Thread: More fun with Bell Mouths

Good job on the print.

It depends how much access you want around a belt sander.
For maximum access I've found locating hood on the end of the belt so they can be swung out the way and also keep the full 360º of hood seems to be the best place.

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And if you are sanding small things you might want to put a bit of mesh on the front
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You're absolutely correct. The mounting on the belt sander was a quick first test of the usefulness of the bolt hole. A lot of dust is carried past the BMH on the belt. There is a factory dust hood at the other end of the belt for flat sanding which works reasonably well. To use the radius sanding end I need to get the BMH almost flush with the belt. And yes, small parts will disappear fast. Will get a screen.

A few years ago, I made an acrylic box to suck up dust from the wood lathe. The idea behind acrylic was that it would let light through when it was close to the workpiece and the box seemed a good idea at the time. The lathe is near a window so it's plenty light enough and the flat sides on the box causes chips to bounce back out.

I made a few BMHs out of PVC according to Bob's recipe so thought I would would use one of these instead. Since there is a sharp bend after the BMC I placed a baffle inside the bend so that the air flow would not concentrate on the outside of the bend. The BMC is mounted on a rail so it can be placed anywhere along the lathe bed. Seems to work well.

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Interesting idea.

I will add a flow line baffle to the next lot of flow tests - should interesting - I have 3 such sharp bends immediately after BMHs in my shed so I am very interested in the outcome.

Do/will shavings hang up on the flow line baffle?

Pete

The flow line baffle idea is really interesting. I wonder what some idealised scenarios might look like if one momentarily ignored any difficulties in the fabrication and fitting...Thinking of number of vanes and their configuration, vane profiles...More fun in waiting for anyone plinking with computer fluid dynamics (CFD) and 3D printing...

But yea I guess the multivane versions will fail a QC test, clogging with long stringy chips...

Gregg

Originally Posted by GreggMacPherson

But yea I guess the multivane versions will fail a QC test, clogging with long stringy chips...

Depends on machine use - I would use one in my lathe BMH but would consider using it on my large sander and the BMH on my bandsaw.

I haven’t used it much but the chips still seem to fall on the ground! It’s the dust and lighter particles I’m after. And the chips make it look like I use the lather a lot more than I do...

Leigh


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Originally Posted by BobL

Interesting idea.

I will add a flow line baffle to the next lot of flow tests - should be interesting - I have 3 such sharp bends immediately after BMHs in my shed so I am very interested in the outcome.

I'm very interested in the results you get with that Bob.

Last one - trying to get better at sheet metal work, so I spent way too much time on a floor sweep. The cross sectional area is constant through the transition to maintain air velocity. To keep it close to the column and less of a trip hazard I had to angle it so that it’s flush at the base and slightly off vertical which is annoying... Otherwise very happy.


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Originally Posted by Ambrosia

. . . . . . To keep it close to the column and less of a trip hazard I had to angle it so that it’s flush at the base and slightly off vertical which is annoying...

It looks like you might have the room/space, but otherwise I think it maybe still sticks out too far for most sheds .

Nice sheetmetal work..!

I hope this is not too far out of context here but I am trying to set up D/E for a new lathe located adjacent to the workshop and I have been concentrating on
setting up a bell mouth for sanding debris adjacent to the headstock.

I have two concerns at the moment; how it will effect the CFM because the 2hp dust extractor is in an adjacent room.
Secondly, should I be considering a floor sweeping inlet as shown above.

I am a newcomer to the turning fraternity and have been trying hard to set D/E up effectively.
Can you refer or point me in the right direction?

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Pics are where I am up to at this stage.

Just my personal experience.

I have a floor sweep behind my lathe, and don’t actually use it as much as I thought I would. It can handle all the shavings I throw at it, but they tend to block the impeller and also fill the bags quite quickly. What I do now is sweep and shovel the shavings into a bag (it ends up in the beds in the garden, where the dogs lie on it in the sun and then bring it into the house where the shavings end up on the carpet in the house), and let the dust extractor just deal with the dust. If I were to redo things, I’d probably not bother with a floor sweep, if I did put one in, it would be for general dust and floor sweepings, not the lathe shavings.

It’s still great fun to sweep a pile of shaving up to the floor sweep and watch it vanish. But the schlep of clearing the impeller makes it something I hardly do.