How do I stop my planer clogging my dust extractor

[EightyTwo]

I bought a Scheppach planer thickesser to help me turn old timber into useable stuff and an Axminster APW1000DE dust extractor to clear away the chips. I've had a few goes with it but, whenever I try to plane or thickness anything wider than about 2" with a cut over over 1mm, the chips get stuck on the grill at the entrance to the extractor. I have about 6' of 4" flexible hose between the two units and I have to disconnect the planer and shove my arm down the hose to 'tickle' the chips until they go through.

This can't be right - I must be missing a trick! Should I try using rigid ducting or make sure that final 18" of duct is vertical or cut the grill out of the inlet or build some sort of swirl device or...?

Any help or positive suggestions gratefully received!

 

[big-all]

suspect the extraction rate height off hose or length may be the problem

is the extraction unit on a similar height to the planner ??
try reducing the height or hose length and see how it works

 

[EightyTwo]

Yes, the outlet from the planer is about the same height as the inlet to the extractor but, because the six foot length of hose is flexible, it does sag down a bit. Do you think that I should try tying it up with a piece of string so that it makes a kind of inverted 'V'? When you say "try reducing the height...", of which end do you mean?

 

[big-all]

level should be ok
have you any reducers on the hose ??
what is the flow rate [cubic metres or what ever]
planers or routers tend to need a high flow rate due to extremely heigh material removal

 

[Norcon]

Seems an old model. Axminster don't sell it anymore.

Where did you buy it, E bay?

 

[EightyTwo]

No reducers. No idea of the flow rate - yes, it's an old model off eBay. It looks like the little Jet model, 1hp with a central, horizontal impeller, dust bag down and filter bag up. So, guessing at ~1000 m3/hr

It looks just like this:

http://www.ebay.co.uk/itm/Axminster...ies_Carpentry_Woodwork_ET&hash=item4172fc4390

 

[Burnerman]

Not trying to be a wet blanket mate but those - good that they are - are really for extracting dust from sanding discs....i.e not particles the size of stuff that comes from planers.
For that its best to use a much more powerful model in the region of 3 hp
(fitted many to schools, on my recommendation).
Keep the hose run short, with no obstructions and keep tapping the hose to keep stuff moving.
John

 

[EightyTwo]

Thanks John (I think!).

I 'rescued' a length of rigid metal ducting from a skip. Is it worth using a shortish length of this at the extractor end? If so, should I make it vertical, horizontal or at a jawnty angle?

Is it a really bad idea to remove the grill? I might be able to refit it, or something similar, at the planer end...

I'm trying to imagine all the little chips driving down the pipe towards the extractor and coming up to a constriction. Do they need a "queue ahead - please slow down" sign or do they need to speed up (and spread apart) like Bernoulli said? Once the blockage starts, I guess that it'll only get worse, unless I tap the hose.

 

[Burnerman]

I guess the only thing you can do is to avoid loops in the pipe, so the extractor doesn't have to suck the chips up from ground level, and keep the duct as high and as level as you can, so there's only one turn up into the extractor.
Smaller, lighter chips will help, but presumably your machine has claw feeding so its only the depth of cut you can alter.
No problem removing any grilles, but a huge timber chunk wouldn't go down too well with the fan blades!
A smaller diameter duct would increase the air speed to some degree but any stepping wouldn't be a good idea.
John

 

[EightyTwo]

The extractor feed is vertically downwards so I guess that a straight drop into it is a good idea. When I use the hose to clean the pile of chips off the floor, like a big elephant's trunk, it sucks everything up luverly.

I'm not so worried about a big chunk of timber going into the fan blades - I sucked up a rag yesterday!

"A smaller diameter pipe would increase the airspeed..." sounds like I need a venturi just before the inlet - Bernoulli was right!!

 

[big-all]

lets look at this a different way

you can drink 1 pint per hour and the planer can produce 2 pints per hour
in a short while you have an excess on the table that you can only clear by turning the planer off

in other words if your extractor cannot remove more than the maximum your are asking it to remove it will block the hose needing frequent stopping and shaking to try and catch up with the outflow

using the extractor as a hoover it will take what it can cope with and no more so tells you nothing about its ability to cope with your planer

 

[EightyTwo]

Thanks again.

I had another go this evening and tied the hose up in the middle, like an inverted "V". It didn't clog once (but I did knock the hose off the planer... ).

Thanks for all your help- you've given me food for thought. I'll do some more experimentation.

 

[Norcon]

On my EB the motor sits on top and sucks upwards.
So maybe thats a design flaw on yours and why you can buy it for peanuts on e bay.

Usually when you have a 4" hose its designed for chips and not dust.
Also the filter won't be designed for dust anyway.

 

[EightyTwo]

You could well be right. I should have called it a chip extractor. The new Axminster Jet DC-950A has exactly the same layout as mine but a smaller motor. They say it'll cope with a 10x6" planer thicknesser, like my Scheppach. Maybe users of this will have the same problem! This is not really my area of expertise!