Check it out! A battery-powered scroll saw made entirely out of recycled bits and pieces around my garage! B)
For my entry in the woodworking contest I wanted to do try something poetically geeky. Something a little hardcore, yet still something that anybody could do with a little patience. Most of all, something useful to have which would increase the overall coolness of the shop.
(Also found on my projects blog, here and on LumberJocks, here)
It's been over a year since I published this, but I also found another variation:
It definitely trumps mine in the slap-together-itive-ness factor. Not to mention the guy's accent is way cooler than mine.
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Step 1: So... What Are We Doing Here?
So the first thing we need to do is figure out where we're headed.
After a little research, I found out that Roy Underhill (henceforth referred to as, "Da Man") has released some scroll saw plans online.
Of course, his was meant as an afterthought to his treadle lathe project. Still it provided a good starting point for a more modernized / less difficult to fit on a workbench design.
(Also, if it helps, some nice person made a sketchup model of it.)
Now that we know where we're going, time to figure out a plan to get there.
The only thing left to do now is to erase the doodles off a sheet of graph paper and start designing!
Besides being a coping saw blade moved by oak arms, I soon found that my design was significantly different from his. I guess that's part of the fun, though.
Step 2: Materials
As part of the challenge, the goal of this project was to use only scrap materials, so obviously your list will be different. (That's part of the fun!)
Some things you'll definitely need:
1) A coping saw where the blade attaches with pins. In case you don't have one, I originally got mine for like $5 from here.
2) A drill of some kind. Mine was a cordless Makita I found at a thrift store for $10. Score!
3) A stout steel bar. Mine is about a 1/4 inch diameter stainless bar that was salvaged from an dead printer.
5) A couple pieces of hardwood. I had a 1x4 oak board left over from a cabinet project.
6) Some long bolts
Other items of interest::
1) Assorted scrap plywood and 2x4 ends.
2) A fist full of grabber screws.
3) Some rope, a heavy spring, or a turnbuckle (for blade tension)
4) Something for feet. Like maybe some appliance feet, old shoe rubber, or I just used some sidewall from an old tire.
5) A few assorted metal bits. Nothing fancy. I've got a metal frame piece out of a VCR and a short piece of steel plumbers' tape in mine.
This project can be made with simple hand tools. In fact, the coping saw and drill above provides 90% of everything you need.
Step 3: Learning to Cope
Below is a picture of my coping saw all taken apart. What we're going to to is use the end pieces to hold the blade, and use the threaded handle as a tightener.
If your coping saw is like mine though, it was never designed so the blade could pivot forward and back. This is a problem. If you try and use it like that, then the blade will bow and possibly break. Therefore, you'll need use a hacksaw to cut the slots so that they can angle back.
I may be jumping ahead a little, but I also added a picture of how all these pieces will be used in the finished product.
Step 4: Parallelogram Arms
Okay, now time to start cutting wood!
This is very important!! The goal here is to make a parallelogram where the the center of the bolts and the center of your blade pivot pins forms the corners.
In other words:
1) The two oak "arms" are the top and bottom of the parallelogram.
2) The blade and the post are both sides of the parallelogram.
3) The distance between the center of the bolts MUST BE EXACTLY the same distance between the blade pivot pins.
4) Likewise, the distance between the center of each arm's bolt and it's corresponding blade pivot pin, MUST BE EXACTLY the same!
If any side of the parallelogram does not match the opposite side, then the blade will not stay parallel to the post as it goes up and down. Instead it of sawing straight up and down, it will also tilt back and forth and be impossible to saw with.
Both of my blade mounts go up through the bottom of their arm, and the handle is on the top of the top arm. Also, the arms extend slightly past the opposite side of the post. You'll see why in the next step.
For the mounting bolts, I went bolt->washer->arm->washer->nylon washer->washer->post->washer->lock nut.
(The nylon washers originally came with a set of toilet mounting bolts. I just through them in there to try and make things quieter. Don't know if it was necessary, but hey, whatever.)
Step 5: Feeling the Tension
To keep our blade nice and tight, we need some tension for it to pull against. That's why we needed to leave a little bit of our arms sticking out past the post. Now we can drill holes in each of the arms on the side opposite the blade and use something to pull them together.
1) In Da Man's original pattern, he used a turnbuckle. If I wasn't doing this ala dumpster that's probably the way I'd go. You can get a small one for only about $2.50 at box hardware stores.
2) A heavy spring. I've heard of people using this method, but frankly I'm not sold. It seems like it could introduce some ringing / vibration to the mechanics, which is something we could do without.
