Dado blade

[kas20amc02]

Hi everyone. I’m considering adding a dado blade to my collection. After my last post, I bought a set of cheap Dewalt saw blades (rip, general purpose and cross cut) figuring whichever blade I wear out first, I will replace with something better.

My next idea requires making a 1/4 inch deep dado about 3x1.5 inches square. I want to leave 1/4 inch protruding on each side, like a U shape.

If I did get a dado blade, would 6 or 8 inches be a better choice? Also, I need the dedicated Shop Smith dado arbor, correct? If this is a bad idea, I could cut the edges with a table saw to make them crisp then rout the center. Conceivably I rout the entire thing but I don’t know if there would be solid support for the base. I don’t think a bandsaw would leave it smooth enough but I guess it could be sanded or chiseled???.

Many thanks,
Karl

[JPG]

A dado creates a groove. What you are describing (1/4 x 1.5 x 3) is not a groove.

Seems to me a job for the SS router bits in drill press mode. The fence can provide the straight edges, the quill feed the ability to plunge rout, the main table provides support.

[chapmanruss]

Karl,

Like JPG I am confused as to what size of a Dado you are wanting to make from what you said in the following.

My next idea requires making a 1/4 inch deep dado about 3x1.5 inches square. I want to leave 1/4 inch protruding on each side, like a U shape.

A 6" or 8" would work but the difference is the 8" could cut a deeper Dado than the 6". Dado sets do have a limit as to how wide of a cut they can make. Wider Dados would require more than one pass to get to width.

You would need a Dado Arbor. From Shopsmith that is part number 505506 the Molder/Dado Arbor previously known as the 5/8" Universal Arbor. There have been 4 versions of it with that part number (505506) since 1964 as seen in the picture below.

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505506 V1-4 r.jpg (71.38 KiB) Viewed 433 times

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Prior to the change in 1964 there was 3 versions of a 5/8" Universal Arbor simply called the 5/8" Arbor and were part numbers (in descending order) 22 031, 12 031 & 126-1X. Those three did not have the black protective coating which also started in 1964. The picture below shows those 5/8" Arbors plus some others used for different purposes.

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Arbors page 1 - labeled.jpg (150.85 KiB) Viewed 433 times

[kas20amc02]

Thanks guys. I appreciate the advice. I’m sorry if my description was confusing. A picture might have been better.

[RFGuy]

Thanks guys. I appreciate the advice. I’m sorry if my description was confusing. A picture might have been better.

Just to be clear, you can only do through cuts with dados and saw blades. You can plunge cut with a tracksaw, but on a table saw, every cut should be a through cut. The description you gave has at least me worried with how you intend to make what you describe.

PS: By through cut, I mean cutting from end of the board to the other, NOT through the depth of the board.

[DLB]

Thanks guys. I appreciate the advice. I’m sorry if my description was confusing. A picture might have been better.

Just to be clear, you can only do through cuts with dados and saw blades. You can plunge cut with a tracksaw, but on a table saw, every cut should be a through cut. The description you gave has at least me worried with how you intend to make what you describe.

I think this use of 'through cut' adds to the confusion. To me, a dado is generally an example of a non-through cut. Because, to me, a through cut is one in which the blade goes through the material (for example a typical rip or crosscut) while a non-through cut is one in which the blade is adjusted to not penetrate the material (example, a typical dado or rabbet). In other words, as I use the term, a 'through cut' can usually be done with the upper saw guard in place and a non-through cut can never be done with the upper saw guard in place. Thus, Shopsmith offers a Non-Through Cut Riving Knife for 510 and on. You're using the term 'through cut' to describe something else, and while I understand your intent I'm not sure a "Total Rookie" would.

My thoughts about dado blades: There are two common types, a "wobble" dado and a stack dado. In operation, a wobble dado is less expensive but creates an imperfect cut. In particular, the bottom of the "U" shaped channel will have a radius to it. While this is okay for many uses, a stack dado cuts a better dado or other cut. I have a 6" stack dado and it is pretty good, but I occasionally run out of depth of cut especially with a sled. All things considered, my preference would be a carbide 8" stack dado.

A picture or drawing of what you want to cut is a good idea.

- David

[RFGuy]

Thanks guys. I appreciate the advice. I’m sorry if my description was confusing. A picture might have been better.

Just to be clear, you can only do through cuts with dados and saw blades. You can plunge cut with a tracksaw, but on a table saw, every cut should be a through cut. The description you gave has at least me worried with how you intend to make what you describe.

I think this use of 'through cut' adds to the confusion. To me, a dado is generally an example of a non-through cut. Because, to me, a through cut is one in which the blade goes through the material (for example a typical rip or crosscut) while a non-through cut is one in which the blade is adjusted to not penetrate the material (example, a typical dado or rabbet). In other words, as I use the term, a 'through cut' can usually be done with the upper saw guard in place and a non-through cut can never be done with the upper saw guard in place. Thus, Shopsmith offers a Non-Through Cut Riving Knife for 510 and on. You're using the term 'through cut' to describe something else, and while I understand your intent I'm not sure a "Total Rookie" would.

My thoughts about dado blades: There are two common types, a "wobble" dado and a stack dado. In operation, a wobble dado is less expensive but creates an imperfect cut. In particular, the bottom of the "U" shaped channel will have a radius to it. While this is okay for many uses, a stack dado cuts a better dado or other cut. I have a 6" stack dado and it is pretty good, but I occasionally run out of depth of cut especially with a sled. All things considered, my preference would be a carbide 8" stack dado.

A picture or drawing of what you want to cut is a good idea.

- David

David,

Nitpicky, but okay, please give your alternate way of saying what I intended to say. Otherwise I will ask admin to delete my post to avoid the confusion, but you are NOT clearing it up by not explaining it differently from me either. I edited my post above to make it a little clearer.

[JPG]

Why is a discussion re through cut occurring? The OP said 1/4" (deep).

Missing is the inability of a circular saw to cut a square corner. A circular saw cuts an arc with a plunge cut.

[RFGuy]

Why is a discussion re through cut occurring? The OP said 1/4" (deep).

Missing is the inability of a circular saw to cut a square corner. A circular saw cuts an arc with a plunge cut.

JPG,

What he describes, implies a plunge cut, which would be a no-no on a tablesaw, which is why I tried to question what he is doing. Sans a picture, it is difficult to discern what he meant. Routing may be the best choice for what he intends to do...

[chapmanruss]

Karl,

Going back to your first post you said,

My next idea requires making a 1/4 inch deep dado about 3x1.5 inches square. I want to leave 1/4 inch protruding on each side, like a U shape.

With what RFGuy questioned, are you looking to make a Dado cut at 1/4" deep and have it 1-1/2 " wide by 3" long and not going the length of the board? That, for me, seems to be a better explanation of what you desire to make from the text above. I agree a picture or drawing of what you are looking to do would better explain it. If it is what I describe, a Dado would not be the way to go. I could be wrong with my guess at what you are trying to achieve.

As David said about using a Dado Blade,

the bottom of the "U" shaped channel will have a radius to it.

It would not be 1/4" deep for the entire length of the cut. Routing it would make it easier and more importantly safer.

I have not thought about what a term should be for making a saw or Dado cut that does not run the entire length or width of a board although I may have known one at some point in time and forgot it. I do understand the confusion of the "Through Cut" term used for that, but does anyone know an actual term for this type of cut?