Building a bandsaw on the cheap from mostly scrap wood

[glatt]

5/29/16 part IV

I tried to put the blade on, and was unable to do that. The frame wouldn’t lower far enough to give me the blade slack I needed. My bolt was too short. I needed a longer one. So to just make do for this test, I removed on of the leaf springs. That meant I could make do with a shorter bolt for now.


The blade seemed happy with this inner tube tire. I adjusted the tracking by turning the bolt in the bearing block which bears against my old hacksaw blade on the frame. It worked well. The blade is right on the crown of the wheel.


The two leaf springs, however, were not happy. They needed their third buddy. I needed to get a longer bolt. But it’s neat to see how far they can flex without breaking.


I spun the wheel by hand, and the blade stayed nice and centered on both the top and bottom wheel. It seemed to track well. So I grabbed a popsicle stick piece of wood, and I CUT MY FIRST WOOD ON THE BAND SAW!!! Just held it against the blade after spinning the wheel by hand and getting it going.

[glatt]

5/29/16 part V

So the evaporator motor I bought on Ebay for like $20 is nice and round. No mounting bracket. But it has a rubber bushing mount. I figured that if I took advantage of this when I mount it to the saw, it will reduce vibrations just a little.


So I measured the diameter of the rubber mount, and divided it in half to get the radius. Set a compass to that distance and drew some semicircles on the edge of a board. I cut them out with a coping saw. I sure would be nice to have a band saw for this. It would have been a lot easier to cut and better quality.


I cleaned up my sloppy cuts with my home made sander in the drill press.


And I screwed together a motor mounting bracket. I tested the fit in the motor location on the frame. It looks good here. I’ll need to clamp the motor down in the bracket. I’ll probably use steel baling wire attached to a couple screws on each end of the bracket, and twisted to snug it down tightly against the rubber bushings.


Not shown: I made a couple of large wooden washers to go on the shaft behind the lower wheel to keep it from rubbing against the frame.

[xoxoxoBruce]

Well done, you're making good progress.
I don't understand the three maple "leaf springs"? If they are to compensate for minor out of round differences in the two wheels, I suppose they would give a little. But if the blade seizes in the work, either the blade will slip on the wheel, or more likely the motor belt will slip. Barring that, the motor stalls. But absolutely nothing should pull hard enough to break those "springs".
Experience has taught me painfully, when the shit hits the fan, even if the motor switch is handy, it's often dangerous to let go with either hand. They make foot switches that plug in before the motor for $15.

Now, sally forth brave hobbit, bandsaw the Ents into furniture, but for god's sake, safety first.

[Griff]

Most excellent.

[glatt]

Originally Posted by xoxoxoBruce

I don't understand the three maple "leaf springs"?

I think they are meant as a safeguard against over tensioning the blade. They are supposed to break before the blade does if I go nuts tightening the blade.

And I have no idea who's bare toes those are. Certainly not mine. I have a rule against bare feet in the shop, and I would never just scamper down into the shop for "just a few minutes this time" without putting shoes on.

[xoxoxoBruce]

OK, I can see the anti-over-tensioning. You will find the necessary tension for making the saw work well is a lot less than you think it is. The friction between the blade and drive tire is surprisingly big with a tight blade so unlikely to slip. Most of the tension (plus the guides) is to keep the blade from twisting when you're cutting shapes that make you glad you have a bandsaw. Charge!!

[lumberjim]

Busted.

Very cool glatt

[classicman]

Awesome sauce!

[glatt]

Sunday 6/12/16. I spent 15 minutes this afternoon cutting a proper sized hole in a nylon faceplate to fit the special switch I bought to go to this thing. Add $15 to the total for the switch, metal box, cable clamp for the box, and nylon faceplate.

[xoxoxoBruce]

Nice.

[Happy Monkey]

Originally Posted by glatt

This project is building a band saw based on plans by Matthias Wandel. I wish I could take credit for designing this band saw, but that would be a considerably more time consuming undertaking. I paid $21 to Matthias for the plans, and despite numerous spelling errors throughout, the plans are very detailed and helpful.

Coincidentally, I've been watching a lot of his Youtube content, and ran across his bandsaw, which looked very familiar.

[footfootfoot]

OK, this has been bugging me so I have to put my oar in the water.

I'm all for re-designing the wheel but if you are going to do that you should improve it. The leaf spring concept is silly at best. First of all, if they are made of wood the tension on them will eventually cause them to set and ultimately lose their spring. As they are made of wood, their springiness will be forever changing with age, humidity, and sideways glances.

You can tension a bandsaw blade by ear if you need to, or use the deflection rule of thumb. The leaf springs will not break before the blade in any type of realistic scenario. If you try to over tighten a blade to the point where it snaps you'll see it isn't something that happens by accident unless you've got a 24" cheater on the end of your wrench.

If I may propose a simpler solution; replace those leaf springs with a solid bridge of steel or rock maple or anything that will not flex. Then put a proper spring in between two washers on top of the bridge. Run your threaded rod through the bridge, washer, spring, washer and up into your tightening nut. You could also replace that nut with a handle so you don't need to have a wrench to adjust it. (looking at the photos it seem that wold require re-doing the fixed nut on the bottom so maybe not worth the time.)

If you wanted to go bonkers you could even affix an indicator for proper tension for each blade width.

You can get tensioning springs like this anywhere or google bandsaw tensioning spring and order one.

That leaf spring is my only 'nails on the blackboard' moment in your truly awesome and inspiring project. And I'm an asshole.

[glatt]

Not my design, so my feelings aren't hurt. So what does a spring in a band saw even do? The nut on the bolt tensions the blade. Why even have a spring? Off to Google this shit...

SOME WEB PAGE:

the blade heats up while cutting the wood and expands its length. This allows the blade to become slacker and lose its tension. To overcome this, the bandsaw has a compression spring that allows for the expansion and keeps a constant pressure on the blade. The spring will compensate for the expansion in all but the most severe cases, such as cutting very hard, thick woods for long periods of time.

I think the wood slats will work as springs. I've seen beds with wood slats that serve that very purpose.

I'm going to try it with the wooden slats and if it performs poorly, I'll check out replacement springs.

[xoxoxoBruce]

Yeah, I had the same hemorrhoid.

[glatt]

I was working on the little bracket thing on the right last night. Spent about an hour, but then it didn't fit. At first I couldn't understand it, but then I realized I had built my frame a little thicker than the plans called for since that was the thickness of the wood I had.

So now I need to be mindful that when I'm making parts that fit along the thickness of the thing, I've got to measure against my own machine "as built," and just use the plans for guidance.