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Thread: Dado set issues

  1. #1
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    Default Dado set issues

    I have a Freud 6" dado set. I find it annoying that when I use it, no matter what width, I am not getting a smooth finish across the cut. I have to do a bunch of hand sanding to eliminate lines. Is this normal?
    Gerard>
    ​Freeland, WA

    Next election, vote against EVERY Republican, for EVERY office, at EVERY level. Be patriotic and stop the madness. Save the country.

  2. #2
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    Default Re: Dado set issues

    So it's the bottom of the dado that's rough,or the cut edges?
    If it's the bottom,quite likely the centre sections aren't cutting the same diameter of circle and will need to be reground properly.
    Cutting too quickly will also leave a ripply bottom.
    R
    Sleep with one eye open.

  3. #3
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    Default

    Someone mentioned something about spin the set in reverse against a diamond hone plate?
    Edit: seems to me. It must be done manually spinning the set. If someone wants to live to talk about it!
    Last edited by DeniseO30; 09-02-2018 at 08:10 AM.
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  4. #4
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    Default Re: Dado set issues

    Quote Originally Posted by Gerarddm View Post
    I have a Freud 6" dado set. I find it annoying that when I use it, no matter what width, I am not getting a smooth finish across the cut. I have to do a bunch of hand sanding to eliminate lines. Is this normal?

    Have you checked arbor runout? That could be a source. Also, what grade Freud is this? Two cutter chippers or four cutter chippers? Two cutter is a lower grade and probably not worth resharpening. The cost may be comparable to a new set. I struggled for years with a cheap two cutter chipper dado set and hated it. I finally bit the bullet and picked up a Forrest Dado King and never looked back. Dado bliss!


    A good dado will have the two outer cutters a little proud to produce a scoring cut that reduces or eliminates tearout. They leave a tiny "batwing" that is barely noticeable. A cheap set will leave a bigger batwing and still produce tearout. Best to leave sharpening to the pros.

  5. #5
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    Default Re: Dado set issues

    Quote Originally Posted by Dusty Yevsky View Post
    Have you checked arbor runout? That could be a source. Also, what grade Freud is this? Two cutter chippers or four cutter chippers? Two cutter is a lower grade and probably not worth resharpening. The cost may be comparable to a new set. I struggled for years with a cheap two cutter chipper dado set and hated it. I finally bit the bullet and picked up a Forrest Dado King and never looked back. Dado bliss!


    A good dado will have the two outer cutters a little proud to produce a scoring cut that reduces or eliminates tearout. They leave a tiny "batwing" that is barely noticeable. A cheap set will leave a bigger batwing and still produce tearout. Best to leave sharpening to the pros.
    Yes - take your set, and your questions (with a sample cut) to the pros. It's possible, of course, to get a decent bottom to your cut - but a dado set is naturally going to leave a rougher surface than the same dado cut with a router.
    David G
    Harbor Woodworks
    http://www.harborwoodworking.com/boat.html

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

  6. #6
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    Default Re: Dado set issues

    Quote Originally Posted by DeniseO30 View Post
    Someone mentioned something about spin the set in reverse against a diamond hone plate?
    This operation as suggested has a high likelyhood of causing personal injury and property damage.

  7. #7
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    Default Re: Dado set issues

    Quote Originally Posted by navydog View Post
    This operation as suggested has a high likelyhood of causing personal injury and property damage.
    Not to mention sounding absolutely terrifying, and I'm not one to shy away from shop tools.
    Tom

  8. #8
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    Default Re: Dado set issues

    There is that as well. Even if someone did this without a calamity the grind on the tool would be wrong.

  9. #9
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    Default

    I've never felt that a smooth bottom cut is really necessary for dado cuts.
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  10. #10
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    Default Re: Dado set issues

    Stacked dado cutters will always leave a grooved bottom in the dado, no getting around it. To cut absolutely clean bottoms in dados, rabbets and cross cut recesses I use a quarter inch groover. It's a saw blade with a thick body and quarter inch wide teeth ground straight across the top. It takes more passes but does a better job.



  11. #11
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    Default Re: Dado set issues

    Or if your saw will take it you can stack 2 or 3 rip blades. Rip blades typically have square ground tops. They have to be the same diameter though, and the same number of teeth so they will fit together well with the cutters staggered.

