Rob Keeble
Member
- Messages
- 12,633
- Location
- GTA Ontario Canada
Okay, so I am opening a chapter of this subject again for debate. I would like to get some mech eng boffins to weigh in here on this subject with some science.
I saw the latest post on Stu's bench and rather than hijack his thread on the bench I decided best to start one of my own.
Stu went and put a 4 inch connection onto his saw and then feeds that ultimately into a 6 inch pipe.
Here is my question relating to this.
From what i have read and researched the 4 inch diameter duct whilst supplied by all the manufacturers limits the cfm flow of air to around say 500 cfm. As I understand it the larger diameter 6 inch increases this permissible max airflow.
What i do not understand fully is what happens when 4 meets 6. Does the flow of material (dust) stall at that junction due to inability of the size of the prior pipe 4" to deliver enough air to feed the 6" main.
I would love someone that trullly understands this and can supply the math behind it to weigh in here.
I need the math to understand and believe all this.
Something does not seem right here to me from what i have read.
The next thing is what size should the port be to have the best dust removal without build up in the pipe? Regardless of what the manufacturer has fitted.
I have read from the famours Bill Pentz site that 4 inch is inadequate on a TS when one wants to deal with fine dust and not just "chip collection"
I have read enough on this subject in terms of conflicting opinions that I am now totally confused and only the math will set me free.
I also buy the issue that there is no perfect fine dust collection system, that you need to capture the dust at source, and that a huge %tage of the fine dust created at machines gets into the air directly from the active area where cutting, planning etc takes place.
What i percieve is that rather than actual vacuum (high velocity cfm) for the purpose of fine dust collection one is looking at volume of air movement and frequency or rate of flow (turnover). Hence the 4 inch port limits that compared to 6 inch port.
But then one has to have a fan on the other end that can cause that volume of air movement. Which in Stu's case is capable of the movement.
So weigh in all you pros. I know form pictures i have seen of some of your shops (the pros that is) that some of you dont seem to take the fine dust issue to heart enough in my opinion.
Looking forward to the responses here.
Just in case someone reads this post with an error of parallax again, this is nothing to do with critizing Stu's config. I am trying to learn and understand and fundamentally temper my own nuttyness towards this subject. My most expensive investment and part of the reason for my own dedicated shop was dust treatment and control.
I saw the latest post on Stu's bench and rather than hijack his thread on the bench I decided best to start one of my own.
Stu went and put a 4 inch connection onto his saw and then feeds that ultimately into a 6 inch pipe.
Here is my question relating to this.
From what i have read and researched the 4 inch diameter duct whilst supplied by all the manufacturers limits the cfm flow of air to around say 500 cfm. As I understand it the larger diameter 6 inch increases this permissible max airflow.
What i do not understand fully is what happens when 4 meets 6. Does the flow of material (dust) stall at that junction due to inability of the size of the prior pipe 4" to deliver enough air to feed the 6" main.
I would love someone that trullly understands this and can supply the math behind it to weigh in here.
I need the math to understand and believe all this.
Something does not seem right here to me from what i have read.
The next thing is what size should the port be to have the best dust removal without build up in the pipe? Regardless of what the manufacturer has fitted.
I have read from the famours Bill Pentz site that 4 inch is inadequate on a TS when one wants to deal with fine dust and not just "chip collection"
I have read enough on this subject in terms of conflicting opinions that I am now totally confused and only the math will set me free.
I also buy the issue that there is no perfect fine dust collection system, that you need to capture the dust at source, and that a huge %tage of the fine dust created at machines gets into the air directly from the active area where cutting, planning etc takes place.
What i percieve is that rather than actual vacuum (high velocity cfm) for the purpose of fine dust collection one is looking at volume of air movement and frequency or rate of flow (turnover). Hence the 4 inch port limits that compared to 6 inch port.
But then one has to have a fan on the other end that can cause that volume of air movement. Which in Stu's case is capable of the movement.
So weigh in all you pros. I know form pictures i have seen of some of your shops (the pros that is) that some of you dont seem to take the fine dust issue to heart enough in my opinion.
Looking forward to the responses here.
Just in case someone reads this post with an error of parallax again, this is nothing to do with critizing Stu's config. I am trying to learn and understand and fundamentally temper my own nuttyness towards this subject. My most expensive investment and part of the reason for my own dedicated shop was dust treatment and control.