DWE7491

[skyehigh]

Now that this table saw is released in UK , can anyone tell me if you can use dado blades with it , like they do in US ?

[dewaltdisney]

I doubt it, it has probably been modified and the motor has got a short arbor to meet EEC Regs. I think that it is only the big professional saws that can take a dado set in the UK but even then I am not sure on that.

DWD

[steviejoiner74]

Apparently you can use stack dado's here!! I was told they were a no-no in the uk as well.

Everything you ever wanted to know about Dado Heads.

The major points to note are:
The HSE state it is perfectly acceptable to use saws fitted with a dado blade if the saw table is designed to accept it.
The current BSI guidelines allow for saw tables to be manufactured for sale in the UK today with a dado up to 15.5mm, possibly wider see below.
Riving knives can be removed during grooving operations as long as the blade is guarded. A safety guard doesn't have to be attached to a riving knife.
For more details on this issue please read on....
One of the things we get asked most about is the use of Dado Head cutters in the UK. The table saw David uses in the show is his personal equipment, he's had it for years and in fact imported it from Australia where extended arbors are available.

It was strange when we started talking to people in the UK woodworking industry and finding out that they were just as surprised as we were that saw tables couldn't take these wide blades because they always used to be able to. It is a fairly recent change to the UK safety recommendations. There are actually a lot of English saws around that will accept a Dado blade but they are older saws. None of the ones on the market currently will take these blades and it is a mistake to try and make one fit. So if you want this ability you have to either buy an old saw second hand here in the UK or buy one from an overseas supplier and import it yourself, a lot of countries in Europe have saws capable of using this type of blade as does, US, Canada, Australia, New Zealand but there is good news afoot. Read on!

A saw has to be designed to accept this type of tooling and still function within the manufacturer’s specs. It isn't just a matter of bolting on an extra long arbor or spindle and then get to work cutting dados. There are many safety related reasons why this should not be attempted.

The other misunderstanding is that people think it is illegal to use a saw with this facility. This is totally false. It is not an issue of legality or safety. We spoke to the Health and Safety Executive and to the BSI and here's the reality of this issue.

The Health and Safety Exec. are an advisory board making recommendations on the safe operation of woodworking machinery. They are interested to see that businesses ensure their staff operate equipment safely and within the recommended guidelines. If a company does not fulfil their duty of care and an accident happens, a company can be held responsible and prosecuted and they frequently are. The Table Saw in particular is one of the most dangerous tools in any woodworking shop.

This is not the same as you working in your on home workshop. Safety is your responsibility and if you have an accident it's your fault. This is why on all the TV shows involving the use of machinery a safety announcement is made to remind people of the importance of understanding the proper use of equipment and to make sure you follow the safety guidelines as there is no one there to supervise you.

The safety guards are sometimes removed on the show to allow the camera to show you what operation is being performed more clearly, this is not a recommendation for the audience to do the same, you should always treat your tools with the greatest of respect. Power tools can be dangerous and they don't mind what they cut, they leave that up to you, so work safely at all times and take your time, DON’T RUSH a job.

The next piece of information is hardly known at all even to manufacturers it seems.

The specification for saw tables as issued by the British Standards Institute, (this is the body that issues the CE certification to tool manufacturers), states that the maximum width of cutting blade (currently acceptable to the BSI) must not exceed 15.5mm, that’s over a half an inch in width, and this is what is currently allowable, but none of the manufacturers we have seen are taking advantage of this, we are not sure why. That's a pretty wide dado and would certainly make life easier for all the British woodworkers that long to perform this type of operation.

There are a couple of other issues that must be accommodated for example, the blade must come to a standstill within 10 seconds of the machine being stopped, a restriction on the saw blade diameter, they must make sure the saw blade can not come loose during start up, running, run down or braking and recommendations are made in the BSI document on how this can be achieved and flanged bushes need to be provided where the spindle diameter is different from the bore size of the saw blade. All these things considered there certainly seems room for manufactures to take advantage of grooving operations for UK saws. The other point to make is that manufacturers do not have to follow the guidelines outlined in the BSI document. These are purely guidelines, any manufacture can submit a design to the BSI and they will check it and test it to ensure it meets their requirements and if it does it will be passed even if it’s not exactly the way the guidelines are currently written. This allows the manufacturer room to be inventive in how they design their equipment.

