Why buy a big dust collector? - Woodworking Talk

TS3660 · 07-02-2009, 11:27 AM

I am in the market for a DC. I'm only one guy and can only run one machine at a time. So, why would I need a DC that is capable of doing multiple machines? Wouldn't it be fine to buy a decent DC, say 1200 CFM? Of course I'd still plumb it to all my machines but there would only ever be one machine running at any time. So, I'd simply open the gate for that machine while I'm using it. Am I missing something?

**Leo G** · 07-02-2009, 12:20 PM

I have a medium if not smaller medium collector for my shop, a 2 1/2 HP Cyclone. It is plumbed to all my machines and I use two machines at a time all the time. Especially the jointer saw combination. It just makes it easier to be able to have more than one blast gate open. Sometimes you forget to close one and it wastes your precious time to go over and close it and walk back over. If you are a hobbyist, not so much, but if you are in business it makes a big deal. Plus it justs adds to the fatigue of the day to have to open and close the gates if you forget.

Do you need the big dust collector, no. Is it nice to have, yes. Plus if you get a bigger one in the beginning and get some larger machines that require a more robust DC you don't have to spent your money again. If you are on a budget, buy as big as you can afford for the future.

autoBrad · 07-02-2009, 12:27 PM

Well, cfm's also has to do with how much ducting you'll run and the loss associated with that. Also, if you are going non-cyclone, i would consider getting more cfm's since the effectiveness drops as the filter gets more on it, etc. Another thing about cfm's is it really depends on what level of collection you want to get obviously you need less cfm's to get large chip collection than you do to get the finer dust.

I am in the market as well and keep debating how much I need, but I agree with Leo get as much as you can afford. And look at the tools you have. The more fine the dust they create the harder it is to collect it. Just my 2 cents. This is a topic that can get real out of control real quick.

TS3660 · 07-02-2009, 12:43 PM

Forgetting to close the gates makes sense. Or even not WANTING to close the gates.

Here's another question: My shop is the second floor of my garage. I'd really like to put the DC on the first floor so I don't take up floor space in the shop and to keep the noise down. However, this poses a few problems and questions. Should I run the ducts from the DC, up to the shop, then up to the ceiling in the shop, then drop to my machines? Or should I run to ceiling of the first floor, then to the machines up through the floor?

**Leo G** · 07-02-2009, 01:16 PM

Already sounds like you are setting yourself up for a failed system if you are planning on getting a smaller system with long duct runs. I only have 20-25' duct runs on the far end and I can see the difference from the beginning of the line and the end using 6" ducting and a 7" main.

TS3660 · 07-02-2009, 01:29 PM

I'm not setting myself up for anything yet. I'm here for answers. If I put my DC on the first floor, the longest run, from DC, up through the floor, up to the shop ceiling, over to the furthest machine, and then down to it will be around 40 feet. It will have 2 elbows on that furthest run. All other runs will be shorther. The shortest will be around 24 feet. But here's the thing I keep thinking: If I put the DC on the shop floor, I only shorten every run by 8 feet. So my longest run will be 32 feet. If I put the DC on the first floor, then run the ducts along the underside of the shop floor and then up to the machines, the longest run will be 26 feet. But the problem I see with running every line up through the floor is that it may cause tripping hazards. Plus, my machines are now immobile. These are my thoughts and I am definately no expert. I am just a beginner. So, I welcome all ideas here. Thanks.

knotscott · 07-02-2009, 01:34 PM

More CFM usually provides better dust collection, but if you've got a true 1200 CFM you should be fine. The ratings on DC units are suspect. The problems come when you've got a "claimed" 1200 CFM that actually won't do better than 600 CFM under any circumstances, then your ducting and losses drop it to more like 400 CFM, and you end up with lousy DC.

Aside from CFM, consider the size of the impeller, the HP, and the inlet size. A 10" impeller isn't likely to move as much air as a 12" impeller even if equipped with a slightly larger motor. If you get an 11-1/2" to 12" impeller with a 1-1/2hp to 2hp motor you should get decent collection, depending on your setup....generally 5" to 6" inlet and outlets will move more air than 4". Google Bill Pentz for bonafide good DC information.

TS3660 · 07-02-2009, 01:37 PM

Wow, lots of good info from Bill Pentz. I'll have to print some of that out and sit down and read. If a company claims 1200 CFM, how do I know it is?

Geoguy · 07-02-2009, 02:07 PM

Bud, I'm also a one-guy crew with a relatively small shop for evenings and weedend work. I have a 1200 CFM collector piped to some of my machines (many machines share a drop hose depending on which one I'm using at the time). I also ocasionally use the table saw and jointer at the same time and my 1200 CFM unit works fine with both at the same time. The point of all this rambling is - you probably don't need anything more than your proposed 1200 CFM unit. Keep in mind, you likely won't actually get 1200 CFM out of it but I'm not going to get into a discussion of piping runs, vacuum loss, etc. It works for me but if you can afford more, you won't regret getting a bigger machine.

And, with regard to your question about how to run piping - it seems that if you were able to have the blower down stairs and piping drops in the floor beneath the machines, you would have both vacuum and gravity assisting with dust collection. Just my two cents.

