Pbmaster11 Posted December 5, 2012 Report Share Posted December 5, 2012 When cutting a dado in the table saw cross grain I am getting some serious tear out on my sample cut. I have switched to a plywood sized bit on my hand held router... this is much more time consuming in the setup and cutting process. With much more dust! I have a 6" STACK from frued. It is the quality of my dado stack (need more teeth?) or is this the general situation with cross cutting? Quote Link to comment Share on other sites More sharing options...
Jfitz Posted December 5, 2012 Report Share Posted December 5, 2012 PB, is a new dado set? are you using a ZCI? I use a Freud dado stack and never seem to have that problem. Quote Link to comment Share on other sites More sharing options...
Pbmaster11 Posted December 5, 2012 Author Report Share Posted December 5, 2012 http://www.freudtool...o-dado-set.aspx 6 inch model... when i get into the shop i will check exactly which model. Stack is used but only 15 times or so. EDIT: I bought it new Quote Link to comment Share on other sites More sharing options...
Beechwood Chip Posted December 5, 2012 Report Share Posted December 5, 2012 You can reduce tearout with a Zero Clearance Insert ("ZCI"), scoring the edges of the dado with a utility knife or marking knife before the cut, and/or putting blue tape over the cut. Quote Link to comment Share on other sites More sharing options...
rodger. Posted December 5, 2012 Report Share Posted December 5, 2012 I use blue tape all the time when cutting plywood. Works great. Quote Link to comment Share on other sites More sharing options...
Trip Posted December 5, 2012 Report Share Posted December 5, 2012 blue tape is a good idea... but i wonder... with a new blade from freud, i am surprised you are getting 'serious' tearout. Can you take a photo? i'd like to see your definition of serious. Quote Link to comment Share on other sites More sharing options...
Pbmaster11 Posted December 6, 2012 Author Report Share Posted December 6, 2012 i was not using a ZCI. i will try blue tape Quote Link to comment Share on other sites More sharing options...
dcustoms Posted December 6, 2012 Report Share Posted December 6, 2012 I always just use a ZCI and never blue tape that would be far to time comsuming. I have the 8 inch version of what you are talking about. Make yourself a ZCI and you will be fine. Also what type of plywood are you using? Cabinet grade plywood should not tear out like a low grade fir ply. Just a thought. Quote Link to comment Share on other sites More sharing options...
rodger. Posted December 6, 2012 Report Share Posted December 6, 2012 I use both a ZCI and blue tape. Very clean cut. Quote Link to comment Share on other sites More sharing options...
Eric. Posted December 6, 2012 Report Share Posted December 6, 2012 For those who suggest a ZCI...do you guys make a new one every time you use a new combination of blades? I mean, if you have your stack set up for 3/4" and you use a ZCI, and then you go to make a 1/2" dado, that ZCI is no longer ZC...am I wrong? Quote Link to comment Share on other sites More sharing options...
dcustoms Posted December 6, 2012 Report Share Posted December 6, 2012 I have one that is 3/4" and one that is set for plywood thickness. If I use a smaller dado setup I just use the 3/4 one. I don't really have problems with tear out though. Quote Link to comment Share on other sites More sharing options...
rodger. Posted December 7, 2012 Report Share Posted December 7, 2012 For those who suggest a ZCI...do you guys make a new one every time you use a new combination of blades? I mean, if you have your stack set up for 3/4" and you use a ZCI, and then you go to make a 1/2" dado, that ZCI is no longer ZC...am I wrong? I have 5 or 6 ZCIs for various standard and dado blade widths. Quote Link to comment Share on other sites More sharing options...
CessnaPilotBarry Posted December 7, 2012 Report Share Posted December 7, 2012 What kind of plywood? A reasonably new Freud dado shouldn't be ripping it up unless the dado is damaged, or you're cutting something like Luan. With or without other aids... Quote Link to comment Share on other sites More sharing options...
Pbmaster11 Posted December 10, 2012 Author Report Share Posted December 10, 2012 here is picture of tear out and my new ZCI Quote Link to comment Share on other sites More sharing options...
nateswoodworks Posted December 10, 2012 Report Share Posted December 10, 2012 Yup serious tearout, did the problem go away after the new insert? For the dado inserts i use scraps of MDF and i have one for 3/4, 1/2 and 3/4 ply (even though the thickness always varies a bit it still gets the job done) When cross cutting I score before a every cut unless its in an unseen area, even though 99% of the time I wouldn't need to the 1% would ruin my day and work piece. Quote Link to comment Share on other sites More sharing options...
Pbmaster11 Posted December 10, 2012 Author Report Share Posted December 10, 2012 I have not tried again... I had 4 phenolic inserts that i purchased from rockler awhile ago.. just have not get to them yet. I am going to use 2 blades/ insert and then each dado with will have its own inserts Quote Link to comment Share on other sites More sharing options...
CessnaPilotBarry Posted December 10, 2012 Report Share Posted December 10, 2012 "For the dado inserts i use scraps of MDF and i have one for 1/4, 1/2 and 3/4 ply" Same here... I keep a stack of blanks around for sizes I don't have... Since I don't need the riving knife while dadoing, I make mine reversible, with two slots per insert, by eighths. Another thing I haven't seen mentioned... I crosscut my plywood on shop-made sleds, including dados. By "crosscut", I'm referring to the face veneer. BTW... some cheap plywoods just WANT to splinter. This includes luan and lots of Chinese birch. "Cheap" is relative. Chinese hardwood plywood may seem expensive, compared to construction grade stuff in the home center, but it's CHEAP when compared to the real deal. Quote Link to comment Share on other sites More sharing options...
Pbmaster11 Posted December 11, 2012 Author Report Share Posted December 11, 2012 I used my inserts today. Dado is perfect. Will batch out a bunch out of MDF one of these days. Quote Link to comment Share on other sites More sharing options...
GeorgeTheGamer Posted December 11, 2012 Report Share Posted December 11, 2012 A ZCI helps MUCH more than people naturally seem to assume. It's a pretty common sight around the shop for a newer person to be scratching their head wondering why the new set of blades they just put in are tearing up their material just as bad as the "old" ones. 9/10 it's because their inserts are banged up from someone raising the blade too high. So make yourself a jig to cut them and when in doubt, just throw a new one in. Quote Link to comment Share on other sites More sharing options...
Pbmaster11 Posted December 11, 2012 Author Report Share Posted December 11, 2012 Sheets of phenolic... anyone have a good source? or i was thinking laminating some MDF with laminate... i know plain MDF will work for inserts but i like the beefiness of the phenolic. Quote Link to comment Share on other sites More sharing options...
Alan Bienlein Posted December 11, 2012 Report Share Posted December 11, 2012 I was curious and went out to my shop, got my worst dado set and some Chinese plywood and purposely setup the dado so the insert would be of no use to prevent tear out. These are the results. A picture showing the clearance between the dado set and the insert. And a couple pictures showing how bad the teeth on the dado set are. This is an 8" Freud dado set that's seen better days. I feel if you need to use a zero clearance insert when you cut or dado on the table saw to prevent tear out then your not using the proper blade for the job. Quote Link to comment Share on other sites More sharing options...
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