No vacuum to crown guard - help!

[redmoorphil]

Hi guys,
I am just about ready to tear my hair out. I have an axminster AW10BSB2 table saw and also a numatic NVD750 for dust collection (connected via a 100mm cyclone).
The original connection port on the table saw was worse than useless and whilst the dust collection from the cabinet was OK the branch off to the crown guard just produced no vacuum so the sawdust was still going everywhere.
I have adapted the original port a number of times, experimenting with different angles and pipe diameters etc to try and increase the crown guard pick up but I am just getting nowhere.
I did think about adapting the crown guard itself but as there is no vaccum reaching it anyway I dont really see the point.
Cutting today I just gave up and connected my karcher to the crown guard so I was running two dust extractors! but there must be a better solution than that.
I had thought of branching off to the crown guard nearer to the vacuum but don't know if that would make any difference.
Has anybody else had this problem, and if so how have you managed to fix it (assuming it can be fixed).
Many thanks,
Phil

 

[Lord Kitchener]

I've had various crown guards with a vacuum spout, including the big Axminster one that mounts on its own stand, and none of them have worked to my satisfaction. Now I do all my ripping and crosscutting with a pair of Festool TS55s and the problem has gone awat (and I get better cuts too).

 

[joiner_sim]

Just make a guard of your own...? At work our panels saws have bespoke guards, much bigger than your normal sized guard too. About 3 inches wide and covering a hell of alot of the front of the blade. Also they have a 1" brush all the way around. With a large extraction point at the front of the guard.. which could raise some controversy.... as machine guards have the extraction point at the back of the blade, however I have used saws setup like that before and the extraction has been nowhere near as good as what I have from the current setup.

After typing all that, realised I have got a photo of this guard! :lol:

 

[Chems]

I have the same saw as you. What I've done with mine is cut put a 63mm pipe onto the crownguard and run that back to a Y adaptor on the Cyclone. Block off the small take off port on the tablesaw and run the machine with the 100mm in there and the 63mm direct back to the Cyclone and extractor.

I do however use mine much more often with the Festool vac onto the crownguard and the 100mm onto the saw from my Cyclone. I do this just because I haven't ducted properly for the 63mm and it really gets in the way. When I get around to fixing this I will retire the Festool as a crown guard collector.

 

[Benjamin]

Phil - I can share your frustration, I also have the same Axminster Table Saw and Numatic Dust Collector. The dust tends to spew out over the table and floor. I'm guessing mine collects roughly 95% of the dust which I can live with but it's just annoying having to tidy up the remaining 5% after each session.

 

[Giff]

There is an article in this month's British Woodworking (no:32 ) by Gerwyn Lewis ( hope he doesn't mind me mentioning it ), about dust collection and two points that he makes are making a zero clearance insert and putting the extractor on the crown guard at the front instead of the back...that does make a difference. I have made a larger polycabonate guard and can now see what the blade is doing as well. This is on a Record TS315. Geoff

 

[MickCheese]

But I think the OP was saying he had no suck at the crown guard.

So

Surely you need a bigger extractor or a larger pipe to the crown guard and a smaller pipe to the saw body. Have you tried blocking up all the holes in the saw body. That makes a big difference to mine.

Mick

 

[Giff]

I have the NVD750 as well and use it with only the smaller pipe on the guard and it is very powerful and takes up most of the fine dust as well.. When I use it with the 100mm connection as well there is very little suck through the small pipe. I use a cheap B&Q 100mm unit to extract through the casing. Geoff

 

[wallace]

I too am haveing problems collecting dust from the table saw. I have an old Pk and in an effort to collect as much as possible I have 6" spiral ducting on the dust collection point at the back going to a 2hp extractor fan and a big thein separator. On the crown guard I have 5" pipe going to a 1.5hp collector. With all this I am still getting dust escaping.
I think haveing the crown guard dust port at the front might be an option.
Mark

 

[maltrout512]

I too am haveing problems collecting dust from the table saw. I have an old Pk and in an effort to collect as much as possible I have 6" spiral ducting on the dust collection point at the back going to a 2hp extractor fan and a big thein separator. On the crown guard I have 5" pipe going to a 1.5hp collector. With all this I am still getting dust escaping.
I think haveing the crown guard dust port at the front might be an option.
Mark

This is what I made and works well.

 

[Giff]

Hi Mark

I do think a lot of the dust,especially fine dust, comes up ( into the crown guard ) and a powerful vacuum type extractor with a small bore hose seems to work. On my saw it originally had a small pipe that went into the 100mm pipe and it was useless and didn't collect anything. Geoff

 

[redmoorphil]

Hi guys,
thanks for all your replies. I had tried sealing the cabinet but its pretty much impossible to make it reasonably air tight.
It looks like the two vacuum option is the best one. I suppose its not a big deal but I'm glad that I already had a Karcher shop vac lying around. Just a shame that the dust wont then be collected into the cyclone so it looks like I may need to build another smaller one.
I did find a nice plan for crown guard in shop notes 92 so I started building that this morning. There was a video of it on youtube and it seems to work really well (providing the port gets some suck!)
Im dreading the electric bill coming in with two vacs and a tablesaw running!
Obviously there is no perfect design but it does make me wonder how the sawstop table saw appears to perform so well with dust removal.
Thanks again for all your input.
Phil

 

[Chems]

I think the trick to saw stop is that it uses the airflow created by the blade to channel the dust into a port at the front of the guard and then this is sucked back. It also has some nifty drop down side skirts for those dusting cuts.

 

[andersonec]

Try reducing the size of the pipe extracting from the cabinet to 2.5", this will let more suction go to the blade guard, ideally both pipes should be the same diameter (the same amount of suction will then be directed down both pipes) but that is obviously not feasible so the next best thing, you may be able to block off some of the 4".

Obviously the larger pipe (more volume) is using all the power from the vac and only a mimimal amount is being sucked from the smaller pipe, this will happen no matter what make of saw you have.

Andy