crown guard/ dust collection

[wallace]

I want to create a crown guard that will work in conjunction with my saws original one. It also has to have a place to attach a hose. I quite like the ones that have Perspex sides that reach the table and move up when wood is pushed under it. I would imagine they would stop dust being chucked out.
Heres what I have, I don't want to alter this in any way. Anything I do must be reversible.





Anyone got any links or ideas that will achieve what I want
Thanks

 

[nathandavies]

Hi Wallace

I need to make a new dust extraction cover for my saw as well.

My current one is like Frankenstein's monster, but it does a good job of getting the dust.

If you look at this :

https://www.youtube.com/watch?v=HkZD42a2gtM

This is Altendorf, who have got a pretty good idea of what they are doing. Looking at the slide that they use to raise and lower it, makes me feel that with my oaf like engineering skills I would probably not be able to achieve the same smooth movement. What are the components in there? Is there a very specific angle that it rides on to work?

My current cover which as I said works very efficiently, does not move as I push material through, but I made it so that I could move it up and down manually and lock it, and as such I use it as low as I can get away with. However it is hooked up to a 5hp 3 bag extractor and I currently have a 120mm ish pipe going to this above saw unit.

As far as your situation goes, I would have thought that putting a totally independent hood on that arm instead of the proper wadkin one. You can then put the wadkin hood on the mantelpiece in the lounge seeing as it is so pretty. That arm is a good starting point for you, and I would have thought looking at altendorf, and the other big table saw manufacturers and stealing their well researched designs will get you there.

Keep this updated, so I can see what I should do. Only joking, if I come up with anything I will put it on here, I need to do something quite soon.

Hope this babble has some use

Cheers

Nathan

 

[custard]

I want to create a crown guard that will work in conjunction with my saws original one. It also has to have a place to attach a hose. I quite like the ones that have Perspex sides that reach the table and move up when wood is pushed under it. I would imagine they would stop dust being chucked out.

The great thing about SUVA guards (ie where the guard is not attached to the riving knife but is independently suspended above the blade) is that because the riving knife is a fraction lower than the saw blade you can cut tenon shoulders quickly and accurately, by just lowering the saw blade until it's at the required height of the tenon shoulder.

The bad thing is that in every workshop I've been in that uses them, they're as often as not left fully raised most of the time, so that there's actually no effective guard and dust extraction is actually impaired.

Regarding dust extraction, I don't think the guard actually collects that much dust, obviously with MDF you want as much dust collection as possible, but I haven't connected the dust extraction to my crown guard and there's virtually no dust left on the table. The dust seems to circulate within the crown guard and is then sucked down the gaps next to the saw blade and out through the main extraction port, so what a traditional crown guard does very well is contain the dust until the main extractor deals with it.

 

[wallace]

Thanks Nathan, Custard. ideally I would prefer to keep the pretty crown guard and add to it but it may be better to start with a blank canvass. I did have the saw connected to 6" ducting with a 2hp chip collector, this did not seem to work as well as I wanted so I moved the extractor right behind the saw with a short hose which has improved things. The problem I have is that when ripping I get dust straight in the face. I have a twin motor nilfisk hoover which I thought would work on the crown guard. Nathan I like that guard you linked to, does it come in brass and cast iron. I have a monster 4kw fan but when I set it away my neighbours thought we were getting invaded. It would need some serious noise reduction before I hooked it up

 

[Myfordman]

Since I tuned up my cabinet saw extraction by blocking up excess gaps so the total area of the open gaps was equal to the cross sectional area of the extract hose, I found very little dust was deposited on the table and so extraction from above was redundant.

 

[wallace]

This is after a days cutting :shock:



The Pk chucks dust out everywhere and I think it would be really hard to block up all the gaps. I think the best solution would be to improve the volume of air being moved. This should help

 

[nathandavies]

Is the noise on the fan from vibration or the actual motor and rotor?

 

[custard]

ideally I would prefer to keep the pretty crown guard

Don't blame you...it's beautiful!

 

[Steve Maskery]

I built a clear SUVA-style guard for mine, with overhead DX and it is excellent. It's the MkII version and I don't think I would change anything if I had to make a replacement. It sits on the table itself and rises as the work is pushed underneath, and it is articulated so that the front end comes down as soon as it can. The blade is always covered. The only way I can cut my fingers off is to push them underneath deliberately.
I don't want to abuse the forum, so you'll have to work out the route on your own...

 

[wallace]

Nathan the noise is not the motor, when I got it I took the motor off to check it and it is sweet as a nut. The noise was coming from the steel fan blades and the sheer amount of air being moved. I would say it was the noisiest thing I have switched on. My MJ planer was near 100db and I think it is louder. I have a meter so might get some numbers. When I first switched it on I noticed it was drawing 20amps :shock: then I realised the fan intake was unrestricted as soon as I reduced the intake to 8" the amperage went down to the rated 8amp. Whats a good material for sound proofing. I can get used lengths of worktop from a friend who fits kitchens, that should be good to stop noise?
Steve thanks, I do like the look of that type of guard I will have to do some investigating.

 

[Shrubby]

Crown guard extraction is the important one because it gets the very finest dust that stays in the tooth gullets all the way round until the tooth re-enters the workpiece and fresh chippings force the finer dust out towards the saw operator
A well designed hood should work with the airflow created by the blade spinning - not conflict against this as many cheap ones do
The best example I can find you is the INRS CAPRO
Matt

 

[Spindle]

Hi

Can you give more details or a link to an exploded drawing of how the current guard is attached?

Regards Mick

 

[Krysstel]

I've got one of these mounted on my RP TS250RC http://www.thesharkguard.com/. See the pictures in this thread https://www.ukworkshop.co.uk/forums...dification-recommendations-please-t80032.html

Mine is the type that attaches to the riving knife, not the newest version that attaches to an overhead mount. As the guard is only attached at the back it hangs down at the front and always covers the blade and material in the way Steve describes his does. Works extreamly well and extracts as good as 100% from above the blade. Even so I have issues with the design and am planing to rebuild it so it hangs above the table, SUVA style. The main problem when mounted from the riving knife is that the guard is around 40mm wide and gets in the way of the fence whenever I rip anything narrower than 20mm. Also, the guard is large and top heavy and bends the riving knife out of line with the blade. Even so the Shark Guard is a very good (and simple to reproduce :wink: ) design although at a price (I was lucky and got hold of mine second hand).

Mark

 

[Steve Maskery]

Mark
The way to get round your problem of ripping stock narrower than 20mm is to make a short fence with a lip on it. Many "proper" fences are L-shaped like this, for the same reason. You can then get the lip of the fence under the guard so you are still protected.
S