TS3660 · 07-02-2009, 02:34 PM

Geoguy, That gravity + suction is a good thought. I'm still hesitant on the "up through the floor" idea though because of machine immobility. Here's a link to the DC I'm thinking about. I know cyclone styles are best but I'm a hobbyist, not in it for business.

http://www.grizzly.com/products/2-HP...ollector/G9975

woodnthings · 07-02-2009, 02:40 PM

QUOITE [Here's another question: My shop is the second floor of my garage. I'd really like to put the DC on the first floor so I don't take up floor space in the shop and to keep the noise down. However, this poses a few problems and questions. Should I run the ducts from the DC, up to the shop, then up to the ceiling in the shop, then drop to my machines? Or should I run to ceiling of the first floor, then to the machines up through the floor?]
There is no doubt in My Mind that I would run up throught the floor if possible... NO TRIP HAZARDS...All piping is below and guess what, gravity is also on your side this way. I have the same set-up Shop over garage/workshop and I have 2 separate 1 1/2 HP Jets on wheels with short,(less than 10' long), 4" collector hoses and "Quick Connect" fittings I dreamed up my self out of 4" schedule 30 and dust collecter 4" and 6" to 4" transitions, all of which is "propritary"

of course. 4" dust, 4" PVC and 4" sheetmetal are all just off enough so they don't slide together.

I'm also thinking of getting a larger cyclone for the lower shop, but that's a ways off for now, more research is needed. I do like LeoG's set-up! Penn State Industries has some pretty reasonable cyclones.
www.pennstateind.com
Also, 32' sounds like a very long run especially with 2-90 degree ells!

bill

TS3660 · 07-02-2009, 03:06 PM

I just looked up CFM of shop-vacs and I can't believe their low rating. A 6.5 hp is only 185 cfm. What's up with that? How can a Grizzly 2 hp get 1550 and a 6.5 hp shop vac get only 185????

**Leo G** · 07-02-2009, 03:27 PM

A shop vac is not a dust collector. Plus they rate the shop vacs motor on peak brake HP which the machine only makes in an instant and never continuous. The most you can really get out of a standard 15A outlet is around 1 1/2 HP. The DC motor is an induction motor and is likely a true rated HP. Did you really expect a shop vac with a 2" hose and that dinky motor and impeller to create any substantial air flow? Compared to a DC with 12" impeller and a motor that looks like a motor.

TS3660 · 07-02-2009, 03:37 PM

No, I didn't expect a shop vac to be a dust collector but sheesh. It's 9 times less powerful with 3 times more horsepower ! The reason I even looked it up was because that's what I use now and it does just ok. So, if I go with a 1550 cfm real DC, I will probably be happy.

rrich · 07-02-2009, 04:29 PM

Bud,
A gentleman at Rockler passed this bit of wisdom to me. "You are a one man shop. You will be running one machine at a time. Get the largest DC that you can afford that is on wheels and move it from machine to machine."

Looking back at it, it was excellent advice. I do just about that except I switch hoses to the trash can cyclone depending upon the machine in use. It take less than a minute to switch between planer and table saw.

In your case, I understand the reluctance to have multiple holes in the floor of the second story and the possibility of shop arrangement changes. If it were me, I would make a single hole in the floor of the second floor and run a hose from there to the machine in use. The only addition that I would add is a "Long Ranger" to turn the DC on from the machine.

Geoguy · 07-02-2009, 04:38 PM

Quote:

Originally Posted by TS3660

Geoguy, That gravity + suction is a good thought. I'm still hesitant on the "up through the floor" idea though because of machine immobility. Here's a link to the DC I'm thinking about. I know cyclone styles are best but I'm a hobbyist, not in it for business.

http://www.grizzly.com/products/2-HP...ollector/G9975

That's very similar to the one I have (I have a 2HP, 220volt, Grizzly but I think it only runs 1200 CFM).

Rich has a good idea about limiting the number of holes/hoses run through the floor. I have one 4"PVC pipe though the floor but it's under my table saw, which is rarely moved. The other drops are overhead. Check out some of the pics in my gallery if you need some ideas on "how not to do it."

TS3660 · 07-02-2009, 04:40 PM

Rich,
Those are some good thoughts. I'll have to think this over for a bit before I decide. All the ideas here have good points and bad. Just like anything I guess. I just have to decide what will work best for me.

**Leo G** · 07-02-2009, 05:28 PM

Quote:

Originally Posted by rrich

Bud,
A gentleman at Rockler passed this bit of wisdom to me. "You are a one man shop. You will be running one machine at a time. Get the largest DC that you can afford that is on wheels and move it from machine to machine."

Looking back at it, it was excellent advice. I do just about that except I switch hoses to the trash can cyclone depending upon the machine in use. It take less than a minute to switch between planer and table saw.

I would have to disagree with that advise. I had a DC on wheels for the first 7 years of my career. Oh, gee, I need to use the tablesaw, just a few cuts. Don't hook the DC up. And this goes on a lot. Next thing you know your TS is full of chips, your jointer drops a few chips here and there on the floor. After a day of working in the shop you have a big mess, BIG MESS. Having a stationary unit with each machine plumbed in with a gate was the best thing I ever did.

If you are a small shop and everything is on wheels and then put away because of space constraints then this is a good strategy. If you have your machines permanently located, plumb everything.

Jason W · 07-02-2009, 07:58 PM

In theory, the DC on wheels sound good, but I gotta agree with Leo. You wont take the time to hook it up for just one or two cuts. I have my planner and joiner sharing a hose that has to be switched back and forth. I'm constantly skipping that step when it's time to use the joiner becuase it's just one or two passes.

By the end of the day it's a mess!

Tom Clark · 07-02-2009, 10:16 PM

I bought a 1hp grizzly, and it was a bad joke when I hooked it up to my planner. Chips were everywhere except in the bag. Since then it has been used on my band saw where it does keep the dust cloud down. Then bought a 2hp grizzly 1029, and it works great on the shaper, 15" planer, and tablesaw. (I never run more than one at a time.)

Buy a small one first and you will end up buying a larger one very quickly…