Good reason to leave your table saw guard on

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John Brown

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You still haven't explained why you need an over head crown guard rather than the simpler riving knife attachment.
No need to copy mine it's off the shelf it came with the machine and is commonplace. They are all much the same because people have realised they are the safest, simplest and cheapest.
PS identical to Doug's in first post Good reason to leave your table saw guard on
Mine has the usual connector for HPLV hose but most of the dust is LPHV from below via 5" port.
I'm guessing it's for those times when he doesn't have the riving knife in place.
 

Sgian Dubh

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I was just ripping down a 2' length of Walnut when without warning there was a bang as the wood was thrown violently upwards into the guard, normally you can feel the wood tighten around the blade and back off but for some reason the tension was suddenly released in this piece gripping the upward spinning back of the blade and flipping it up. If the guard wasn't on the timber would have been flying across the room (if my face didn't stop it).
Doug, I meant to mention following suggestion for reducing the chance of kickback when ripping shorter pieces of wood where you suspect the material might pinch on the blade before it reaches the riving knife. I forgot to do so yesterday, but I'll throw it out here.

The suggestion is as follows: Let's say you want to rip a piece 100 mm wide out of a piece ~150 mm wide, and that the piece is short at, let's say roughly 400 - 700 mm long. Set the rip fence to something like 101 -102 mm and push the wood into the saw blade to just a bit beyond the centre point of the blade. Back out the piece of wood, either as the saw's running or after turning it off depending on the length of wood you're handling and how easy it is to back the wood out in safety. You'll probably know by this point if the wood is going to pinch. Anyway, whether or not it pinches you can reset the fence to your required 100 mm and complete the cut. If the wood pinched during your earlier 'exploratory' cut you've now created a gap via the existing saw kerf that's less likely to close up on the upward rising rear part of the blade, and if the kerf does close more as you make this second cut, by this point, the kerf should be held open by the riving knife.

Of course, it's pretty much impossible to tell if a piece of wood has stress in it likely to be released and pinch on the blade through a simple visual inspection. On the other hand you may know stress is present through previous experience of working the board.

Anyway, the suggestion is there now. I've used it quite often, but there are also many times where it may not be useful in the general run of things. Slainte.
 
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Ttrees

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I'm guessing it's for those times when he doesn't have the riving knife in place.
No the riving knife stays there, it's because some putty is hard, and often the metal detector will miss some tack nails or staples if embedded, so the need for a trenching cut is required.
I thought that would be fairly clear.

As I said, I'm no expert, but I can guess there's plenty of reasons one might have want to have an overhead guard.
Regardless even if not the case, and I am the odd scenario, that's no excuse for saying something is an over complicated contraption, just because it's different.

Unless you have vested interests in some project putting an alternative overhead guard on the shelves.

Tom
 

Jacob

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No the riving knife stays there, it's because some putty is hard, and often the metal detector will miss some tack nails or staples if embedded, so the need for a trenching cut is required.
I thought that would be fairly clear.
No it wasn't, but got it now! Should be able to cut hard putty with a TC tip blade unless you are talking of something out of the ordinary. If you cut a lot of nails wouldn't you be better off with the right band-saw blade? Try Tuff Saws? Or even a better TS blade?
As I said, I'm no expert, but I can guess there's plenty of reasons one might have want to have an overhead guard.
Regardless even if not the case, and I am the odd scenario, that's no excuse for saying something is an over complicated contraption, just because it's different.
Riving knife plus crown guard could hardly be simpler - the others are all much more complicated and hence likely to be unused on occasions, especially if you do a variety of work with just the odd usage and suddenly find them inconvenient.
Unless you have vested interests in some project putting an alternative overhead guard on the shelves.

