Dust collection fromm a mitre saw

[graduate_owner]

Hi everyone,
I've been looking anew at my dust extraction arrangements and have built a shroud to catch the dust from my SIP mitre saw. There is a 4" hole at the bottom which connects to my Axminster dust extractor - the 63mm 1 micron kit that they sold about 4 years ago but no longer stock.

I tried it out today and what a waste of time that was. Most of the dust still spews everywhere and the dust that enters the shroud just hangs around there.

Does anyone have a really effective dust collection for their mitre saw? I'd love to know where mine went wrong - size, shape, suction capacity, whatever?

Many thanks

K

 

[Graham Orm]

This works well. I know there's some dust around it but it takes a great deal of what used to be distributed around the saw. It's an old plastic container with the neck used as the hose connection.
Just have a look where the dust flies when the saw is in use and make a scoop to fit there.

 

[graduate_owner]

Hi Graham,
thanks for the pictures. What do you use for the suction? It looks like a small bore system using waste pipe.

K

 

[Graham Orm]

Yes just an ordinary wet dry aquavac. Not a proper dust extractor but much better than any domestic vac.

 

[Graham Orm]

In my opinion (no doubt someone will correct me!) Smaller bore vacs are better as the air has to move quicker giving greater suction at the dust source. If you use a 4" pipe you need a monster machine to create fast enough air movement to give decent suction.

 

[graduate_owner]

Aha - so that's my first mistake then. I have been using a 4" pipe. Time to rethink and redesign.

Many thanks Graham

K

 

[wallace]

I once experimented boxing most of the saw in apart from the front obviously, and having a 4" hose at the back connected to a chip collector. Worked really well. I even had a fan on the ceiling blowing towards the saw. This helped to stop the dust escaping. I cant do that now because I've a big old wadkin thing. Now I use 6" spiral duct just inline to where the dust goes

 

[Graham Orm]

Aha - so that's my first mistake then. I have been using a 4" pipe. Time to rethink and redesign.

Many thanks Graham

K

Try using your existing system but add a small bore pipe at the end. This will cause a Venturi effect and the air will have to speed up to get through the smaller pipe.

 

[[email protected]]

Aha - so that's my first mistake then. I have been using a 4" pipe. Time to rethink and redesign.

Many thanks Graham

K

Try using your existing system but add a small bore pipe at the end. This will cause a Venturi effect and the air will have to speed up to get through the smaller pipe.

I have tried this on my system but experienced the opposite affect?!?!?!

 

[Myfordman]

Aha - so that's my first mistake then. I have been using a 4" pipe. Time to rethink and redesign.

Many thanks Graham

K

Try using your existing system but add a small bore pipe at the end. This will cause a Venturi effect and the air will have to speed up to get through the smaller pipe.

I have tried this on my system but experienced the opposite affect?!?!?!

An inadequate airflow in a 4" pipe will not speed up with say a 2" section at the end. Instead the whole air flow will be slowed down by the small bore section.

If there is plenty of power behind the suction on the 4" hose then the short restriction section will speed up the air flow.

 

[davem62]

hi K
as others have said use a normal wet and dry vac,but i have modified mine using the Steve Maskery mod of enlarging the rear scoop with a flexible material, i.e. a cut up car inner tube .I think Steve has made a you tube video about it or if not ,the dvd's he sells are full of excellent idea's like this and also workshop jig's etc

hth david

ps if you can't find the video let me know and i will take a pic of mine,its simple but gets 95% of the dust