How to use a stacked dado?

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Hi Tombo. This might sound like a stupid response but firstly I'm assuming you have a table saw with an arbor long enough to take a stacked dado set? Like the Excalibur from Woodford?

Assuming that's true you arrange the cutters in the order you want based on the desired thickness. Full set probably gives 3/4" and least I would guess at 1/4"?. I think it important you find instructions from the manufacturer to be 100% sure but my guess would be a spacer always between a blade and a chipper. The chippers go inside the blades and you always stagger the teeth to ease pressure on timber fibres and motor and blade.

But call Woodford and ask if manufacturers website doesnt yield anything useful
 
I'm not an expert on these things but please check your table is compatible with running dado blades before using it. The extra momentum can overload the motor braking requirement for EU standards and end up causing damage to it.
 
Nice looking set. First check that your saws arbor can accommodate the full stack as many modern European saws cannot.
If that is OK, you simply put the number of chippers and spacers required for the width between the two blades making sure that they are on the correct way round (check the arrows on the blade) and that everything is done up securely.
I always try to rotate the chippers equally to try and keep things balanced.
Make a test cut on scrap wood to confirm the width and depth of cut before committing your valuable stock.

SAFETY FIRST
Always unplug the saw before making any adjustments.
The stack is heavier than the normal blade so will take longer to come to a stop.
Most blade guards will not work with a dado so take extra care around the unguarded blades.
 
I'd add to the above don't put more than one or two shims between the same chipper or outside blade as you could end up with a sliver of wood in the middle of the dado. Ideally they should be evenly spaced out between whatever combination you've put on the arbor.

You should have got a leaflet on how to set it up - although you can readily find information and videos online on how to do this dados can be a dangerous affair if they're not used properly.
 
Thanks a lot! I bought this one specifically as I knew it would fit my saw (excalibur). I also have the table insert that fits the blades perfectly. I figured this was how you used it but wanted to make sure. I'm guessing you space the blades teeth as evenly as possible?

Thanks again,

Tom
 
I thought under EU regs that it was illegal to buy/use a stacked dado set over here. Like a lot of peeps I'm a huge Norm fan and when I was looking to buy a table saw a few years ago I wanted one that would take a stacked dado set because they look very useful. All the European saws I looked at were deliberately sold with a short arbour to stop stacked dados being used. I seem to remember that I considered importing one but was told I couldn't.

Does anyone know if the EU regs have now been relaxed?
 
bodgerbaz":1qhx8kuk said:
I thought under EU regs that it was illegal to buy/use a stacked dado set over here. Like a lot of peeps I'm a huge Norm fan and when I was looking to buy a table saw a few years ago I wanted one that would take a stacked dado set because they look very useful. All the European saws I looked at were deliberately sold with a short arbour to stop stacked dados being used. I seem to remember that I considered importing one but was told I couldn't.

Does anyone know if the EU regs have now been relaxed?
I think the rules are for the commercial shops and do not cover the home user. I don't think they are banned in the uk, it's just the arbours are shortened as the braked motor ( required under the regs) cannot cope with the extra weight and it slows the stopping time down considerably.
 
Tombo, when you use a stacked dado set it tends to lift the workpiece which results in the rebate or groove that you're cutting being shallower than you want. To overcome this you have to keep constant downward pressure on the workpiece directly above the cutter, this is where a lot of the safety problems come from. At the very least use hefty push blocks, never ever feed the workpiece with bare hands, and you may well have to feed the workpiece through twice to get a consistent depth.

Personally I use a combination machine and it's easier to install the dado set rather than change the machine to use the spindle moulder, which is by far the better tool for the job (it gives a cleaner and more accurate cut), so for many jobs I will actually use a dado set, but on my machine I can swing the power feed over the dado set and feed the workpiece through with that. If I didn't have a power feed I'd be more inclined to look for another way to achieve the cut, such as a router or spindle moulder, and I'll only use it for cutting with the grain, it spelches badly on cross grain cuts..

I tend to think of a dado stack as being a bit dangerous and also a fairly crude tool that's more appropriate for joinery than cabinet making. You need to think about how you'll use the dado stack in order to overcome these two limitations, it's not a tool that gives safe, high quality results straight from the box.
 
I agree with Custard guarding is the issue along with the extra weight causing problems with our 10 second braking requirements , the older Wadkin style machines had provision for shaw guards that form tunnels to hold the workpiece and protect the user from contact with the cutters. Cutting grooves and rebates over the top saws is considered dangerous and should only be done with sufficient guarding in place. See fig 8 on the HSE sheet
http://www.hse.gov.uk/pubns/wis16.pdf
Under the Acops these machining processes should not be undertaking in commercial workshops, which I feel are far safer than home workshops.
Peter
 
Thanks again everyone. The dado stack only has 1 purpose for the time being. I am making some ticket rails from old scaffold boards. essentially I am only cutting 3mm deep but the width of the cut is going to be 150mm. The total length of all the wood being cut is also about 60ft which is why I decided to invest in the dado stack. I will follow the advice people have given in regards to downward pressure and push blocks etc. The scaffold boards are about 2 1/2 inches thick so only taking away a small amount.
 
If it were me, I think I'd sooner make a few passes with wide router cutter, table-mounted; would give a better finish, surely? Cheaper, too...
 
I'd fit a sacrificial fence on the saw, raise the blade to maximum and take the three mm off, holding the board vertical. then finish the rest with the router.
 
petermillard":1v1pgext said:
If it were me, I think I'd sooner make a few passes with wide router cutter, table-mounted; would give a better finish, surely? Cheaper, too...
Ordinarily I would (and have in the past) but my router table isn't anywhere near as solid as my table saw and it is difficult to manage massive scaffold boards on it. Turns out the dado did a plenty good enough job though =]



 
Well you have obviously got a good result there.
Just for the record, and for when someone else stumbles across this thread in the future, here is the (I hope) definitive guide, as given to me by the very helpful HSE when I was researching this subject for filming.

You can do pretty much what you want in your own workshop. That doesn't mean that it is a good idea to ignore sound advice.

If you are working in a commercial workshop, then you have to abide by the regs, in which case:

The blade should stop within 10 seconds of the power being cut
The blade must be guarded properly

These last two are quite difficult to achieve on some saws and it is these aspects which usually result in the rules being broken, not the use of a dado stack per se. On some machines the braking system is compromised with the extra weight of the stack and if the crown guard is mounted on the riving knife then you can't use that guard and the stack at the same time, so other guarding arrangements have to be built.

Dado stacks are jolly useful pieces of kit, but used improperly they can be lethal. Make sure you know how to make sure you are in control.

S
 
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