Items that were lost in forum change

[phil (admin)]

We lost a few messages when I decided to change forum software (to make registering easier and photo uploads possible).  So here is a recap:

*****
Rick:  The baffel has a 240 degree by 1.125 relief.  What is the relationship between the elbow outlet and the 240 degree cut out?

JPT:  The elbow is under the portion of the baffle that is not relieved.  My tests have shown that the baffle should be placed so the back of the elbow is aligned with the beginning of the larger radius.

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fishnskiguy:  Neat design, I'm impressed!

My question is similar to Rick's.  I'm having a very hard time orienting the inlet elbow with the baffle.  As I understand your reply to Rick, a particle of dust would exit the elbow and then travels along the entire 120 degree portion of the baffle that is tight to the can, and then reaches the beginning of the 240 degree 1.25 inch relief, and then drops into the can somewhere along this 240 degree section.  Do I have this correct?  A drawing or photo showing the location and direction of the elbow relative to the baffle would be a big help.

JPT:  You are nearly correct, except the 120-degree portion starts back at the bend of the elbow.  So the particle travels along all but approx. 2" of the 120-degree portion.  I found this design worked best to reduce turbulence at this critical point.

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fshagan:  Love the design of this...simple and elegant.

How large have you scaled it up?  I'm wondering if the limiting factor to using it with a shop vac is the diameter of the container rather than the overall size...if you could find a taller can that is the same diameter you might be able to increase the capacity without losing any performance.

JPT:  I don't have a single tool with a 4" port on it.  I have a Ryobi BT3K table saw (heavily modded) w/ a 2.5" port, a home-built router table with down-draft box (2.5" port), and Inca jointer/planer (2.5"), and an Inca bandsaw (1.5" port).  All in a tiny basement.  The shop vac is my friend.  :)  Perhaps a dust collector would work better w/ the table saw (even through the 2.5" port), but it would certainly work worse with the router table's down-draft box.

I did make a 20-gallon version w/ 4" in and out.  I tested it a little bit with someone else's blower for a couple of days in my shop and it worked great.  I rigged it so the blower sucked the can, and blew a cloth (1-micron) filter bag.

That was approx. six months ago.  At that time I thought a nice system would be a 30-gallon can with two 4" inputs (on opposite sides of the top) and a single 6" output.  That output would connect to a 1.5-2-HP blower motor, which would push into a large cart. filter like you see on the tops of nicer Jet and Delta single stage collectors.  I would rig the filter in such a way that there would be a clean-out on the bottom (much like large cyclones have on their filter stacks.  You could probably assemble an entire system like that for under $250 if you carefully assembled the parts of eBay/craigslist.

To answer your other question, the taller the can (provided you have the room) the better.  Or at least, the taller the can the more it will hold (someone has to lift it when it is time to empty.   :o)

The diameter of the can does affect the performance.  Too large and the baffle will never be cleared of the debris.  That is the worst case scenario.  Too small is a problem, too, as things can spin too fast to settle from the stream.  HOWEVER, in spending the last couple of years observing these things working, I'm amazed how quickly even the finger material will escape.

[fshagan]

JPT:  I don't have a single tool with a 4" port on it.  I have a Ryobi BT3K table saw (heavily modded) w/ a 2.5" port, a home-built router table with down-draft box (2.5" port), and Inca jointer/planer (2.5"), and an Inca bandsaw (1.5" port).  All in a tiny basement.  The shop vac is my friend.  :)  Perhaps a dust collector would work better w/ the table saw (even through the 2.5" port), but it would certainly work worse with the router table's down-draft box.

I did make a 20-gallon version w/ 4" in and out.  I tested it a little bit with someone else's blower for a couple of days in my shop and it worked great.  I rigged it so the blower sucked the can, and blew a cloth (1-micron) filter bag.

That was approx. six months ago.  At that time I thought a nice system would be a 30-gallon can with two 4" inputs (on opposite sides of the top) and a single 6" output.  That output would connect to a 1.5-2-HP blower motor, which would push into a large cart. filter like you see on the tops of nicer Jet and Delta single stage collectors.  I would rig the filter in such a way that there would be a clean-out on the bottom (much like large cyclones have on their filter stacks.  You could probably assemble an entire system like that for under $250 if you carefully assembled the parts of eBay/craigslist.

I may try something like this ... I have a few blower motors from vacs, although I don't know if they are large enough to create enough velocity through a 4" port.  Probably not. 

The other thing I really should try is to use the standard configuration; my table saw (a Jet 10") is modded so that most of the dust falls through the bottom port (I have a baffle on the back to avoid shooting dust out the back). 

[eccentrictinkerer]

I saw your original post on bt3central.  I really like your design and am anxious to try it soon. I'm in the middle of a major re-do of my shop so I can't start it immediately.

You mentioned that you have a modded BT3xxx. I'd be interested in your mods. I just got a Wixey digital fence gauge. While testing it I found that the Dark Angel of Shim Death had visited me. I have a Sears 21829 that I thought was immune.

I'm a newbie to the BT3000 and clones, and I'm really impressed with this inexpensive saw. I put a $60 blade in it and impressed my cousin no end.

Well, I'm off to order parts. Thanks for your well thought-out design and forum. I hope to compensate you for your efforts.

J.D.

[phil (admin)]

I saw your original post on bt3central.  I really like your design and am anxious to try it soon. I'm in the middle of a major re-do of my shop so I can't start it immediately.

You mentioned that you have a modded BT3xxx. I'd be interested in your mods. I just got a Wixey digital fence gauge. While testing it I found that the Dark Angel of Shim Death had visited me. I have a Sears 21829 that I thought was immune.

I'm a newbie to the BT3000 and clones, and I'm really impressed with this inexpensive saw. I put a $60 blade in it and impressed my cousin no end.

Well, I'm off to order parts. Thanks for your well thought-out design and forum. I hope to compensate you for your efforts.

J.D.

I saw your shim post at bt3central.  I am surprised you'd have this problem w/ the zip code version of the saw.  But I guess it is the exception that proves the rule?  In any event, replacing shims will allow you to become one with the saw.   ::)

There are some posts of my saw mods at bt3central, you can search my handle.  Basically, they are an extended-length left-side miter slot, a right-side router table, and a support "truss" that holds the entire saw solid as a rock.  I should really write something up for at least the support truss, but here is a link to the appropriate post at bt3central:

http://www.bt3central.com/showthread.php?t=24309