If you want to use a dado blade in a saw capable of accepting it then the blade should be effectively guarded but there are many options available to achieve this. The Health and Safety Exec. publish a document explaining how to effectively guard a dado head blade. It is called “Woodworking Sheet No 16 (rev) and it discusses the Safe working practices for Circular saw benches. It certainly seems possible that such saw tables should be available on the market in the future.

We have also learnt that a submission has been made by a member state ( i.e. a member of the council that votes on, and agrees to changes to manufacturing guidelines that countries have to abide by. Each country in Europe has a representative on this council) to increase the width from 15.5mm to a greater width. This would possibly bring the blade width to 3/4" as is available in the US, perfect for all that grooving work. This submission is currently under review and there should be an answer on this in 2004.

Check out the HSE website by clicking on the link to the left to view their safety booklets and other information. The BSI will issue a copy of the standard relating to this issue which is "BS EN 1870-1, 1999 Safety of woodworking machines - Circular sawing machines, Part 1: Circular saw benches (with and without sliding table) and dimension saws" but this is not free.

The first manufacturer to release a saw table that can take the wider blade will certainly be popular. Let’s keep our fingers crossed.

Copyright 2008 by Great British Woodshop
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[Job and Knock]

The first manufacturer to release a saw table that can take the wider blade will certainly be popular. Let’s keep our fingers crossed.

Copyright 2008 by Great British Woodshop

Did you know that Scheppach TS4000 and TS4010 table saws have been able to use a Scheppach-designed 2-part trenching head since the early 1990s? Did you know that Felder have offered fixed width trenching blades for many years and that they also offer a 2-part trenching head on their combination machines? Did you know that from the 1970s until relatively recently deWalt offered brazed-tip 2-part trenching head specifically designed for use with their 10in radial arm saws? GBW obviously didn't know that when they made their (erroneous) comments in 2009.

There is a considerable amount of difference between a stacked saw dado head (the tool popular in the USA) and a purpose designed 2-part trenching head in terms of both safety and performance - especially when you take into account the requirement to brake to a stop with 10 seconds on new saws. So load an extra couple of pounds on the spindle on a lightweight saw and the braking mechanism (often just the friction of the belts) just won't work any more. So far as I am aware many European manufacturers (not just suppliers in the UK, as GBW state wrongly) shy away from supporting the stacked saw dado head because they have no effective way to brake or guard them (Scheppach TS4xxx and Felder saws have suspended overhead crown guards available, at a price) - and that someone unaware of the dangers of using an unguarded dado head might presumably have an accident and then sue the manufacturers. Another reason they shy away from them is because modern safety practice (i.e. post 1974 Woodworking Regs in the UK) teaches that a job should always be done on the safest available using the safest available method; for rebating that often means a spindle moulder or a hand held router - for trenching it's a hand held router.

Posted to throw some light onto an erroneous article by a magazine which should have known better IMHO

[Job and Knock]

One question to add to the above - just how much use is a 15.5mm dado head? I'm asking because for almost all furniture where you'd want a trench or housing to be cut you'd need to be able to cut a full width trench of 18 to 25mm (the thickness of your shelves) and to be able to do it in one pass. Same seems to go if you want to use it for rebating - you'd surely want to rebate to the full width of your material in one pass, wouldn't you?

[skyehigh]

Thanks for replies , heard back from a few companies selling this and none of them say you can use dado blades on this machine over here .
Statistics show plenty of table saw injuries not involving dado blades , but so far i have not seen any involving these blades that have been used in US for decades .
Once again we lose out because of crazy EU laws ..........

[Job and Knock]

Once again we lose out because of crazy EU laws ..........

FFS. You can't have your own way so the EU are automatically to blame for being a "granny state"

Those "crazy" rules started out in the UK with the 1880 Employer's Liability Act then the 1897 Workmen's Compensation Act which were designed to protect the ordinary working man from injury at work by making employers liable for the safety of their workers. They gradually developed to encompass safety aspects of machinery design - and woodworking machinery came into the scope because it is one of the more dangerous categories of equipment. Over more than a century, both here and in other countries, notably Germany, they've been built on to provide a modicum of protection to the workman - in conjunction, I might add, with the insurance companies and the trades unions. As a tradesman I might rail against the regs at times, but in general I have to admit that they are designed for my safety and overall they seem to work (as witnessed by falling accident rates over the last 40 odd years since we started to unify our approach with the rest of the EU). The Provision and Use of Work Equipment Regulations 1998 (PUWER), which incorporated much input from the UK trade sector, is what you are actually railing against - but from my reading of them they don't really ban anything specific (unlike the 1974 Woodworking Machinery Regulations which did). What they do, however, is to place a duty of care on manufacturers and employers to supply and/or furnish safe equipment - and an unguarded multiple saw blade with open gullets (i.e. a non-chip limiter design "dado" head) as routinely usd by American amateurs cannot possibly be regarded as safe. Hence most suppliers avoid them like the plague in the EU. In the USA the burden of proof is somewhat different and it has to be said that they have a higher rate of amputational injury amongst "weekend warriors" than we do, probably because they have a higher percentage of folk with the disposable income to purchase the equipment in the first plavce, but secondly because there is a higher percentage of people using kit they don't understand. The situation is a lot like giving kids access to small motorbikes without supervision IMHO