    Dadoes are not usually very deep so skil saw blades are easier and cheaper, 2 or 3 of the same exact model and brand, reserved just for cutting dadoes.

  12. #12
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    Default Re: Dado set issues

    Quote Originally Posted by Jim Ledger View Post
    Stacked dado cutters will always leave a grooved bottom in the dado, no getting around it. To cut absolutely clean bottoms in dados, rabbets and cross cut recesses I use a quarter inch groover. It's a saw blade with a thick body and quarter inch wide teeth ground straight across the top. It takes more passes but does a better job.

    I hadn't heard of groover blades. Can you give us a specific maker and number?

  13. #13
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    Default Re: Dado set issues

    Dadoes are not usually very deep so skil saw blades are easier and cheaper, 2 or 3 of the same exact model and brand, reserved just for cutting dadoes.
    I've done this. It works, especially with a shim set to get the precise width of dado that you want, but the bottoms of the dadoes end up very grooved from the ATB grind (typical) of the skil saw blades. Also, skil saw blades are typically very thin (~1/16") kerf, to reduce cutting friction and maximize efficacy of a small saw's small motor, so expect to stack quite a few for a dado of any size. Also, those thin blades seemed to flutter a bit on deeper dadoes, which made for less-than-precisely-straight shoulders.

    I'll also mention that the Forrest 3/16" - 5/16" two-blade finger joint cutter cuts exquisitely clean, flat-bottomed dadoes without the "batwing" scoring of a typical dado stack. I broke down and bought one after I became frustrated with the stacked-skil-saw-blades approach. It's one of the few specialized tools I haven't yet had buyers remorse about.

    Alex

  14. #14
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    Default Re: Dado set issues

    Quote Originally Posted by JimConlin View Post
    I hadn't heard of groover blades. Can you give us a specific maker and number?

    Here's one, Jim, there's more out there. The one I have is a ten inch blade. I didn't buy it new and the manufacturers markings have long since worn away. They do an excellent job removing the waste from tenons and leaving a smooth surface on the tenon. You might expect tearout along the edge, but this doesn't seem to be a problem.

    Jim

  15. #15
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    Default Re: Dado set issues

    We have this one, with a 1" bushing pushed into the 1 1/4" bore.
    http://dimar-canada.com/pdf/Grooving...ionDesign1.pdf
    R
    Sleep with one eye open.

  16. #16
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    Default Re: Dado set issues

    For background - here's a bit about the various tip shapes

    https://vermontamerican.com/circular...y-grind-types/

    http://www.carbideprocessors.com/pag...ip-angles.html

    It's true that a pure 'rip' blade is most often a Flat Top Grind. But not all are.

    Most other blades are not a FTG... or have only some teeth with FTG.

    One of the reasons that dado sets can leave a rough bottom is that a FTG tend to tear, rather than slice, when cutting across the grain. So... if your dado is a 'rip' cut in solid lumber... it'll come out cleaner than a crosscut dado... or a cut in plywood or other panel product.

    Like Denise, I don't expect a dado set to leave me a crisp clean bottom <shaddup Pless>. If I need that... I use something else. Might be a router. Might be a dado set with a slightly shallow cut finished off with a plane or chisels. Depends upon the task.

    I agree that having a pro shop sharpen your dado set is a grand idea. I send all my blades to the shop. Some I COULD do... but what a waste of time. And others (we have a couple of hollow-ground blades, for instance)... I wouldn't know where to start, and don't particularly want to learn. Cheap investment in accuracy to have the pros do it.
    David G
    Harbor Woodworks
    http://www.harborwoodworking.com/boat.html

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

  17. #17
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    Default

    Someone refresh my memory? The wobble blade from back whenever, did they create a crowned or dished bottom dado?

    It does however appear that the problem has been solved very well at nearly $300 .
    https://www.woodmagazine.com/review/...dado-set-sd608
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  18. #18
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    Default Re: Dado set issues

    You won't go wrong with Forest dado sets. If indeed you need one, call them and ask for Tony. He has been there for a very long time. However, if you need another way to go, look on eBay for an old Stanly 45 or 55 combination plane. With this tool, one can hand cut a dado or clean the bottom of one that is not really as smooth as you want. In fact, if you are in need of an odd patterned piece of moulding for the restoration of a piece on antique furniture, the Stanly 55 is capable of cutting any molding shape you could wish for.
    https://www.woodcraft.com/blog_entri...ination-planes
    Jay

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