Tom
No nothing. You would be the first to know! Mind you I have a design for a honing jig which would be totally superior to anything I've seen so far. :cool:
 

Ttrees

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It seems so Jacob, but occasionally there is some harder stuff what's like cement.
I've no doubt that it would quickly blunt a tablesaw blade, not to mention a missed tack or two.
And If you're referring to the M42 blades for the bandsaw, they seem to last an equal amount of time as regular blades if one accidentally or otherwise, makes contact with even the soft putty.
That's my experience with a bandsaw what wasn't set up well, I'm guessing the set is what is the problem was and the putty made this happen in a jiffy.
Maybe the carbide tipped blades would handle it, but yet to hear of anyone like Ian who's bought some stock to see what the public think.
Seems you can get them for less than M42 blades if you can speak Chinese.
(brazed tips mean no set to be damaged)

So back to the topic again
A good design makes these things simple surely?, how many overhead guards have you used I wonder...
Tell me you're gripe with them, as it seems that you're making assumptions, rather than talking from experience.
Something different doesn't always mean bad.

I can't see what would make them sit idle, especially from one who makes point that the riving knife
should be always installed and never taken off in the first place

Has anyone ever heard of an accident/occurrence involved, because someone decided not to use the overhead guard they had, because it was too much faff?
Was it a good design?

Last occurrence of injury I heard with a guard, (on the creek)
involved a cats tail getting sucked up into it,
The cat came out without a scratch, unfortunately not so for the operator.
I hope he heals well.
I can't recall if it were a standard crown guard or an overhead guard,
one could say that might not have happened if the blade was exposed.

Daft reason to assume, but on a more cynical approach
Maybe there's room for improvement even on you're one Jacob?:dunno:

Tom
 

Jacob

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It seems so Jacob, but occasionally there is some harder stuff what's like cement.
I've no doubt that it would quickly blunt a tablesaw blade, not to mention a missed tack or two.
And If you're referring to the M42 blades for the bandsaw, they seem to last an equal amount of time as regular blades if one accidentally or otherwise, makes contact with even the soft putty.
That's my experience with a bandsaw what wasn't set up well, I'm guessing the set is what is the problem was and the putty made this happen in a jiffy.
Maybe the carbide tipped blades would handle it, but yet to hear of anyone like Ian who's bought some stock to see what the public think.
Seems you can get them for less than M42 blades if you can speak Chinese.
(brazed tips mean no set to be damaged)

So back to the topic again
A good design makes these things simple surely?, how many overhead guards have you used I wonder...
Tell me you're gripe with them, as it seems that you're making assumptions, rather than talking from experience.
Something different doesn't always mean bad.

I can't see what would make them sit idle, especially from one who makes point that the riving knife
should be always installed and never taken off in the first place

Has anyone ever heard of an accident/occurrence involved, because someone decided not to use the overhead guard they had, because it was too much faff?
Was it a good design?

Last occurrence of injury I heard with a guard, (on the creek)
involved a cats tail getting sucked up into it,
The cat came out without a scratch, unfortunately not so for the operator.
I hope he heals well.
I can't recall if it were a standard crown guard or an overhead guard,
one could say that might not have happened if the blade was exposed.

Daft reason to assume, but on a more cynical approach
Maybe there's room for improvement even on you're one Jacob?:dunno:

Tom
I'm all for recycling and what you are doing looks like a good idea. I've been recycling quite a few bits too.
The nails I do with a rare earth magnet - just work the end slowly over the whole surface and you can feel where they are and dig them out. Works better than a metal detector and is more precise if the magnet is a thin bar, pencil dimensions. Then do it again after each pass through the planer in case there's another one bit deeper.
Ali, brass, copper are no prob if not too thick. Stainless is as some is not magnetic
 

Ttrees

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Aye I really must try getting some of those fancy magnets, cheaper than cutting tools.
It's usually just mild steel tacks or maybe some brass that I encounter.
Normally snapping the putty line is enough to spot one out.
That's another reason for having the guard as it's not just wood that could get flung back at the operator, I have seen, or should I say heard a bit of putty shoot from the machine...
hence why I want to copy the best out there.

Glad to see some posting of their shop made ones, as everyone's got something to bring to the table in regards design or need.

Tom
 

JoshD

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I didn't like the guard that came attached to the riving knife with my ags10 because (a) no dust extraction; (b) opaque, you couldn't see what was going on; (c) riving knife had lugs for guard, so too fat to allow crosscut sled to be fitted over the top; (d) no part depth cuts possible; (e) on bevel cuts you need a lot of blade out to keep the guard clear, ultimately you're very limited in the depth of bevel cut you can do without removing the guard altogether; (f) the guard was lightweight aluminium but still heavy enough to twist the riving knife slightly out of true on a big bevel (eg,45 degrees); (g) I use Jessem guide wheels which I really like and which add to safety: on some occasions it's tricky to use them with the guard.