Statistics show plenty of table saw injuries not involving dado blades

Indeed they do, but I feel that you are misquoting the stats. I managed to cut a neat (actually the surgeon used the word "ragged") little groove down to and into the tendon on a finger a while back. Had I had the same accident with a stacked saw dado head I wouldn't have a finger left to repair, and because of the width of a dado head it might have been more than one finger. Contact between a hand and a stacked saw dado head quickly converts the hand into sausage meat..... The reality is that when I started, about 40 years ago, trenching and dado heads were already generally used on crosscut or radial saws rather than table saws saws because they were easier to guard and considered much safer. Then only shops using them on table saws even back then were generally small, ill-equipped and under-financed. That trend has continued, which is why there are so few trade injuries caused by dado heads (in the trade) these days

... but so far i have not seen any involving these blades that have been used in US for decades .

As I said, trenching and dado heads are nothing new, having been in common and widespread use before WWI in the UK, although we Brits tended to favour proper expanding trenching heads like these:

Wadkin trenching head cc2_zpsdcb20b35.jpg (55.45 KiB) Viewed 13916 times

and I can attest to the high quality of cuts they were capable of, but they weren't lightweight and so they could never be used on a lightweight saw because they'd wreck the bearings in all probability. One of the nice features was that they produce a proper chip as opposed to sawdust, but boy can they be noisy. Of course these are now illegal because of their non-chip limiter design and the method of securing the cutters which occasionally resulted in a tip ejection, but the modern equivalent is tooling like this Scheppach 2-part trenching/grooving head:

Scheppach Trenching Head.jpg (7.75 KiB) Viewed 13916 times

works just as well and has the twin advantages of being a lot quieter and well as having a chip limiter design. Note the limited gulley depth and circular saw body which tend to eject foreign bodies, like hands, rather than hooking them and drawing them in like a stacked saw dado head would:

Stacked saw dado set.jpeg (17.88 KiB) Viewed 13916 times

(Note: this is an "exploded" view to illustrate the shape of the rakers) Obviously a trenching head or dado set in a small table saw requires an adequate guard, such as this Scheppach model:

Scheppach crown guard.jpg (119.25 KiB) Viewed 13916 times

Whilst Scheppach and Felder/Hammer have designed kit to use trenching heads (with appropriate guarding) most of the lightweight manufacturers haven't. Equally they ir manufacturers haven't seen fit to spend the money on providing an adequate braking system capable of stopping the extra weight of a dado head in 10 seconds. It's more likely tht it's these aspects which are behind the decision of manufacturers not to fit long arbosr in the EU - something the GBW article misses.

So I'd say if you don't like the rules, then man up and either move to the USA or stump-up the money to buy the right equipment to use trenching heads (it is available) - equipment which has been designed to use a properly designed grooving head with competent guarding as opposed to buying a cheap saw which can't do the job then bellyaching about its' shortcomings. Whatever you do, though, try to understand that there are genuine and long term safety concerns about the use of this type of head and that that current legislation has come about at the heavy cost of many amputations and mutilations to working joiners in the past

[skyehigh]

What a *****you are , the type of guy who just loves the sound of his own voice no doubt .
Do one clown ........

We don't tolerate abuse on this forum. Goodbye. Mod 2.

[dewaltdisney]

I experimented using two blades clamped in on my table saw with a washer as a spacer. That was the maximum I felt I could put on the arbor and still get the lock nut well on to bite it up. I turned on and spun it up and firstly noticed that it appeared unbalanced and on switching off the momentum appeared greater and it took longer to stop spinning. I tried a cut and got as expected two parallel cuts but the absence of a chipper between the blades meant that the centre of the cut was still intact.

I decided that it was not going to work and never bothered again.

DWD