Duct fitting for jointer

[JMcanoe]

My Shop Fox jointer came with a plastic fitting for 4 inch ductwork. I would like to switch this to a fitting for 5 inch duct, not just put a 4 to 5 inch adapter on it. I found an online spiral pipe vendor that would do a rectangular to round offset 20 gage metal fitting. It looks real nice, but the cost is about $100 with shipping.
Anybody know of a better source or a place here in the Raleigh/Durham area that could produce this fitting at a better price?
Thanks
Jim

 

[Mike Davis]

What size jointer is it?

Up to 8 inches wide a 4 inch duct is plenty.

 

[zapdafish]

I used something like these for my top hat to connect it to 5 inch hose.

http://www.homedepot.com/p/Master-Flow-Spiral-Pipe-5-in-Coupling-SPC5/205330680?cm_mmc=Shopping%7cBase&gclid=CjwKEAjwovytBRCdxtyKqfL5nUISJACaugG18YG8AoO7-rezwhjZLDkcYfLiLax0lhEll5LROPL8ZxoCvZfw_wcB&gclsrc=aw.ds

http://www.homedepot.com/p/Master-F...PIPHorizontal1_rr-_-205330680-_-204169130-_-N

I used tin snips to flay out one side.

 

[Jeremy Scuteri]

This is what I did:

http://www.ncwoodworker.net/forums/showthread.php?t=55825&highlight=jointer+dust+collection


I bought a 6" standoff from Oneida (http://www.oneida-air.com/inventory...&CatId={C068CD85-D0CE-4C39-99D2-F0F0E0617978}). It was very high quality and very heavy duty. Cost is about $22. Shipping can change that price by quite a bit if it is the only thing you are ordering.


I just recently got a 5" standoff from Penn State Industries. (https://www.pennstateind.com/store/R-ATT05.html). It isn't as nice or heavy duty as the one from Oneida, but it was only $10. If I had it to do over again, I would probably spend the extra money on the Oneida fitting. The Penn State one is probably good enough though.

 

[Bill Clemmons]

I've used East Coast Metals for some duct work. Looks like they have a Apex location.

 

[Rwe2156]

I would just use the adapter.
Its not going to make that much difference.

 

[Jeremy Scuteri]

I would just use the adapter.
Its not going to make that much difference.

I have not taken any measurement's myself and I don't know what you are basing that statement on, so it is possible that you could be correct. However, Bill Pentz (who has done lots of research in this area) certainly disagrees with you. Here is an excerpt from here (http://billpentz.com/woodworking/cyclone/ducting.cfm#resistance)


Air at the low pressures we use in dust collection, air is more like water, and does not compress. Any obstruction, small pipe, or tight turn will kill our airflow dramatically just like closing a water valve. This means any obstruction, small port, undersized hood, restrictive internal air pathway in a tool, small section of hose, or restrictive duct fitting will act just like a water valve and seriously reduce flow. This also means our tapered and smaller adapters from our ducting to our tools are all but useless because they also kill our needed airflow.


While Bill Pentz is regarded as an authority on this topic, that doesn't mean that everything he says is gospel. I just don't know of a better source for information on this topic. It sure would be fun to be able to run some experiments on some of these things and have some hard evidence to back up claims made one way or another.

 

[Rwe2156]

No, I don't have anything to base that on other than my own system and the advice of knowledgeable DC people I've talked to.

Alot of the things like you mentioned about undersized hoods, etc, are splitting hairs and won't make a practical difference.
His designs are OSHA type "clean lung" systems designed for industry.

If you'll notice, Clear Vue also sells one size DC - 5HP and that maybe overkill for the average ww'er.
Not my opinion - the opinion of many knowledgeable people in the industry.

I'm just sayin many people get anal about DC and waste alot of time to get a few percent better performance.

 

[Mark Johnson]

RON J's solution is a very good solution for this problem. I have Oneida duct work as well and find that their parts are excellent. The internals of the jointer might also provide a restriction to the air flow. I also agree that using an adapter to go from the existing 4 inch duct to a 5 inch will have little negative impact. Yes it is a restriction, however the distance involved is short enough not to create a major issue if the overall pipe run is not too long and NOT ALL FLEX duct. Minimizing the length of flex duct will have more impact on the delta Pressure and drag in the overall run than the one adapter.

 

[Jeremy Scuteri]

I agree that people get anal about dust collection. My posts are probably proof of that. I can admit that I tend to be an anal person. I prefer to label it as passionate and thorough, but anal is probably an accurate description as well.

Without measurements there is no way to know if they get a few percent better performance or much, much better performance. (How is performance even measured? The amount of chips on the floor? The amount of visible dust in the air? The accumulation of visible dust on surfaces over time? Testing with an air quality meter like a Dylos?).

"Alot of the things like you mentioned about undersized hoods, etc, are splitting hairs and won't make a practical difference."
Again, how can you possibly say this without measurement or data to back it up? The things specifically mentioned are:
1) Any obstruction
2) small port
3) undersized hood
4) restrictive internal air pathway
5) restrictive duct fitting

Undersized hood seems like the only thing here that doesn't directly apply to things a normal woodworker will encounter with dust collection of common tools.


I am not sure what constitutes a knowledgeable dust collection person. Most of us put a system together based on whatever internet research we do, then we say "yup, that seems to work pretty well" and we never look back. No measurements are taken, no experiments are run in any kind of scientific fashion to see if the system can be improved. If the only goal is to prevent the tools from spewing chips all over the floor, then pretty much anything will work.

 

[DanR]

I would take the measurements of the area where it sits, the 4 inch plastic fitting, and a piece of your 5 inch pipe/hose to an hvac place or big box store and look in the heating aisle then the plumbing aisle.

 

[Jeremy Scuteri]

This came up on another forum that I am a member of. I thought it was very interesting.


"Following up on the CFM measurement conversation in the FB510 thread, but I thought I'd start a separate thread..


5HP Clearvue with 6" PVC. Measured 35' from collector, with three 90° bends and two 22° bends in the path (plus a couple wyes in the path that are closed off). I know there are few joint leaks, but I don't think there's a lot of leakage. Maybe later I'll try to tighten things up and see if affects readings.


I see ~950 CFM (4750 fpm) at the 6" port.


When I restrict that to 4" by adding a 6"x4" reducer, I get ~700FCM (8000 fpm).


When I add a 6' length of 4" flex, I get 685 CFM (7800 fpm)


I am using a $30 Pyle PMA82 Anemometer, which I "calibrated" by holding out the window of my car. At various speeds it is consistently ~5% under the car speedo reading, so I think it's reasonably accurate. My duct readings are a rough average of about +/- 15% variation I get depending on exactly where I hold the anemometer.


My system is surely not CFM optimized, with 35' and 320° of bends before the first port, but it's space and convenience optimized -- the collector is tucked away in a corner and the ductwork is underground."


I don't know how accurate these results are, but this experiment shows 26% reduction in CFM by a single 6" to 4" reducer 35 feet from the collector with multiple bends and turns. I am currently looking into getting a gauge/meter to make some measurements myself.