Dado cutters - Please, what is so dangerous about them

[Sawdust]

Hi,

I am trying to find out why it is that so many people on here are against dado cutters. I’ve searched the forum and have found loads of topics talking about them and while most people seem to agree they are the spawn of the devil, no-one actually gives any reasons why. I am seriously thinking about buying one but would like to know what the real dangers are and how the compare to other potentially dangerous machines.

If I do buy one, it would initially be for use on a radial arm saw, but if and when I acquire a table saw, I would also like to use the dado on it.

I appreciate that on most saws they have to be used without a guard in place but is that the main reason for people not liking them and if so, surely it’s possible to devise some sort of guard for them. I can also see that a riving knife is not practical with them but given that in most cases they will be making very shallow cuts and I presume would never be used to cut all the way through the stock, is there much of a risk of kickback?

I also understand that the HSE don’t like them, but then they also told me I can’t use Tipex or a craft knife at work and haven’t they banned ladders? I also can’t understand why they are not considered so dangerous in the States, surely our American friends are every bit as keen to remain attached to their fingers as we are?

So am I missing something; do they explode unexpectedly, come undone and fly across the workshop, give off radiation or maybe fire bullets at the operator?

Finally, how do people think they compare with other dangerous activities, for example using a spindle moulder, a chainsaw, a 9inch angle grinder or driving on the M1?

I am not trying to sound flippant, and if I am missing something vital then I would be grateful for finding out but to me they don’t look any more dangerous if used carefully than quite a few other machines which don’t seem to attract the same criticism.

I would really appreciate people’s thoughts on this, particularly people who use them and are still alive and also from anyone with any bad experiences (assuming they can still type!)

Thanks
Mike

 

[prawnking]

one thing i do know is you r not supposed to use a dado cutter on a table saw that has a brake to slow the blade down when it sturned off. i belive this is a feature of more modern table saws and thats 1 of the reasons why u cant use them, also because of the gaurd thing. but i maybe wrong feel free to correct me.

cheers

shaun

 

[Sawdust]

one thing i do know is you r not supposed to use a dado cutter on a table saw that has a brake to slow the blade down when it sturned off. i belive this is a feature of more modern table saws and thats 1 of the reasons why u cant use them, also because of the gaurd thing. but i maybe wrong feel free to correct me.

cheers

shaun

Thanks Shaun,

That is a good point, I understand that it could be possible for them to come undone while the saw is braking, but I suspect that the same applies to a large 'standard' blade with the same momentum. My RAS is old and unbraked, so it wouldn't be a problem there, but I wonder if there is some kind of locking mechanism on modern braked table saws to prevent blades coming undone?

Cheers
Mike

 

[SketchUp Guru]

Mike, I've used a dado set many times. Never had any problems. No kickback, no worries about a lack of blade guard (the blade is buried anyway so it's almost like having the guard in place.

In the US, a dado set with a tablesaw is almost as common as windshield wipers on a car. If you've got one, you've got the other.

A dado set does have more inertia that a single blade and depending on how the arbor nut is locked, I could see the validity of worries about it coming loose during breaking. I don't know about breaking on tablesaws--we aren't that sophisticated here--but on other tools that have the breaking action, they essentially try to reverse the motor while it is spinning. The circuit cuts out at some lower RPM. There might be some concern about the electronics because it would take longer to slow the motor to the "cut out" RPM. I suppose that could let the magic smoke out.

 

[Sawdust]

Mike, I've used a dado set many times. Never had any problems. No kickback, no worries about a lack of blade guard (the blade is buried anyway so it's almost like having the guard in place.

In the US, a dado set with a tablesaw is almost as common as windshield wipers on a car. If you've got one, you've got the other.

A dado set does have more inertia that a single blade and depending on how the arbor nut is locked, I could see the validity of worries about it coming loose during breaking. I don't know about breaking on tablesaws--we aren't that sophisticated here--but on other tools that have the breaking action, they essentially try to reverse the motor while it is spinning. The circuit cuts out at some lower RPM. There might be some concern about the electronics because it would take longer to slow the motor to the "cut out" RPM. I suppose that could let the magic smoke out.

Thanks Dave,

The only concerns expressed so far are to do with braked motors - not a problem on my RAS as it's old and possibly a good reason for finding a nice old table saw without a brake!

Cheers
Mike

 

[engineer one]

mike,
i do not think people here as users have a down against dado cutters,
it is purely an HSE thing. the manufacturers here cannot sell a
saw without the guard and riving knife. should they seel the
accessories, then they would be liable for any accidents due
to bad fitting of the product.

it used to be possible to buy cutters for cabinet hinges, i.e. 35 mm
ones to use in the drill press. now however the same product without
any changes has to be sold for use in a router. HSE again.

because of space limitations, we in england tend to make more use
of router tables, and cut dado's there, or freehand with a guide.

finally i think the major complaint from hse is that people tend not
to remove the blade from there saw whilst not in use, and in a
production shop mistakes could be made.

paul :wink:

 

[Alf]

Scrit summed up the important bits pretty well here.

Cheers, Alf

 

[Sawdust]

Scrit summed up the important bits pretty well here.

Cheers, Alf

Alf,

I've read the post by Scrit that you pointed me at and it seems the salient points are:

They are OK on a RAS - that's great as I have one! We will ignore for the moment the fact that I removed the lower blade guard from it because it was a pain in the bum and just got in the way. (my personal feeling only of course - not a recomendation to others)

Manufacturers are scared of supplying them in case they get sued. Well that applies to everything now, I'm sure lawn mowers will be banned soon.