I replaced the riving knife with a curved one the right thickness for the kerf, and built a polycarbonate guard around a length of 40x100 aluminium box section which is structural but also a dust extraction route. My new riving knife have an attachment point for a guard so I built an overhead arrangement. The SUVA ones are dynamic in that they lift as you push the work piece under. My guide wheels do that, but I didn't trust myself to recreate that in the guard so mine is static: you adjust the height so it's clear and that's that. Can't see how it would foul the blade. First attempt to mount it on steel frame was way too wobbly, so now it's mounted on two MDF torsion boxes: ugly as sin, but rock solid.

What I particularly like is that it's always there, admittedly sometimes a bit high (eg with cross cut sled), but it's hard to imagine the workpiece getting properly airborne without colliding with the guard first ... But I'm never complacent with the TS!

I'm away at the moment but when I'm home I'll post some photos and you can all "let rip" (ha ha ha).
 

MikeJhn

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Looks good :unsure: but wouldn't you need some sort of technician always on hand to keep it working and properly set up? That would be me.
What happens if you want to tilt the blade? Never do.
Would it stand a sidewise knock from clumsily handled 3x6" timber? You may be, but I am not that clumsy.
Would there be a special brush kit or something to clean the transparent bits every ten minutes or so?
2000cu/ft/hr extractor seems to cope admirably without manual cleaning.
Top marks for complexity!
Does being a twit come naturally or do you have to work at it. 🤔
 

Jacob

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Does being a twit come naturally or do you have to work at it. 🤔
Sorry didn't mean to offend - it's all knockabout stuff here!
But it is easy to lose sight of the fact that the simple crown guard is extremely effective and not just a crude add-on begging for "improvement".
 

Sporky McGuffin

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Is there a decent after-market crown guard with a dust port? My Bosch site saw has a riving-blade-mounted guard, but there's no dust port on it (previous Bosch had one but they've changed this bit) and the under-table port doesn't catch as much as I'd like. It's a 10-inch blade.

Axminster do one but the reviews suggest it's a bit flimsy.
 

Jacob

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Is there a decent after-market crown guard with a dust port? My Bosch site saw has a riving-blade-mounted guard, but there's no dust port on it (previous Bosch had one but they've changed this bit) and the under-table port doesn't catch as much as I'd like. It's a 10-inch blade.

Axminster do one but the reviews suggest it's a bit flimsy.
I'd have thought that most of the common ones would be interchangeable so another brand will probably do. Mine's an SCM and is available as a spare part. Very solid bit of kit with a port. Might need another hole drilling in a non SCM riving knife.
Not much dust comes out at the top compared to below, if the extractor is big enough. I never bother with the top extractor but I suppose I might if I was doing a lot of mdf etc
 

Sporky McGuffin

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I'll have a look around - ta.

The Bosch doesn't have the normal slot and wingnut approach - it's got a lever which expands two pins into, erm, I'll take a photo. I'd think a wingnut type ought to attach easily enough though.
 

Keith 66

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I must get round to fitting a riving knife to my Startrite table saw, i bought it from a scrap dealer in beat up order with bits missing! My dad had a similar one & used to cut all sorts on it, In fact the first accident i ever saw i was about 7, dad went to cut a small wooden section on the saw, It was very short about 7" long & i kicked back violently flew up & hit him straight on the chin drawing blood.
Regarding warping timber I once cut a keel for a 17ft rowing boat out on a big board of 2" thick Iroko, the keel had a full length curve or rocker in it of approx 2.5". Marked it out & started cutting on the big saw freehand the keel part sprang away from the cut violently & before i had cut 4 feet the kerf was already an inch wide at the end of the board, no wedges needed on this one! Kept cutting & the whole thing sprang away completely the opposite to what i had marked. At first i thought "Wont be able to use that" But flipped it upside down & the curve matched the pattern nearly spot on!
 
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