Table saw Crown Guard angle.

[MikeJhn]

Noel

Better picture of the boom, not a lot better, but gives the idea:

Better view of the crown guard support.

Mike

 

[ScottandSargeant]

These might be useful references:
https://www.scosarg.com//leaflets/Suva/ ... -Bench.pdf
cheers
Paul

 

[MikeJhn]

There is much more information on the HSE web site for the correct use and set up of Table saws and any other type of workshop equipment:
http://www.hse.gov.uk/pubns/wis16.pdf
http://www.hse.gov.uk/woodworking/ripsaw.htm
http://www.hse.gov.uk/pubns/wis31.pdf
http://www.hse.gov.uk/woodworking/crosscut.htm
http://www.hse.gov.uk/pubns/wis36.pdf

Mike

686/08/06

 

[SLM]

This has prompted me to think about the best form of above table extraction. Whilst I have experience of big saws, with very powerful extraction, leaving almost no *visible* dust, I’m considering how this applies to my home workshop, where my extraction unit, considering length of flexi hose, elbows etc, just about shifts enough air for my cabinet saw (a Sedgwick ta315).

I haven’t actually tried the crown guard extraction; I’m trying to decide what will be the best source of extraction for this.

The simplest, cheapest option is to spur off my existing 150mm diameter extraction hose (on a 2.2kw extractor), bringing that down to the right diameter, which will of course introduce further loss of suction to that system.

Or, I could use a second extractor, in the form of a Neumatic workshop vacuum or a Yorkleen VW2, both of which I have, sitting unused.

Or, I could upgrade my main extractor, and spur off that. There’d still be losses introduced, of course, but starting from a higher volume.

Has anyone and thoughts?

 

[Jacob]

This has prompted me to think about the best form of above table extraction. Whilst I have experience of big saws, with very powerful extraction, leaving almost no *visible* dust, I’m considering how this applies to my home workshop, where my extraction unit, considering length of flexi hose, elbows etc, just about shifts enough air for my cabinet saw (a Sedgwick ta315).

I haven’t actually tried the crown guard extraction; I’m trying to decide what will be the best source of extraction for this.

The simplest, cheapest option is to spur off my existing 150mm diameter extraction hose (on a 2.2kw extractor), bringing that down to the right diameter, which will of course introduce further loss of suction to that system.

Or, I could use a second extractor, in the form of a Neumatic workshop vacuum or a Yorkleen VW2, both of which I have, sitting unused.

Or, I could upgrade my main extractor, and spur off that. There’d still be losses introduced, of course, but starting from a higher volume.

Has anyone and thoughts?

TS sawdust nearly all goes below the table which is where your extraction is most needed.
A little also gets carried back up by the blade and if you need top extraction too then the best place is at the back of the guard.
Crown guards fitted to riving knife much less bother, safer and neater IMHO.

 

[SLM]

TS sawdust nearly all goes below the table which is where your extraction is most needed.
A little also gets carried back up by the blade and if you need top extraction too then the best place is at the back of the guard.
Crown guards fitted to riving knife much less bother, safer and neater IMHO.

Yes, that is now my crown guard has always been configured, attached to the riving knife, and with an extraction port (as yet unused) toward the rear.

 

[Jacob]

Yes, that is now my crown guard has always been configured, attached to the riving knife, and with an extraction port (as yet unused) toward the rear.

Mine too - and the right place if I need it! Though I've never felt the need for top extraction but I suppose I might if cutting a lot of MDF or other dusty stuff. It blows up from the back of the blade.

 

[Doug71]

I use a workshop type vac on my crown guard and it works really well, I have it plugged into one of those remote sockets and have the on switch next to the saw so it's easy to turn on and off when needed. I originally tried taking a spur off the main hose but that didn't seem to work very well. I find extraction on the crown guard makes a big difference, I can definitely tell when I forget to turn it on.

 

[SLM]

I use a workshop type vac on my crown guard and it works really well, I have it plugged into one of those remote sockets and have the on switch next to the saw so it's easy to turn on and off when needed. I originally tried taking a spur off the main hose but that didn't seem to work very well. I find extraction on the crown guard makes a big difference, I can definitely tell when I forget to turn it on.

Thanks Doug, that was my hunch, and it will be the simplest option to experiment with!

 

[MikeJhn]

Crown guards attached to the Riving knife, with extraction to the rear are just for manufacturers convenience, I have made reference to the high speed film that shows the dust brought up from under the table being ejected forwards from the blade gullet.

The premise that a crown guard attached to a riving knife is safer leaves me somewhat baffled.

 

[Jacob]

Crown guards attached to the Riving knife,

.... stay attached, they move up and down or tilt with the blade, small and compact, simple, cheap, effective.

with extraction to the rear are just for manufacturers convenience,

That's an odd idea - it'd be just as easy to extract from the front if that was more effective. All the commercial offerings seem to extract from the back - are they all making a mistake? I think not.

