hd03king Posted October 7, 2015 Report Share Posted October 7, 2015 I'm just started getting started in woodworking and have been trying to read a lot and watching a lot of videos. I have build the odds and ends thing around the house and I would call myself above average for general knowledge of DYI, but very low knowledge or ability at woodworking. A few months ago I go a new Delta 36-725 and have been just using the blade that came with it. Well a week or so ago I decided to buy a new blade and a dado set. For the blade I got a Forrest WWII and for the dado set I went with the 6" Oshlun Dado set. I also ordered the dado throat plate for my saw at the same time.So tonight I decided to make some shelves and wanted to put a dado in the side and back of the plywood pieces to accept a solid shelf in the middle. Because I'm new it took me 2-3 times longer than most people to figure everything out and get the dado set to the correct width for my pieces. So I'm finally ready to start dadoing my pieces and I do the first (the sides) and it didn't look good. I thought I was going to fast so I decide to do the back piece and slow down a little. That didn't help either. Any ideas on what I'm doing wrong. I'm guessing I ruined both pieces and will need to go get some more plywood. I'm attaching a picture of both pieces. thanks in advance for the help Quote Link to comment Share on other sites More sharing options...
4square Posted October 7, 2015 Report Share Posted October 7, 2015 When I dado plywood I cover the cut lines with painters tape before making the cut.. This will usually eliminate tear out. Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted October 7, 2015 Report Share Posted October 7, 2015 It looks like a combination of going too fast and not having the outside supported better. Quote Link to comment Share on other sites More sharing options...
Eric. Posted October 7, 2015 Report Share Posted October 7, 2015 When I dado plywood I cover the cut lines with painters tape before making the cut.. This will usually eliminate tear out. I don't know about eliminate, but it can certainly help.I'm not familiar with Oshlun dado sets, but when I see tearout like that on ply, I have to assume the set you're using doesn't have high ATB teeth on the outer blades. Look closely at your blades, then compare them to something like the Forrest Dado King. Without a high ATB set you're gonna have a hard time getting clean cross-grain cuts on plywood. Quote Link to comment Share on other sites More sharing options...
Tom Cancelleri Posted October 7, 2015 Report Share Posted October 7, 2015 Ideally you'd make a light scoring cut with a high ATB blade to score the top layer. A lot of dado stacks have flat ground teeth on the outer blades. Quote Link to comment Share on other sites More sharing options...
Tpt life Posted October 7, 2015 Report Share Posted October 7, 2015 A factory throat plate likely is not doing you any favors. Quote Link to comment Share on other sites More sharing options...
Andy Wright Posted October 7, 2015 Report Share Posted October 7, 2015 (edited) Some tips1) lower the blade so the first pass is a shallow cut.2 apply blue tape3) be sure none of your dado blades/chippers are installed backwards4) don't cut into your new plywood until you have this figured out. Edited October 7, 2015 by Andy Wright Quote Link to comment Share on other sites More sharing options...
Boatworks Today Posted October 7, 2015 Report Share Posted October 7, 2015 I'm wondering if the inner / outer blades are set correctly (maybe reversed?). That's some terrible tear out especially with new blades.. 1 Quote Link to comment Share on other sites More sharing options...
JohnDi Posted October 7, 2015 Report Share Posted October 7, 2015 +1 For backwards blade. If all else fails, you could use a straight edge and a sharp utility knife to score your lines before you cut them on the saw. 1 Quote Link to comment Share on other sites More sharing options...
Cliff Posted October 7, 2015 Report Share Posted October 7, 2015 I have the same table saw and dado set. I haven't tried it on plywood but if I did, I'd either score it first or use painters tape. Probably score it cause I've never had great luck getting tape to stop tearout. Quote Link to comment Share on other sites More sharing options...
Janello Posted October 7, 2015 Report Share Posted October 7, 2015 (edited) My dado set is a house brand from a local sharpening brick and mortor location. It makes perfectly flat bottom clean cuts with no tearout in plywood. If the outer blades are not reversed causing that issue then you need to bring that set back and buy a real dado set. In other words....I don't need blue tape or magic tricks to get a quality cut, nor should you. Edited October 7, 2015 by Janello Quote Link to comment Share on other sites More sharing options...
hd03king Posted October 7, 2015 Author Report Share Posted October 7, 2015 thanks for all the tips and help. I'm second guessing myselft about having the blades installed correctly too. With new blades it just seemed like a lot of tearout. Of course I took it off and did not take a picture. I will be more careful next when installing the blades and follow the tips you all gave to me. thanks again! Quote Link to comment Share on other sites More sharing options...
Janello Posted October 7, 2015 Report Share Posted October 7, 2015 Typically the outer blades lettering point outward from the center. Also make sure all the teeth are staggered throughout the set. Quote Link to comment Share on other sites More sharing options...
wdwerker Posted October 7, 2015 Report Share Posted October 7, 2015 Don't buy cheap imported plywood either. Thin veneers with poor adhesive can also cause the same issues. There are cheap domestic ply woods too as well as quality imports.Another approach is to use a router and a straight edge. Quote Link to comment Share on other sites More sharing options...
Guest Posted October 7, 2015 Report Share Posted October 7, 2015 I could be wrong but it looks like red oak ply. n Red oak is tear out prone so that might be an aggravating factor. Quote Link to comment Share on other sites More sharing options...
wouldwurker Posted October 7, 2015 Report Share Posted October 7, 2015 Guessing one or all of the chipbreakers are backwards. I've made the same mistake and got the same results. Quote Link to comment Share on other sites More sharing options...
BobInAustin Posted October 7, 2015 Report Share Posted October 7, 2015 Was the insert you bought blank such that you had to raise the blade up through it initially? If not, I would dedicate one to the 3/4" plywood size. I agree that it sounds like the outside ATB blades might be on the wrong sides. Quote Link to comment Share on other sites More sharing options...
jmack77 Posted October 8, 2015 Report Share Posted October 8, 2015 I'm with Vinny about the blades being backwards. I did that once a while ago, and it looked like that when it was all said in done. When you were making the cut, was there some smoke and or a lot more sawdust then normal? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.