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Dado set questions

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11K views 15 replies 7 participants last post by  woodnthings  
#1 ·
I have a 10" Dewalt 7492 contractor saw. This is the European 220V version of the 7491. I would like to purchase a dado set for my hobby work and have a couple of questions:
1. How many teeth for hardwoods, softwoods and plywoods? I am looking at the Oshlun 42 tooth and the Dewalt 24 tooth sets, but open to suggestions.
2. Can I get by with a 6" set or should I go for an 8" set? Cabinets, drawers, box joints, tenons, dados and rabbets...
Thanks in advance for sharing your experience.
Mo
 
#2 ·
For your (and most woodworkers) applications, a 6" set is more than sufficient. Given a choice between a good quality 6", and a similarly priced- but lower quality 8"- definitely go 6". Rather than looking at the number if teeth, I'd look at how evenly the chippers match the outer blades; better sets will leave a smooth bottom (no ridges or gullies) across the dado. All other things being equal, I suppose a 48 tooth blade will give a somewhat smoother edge cut, but then again, a 24 tooth blade with better quality and sharper carbide tips would be preferable. Just my $0.02 (or shekel equivalent).
 
#4 ·
When I was looking at dado stacks, I read here a post explaining the difference in weight between the 6” and 8” is considerably different. The power draw to spin the larger blade is a factor. I would rather use the power to cut then just spin the blade. The explanation also talked about there not much difference in the capacity of the 8” over the 6”. I will post a link to that thread.
 
#7 ·
@sunnybob has it right. Saws made for the European marker (e.g., DWE7492) have short arbors to discourage dado use, Table saws made for the European market have short arbors to discourage users from running dados on their table saws, out of safety concerns.

-> Check the length of the arbor - it may be too short to allow a regular dado stack.

If you buy a dado stack, it may not fit, or it may be limited to just the blade bodies or narrow widths only. DO NOT be tempted to run a wide stack with the arbor nut incompletely threaded on the arbor. The arbor nut must be well seated against the blade or washer. In addition, you may need a compatible throat plate.

I looked at the instruction manual for the DWE7492. The word "dado" is only mentioned in the throat plate section, "If using a dado blade, use proper dado throat plate (sold separately)." My hunch is that DeWalt removed all references to "dado" from the 7491 manual, but missed one by accident. It is clear to me that DeWalt does not want their customers to use dados on the DWE7492 table saw. (In contrast, the manual for the DWE7491 has many references to using dados, etc. - how to use them, how to attach them, which dado stack is recommended, etc. The DWE7491 is sold in the US.)

Have you considered buying a single 10 inch joinery blade? They have a flat top grind. Some people use them in lieu of dado stacks. Obviously it takes more passes over the blade to cut a wide dado. See this video:
https://www.youtube.com/watch?v=PZXg5KA0P-Q

I have a Ridge Carbide joinery blade. I recommend it. It may not be available in Israel or Europe. Be warned: it is expensive.
https://ridgecarbidetool.com/collec...w-blades/products/10-x-40t-ar-4-1-15-hk-094-125-ts2000-flat-top-box-joint-blade


Bad Humor:
The Spanish language section of the 7492 manual mentioned "Cuidado!" a lot, but that's a different kind of "dado." :)
 
#8 ·
Many powered miter saws (as an example) use a quick slowing feature to slow the blade when releasing the trigger. I was wondering if the newer table saws also incorporate this feature. If so that may me the reason many manufacturers say no dado blades, because the quick slowing of the arbor shaft may cause the arbor nut to spin off due to inertia when using a heavier dado stack. I have an older table saw without the quick slow feature and am not aware if the newer table saws have that feature in them.
 
#9 ·
It isnt the blade, as such, that is the problem here. European health and safety laws require a spinning saw blade to come to a stop within 10 seconds of the power being cut. The dado set is so heavy that it can run on for many times that.
Its impossible to brake the dado blade on a saw with the motor on the left without reversing the arbor thread, and massively increasing the overall weight of the machine. Thereby making a "site saw" too heavy to easily transport.
Its easy to cut a dado with a single blade, it just takes a little bit longer to ease the fence over a bit at a time to take multiple cuts. I do this a lot on my DW745.
 
#10 ·
It isnt the blade, as such, that is the problem here. European health and safety laws require a spinning saw blade to come to a stop within 10 seconds of the power being cut. The dado set is so heavy that it can run on for many times that.
Its impossible to brake the dado blade on a saw with the motor on the left without reversing the arbor thread, and massively increasing the overall weight of the machine. Thereby making a "site saw" too heavy to easily transport.
Its easy to cut a dado with a single blade, it just takes a little bit longer to ease the fence over a bit at a time to take multiple cuts. I do this a lot on my DW745.
What I was refering to was... Does the newer European type table saws have the magnetic quick slow feature built into the electric motors, to make the motor slow quicker? If so it could cause the arbor nut to loosen due to inertia when having a heavier dado set installed. In other words the dados would try to keep spinning while the arbor slows too quickly. My question is about the magnetic slowing feature built into the motor. I am not familiar with the smaller European type saws.
 
#12 ·
Thank You Tool Agnostic, Apparently European table saws ARE EQUIPED with electronic (magnetic) braking systems that cause the blade to slow quickly, which can easily cause a heavy dado set to loosen due to the inertia. Watch this video. Have they BANNED table saw dado sets???? - YouTube
 
#13 ·
This discussion is very much appreciated and has helped me come to some conclusions.
My Dewalt DWE 7492 has an arbor that extends a bit more than 5/8" when the washer and nut are closed down without a blade. That means that I could fit a dado set up to certainly 1/2 inch and probably 5/8". However, the word dado is not mentioned once in my owner's manual. The same machine sold in the US with 120 volts is called a DWE7491. Amazon's specs list usage of a dado set up to 13/16". So yes, it is possible.
The discussions and the reading and viewing material suggested here made me do a double take, bringing up problems that I did not expect.
So for now, I plan to improve my router skills and purchase the necessary good quality bits needed for my projects. I will also continue to do some of the work with a single blade on my table saw and perhaps invest in a flat tooth blade.
And I thank you all very much.
Mo
 
#14 ·
This discussion is very much appreciated and has helped me come to some conclusions.
My Dewalt DWE 7492 has an arbor that extends a bit more than 5/8" when the washer and nut are closed down without a blade. That means that I could fit a dado set up to certainly 1/2 inch and probably 5/8". However, the word dado is not mentioned once in my owner's manual. The same machine sold in the US with 120 volts is called a DWE7491. Amazon's specs list usage of a dado set up to 13/16". So yes, it is possible.
The discussions and the reading and viewing material suggested here made me do a double take, bringing up problems that I did not expect.
So for now, I plan to improve my router skills and purchase the necessary good quality bits needed for my projects. I will also continue to do some of the work with a single blade on my table saw and perhaps invest in a flat tooth blade.
And I thank you all very much.
Mo
I mentioned a single joinery blade above, but have you looked at box joint sets?

A box joint set is like a dado stack with two blades, but no chippers, spacers or shims. The carbide teeth on each blade are not centered on the blade bodies so they can overlap in two different ways. Stacking the blades one way gives you one cut width, and swapping the blades on the arbor gives you a different blade width. A typical box joint set offers both 1/4 and 3/8 inch cut widths.
 
#16 ·
I own a Freud set and they are very nice, but before I sprung for those, $$$ I would consider a "wobble dado" also called an "adjustable dado". I own 3 of those of differening brands, but the Craftsman is one I use most often. The advantage is the blade's plate is only about 1/4" thick so it will fit on your arbor.
Ebay has used ones:

This one looks nice: