Re: Positive rake dado set
There is a type of Dado blade that is adjustable to all widths. It is much cheaper. I have used one for years. It has no rakes. It cuts every from evry tooth.
http://www.toolking.com/vermont-amer...le-dado-blade/
Re: Positive rake dado set
Quote:
Originally Posted by
jrbbees
I have the same one.
Re: Positive rake dado set
The rake angle refers to the angle of the front side of the tooth vs the perpendicular from the arbor. Negative rake dados are common because they don't tear out so badly in composites and laminates. Not the best for end grain, but nothing is, really, it's hard to cut no matter what. Best thing to do is have your new one sharpened immediately by someone who knows how to do it right.
You also need to have enough power (minimum 2 horsepower) and proper blade speed (3600 rpm minimum). Too slow or not enough power, the blade slows down, won't cut properly, and proceeds to fill your shop with smoke. Takes a ton of torque to cut a 7/8" dado in end grain, even in soft wood. Hardwood actually cuts better because it doesn't crush so badly and the negative rake still removes the sawdust.
Wobble dado blades are fine, but they don't cut flat bottomed dados (as the name implies, the blade isn't square to the arbor, it's tilted, so the bottom of the dado is curved) and the sides are not a smooth. Should be fine for bee boxes if you use glue in the bottom of the dado.
However, a typical low cost (under $200) dado set usually doesn't cut flat dados either as the rakers are never sharpened together with the side blades, and there is a nasty habit among the manufacturers of leaving HUGE "glue slots" on the edges, which makes me crazy. I had to sharpen the first one I got, it was burning everything because the back of the tooth was rubbing, the edge was lower that the back side. Total crap.
Someday I'll get mine sharpened properly and hopefully get rid if the grooves and uneven bottoms. Not particularly pleased to have to spend $40 to get the darned thing to cut like it should have out of the box though.
Peter
Re: Positive rake dado set
Quote:
Originally Posted by
psfred
Wobble dado blades are fine, but they don't cut flat bottomed dados (as the name implies, the blade isn't square to the arbor, it's tilted, so the bottom of the dado is curved) and the sides are not a smooth. Should be fine for bee boxes if you use glue in the bottom of the dado.
Peter
True. the bottom of the dado does have a very slight arc rise. You will find it is not noticable unless you look for it. For bee boxes it is a not issue. It has also not been an issue on the custom made oak book cases I have produced and sold. As for the sides of the cuts being smooth, that is more as issue of blade sharpness and the speed with which you feed the stock. I have not had to sand any of the cuts on my book cases.
Save the extra money for more wood that =s more bee hives. The blade will do you fine.
Re: Positive rake dado set
You might try scoring the line where the notch will end with a knife before cutting it. this will make a line where the tear out will end.
Re: Positive rake dado set
The other thing to consider is that there are more than double the number of teeth on a regular dado set than a wobble head (Two blades plus 2 teeth per chipper). This, I find lets you ram pieces through a lot faster without running into much chipping as long as your saw has the horse power to handle it. I currently have a king (I think) dado blade that was around 60 bucks... Works alright but it pretty much needs replaced every 1000 to 1500 boxes due to lost/dull teeth etc but I don't know if a wobble head would hold out much better. Just my 2 cents
Re: Positive rake dado set
Forrest Dado King works well in rip or crosscut. Expensive.
Re: Positive rake dado set
psfred..Don't know if you have any experience with onsrud dado sets, but I can attest they are very good, and under $100.
Before I bought my first dado set I researched dado sets and onsrud came up with very good reviews. To see a thorough review of the onsrud for less than $100.00 go to WoodworkingTalk.com and search Onsrud dado stack review. They tested them in about 6 or 8 different woods, and even ran it through 2 1/2 deck screws. The reviews were very, very, good for onsrud.
I would certainly highly recommend them.
cchoganjr
Re: Positive rake dado set
Thanks Cleo, I'll check them out. Hopefully they won't have chippers with seven different diameters on six blades like the ones I have!
Peter