DC Question

[Jason Christenson]

The more I look into dust collectors, the more confused I get. How many "CFM" is enough. I primarily want to use it to suck up dust created when sanding on the lathe. I may occasionally hook it up to my table saw but will probably never expect it to collect from more than one machine at a time.

Thanks,
Jason

[Steven Wilson]

How much is enough? Depends on the pipe run. let's take the lathe. You can take a little Jet DC650C (canister top) and replace the bottom bag with plastic and run a 3' piece of 4" hose up to a small hood and it will do a pretty good job of collecting the dust (well to 2 micron IIRC). In this case your piping run is short. On the other hand if you want to use the same collection hood from 20'-30' away, then you would need a 2HP-3HP cyclone and a long run of 6" and/or 5" pipe down to the blast gate and then a short segment of flex to the hood. This setup would support a slightly larger hood fed with 5" flex (instead of the 4" in the first example). Now let's say you wanted to properly collect from a lathe using the Oneway dust collection hood, or wanted to collect sanding from the entire length of 30" lamps, then you would probably want a minimum of 3hp, maybe 5hp and at least a 6" feed at termination (you may need a 7" main). It really depends on what you want to do. In any case you can always wear a respirator and protect your lungs properly.

Same thing applies to the table saw. If you have a typical American style contractor or cabinet saw with anemic dust collection (4" port on the back of the cabinet) then the best you can do is just collect some of the chips. So really it doesn't matter what you use. On the other hand, if you have a saw of more modern design (i.e. has dust collection hose in the cabinet that goes to a guard under the table that enshrouds the blade) then you're documentation should tell you how much CFM you need at the cabinet port. In addition to the cabinet you need to collect from above the blade. An aftermarket guard can be good and some saws have dust collection built into the blade guard that attaches to their riving knife. You're total CFM will be the sum of the CFM for the guard and the cabinet. This will be somewhere around 600-800 cfm which will take a 6" main line to fulfill so a 2hp-5hp DC unit should suffice depending on your piping layout. Or, if you move the DC up next to the saw (with minimal amounts of flex hose) then you can use a Jet DC1200C and it will work pretty well. Of course you should consider wearing a respirator if you're not able to capture the dust properly (depends on the saw and the operation you're doing).

[Frank Kobilsek]

Jason

As you can see from Steve's responce the science of air flow related dust collection can quickly conflict with flow capacity of your wallet. I suspect others will add flow dymanics calcualtions for your consideration.

I have the 110V 1.5 HP 1100 CFM Jet with the cansiter top. Recently I've set it up with gates to control:

4" line to Lathe
4" line to bandsaw
2.5" line to Disc sander & Drill press
2.5" line to Table saw (the Dewalt plastic bodied portable contractors saw)

Longest run is about 12'. I'm impressed by its performance at the lathe and disappointed by its performance at the table saw. My experience was not counting the dust collector using quick connect plastic fittings you should be able to outfit a small shop for less than $200 not counting the DC unit itself.

Frank

[Bernie Weishapl]

Jason you have gotten some good advice. I have a 2 hp Harbour Freight DC and put the Wynn cartridge filter (.5 micron) and plastic bag on the bottom. I have 15 ft of 4" to the lathe with a big gulp hood with a Y fitting going 5 ft to my Rikon lathe with a big gulp hood and 10 ft to the bandsaw with a Y to my little bandsaw. It doesn't do well picking up chips while turning but it does a great job sucking up the dust when sanding which is mainly what I want. I have blast gates to each machine and it does a great job on the bandsaws keeping them clean.