Results 1 to 10 of 10

Thread: Idea for drawing outside air directly to a lathe

  1. #1
    Join Date
    Apr 2016
    Posts
    1,128
    Blog Entries
    1

    Idea for drawing outside air directly to a lathe

    Perhaps this has been tried, perhaps common knowledge, but it seems to me that using ductwork to draw intake air from outside for a dust collector would not only reduce the heat lost in winter but also improve dust collection.
    I'm referring here to a wood lathe.
    Couldn't you affix the ductwork under the bed, between the ways, and creating a bit of an up draft that would move directly into the DC's hood.
    Less chance of whatever flows through it to absorb heat.
    Also, maybe help keep the shop just a bit cooler in hot wearther.

  2. #2
    I'm not sure that I want to turn wood with a -15F updraft coming from the ways. Not to mention that the lathe would condense moisture on it after shutting off the draft and it is 80 degrees cooler than the shop air.

  3. #3
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    1,896
    Depends on your climate. Does it get freezing cold or so hot as to be dangerous outside in summer? Look at how commercial kitchen hoods supply makeup air.
    Bill D

  4. #4
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    46,586
    Honestly, all that work wouldn't likely present much benefit for a lathe since the only time you can effectively collect from it is while sanding the workpiece while it's still mounted on the machine and turning. Collection doesn't work when one is actually cutting because the chips fly pretty much in 360 of direction every time you "wiggle" the tool.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  5. #5
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    6,562
    Quote Originally Posted by Jim Becker View Post
    Honestly, all that work wouldn't likely present much benefit for a lathe since the only time you can effectively collect from it is while sanding the workpiece while it's still mounted on the machine and turning. Collection doesn't work when one is actually cutting because the chips fly pretty much in 360 of direction every time you "wiggle" the tool.
    I'd modify that a bit to say "most of the chips fly". I've been carefully watching my DC pickup (a "mini gulp" nozzle on a 4" hose, 6" duct, 5hp cyclone). I find that although lots of chips go flying everywhere, at the same time some chips, especially finer chips, and a lot of the fine dust produced does get pulled into the collector. Note that a lot of very fine particles are created when cutting, not scraping, with even very sharp tools.

    I was surprised at the airflow pattern around the turning. I put a dark background under and behind the turning and with a bright, narrow beam spot I can watch the fine particles move. I've seen dust come off a spindle almost 2' down from the DC pickup and travel to the pickup. I've seen fine particles/dust come off the front of the piece and make a U-turn under the work and go into the nozzle. Note that some woods produce more dust when cutting than others. I use the DC now during nearly every turning. It is, as mentioned, especially useful when sanding, even more when sanding in reverse.

    I primarily turn spindles and smaller things, not many big bowls. I remember Pentz said that the act of cutting, even using a hand plane, puts some fine particles into the air.

    BTW, the DC is especially useful when turning acrylic. Acrylic can be a pain since long strings of plastic from the gouge get wrapped around the piece and have to be cleared often by pulling and cutting. I discovered the DC can pull the end of a continuous long string away from the work and no bird's nest forms around the piece.

    JKJ

  6. #6
    Join Date
    Oct 2007
    Location
    Falls Church, VA
    Posts
    926
    Blog Entries
    1
    There are air heat exchangers designed for super tight houses. The idea is that some houses these days are made so airtight that they are unhealthy. So there are fans that deliberate bring in outside air and vent an equal volume of inside air. Both ducts flow through a heat exchanger. I don't think the residential ones are made for the kind of volume moved by a dust collector.

    I assume you have your dust collector outside.

    I agree that climate would play a big role. In the winter, I wouldn't want the cold air around my arthritic hands. In the summer, I wouldn't want the moisture.

  7. #7
    Join Date
    Jun 2017
    Location
    Saskatoon, Saskatchewan, Canada
    Posts
    793
    I remember reading on a forum somewhere in the last year of someone doing just that. I believe his duct came in close to a sander but it may have been a lathe. He did it to cut down on the AC losses.

  8. #8
    Join Date
    Apr 2016
    Posts
    1,128
    Blog Entries
    1
    The dust collector will be inside.
    The idea I was following was not to make the ductwork the only source of the volume pulled out by the dc, but to be able to direct some to where the piece is between it and the dc intake, hopefully therefore capturing more fines.

  9. #9
    Join Date
    Aug 2015
    Location
    N. Texas
    Posts
    1,096
    Quote Originally Posted by Bill Jobe View Post
    The dust collector will be inside.
    The idea I was following was not to make the ductwork the only source of the volume pulled out by the dc, but to be able to direct some to where the piece is between it and the dc intake, hopefully therefore capturing more fines.
    Interesting idea. No idea how practical it would be.

    Your description made me think of industrial air curtains: relatively high velocity air stream usually directed down from above a door opening. It's intended to limit mixing of air from one side of the opening to the other. Think about a forklift coming and going with heated air inside and Canad ...er, I mean Antarctica on the other. Not anywhere near perfect, but better than the inbound gale when the door opens??

    Assume your DC exhausts outside and the shop is air tight. If your only source of make-up air is a duct opposite and relatively close to the DC pickup, then you could potentially create such an air curtain between them - with limited mixing (between shop air and 'ducted' air).

    Now just figure out how to do useful work inside that 'curtain'. Unfortunately, this seems too limited and impractical. IMHO
    Last edited by Malcolm McLeod; 11-08-2018 at 5:16 PM. Reason: clarity
    Molann an obair an saor.

  10. #10
    Join Date
    Apr 2016
    Posts
    1,128
    Blog Entries
    1
    A small infrared heater directed at the piece of wood should offset very cold air being pulled in from being uncomfortable to the hands.
    But again, I'm not talking about pulling the entire volume of air required from outside. Just enough that (hopefully) better dust extraction is achieved. As it is a DC pulls air from a wide area and I think causing it to draw more air directly across the piece would result in better dust collection.
    My interest leans more toward better DC, not saving on heat, although that, alone, might create interest in others enough to experiment.
    Last edited by Bill Jobe; 11-13-2018 at 10:54 PM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •