How Tight is Tight

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by chefwong, Jul 19, 2012.

  1. chefwong

    chefwong Member

    Messages:
    710
    Location:
    District of Columbia
    What's the plumbers *feel* when tightening DWV connections under the sink.

    Handtight with a turn on the wrench. Or tight till the nut bottoms out on the threads

    Slipnut on Tubular Brass
    Plastic Slipnut on Tubular Brass where it's goes into wall outlet

    Sink Basket

    For example, Kohlers Sink Basket seems to have changed slightly. On the current one, there is a washer plate that goes under the gasket and then a metal plate that is screwed underneath. Alongside - 3 screws that you're supposed to screw tight pushing the brass washer against the gasket. I've got the locknut as tight as it's going to get....and while the 3 screws can put the brass washer tighter against the gasket to the sink, it's weird...as the 3 points where the screws are going up are getting deformed...and it's not a ~uniform~ pressure pushing the gasket.


    Plastic Slipnut I presume just a 1/4 turn with the handwrench past tight.

    Nuts on Brass Tubular ???
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    A chrome plated brass slip joint nut, needs pliers.
    A plastic slip joint nut can be done by hand.
    If you have a three point installation with screws, it's a judgement thing as to how tight they can go without deforming the metal. You can get by with a little bending, not much though.
  3. chefwong

    chefwong Member

    Messages:
    710
    Location:
    District of Columbia
    Yeah, not feeling this three point system....
    U get only so much tight with the nut....as it's more of a cup nut that it not really flat...
    And then you have the screws
  4. Chad Schloss

    Chad Schloss Member

    Messages:
    330
    Location:
    USA
    i just installed that kohler kitchen sink drain a few weeks ago. i didn't like that system that much.. I had trouble getting the nut tight enough with a little over hand tight, and then using the screws like the directions said. i also noticed it not being uniform pressure. i think i had too much putty under the rim too. so i got it as tight as i could get it with the nut, then pushed down with my hands on the flange ontop, retightened, pushed again, straightened the nameplate on the flange and then locked down the screws. to get them a little tighter than my screwdriver liked, i used my dewalt impact screwdriver. all the screws were straight and even after doing this.

    Attached Files:

    Last edited: Jul 19, 2012
  5. chefwong

    chefwong Member

    Messages:
    710
    Location:
    District of Columbia
    Hi Chad....

    It helps ALOT with someone holding the basin wrench, ends of pliers , etc uptop as you tighten the basket nut....u can apply as much torque down there while someone is just working to keep the *logo* in the correct position.

    Impact is way overkill.....
    The screws are straight...and they will be as they are threaded onto the nut body.
    I just don't like the way the BRASS washer that those screws are pushing against to snug the gasket to the sink...how it's designed. Previous designs allowed for even pressure of the gasket - in addition to just tightening the nut
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    InSinkErator has used a similar method to tighten their basket to the kitchen sink for decades...works fine, lasts a long time
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    You do NOT "tighten" the nut. You merely spin it close to the sink. The three bolts pull the basket down and do the tightening. You also do not have to "deform" the metal ring to get it tight.
  8. chefwong

    chefwong Member

    Messages:
    710
    Location:
    District of Columbia
    The nut doesn't spin flush tight to the brass washer. A wrench get's it a good couple turns more.

    So how much *pressure* is one suppose to use when using the 3 point screws. A smigen just right before you see the brass washer deform ? I guess it goes back to the thread title. How tight is tight. It' a plumbers touch eh.

    Well, that's what I did. I backed off the screw when I saw it deform a hair. Unless the brass is a thinner gauge than of previous yesteryears. I eyeballed the kitchen sink as a comparison and the brass washer is more *flush* overall. However, the current sink I'm working with is CI, so it's a bit more uneven-rougher than SS kitchen sink....
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    You did NOT have to "wrench it a couple of turns tighter". That has nothing to do with whether it will leak or not. You have to use your judgement as to when it it tight enough.
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    It's not like there's much of any pressure on that seal - maybe 10" of water (and that's a pretty deep sink). Now, on a supply line, it becomes much more of an issue. You're just trying to make the rubber gasket conform to the irregularities of the bottom of the sink.
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    quote; You're just trying to make the rubber gasket conform to the irregularities of the bottom of the sink.

    That has nothing to do with the sink leaking. The purpose of the "tightening" is to pull the drain DOWN against the sink so the sealant, putty or whatever, can keep the drain from leaking.
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