Hey hey. All you fine craftsman.
This is my first post over here at knots. Usually i lurk over @ breaktime.
I have been a carpentar for almost twenty years now, and am just starting to get interested in the finer things of woodworking.
So i have been piddling out in the garage trying to set it up a little more like a shop, even though most of my tools are smaller portable models.
So i thought i would start with some toolboxes out of 3/4″ birch. Seen some articles and pics of some cool box joint jigs(seemed pretty basic) I set up the sistimatic dado blades and proceeded on.
Long story short they are not perfect. Little dog ears at the corner of the notch. Did a search and it seems as this is a common problem. But could not find a solution besides a router table which i do not have.
Any help would be apreciated.
P.s. do they sell a dado set specifically for this application?
It is funny none of the articles i have read ever mention the not so perfect joint with the box joint jig.
Replies
fishdog,
I cut box joints with my systimatic and they came out perfect...eventually. First, I was using a cabinet saw(Griz)and needed to make sure the blade insert was level with the table top. Second, I needed to use a backer piece..fresh piece of backer with each cut. Other than that the only thing I can think of is the need to use the minimun number of blades...ie. two, the inner and outer.
Thank you for the reply.
Are the inside and outside blades tapered on your set?
The insert is flat and blade is square to the table.I coud definatly be doing something wrong. but from the previous posts that i have read it seems like a blade issue.
The the joints are square and tight its that little snipe or dog ears that i dont know how to fix.
Fishdog,
Yes, the inside and outside blades are tapered on my set. When I was making my first set I took a sample down to John at Woodcraft for an analysis...he diagnosed the insert not being flat (also, Forestgirl here guessed that as the issue too). When John was finished he looked at me and said " that's why I make my box joints and 1/8""...maybe he uses a rip blade only...
Thanks BG.
I am not sure what you mean, when you say insert?
Are you talking about the throat plate on the tablesaw?In my case i am using a zero clearance insert. and it seems straight and flat.
The two "bat ears ''are equal on both inside corners of the notch. So at this point i will blame the blades.
bummer i thought it would be a pretty slam dunk little project. what else is new.
May as well be a remodel.
"do they sell a dado set specifically for this application?"
Yes. Freud just released a new Box Joint Cutter Set (Item SBOX8) which is two 8" blades that stack back to back to make perfectly square 1/4" joints or face to face to make 3/8" joints. The tooth geometry is also engineered for smooth cuts across the ends of the boards. HTH
Freud America, Inc.
Thanks for the heads up.
I guess i am looking for mabye an old school trick as opposed to purchasing the set you describe....Would also like to be able to make larger notches than 3/8" on occasion.
Thanks again for the help.
The old school way that I know is to use a rip blade (or other flat grind blade) and make multiple passes to nibble away the material. The same technique can also be used with the box joint blades to make wider joints.
Charles M
Freud America, Inc.
That sounds good,i probably should have figured that one out.
As far as the box joint blades go, is that a new thing .
"As far as the box joint blades go, is that a new thing"Yes, they just hit the market a few months back. The patent is pending.
Charles M
Freud America, Inc.
RE: Charles M suggestion. The Freud box joint blade is great, And It comes with instructions on how to build a jig. We have sold hundreds of this set with no returns. Set will cut 1/4" or 3/8". I gave a demo with this set and love it.
Work Safe, Count to 10 when your done for the day !!
Bruce S. Counter Sales, Tech Rep. http://WWW.EAGLEAMERICA.COM
Thanks for the shout.
Trying to work with what equipment i have on hand.
Whats the point of a good set of dado blades if i cant cut a clean notch.
"Whats the point of a good set of dado blades if i cant cut a clean notch."A good set of dado blades has bevel teeth in addition to the flats to help you cut a clean notch and therein lies the problem. Those bevels cut deeper and leave "bat ears".
Charles M
Freud America, Inc.
"bat ears".Thats it . Now at least i know the name of the enemy.
"Now at least i know the name of the enemy." If anyone gives you a hard time about the use of "dog ears" just tell 'em it's a French Bulldog -- they basically have bat ears, ROFL.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another box joint trick, If doing square boxes = double side tape all pieces together, or clamp them together, remembering to offset the two pairs by the width of one joint and run them all at once. If rectangular, do two at once.