Same comments as others have made about braking, although I fail to see why, if a wheels can stay on a car under heavy braking (eg emergency stop with the wheels locked up), manufacturers can't make a blade stay on a saw where the braking is pathetic anyway.

They are dangerous on table saws because they are difficult to guard. I suppose this opens up another question; are they difficult or impossible? I can see that guards attached to the splitter won't work but a lot of those, especially on cheap saws are rubbish and I wouldn't trust one to protect me from anything. How about one of the overarm guards, or something attached to the fence?

Cheers
Mike

 

[wrightclan]

:-$ [-( :-#

Brad

 

[Sawdust]

:-$ [-( :-#

Brad

eh?

 

[wrightclan]

Those emoticons mean 'shh,' 'I'm not talking,' and 'silenced.' Last time, I brought up a common American woodworking practice, that is little used here, I got beat down pretty heavily. So:

:-$ [-( :-#

Brad

 

[Sawdust]

Those emoticons mean 'shh,' 'I'm not talking,' and 'silenced.' Last time, I brought up a common American woodworking practice, that is little used here, I got beat down pretty heavily. So:

:-$ [-( :-#

Brad

Thanks for the explanation Brad, I've never really managed to understand the emoticons!

I was expecting to get a hammering over the question as well, it does seem to attract a lot of replies although most of the ones I've seen in the past are along the lines of "dados are bad because they are".

Cheers
Mike

 

[Adam]

Hi, I am trying to find out why it is that so many people on here are against dado cutters.

I don't think people are against them as such. Its just they are so easily done with a router and a guide. I for one, take the crownguard off my Scheppach table saw but at least the riving knife stays in place. Each person has their own limits I guess. As to braking, remember saws have a single nut on a central spindle, not at all like the multipoint bolts used to secure a car wheel. Additionally, tablesaws run at pretty significant RPM. A dado is heavier, to if it does catch its got more momentum to launch something towards you.

I think spindle moulders also have a reputation (perhaps unfairly - see Scrits post recently) as being dangerous, so its not just the dad thats being singled out.

Adam

 

[johnelliott]

I think it is one of those situations where if people can't see for themselves what is wrong with having a unguarded dado blade in a tablesaw then there is no way that anyone else (even Scrit) is going to be able to explain it to them. That is why there have to be laws about this kind of thing.
Similar situation to when the helmet law for motor cyclists was passed. All kinds of protests, most of which were along the lines of "I've been riding motor bikes for twenty years and never needed a helmet"

All the above IMHO, of course

John

 

[Jake]

It seems safe to say that someone who removes the guard from a RAS is unlikely to be convinced that other safety precautions are worthwhile or of much importance. Given that, this thread is pointless.

This debate has been done to death and the danger or lack of real danger has been discussed at length. No-one is likely to swap sides, so why bother talking about it?

 

[Sawdust]

It seems safe to say that someone who removes the guard from a RAS is unlikely to be convinced that other safety precautions are worthwhile or of much importance. Given that, this thread is pointless.

Pointless eh?

Please read my post before misquoting me!

I have asked the question in order to find out WHY the dado is considered so dangerous, I was hoping the experts here would be able to help.

I did not remove the whole guard; that would dangerous as well as pointless. I removed the lower part of it because, in my opinion, it made the saw more dangerous to use. Granted it may be a badly designed guard. I consider safety to be of utmost importance and after careful consideration I removed the lower part of the guard because I felt safer using the saw when I could see the blade.

If you read some of my other points, one of the things I am asking is how can a dado be guarded. If I was not concerned about safety, I would not of started the original post would I?

Cheers
Mike

 

[Jake]

Yes, it is pointless - as has been proven in a million threads before this one. It has all been discussed before, including guarding, as you'll have seen from the archive if you've read it all.

 

[Sawdust]

Hi, I am trying to find out why it is that so many people on here are against dado cutters.

I don't think people are against them as such. Its just they are so easily done with a router and a guide. I for one, take the crownguard off my Scheppach table saw but at least the riving knife stays in place. Each person has their own limits I guess. As to braking, remember saws have a single nut on a central spindle, not at all like the multipoint bolts used to secure a car wheel. Additionally, tablesaws run at pretty significant RPM.

Fair point, although car wheels turn pretty fast too and are a lot heavier than a dado cutter!

A dado is heavier, to if it does catch its got more momentum to launch something towards you.

Also a good point, although I still feel a dado cutting a shallow groove part way through a board is less likely to bind in the cut than a standard blade cutting right through. I'm happy to be corrected though.

I think spindle moulders also have a reputation (perhaps unfairly - see Scrits post recently) as being dangerous, so its not just the dad thats being singled out.

Adam

We all have our own danger thresholds and I wouldn't go near a spindle moulder !!

Cheers
Mike

 

[Sawdust]

Yes, it is pointless - as has been proven in a million threads before this one. It has all been discussed before, including guarding, as you'll have seen from the archive if you've read it all.

What has been proven?

As I also stated at the start, I did search and read the threads and didn't find the answer to my question so I asked it. I stand by my comments that most answers are along the llines of they are dangerous because they are!

All I wanted to know was why.

Cheers
Mike

Modedit Newbie_Neil

 

[johnelliott]

I think it is one of those situations where if people can't see for themselves what is wrong with having a unguarded dado blade in a tablesaw then there is no way that anyone else (even Scrit) is going to be able to explain it to them. That is why there have to be laws about this kind of thing.
Similar situation to when the helmet law for motor cyclists was passed. All kinds of protests, most of which were along the lines of "I've been riding motor bikes for twenty years and never needed a helmet"

All the above IMHO, of course

John