3) I just used a length of clothesline rope I had on hand. Just melt the ends so they don't fray and tie a taughtline knot and you're in business. With this I was able to easily get the blade tight enough to play a note on. (How to tie one: http://en.wikipedia.org/wiki/Taut-line_hitch)
(Don't worry. This sounds harder than it is.)
1) Slide the knot until it takes significant pressure to pull the arms down far enough to be the length of the blade.
2) Hook the lower blade attacher onto the bottom pin of the blade and pull it up through the bottom arm hole.
3) Hook the top attacher onto the blade and push the threaded side up through the hole in the top arm.
4) While squeezing the arms together, start the handle onto the threads and tighten.
Step 6: Captain Hook
The idea is to beat the metal rod into a hook shape. That way it will turn the rotary motion of the drill into a reciprocating motion for the saw. It works the same way as the crankshaft in a car engine.
Notice mine the metal goes past center after the hook. The purpose of that is to try and counterbalance the metal on the other side to reduce vibration. A better way might even be to make an identical hook on the other side so you're sure they are the same size. (Less like a "?" and more like an "S".)
This was the hardest step for me. If you have a machinist vice or torch or bender this would be a whole lot easier. I just grabbed a hammer and pipe wrench and wolloped on the thing till it looked reasonable. (Not too scientific, I know.)
Also, I should mention that I had to redo my first hook. The more exaggerated the bend, the further your blade will travel. My first attempt was over 2" and the blade traveled so far it was physically impossible to cut anything with. I was able to get it down to 1" but even that is a little excessive. 1/2" to 3/4" is probably about right.
Step 7: Attaching the Drill
Now we need something reasonable flat to attach the drill to. Here's what I came up with.
I traced the contour of the top and bottom halves of the drill onto a scrap 2x4 and cut it out with a coping saw. (You do have a coping say, right? ;) )
Then I mounted both 2x4 pieces to a chunk of 3/4" plywood scrap.
The drill is held down with a length of steel plumbers' tape and two grabber screws. This makes it really handy, because if I want my drill out, all I have to do is loosen one grabber, pull it out, and remove the hook.
The next picture blow shows how the drill mechanism engages the lower saw arm.
Step 8: The Base
The base is pretty self-explanatory. It's just a simple frame with feet.
You don't even have to use those galvanized corner thingys like I did. You could use shelving hardware or even wood blocks screwed to the inside of the corners. Whatever you've got, except...
Just as a general woodworking tip, whatever you do don't screw directly into the end grain of the other piece. That never works out well.
Step 9: Putting the Peices Together
Next we'll attach the post and the drill to the base.
At this point it helps to make sure the post is exactly 90 degrees. to the base This will make installing the deck a lot easier later. (The deck MUST be exactly 90 degrees to the blade or it won't cut well.)
Before permanently screwing both pieces to the base, make sure they are spaced out side-to-side so that the hook engages the lower arm correctly. Turn the hook one full revolution to make sure there is enough room for it to travel back and forth.
Step 10: The Deck
For this step your project will probably look significantly different than mine. Originally I had planned on building my deck out of bits and pieces of scrap wood, but I came across a great wooden box that I decided to turn upside-down and use.
It doesn't matter too much what you choose. It doesn't even matter too much how you choose to mount it. The thing that does matter is THE DECK MUST BE EXACTLY 90 degrees to the blade!!! (That rule goes for BOTH forward-to-back AND left-to-right.)
If you don't take the time to get the deck exactly 90 degrees, you cuts will all be slanted.
I notched the box and attached 3 posts to attach it. The right front and right rear are just two halves of a scrap 2x4 cut to size and screwed to the drill plate. The left post is just a scrap 0f 3/8" plywood. Since height was flexible and width was unimportant I didn't even need to cut it.
The last pic (viewed from underneath) may be especially helpful to look at since it shows how most the parts of this project come together.
Step 11: The Finished Product!
Well, there you have it. A scroll saw made entirely from junk!
Step 12: Gilding the Lily
Here are some other ideas I've had for enhancements to this project. No doubt you guys will have even more cool things to add in the comments, but for now...
1) Carve and/or stain the wood. Sorry, but oak just calls out to me, "don't leave me like this! make me pretty!"
2) Make another motor mount for a corded drill. Cordless is cool and all, but batteries are never charged when you need them.
3) Paint shaker. Since the arm is exposed, it would be really simple to screw on a Velcro wire tie so you could easily shake spray cans.
4) LED light. ('cuz everything's better with LED's)
5) Carrying handle and/or somehow make it fold up. Since it's cordless and technically portable, it would be nice if it was more easy to move like in your car and stuff.
6) Dust blower. Maybe like a PC fan or something??
7) The ability to use other kinds of blades? (For example, a hacksaw blade for cutting metal.)
Runner Up in the