Table Saw kickback and trimmed finger (Graphic description & images)

[scooby]

During my brief stint as a cycle mechanic, I build a fully integrated bike to completion before realising it needed to be set up continental. That was not a fun moment

 

[scooby]

Judging from the OP's bike we clearly have a nutcase offroader who lives bike

I use playing cards. equal number each side orientates the caliper exactly.

We had spacer shims (basically the same as the card but metal) and quite often you could even get it in as the pad clearance on Road hydros is tiny. i think it was the fact that I was doing it so many times a day, whereas on my own bike I need to adjust very occasionally.
i will say, it gave my new a found patience for setting up my bandsaw bearings perfectly

 

[Jacob]

The HSE guidance appears to cover all the key basics and a good starting point.

Figs 2a and 2b are bad. Use 2 sticks not just one, and a crown guard.
Fig 3 shows a very odd push stick. Use the standard pattern - it's more useful than it looks!
These regs are old and need updating. Should not show a hand on the workpiece - that's where trouble begins, though sometimes this would be OK but you should always reach first for two push sticks!

A key point I think is always carry out a mental 'risk assessment' before making cuts.
On a slightly tangential issue wrt safety on the table saw I have a slight issue with my saw. When I first got it I was mainly doing cross cuts. More recently I started to do some rip cuts and found the timber was binding on the rip fence on the final push out. This caused me to recheck all the alignments. After a a few tweaks I was confident I had the blade and fence correctly aligned and parallel, at least to a few 100th's of a mm. This improved things however I still felt the timber binding on the run out. I then found that the riving knife was toeing out from the blade, effectively pushing the cut timber towards the fence. I checked this by passing a cut piece back through. The work piece was free running between the blade and fence up until the piece gets to the riving knife. At this point you can see the work piece starting to deflect the knife and then spring back once it passes right through, I would say about a mm. I can see no way of adjusting the riving knife independently.
I would very much like to hear any thoughts from the more experienced members on this. I.E. is this normal. a safety risk etc. Obviously even more wary now.
The table saw is a Charnwood W629.

Could be thin blade against thick riving knife? Or blunt blade making non straight cut. Bent riving knife?

 

[Jacob]

Cycling has moved on pretty far from the galaxy days Jacob. The in thing is a gravel bike. A cross between a tourer, a cross country and a road bike.
Even a basic gravel is likely to be half the weight of your old steed.

Some of the higher end now use electronic wireless shifting, so gone are antique things like cables

Well I also have an "in thing" bike, at least is was when I bought it; a titanium frame "audax" i.e. lightweight road bike but not as light or specialised as an out and out racing bike

 

[Adam W.]

Thanks for sharing your experiences. Since I started using my table saw last year I have always endeavoured to treat the saw with the greatest respect. This is a sobering reminder for me not to allow any complacency to creep in. The HSE guidance appears to cover all the key basics and a good starting point. A key point I think is always carry out a mental 'risk assessment' before making cuts.
On a slightly tangential issue wrt safety on the table saw I have a slight issue with my saw. When I first got it I was mainly doing cross cuts. More recently I started to do some rip cuts and found the timber was binding on the rip fence on the final push out. This caused me to recheck all the alignments. After a a few tweaks I was confident I had the blade and fence correctly aligned and parallel, at least to a few 100th's of a mm. This improved things however I still felt the timber binding on the run out. I then found that the riving knife was toeing out from the blade, effectively pushing the cut timber towards the fence. I checked this by passing a cut piece back through. The work piece was free running between the blade and fence up until the piece gets to the riving knife. At this point you can see the work piece starting to deflect the knife and then spring back once it passes right through, I would say about a mm. I can see no way of adjusting the riving knife independently.
I would very much like to hear any thoughts from the more experienced members on this. I.E. is this normal. a safety risk etc. Obviously even more wary now.
The table saw is a Charnwood W629.

Likely to be a miss-match between kerf thickness and knife thickness. Had that on a circular saw with a blade supplied and mounted by the local saw doctor - Don't use him any more.

Numpty!

 

[Against_The_Grain]

Fig 3 shows a very odd push stick. Use the standard pattern - it's more useful than it looks!

Used the pattern shown for a very long time in the industry, there’s nothing wrong or odd with it. I think you’ll find if you lay one of them on top of a “standard” pattern they are much the same geometry with the “standard pattern” simply having a larger birdsmouth which can be unsuitable for some jobs.

In the real world, you need a variety of different shapes for whatever you might be cutting, and even a push stick in the right hand and a push stick with a steel spike in the end for control in the left hand is ideal for a lot of work.

 

[Agent_zed]

Mitre saws can be highly dangerous and although the focus is rightly on table saws I'd like to share a photo of what I keep on my shed wall.

