts the next straight line next to it, repeat this process until you have the lands cut for each pair of pins like 1&8 2&7 3&6 4&5 then cut a groove perpendicular to these ribbon lands and you have a place to solder your IC on top like the surface mount components. Just thought I would mention it as there are no instructables on how to do that.
Wilmette1 year ago
My only suggestion is that instead of modifying the blade of a utility knife perhaps a different blade or knife. Linoleum and carpet knives digest themselves. Good job and thanks
andrea biffi (author)  Wilmette1 year ago
Oh, you're right, looking for those I've also found these blades, they seem exactly what I need! Thanks
Those blades will probably work, but I would recommend this: http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100046621&R=100046621 the carbide tips on this cutter are fairly robust and you will have no worries about breaking them. I have and use this tool, there are only 2 tips, not sure why the description says 3, but I've been using it to scribe and break cement board, lexan, kydex and a whole host of other things for years and see no degradation of the tips. If you "use this up" you are cutting enough PCB's that it is time to invest in better equipment.

It is burly enough that you can really put pressure on it and get a good deep scribe. Plus, the metal that the tips are brazed to is thick enough that it wont wander off your line.

Nice 'ible.

Glen
I like that scriber, but I still think chisel is the way to finish, a cheap set would last for this purpose many times, no risk of snapping a blade. There is a dude (Egyption accent? He pronounces it "cheyezil") on youtube. He gave me the chisel idea, this is a great jig for that. Perhaps score with something more nimble like the scriber, then final blows with a chisel?
Well I'll be durned. I got my scribe out tonight, and there's a third cutter on the other end of the metal blade, inside the handle. I learned something new about a tool I already own, thank you.
andrea biffi (author)  Lazy Glen1 year ago
You should wait Christmas night to open your surprises! ;-)
andrea biffi (author)  Lazy Glen1 year ago
good, they seem the right choice
I have one of these as well and have used it as Glen well describes.For someone who will do crafting with heavy materials I would describe it as indespensible . Thin cement board is a very tough material, abrasion resistant, water resistant, strong when wet, fire proof not very expensive. This tool will give you and friends the ability to make more use of it. ( I do hope you share tools and projects ). So do give it a thought. Good observation Glen
andrea biffi (author)  Wilmette1 year ago
these blades (link didn't work in other post)
thegrendel1 year ago
Very clever, and much handier than using a Dremel tool
for trimming PC boards. Nice!
Right, I heard you don't want to breathe ground up PCB. Dremel flings stuff all over the shop and into the air. I might make mine to fit a chisel tip.
static1 year ago
Both downloaded, and made a favorite fo future reference. But I'm still home to find a used heavy duty paper cutter is good shape for a good price. However if this was something would do a lot new paper cutter isn't terribly expensive.
eyesee1 year ago
Great
ac-dc1 year ago
It's easier to use an office rotary paper cutter. That way you have a ruler already there for the measurement and no need to mark either side prior to cutting.

Granted, a decent rotary cutter costs quite a bit more than a utility knife, two metal rulers, fasteners and a board.
For me, and I am an odd one, I find the rotary cutters don't always cut a straight line. If the handler wobbles, so does the blade, as mine do because I'm wobbly ;)
A blade & a metal straight edge make much more precise cuts, but If you have a lot to cut & precision isn't essential then the rotary ones are muck quicker & less of a (anal retentive) pain!
andrea biffi (author)  ac-dc1 year ago
Yes but I think the blade of a rotary paper cutter isn't so effective with copper layer, maybe one could change it with a different blade... it should be next instructable ;-)
very handy for one-off boards
andrea biffi (author)  KROKKENOSTER1 year ago
yes, mine are very often one-off projects ;-)
ajoyraman1 year ago
Very simple and extremely good idea. Can you consider an L-angle instead of one of the half-rulers, it would help in holding down the PCB much more firmly.
andrea biffi (author)  ajoyraman1 year ago
I don't know, I need the flexibility of rulers to push pcb against the rubber sheet... your idea should work in case I tight everything with the bolts.
actionjksn1 year ago
You can buy blades that are already like your modified blade. They're called hook blades and they are made for cutting roof shingles. It would have a better edge than anything you could do with a Dremel.
andrea biffi (author)  actionjksn1 year ago
yes, thanks, I've discovered it, now I've to search them in shops
I see a lot of great projects on this site but to me and my stripboard site HERE (sorry for the plug haha)
that is the most useful project I have see so far. if you have a actual site where you post this stuff I would love to put a link on mine to it.
andrea biffi (author)  Insonicbloom1 year ago
I've to be honest, this concept is not all from my mind, because years ago I've seen a video on eBay in which a chinese guy (if I'm not wrong) cutted a board in this way. At that time I've thought it was handy, and I begun to do it myself. Now in Instructables I can share this concept with you all, so... thanks chinese guy! ;-)
Anyway Paul, your site is so rich of nice projects! I really think as well stripboards are handy for simple circuits. You can insert a link to this instructable if you wish.
rnes3511 year ago
It might be worth trying a carbide tip knife used to cut formica counter top material.
profpat1 year ago
great instructables, very simple and affordable!
You know that you can actually buy these blades. They are used for cutting shingles and covering.
andrea biffi (author)  MatthewEnderle1 year ago
yes I've discovered that, thanks! :-)
billbillt1 year ago
Good Idea!!.........
apalacios21 year ago
Olfa makes an acrylic cutting blade that closely resembles your mod. I liked this instructable a lot! Nice rig! I've been cutting (one-sided) pcb's with scissors after heating them a little with a hot air gun or just holding them at a distance over the kitchen range fire. Phenolic can be cut this way as easy as paper. FR-4 is a bit more resistant. I've cut irregular forms this way (even circles!) but your rig looks promising for straight cuts. Also heating might warp the substrate so I'll try your idea. Thanks!
andrea biffi (author)  apalacios21 year ago
that's interesting, I din't knew about heating pcb... I've to try!
Really nice. Thank you. Grande idea. I used an Ikea plastic cutting board.
flashj1 year ago
This is one of those "Why didn't I think of that!" ideas. Well done.
Jayefuu1 year ago
Love the pictures and illustrations :D
Great idea!!...I really have to make that!!....
Tomdf1 year ago
I really need one of these. Thanks for sharing :D
andrea biffi (author)  Tomdf1 year ago
you're welcome :-)