Mark VII Impeller

[Ash1562]

Hi all

I have a 1960's vintage Mark VII and the previous owner had taken the impeller blade off (cuz the noise, I am guessing?). I cleaned things up and re-lubricated and put it back on - and it's not any louder to me with earplugs in. It works fine but I barely see any suction when doing work. If I try to pick up sawdust on the ground, it does a great job, but when I'm working, I still see dust particles and shavings flying around, no matter how close I get the hose inlet.

Since everything on these machines are well-designed and though out, chances I am using this wrong. Am I seeing reduced suction cuz the hose I have is too long (it's about 5 feet). Or am I expecting this to work like a dust collection system when it's really just a nice vacuum to use for clean-up after all the work is done?

thx
ash

[JPG]

You are expecting a dust collector to act like a vacuum.

Dust collectors do not have high 'suction'.

I am curious what you are using for a 'bag'.

[Ash1562]

Thanks for your response, as always!

I have an old burlap bag my wife somehow attained, so I got a 2 1/2" clamp ring, put the hose inside and clamped the bag around it. Working so far as in it's catching all that gets collected inside. Do you think this is choking the air flow? As I type, I realize the bag is water proof so its probably not breathable.

For my edification, can you elaborate on dust collector vs vacuum? Is this the air flow vs pressure difference?

[JPG]

A vacuum typically exhibits great static pressure(suction) with small air flow at high velocity.

A dust collector typically has high air flow(CFM) at low static pressure. However that velocity MUST be sufficient the keep the stuff sucked up in suspension. ALL this stuff is inter related.(static pressure, velocity, cfm . . .) and it all varies as one travels through the 'path'.

P.S. test the 'suction' without the 'bag'.

[jsburger]

Thanks for your response, as always!

I have an old burlap bag my wife somehow attained, so I got a 2 1/2" clamp ring, put the hose inside and clamped the bag around it. Working so far as in it's catching all that gets collected inside. Do you think this is choking the air flow? As I type, I realize the bag is water proof so its probably not breathable.

For my edification, can you elaborate on dust collector vs vacuum? Is this the air flow vs pressure difference?

If the bag is water proof it most certainly is not breathable. That means you have no or very minimal air flow hence no dust collection.