It's perhaps not very obvious, but that's the blade guard on a Makita mitre saw. An insufficiently secured workpiece caught on the blade and impacted the guard, causing the steel to shear. My hand was on the workpiece at the time. The whole saw (all 30kg of it) leapt off the bench with the force of the impact. I consider myself incredibly lucky I can type this with both hands.

As a result I do two things now: Always properly clamp the work piece, never use my hand to hold it in place. The clamp on the Makita is a PITA, especially for trenching cuts, but I'd rather that than the alternative. The other thing I do is take a look at that mangled piece of metal every time I start to use a power tool. Paranoia can sometimes be a useful state of mind.

Yep, I was very lucky when cutting some log slices, back when I didn't know better. It was only a short piece of wood and I shouldn't have been holding it. The saw kicked back and jumped. My instant reaction was to withdraw my hands and fingers and then my brain had to think ok have I been cut? Thankfully I got away with it and it taught me a valuable lesson.

One of the biggest problems with humans is that we cannot share the exact feeling and knowledge of something like this. I can tell you about it but as it didn't happen to anyone else they will not store that information in the same way. They might think about safety but the feelings of a near miss won't be there to drive home the reason not to do something. If we were computers that knowledge would be combined with the exact perimeters and feedback and would be added to the list of things not to do and predict potential problems in the future. I wish I could 'download' all the dumb things I've done, so my son would just understand rather than have to try and tell him not to not do X or Y and hope that he listens.

 

[Bruce Mack]

this

Got what?
Crown guards protect injuries from "falls" and other accidental movements.

"doesn't help on the other 99.999% of machines which don't have it." This isn't a valid objection. If you have a SawStop (I don't) you aren't likely to have a finger amputated. Random orbital sanders, electric drills, oscillating tools, and most other shop tools don't ruin the rest of your life.

 

[Jacob]

this

"doesn't help on the other 99.999% of machines which don't have it." This isn't a valid objection. If you have a SawStop (I don't) you aren't likely to have a finger amputated. Random orbital sanders, electric drills, oscillating tools, and most other shop tools don't ruin the rest of your life.

It is a valid reason for getting the 2 push stick plus crown guard habit, for the 99.999% of table saws, spindle moulders, planers which don't have Saw Stop or equivalent. Once you've got it a SawStop becomes barely necessary - you have learned how not to trigger it.
n.b. having a good ordinary braking system must reduce accidents too.
The point I've been having to repeat for a long time now is that it is very simple and very cheap to almost eliminate the risk of a cut from TS, spindle, planer, just by keeping your hands well away from a spinning cutter or blade.
Shouldn't have to keep explaining this - it's about as difficult to understand as the need to keep your hands away from a fire if you don't want a burn.

 

[Bruce Mack]

I agree with you that having a SawStop or other upcoming tablesaw with similar features doesn't relieve the user from the duty of safe practice. Still most hobbyists who suffer amputations of fingers will do this on the tablesaw and will retrospectively wish they had the blade-stop feature.

 

[Agent_zed]

I agree with you that having a SawStop or other upcoming tablesaw with similar features doesn't relieve the user from the duty of safe practice. Still most hobbyists who suffer amputations of fingers will do this on the tablesaw and will retrospectively wish they had the blade-stop feature.

yep. I would get one if they were a more reasonable price.
It's similar to arguing that you don't need an RCD on an electric circuit as long as you take care whenever you are working on the electrics. Having an RCD doesn't make me less careful when I work on electrics, it just means I don't get dead if for some reason I do something wrong that day, it still gonna hurt a bit. Current tablesaws are like having an old wire fuse system, fine as long as you don't ever touch it accidentally.

I hope in the future table saws will all have similar technology. I don't believe it will make people careless as you still don't want to find out if A. it works and B. how much damage it does to the blade and stop block. It's like airbags in my car, I don't ever want to test their effectiveness.

 

[Jacob]

..... Still most hobbyists who suffer amputations of fingers will do this on the tablesaw .....

Yes, but vanishingly few if they use 2 push sticks and crown guards, making SawStop irrelevant.
Normal braking important though as not noticing that a switched off blade is still spinning seems to be a cause of accidents.

 

[Lons]

if I injure myself it will probably be on the bandsaw or something I see as more innocuous and therefore give less respect... so I try to remember that and respect all tools... it might mean a slight limitation in the functionality I have (though I have a router table which is potentially dangerous), but I would prefer to compromise than risk losing a finger (and the embarrassment of my wife having to deal with it!

To date the only finger injury I have had was a cut from a tape measure retracting too fast - there were three hand surgeons in the house at the time and they were very disappointed that I treated the cut myself with a plaster - though I did remind them that I am the only one with a first aid qualification

The only bad finger cut I've had was years ago on the bandsaw and very definitely my fault, the blade was getting blunt, I didn't have much left to do and kept pushing instead of changing the blade. . Lesson learned. When I do get small general cuts the superglue comes out which makes my wife cringe as she says it isn't medical grade. The glue stings but works well enough.

