Clean cut using dado blades - Woodworking Talk

Beaver242 · 05-24-2009, 09:21 PM

Hi all, hope you can help me out!

I'm using a 7" dado blade. This is the only size that will work for my project at hand. Perhaps a little bit smaller, or bigger diameter would be acceptable, but not much.

I'm making a 3/8" wide cut, with a combination of 2 blades and an insert blade. My problem is, I cannot get the blade to make a clean smoothe cut.

Can anybody enlighten me on any special techniques, blades or any other factor that could help me make the cut as smooth as possible?

Would a wobble blade help me achieve a clean smoothe cut? I've never seen one used.

Thanks!

~Beaver~

rrbrown · 05-24-2009, 09:26 PM

What type of dado set are you using?

Kudzu · 05-24-2009, 09:27 PM

Smooth as is the bottoms is not even from side to side? If so that's the usually a sign of a cheap dado. The arbor holes in them are not precise and one blade is higher than the other resulting in an uneven cut.

Wobble dado doesn't have that problem but the bottom is an arc, it's not flat. So that presents another problem.

Jordy3738 · 05-24-2009, 10:49 PM

Interesting post, what is the material that you are working with? Have to wonder too what kind of saw are you using? It sounds like there could be several things that are not working in your favor. More information would be helpful.

Sleeper · 05-25-2009, 02:56 AM

Yes, this is an interesting thread and I hope you don’t mind me jumping in here Beaver, because I was also wondering about this.
I noticed that I had the same problem today after making 6 dados cuts with a new used radial arm saw that I just purchased. I had just made some dado cuts with my router with very smooth bottoms and then I decided to use my new saw because the router was taking too long. I didn’t think too much about it until I read this thread, I just thought oh well it’s the difference between a router and RAS. I haven’t made any dado cuts on my table saw in a long time and I can’t remember how smooth it was. I’m using an 8” stacked set which I thought was a Craftsman but after looking again it is an Irwin set.
So, just how smooth should it be? Tomorrow I’m going to set up my table saw and see if there is a difference between saws, but if there is a better dado set out there, than I want it.

cabinetman · 05-25-2009, 05:38 AM

WELCOME TO THE FORUM

I have two wobble blades that people have given me, and I don't use them. I wouldn't waste my money to buy one. I have a few stack sets, and the bottoms of the cuts always leave some fuzz. My last pass is is just a skim pass, and it minimizes the fuzz.

I like clean dadoes. I think they make for better joints. I use a few different techniques to clean out dadoes. A good sharp crank neck chisel works about the easiest. Or just a sharp bench chisel used like a scraper. If you're careful not to damage the dado, you could use some fine sandpaper on the edge of a block and make a few swipes.

I get much better dadoes when done with a router. I think it's faster, less set up, and cleaner bottoms.

woodnthings · 05-25-2009, 08:59 AM

The original post was "I'm making a 3/8" wide cut, with a combination of 2 blades and an insert blade. My problem is, I cannot get the blade to make a clean smoothe cut."

First, what material are you cutting, veneer plywood, particle board, solid lumber?
With the grain, across the grain?
Are you getting "tear out" at the edges?
Or is your concern the bottom? In a 3/8ths wide dado the bottom is not crucial. A dado 3/8th wide, how deep?
Are you using a RAS or a tablesaw?
Is the blade set you are using new or old? Sharp or worn?
Is the blade set made of High Speed Steel or is it Carbide tipped?
Do you have a router? A sharp 3/8ths carbide bit?
The answers to these questions will probably determine what the problem is.

bill

skymaster · 05-25-2009, 01:50 PM

As far as a "better dado set" Freud is best for the dollars, if you have a bunch to spend than Forrest is the best both in taking your money and quality

wood shavings · 05-28-2009, 01:25 AM

I have found that if you take the blade to a compatent sharpening sevice explain the problem at hand, if he is good enough at his trade he will get them back to you cutting the same depth. Here is why if you get a inexpensive (cheap set they are normally stamped ) or a better set they are most likelly carbon tipped and are glued on, these small imperfections show up when you make your first cut out of the box so to speak. By taking them to a sharpening place they can be super tuned the resulrs is normally super smooth

Gerry KIERNAN · 05-28-2009, 10:50 AM

Silly me. I am going to weigh in on the side of the very much maligned "wobble" dado set. I have several, and use them whenever I am building boxes, or almost anything where I need a dado. Mind you, I am not building high end furniture, mostly utilitarian shop and household items. I like my wobble dado because if I am going to make dadoes of different sizes or if I have to make minor cut width adjustments, I can do it while the dado is mounted in my saw. I do not have to take it out, I don't have to disassemble it, and I don't have to mess around with a bunch of shims to get the perfect size. I just flip the dado insert out, loosen the shaft nut, and make my adjustment. A quick check with a scrap piece of wood, and I am good to go. One word of advice. It's a good idea to turn the saw off, and unplug it before doing this.
The wobble dadoes that I have all have carbide teeth, and make a good clean cut.

I have dado sets, but I never use them. Too much of a PITA.

Gerry

woodnthings · 05-28-2009, 03:21 PM

Are you out therel, or we just havin' a conversation amongst ourselves? Give us a shout so we'll know you're still there.

bill