I have made reference to the high speed film that shows the dust brought up from under the table being ejected forwards from the blade gullet.

It goes everywhere but most goes down, some comes back up from the back if not well extracted from below, some will find its way forwards. More noticeable I guess, if you are peering at the cutting edge and the workpiece through a clear plastic cover - maybe that's the problem?
These DIY so-called SUVA guards seem to have gone out of fashion, probably more trouble than they are worth.
A few years back a well known contributor posted up about an accident with one of these which could have been much more serious. It got nudged out of line, caught up by the blade and totally destroyed, with a cut finger in the process.
This could not happen with a riving knife mounted guard.
Real SUVA guards are very expensive and cumbersome in use Suva S91 - Narrow Circular Saw Guard complete perhaps only of value in a very dusty shop e.g. involving repetitive cuts with lots of MDF etc

 

[Ttrees]

Dennis from hooked on wood, mentioned the wider guard gives better turbulence, mentioned in the review on the Axi site.

From what I've found as of yet, the Harvey guard looks the smoothest overhead guard to me,
and seemingly loosely based on the guards what you might see on a panel saw.
It certainly has me scratching my head trying to think of some linear rail for the job.

I'd love to get a proper look at one, as there's no proper photos of the interesting bit,
and the three youtubers who've posted about it, haven't been concerned about the interesting details either.

The more expensive Itech one doesn't look too bad either,
but seems like the gas strut version might be the direction things are going in.

 

[Jacob]

......
It certainly has me scratching my head trying to think of some linear rail for the job.
...

Forgot to say - the main advantage of the simple crown-guard attached to riving knife is that it needs no adjustment, no rail, no other superstructure.
Often simple designs and solutions, however brilliant, are disliked by the gadget fans and techies. They tend to distrust simplicity in favour of difficult solutions, plus gadgets.

 

[MikeJhn]

Forgot to say - the main advantage of the simple crown-guard attached to riving knife is that it needs no adjustment, no rail, no other superstructure.
Often simple designs and solutions, however brilliant, are disliked by the gadget fans and techies. They tend to distrust simplicity in favour of difficult solutions, plus gadgets.

The main advantage for the manufacturer is a riving knife mounted overhead guard is cheap to make the additional work and materials required for a correctly set up overhead guard is not in the manufacturers accountants budget.

 

[MikeJhn]

A few years back a well known contributor posted up about an accident with one of these which could have been much more serious. It got nudged out of line, caught up by the blade and totally destroyed, with a cut finger in the process.
This could not happen with a riving knife mounted guard.
Real SUVA guards are very expensive and cumbersome in use Suva S91 - Narrow Circular Saw Guard complete perhaps only of value in a very dusty shop e.g. involving repetitive cuts with lots of MDF etc

The guard I made could not be nudged out of line as the riving knife holds it in line, the internal curved deflection piece is slotted around the riving knife and holds the guard in line accordingly, you can see the riving knife protruding through the curved deflection piece in the picture below.

 

[Jacob]

The main advantage for the manufacturer is a riving knife mounted overhead guard is cheap to make the additional work and materials required for a correctly set up overhead guard is not in the manufacturers accountants budget.

Yes but it's cheaper for the buyer too! Not to mention much more practical and easy to use. Just one piece of plastic added to the riving knife. Safer too IMHO.
Not to forget - the single most effective safety measure is even cheaper i.e. using two push sticks, which also improve handling. Manufacturers do tend to skimp on these and only supply one - but copies are easily made.

 

[Jacob]

The guard I made could not be nudged out of line as the riving knife holds it in line, the internal curved deflection piece is slotted around the riving knife and holds the guard in line accordingly, you can see the riving knife protruding through the curved deflection piece in the picture below.

View attachment 163316

Well that's one way of doing it.
The main prob is that these over the top guards are mounted off centre, to the side somewhere, and if there is any slack in the system at all a slight snatch can pull them sideways. If flimsy the whole contraption could be caught up and ripped off, as happened with the DIY example I referred too.
Doesn't happen with riving knife attached guard - the sides of the guard may well get nibbled away, but with no ill effects.

 

[MikeJhn]

Why would you do it any other way?

No slack in the one I made, can't be pulled sideways and is not flimsy.

So what is your point in posting on this thread?

 

[Jacob]

....

So what is your point in posting on this thread?

because it solves the problem asked - you don't need an angle at the front of a proper crown guard - it is lifted automatically to the required height by the riving knife and blade adjustment. Plus a number of other advantages.

 

[MikeJhn]

If did not solve a thing, the original question was, others experience with the angle of the front of a well constructed crown guard, HSE recommendations: https://www.hse.gov.uk/pubns/wis16.pdf show overhead guards not attached to the riving knife.

You remind me of the Harry Enfield stupid comedy character "You don't want to do it like that"