Building a bandsaw on the cheap from mostly scrap wood

[footfootfoot]

You went to town with those splines. Three per corner would have been overkill. Now you know where to go in case of an earthquake, under your bandsaw. hahaahhahahaha

[glatt]

Friday 5/27/16 - 45 minutes (after work, and before my wife and daughter get home from a college tour.)

Not pictured: Cutting the fucking metal bar to get a 17.5 cm top wheel shaft, drilling a hole in the end of it, and tapping threads into the hole. You can use your imagination, or look at the pictures of the same thing I did on the lower shaft last week.

Saturday 5/28/16 – 20 minutes in the afternoon. The glue had dried on the splines I put in the corners of the upper wheel mount frame, so I cut them off with a utility knife and used a scraper to scrape them flush with the surface of the frame. I will need nice flat surfaces to press against the fence later on the table saw. A belt sanding station would have been awesome, but I used a scraper because it’s what I have. Incidentally, I we just gave my son a bench top belt sanding station for his birthday today, so if I ever need to do this in the future, I can do it in a couple seconds on his belt sander.

[glatt]

Sunday 5/29/16 - This was a long day. Six or seven hours of work.

I cut notches in the edges of the upper wheel mount frame.


I took the old hacksaw blade from last week, and broke a segment off of it to screw to the rear of the upper wheel mount frame to act as a bearing surface for the tilt adjustment screw. The screw would dig into the wood otherwise instead of pushing against the frame and tilting the bearing block to adjust the blade tracking.


I test fit the upper wheel mount frame to the band saw body with the L brackets to hold it in place.


It was a little tight, so I planed down the band saw frame in a spot where it was rubbing.

[glatt]

5/29/16 part II

I tested the fit after planing. It slid nicely with minimal slop.


I waxed the runners anyway to help it slide more easily.


I screwed the L brackets down to lock the frame in place. The plans call for a lot of screws because there will be a lot of force pulling against this frame. I used good structural grade screws. Then I took the bearing block and placed it in the frame and clamped it there to check the alignment.


I used a framing square to be sure the top and bottom shafts were square with the frame before I held the block in place with a couple little drywall screws. The drywall screws just keep the bearing block in the proper location. The frame holds it securely in place when blade tension is applied.

[glatt]

5/29/16 part III

I put the shaft in the top bearing block. I drilled a hole in the side to anchor the shaft in place with a drywall screw.


I put the wheels on just to see how it goes together and to admire it. The wheels make it want to tip over, so I set the motor in the area where it will go and weigh it down.


I cut 3 strips of maple to act as leaf springs to support the top wheel. These wooden strips will break before anything else, so they are a safety device, like a fuse.


These are the leaf springs installed, and a good picture for an overview of the whole top wheel mounting system. You adjust the blade tension by turning that nut at the top and raising the frame that holds the bearing block and top wheel. That’s why the frame needed to slide in those L brackets.

[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.

[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.

[xoxoxoBruce]

One of those Doh moments when it all becomes clear. I never know whether to kick myself for not thinking straight, or hug myself for finally figuring it out.

[footfootfoot]

@ Glatt,

It's the boatbuilder in you...

Originally Posted by some dude said

Machinists work to the nearest 0.001

Carpenters work to the nearest 16th

Cabinetmakers work to the nearest 64th

Boatbuilders work to the nearest boat...