I made a Dust Collector – Part 3

So… I may owe some level of explanation for waiting a year between my last post and this one…

Maybe.

I made a housing for my impeller by arranging several blocks of red oak on a piece of plywood and then tracing the perimeter of my impeller onto the blocks of wood.

I appear to have lost any photographic record of this step, so please view the following for reference:
Step 2 was awesome, sorry you missed it.   I then cut this line on each piece using my bandsaw. I rearranged the cut blocks so that they made the correct shape and then screwed them on to the piece of plywood. i also smeared from Bond-O on to the inside circumference to smooth out inconsistencies and plug any gaps.  I drilled a large hole into the center of the plywood to pass the motor through and made a little platform for the motor to rest on. cowling2
I found a picture!

After cutting a hole in the front piece, I slapped everything together for another test. It Sucked. But not as much as I hoped. I sat and pondered. and then got distracted. For a year. At some point during that year, I realized why my dust collected only sucked a little, but still waited a number of months before doing anything about it. Let’s play a fun game: Can you figure out what was wrong with my dust collector? ...duh.
=== SPOILER ALERT! ===
The impeller is spinning the wrong way. To make matters worse, the motor is unambiguously non reversible.
IMAG2092So I immediately (when I felt like it) got to work. I decided to solve the problem by moving the motor around to the “front” of the assembly. This also meant that I needed to keep the impeller in the same orientation relative to the housing, and so I needed to turn the back of the impeller into the front and re-mount it on the motor shaft:IMAG2093
back coverbalancing
transferring the old hole locations to the new backplugging unnecessary holes
done now. still done.
okay, NOW I'm done.Easy peasy. I powered it up for a test run, and promptly woke my son up (I have a son, he’s almost 2 and he was asleep).

IMAG2100

Needless to say, it was louder than I hoped.

I had recalled Wandel doing some testing around making his impeller design quieter and subsequently much, much louder to make an air raid siren. So I scoured his website and failed to find the article I was looking for, but did find a comment of his on someone else’s dust collector design where he noted that “the smaller the gap between the impeller and the housing, the louder it will be.”

So I shaved 1/4″ off the perimeter of my impeller using my bandsaw and put everything back together.

Then I waited until my son was asleep again (for maximum effect) and tested it again.
This time it REALLY sucked. And it did so very quietly. Almost Dust-Sniper quiet!

And so I set in a corner of my garage until I get time to mount and duct it.

Next June is looking promising…

Advertisements

Inca Band Saw Part 3: The Guides

When I was first examining the guides on my saw, I noticed that they were unlike anything I’d ever seen before.  Actually, they seemed to be a mismatched set.

The guides on my saw are the type that have an asymmetrical pair on each the top and bottom, with one coming from the left, perpendicular to the blade, and the other coming from the right at a 45-degree angle.

I have seen this configuration before, but what was new here was that the perpendicular guide was a small wheel, with a groove on the outer circumference that the back of the blade would ride in; and the 45-degree steel guide wasn’t touching the blade at all.

After digging through the manual, I found that this wheel guide was the “fretwork guide”, meant to support the back of a blade too narrow to be held by the steel guides. This meant that I was missing the horizontal steel guides that I would need for a regular (3/8″-1/2″) blade.

I started looking online for information about Cool Blocks and ceramic guides, having heard that these were the best for guiding the blade and keeping it from overheating due to the friction of the guides rubbing against the blade, however, being a relatively rare European saw, I would have to order custom blocks, which would be tedious and expensive.

I am a regular reader of woodgears.ca, and had seen an article regarding using hardwood blocks as guides. This seemed cheap, easy, and reversible, so I thought it would make a worthwhile experiment.

Wanting to do a little more research on this concept and general bandsaw theory, I bought The Bandsaw Book and found a couple interesting facts: 1.) Wooden guides can provide excellent support for the blade, although they wear out quickly; and 2.) Steel guides do NOT cause blades to overheat (the wood being cut generates far more heat, and the guides are only making contact with a very small portion of the blade).

Armed with the confidence that I could do no harm; I cut out a set of guides from some white oak I had laying around, saturated them with Johnson’s Paste Wax, and tested the cut.

It was terrible! The blade immediately started cutting at what must have been 20-degrees from parallel to the table.

I started to worry about whether the guides would work, but then I remembered: I’m using a saw with chewed up tires and the cheapest Craftsman blade that fits, I should probably address those problems before I start trying to fine-tune the cut.

<To be continued in Part 4: The Wheels and the Blade>