I always use a backer piece, acts as a 0 clearance and prevents tear-out.Work Safe, Count to 10 when your done for the day !!
Bruce S. Counter Sales, Tech Rep. http://WWW.EAGLEAMERICA.COM
That's a good tip but then i will have twice the "bat ears".lol.
It seems that the two outside blade are cutting a hair deeper not really flairing out.
mabye the can be fine tuned by a sharpening guy.
"BAT EARS" Duh !!!!!!!! Stupid me, New termenology for me. Very true that most dado blades leave Bat Ears. The Freud set makes perfectly flat bottoms, NO Bat ears. Think I'll play with the Blades at work to see if more than one set can be staked. Or play with the jig and pin to see if wider joints can be made. I believe it can be done.Work Safe, Count to 10 when your done for the day !!
Bruce S. Counter Sales, Tech Rep. http://WWW.EAGLEAMERICA.COM
It is new terminology for me as well. Good idea on checking to see if you can stack two sets of those blades together.Let me know how it works.
SAFETY FIRST. BUT LET ME KNOW HOW IT GOES.
The Freud Box joint set CAN NOT be stacked with another set, carbide teeth clash, also teeth can not be shifted enough because of the anti-kickback ears. It was worth checking out.Work Safe, Count to 10 when your done for the day !!
Bruce S. Counter Sales, Tech Rep. http://WWW.EAGLEAMERICA.COM
Thanks alot for getting back to me on that.
good to know.
Fishdog,I had similar problems cutting box joints on my table saw. I was never really happy with them. I had better luck cutting them on my router table. As with the TS setup, make sure you use some scrap to back up the work to prevent tearout. Other than that, it's the same jig setup, but the router bits cut a much nicer, flat kerf.I've since moved on to cutting box joints on my WoodRat, but that is a different story.....
Thanks j, for the get back.
I do not have a router table at this point. I will have to try to clean up the cuts by hand i guess.
If you have any advice on that method that would be great.
I'm not sure I understand what you mean by "dog ears". If you mean the kerf is a bit deeper at the edges of the cut than it is in the center, it could be that the blade is the culprit. (If I'm saying stuff you already know, ignore the following, but . . . )
There are various types of blades. One of the most common is an ATB (alternating top bevel) blade. These are pretty general purpose blades, but if you look at the cut they make when you only go partially through a piece, they leave a high spot in the middle of the bottom of the kerf. This is because each tooth is sharpened with a flat side towards the outer edge and a beveled side towards the inside edge. Other blades incorporate a flat tooth every third tooth to level out the "peak" left by the beveled teeth - often referred to as general purpose blades, or ATFB blades. (One variation of this type is known as a tripple chip grind blade, where the flat teeth are not quite as deep as the beveled teeth, still resulting in a deeper cuts along the edges of the kerf, but a bit better than ATB blades.) Still others, mostly used for ripping, only have flat, chisel blades. These aren't great for crosscutting since they don't have the ablility to "slice" the edges of the kerf like a beveled blade does, but they make really nice, flat-bottomed kerfs when ripping. These are nice to use when you are hogging out material by making repeated passes, such as for a quick & dirty half lap joint.
So, rip a slot with your saw blade part way through a piece of scrap. If it looks like a "W" instead of "|_|" when viewed end-wise, you'll need to switch to a blade that leaves a flat-bottomed kerf or else put up with the "dog ears".
If you are using a dado blade set, this should make a nice, flat bottomed kerf, but not all dado sets are created equal, and even some of these are ground to leave a slight "divot" at the edges of the kerf -- it helps prevent splintering on cross cuts. Also, at least on my (crummy) table saw, the arbor is a bit thin, preventing all the blades in a dado set from aligning exactly and resulting in a rough bottom to the kerf. (The same blade set works fine on my RAS, since the arbor is more accurately sized.)
I never used the Freud sets, but if I was planning on a bunch of box joints, I'd have to think real hard to come up with an excuse NOT to get one! (And the price wouldn't qualify as an excuse. Pretty fair for what it is.)
As for venturing over to Knots from Breaktime, welcome to the dark side! <G>
Mike Hennessy
Pittsburgh, PA
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