I got a large thorn in my knee and my wife's uncle, a heart surgeon took it out using a scalpel, I think he forgot I wasn't sedated on the operating table.

 

[sploo]

As I’ve got older I find myself using the tracksaw more & more to breakdown sheet material, taking the tool to the material is far less of a chore than taking the sheet to the tool, nothing wimpy about it just a practicality of aging I’m afraid

Agree completely. Indeed, unless you have a large panel saw it's much safer to do the initial break down of larger sheets using a track saw. Trying to balance/control a large sheet of material on a table saw that's too small for the job is a lethal enterprise.

 

[Jackie H]

Figs 2a and 2b are bad. Use 2 sticks not just one, and a crown guard.
Fig 3 shows a very odd push stick. Use the standard pattern - it's more useful than it looks!
These regs are old and need updating. Should not show a hand on the workpiece - that's where trouble begins, though sometimes this would be OK but you should always reach first for two push sticks!

Could be thin blade against thick riving knife? Or blunt blade making non straight cut. Bent riving knife?

Thanks Jacob,
The blade is relatively new and makes good cuts so IMO not blunt. I will check the thicknesses again but I think they are matched correctly and they are as supplied by Charnwood. Despite the issue with the riving knife the cuts are good and parallel. I checked the riving knife and it appears to be flat but I think something somewhere is bent. The riving knife is literally toeing out from the blade. It seems to flex as I am pushing material through. It is not massive (and this may be a very naïve comment) but it almost seems as though the riving knife is acting like a 3rd push stick keeping the work piece against the fence.
I am minded to contact Charnwood and see what they say. I have not experienced kickback but given the various comments I am wary this may be a factor that could lead to it.
Jackie
PS The HSE document was last issued in April 2022. I do agree the 'hand' looks a little too close in Fig 2a & 2b, seems to contradict the 300mm rule.
I personally will occasionally feed in work like that shown but always have my wrist latched on to the edge of the table and hopefully therefore keep a safe distance and prevent my hand being pulled in. HSE credits for the Introduction to Woodcutting Machinery guides are given to New College Nottingham. I presume there must be someway to offer feedback.

 

[Jacob]

........
PS The HSE document was last issued in April 2022. ....

It's been around for a long time it must be a new edit, just not edited enough!

 

[Jacob]

Used the pattern shown for a very long time in the industry,

I've never seen one like it anywhere.

there’s nothing wrong or odd with it.

Tiny birdsmouth. A bigger mouth means you can hold down as well as in, rather like holding down with knuckes and a thumb, which the standard shape vaguely resembles.
If tiny is needed it's easy enough to trim it, but the standard pattern is best starting point

I think you’ll find if you lay one of them on top of a “standard” pattern they are much the same geometry with the “standard pattern” simply having a larger birdsmouth which can be unsuitable for some jobs.

Not really

In the real world, you need a variety of different shapes for whatever you might be cutting, and even a push stick in the right hand and a push stick with a steel spike in the end for control in the left hand is ideal for a lot of work.

Well yes there are variations and always have been. The main thing is to use them!

 

[TRITON]

My instant reaction was to withdraw my hands and fingers

Funny thing is by the time the brain has registered to quickly pull back your hand, the accident has already happened and the damage been done.

Worked out in college once. Think about the fastest you could touch something, and pull away. 1/10 of a second ?
So look at the speed of a planer block ,we'll say 5000 rpm. so in one second dividing 5000 by 60 =83.3 rps. finger comes into contact with cutter block for 10th of a second, so divide 83 by 10 giving us say 8. Now as there are 2 blades, that number is multiplied by 2 giving us about 16
So in that single quickest you can do the touch, the blades have taken 16 slices from your finger tip.

 

[BarbaraT]

My instant reaction was to withdraw my hands and fingers

Funny thing is by the time the brain has registered to quickly pull back your hand, the accident has already happened and the damage been done.

Worked out in college once. Think about the fastest you could touch something, and pull away. 1/10 of a second ?
So look at the speed of a planer block ,well say 5000 rpm. so in one second dividing 5000 by 60 =83.3 rps. finger comes into contact with cutter block for 10th of a second, so divide 83 by 10 giving us say 8. Now as there are 2 blades, that number is multiplied by 2 giving us about 16
So in that single quickest you can do the touch, the blades have taken 16 slices from your finger tip.

I would agree with this on first-hand experience, It's more like being hit over the head from behind..
You don't have time to even register what's happening, look down and see lots of blood.

I've bought a power feed that hopefully should be with me mid-next week, I'm also going to get the jigsaw out and cut some push sticks..
I might even draw a big red box around the blade... a no-go area... I doubt i will ever forget

 

[TRITON]

I doubt i will ever forget

No. after my industrial accident i approach all machines warily. How im going to feed, where im going to stand, under foot clear, double check tightness of knobs etc. Push sticks readily to hand