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  1. #1
    Join Date
    Feb 2005
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    71

    Default dropping the hip -lose the pitch?

    I am really confused. I know that backing the hip does take a bit more work but the height above plate and the pitch of the top center line of the hip rafter are correct.

    I dont undestand how those relationships are kept when you drop the hip buy cutting a deeper seat cut.

    Seems like when you cut the deeper seat cut that the height above plate would be lower and also the pitch would become steeper.

    Please help me understand.

    Thanks
    Jeff

  2. #2
    Join Date
    Jun 2004
    Location
    Caldwell, NJ
    Posts
    3,153

    Default Re: dropping the hip -lose the pitch?

    Quote Originally Posted by oldjeff View Post
    I am really confused. I know that backing the hip does take a bit more work but the height above plate and the pitch of the top center line of the hip rafter are correct.

    I dont undestand how those relationships are kept when you drop the hip buy cutting a deeper seat cut.

    Seems like when you cut the deeper seat cut that the height above plate would be lower and also the pitch would become steeper.

    Please help me understand.

    Thanks
    Jeff
    Jeff,

    The the reason for the hip drop is because the hip is turned at a 45° angle, so therefore the outside of the hip where it hits the plate has to be the same H.A.P. cut as the common rafter H.A.P. cut.

    Since you measure a hip to the outside corner of the top plate, when you twist the hip to 45°, the outside corner doesn't hit the plate, it has a small run and a rise that makes the hip higher if you mark the H,A,P. cut where you make your hip length mark and then plumb it up from there, the H.A.P. cut will be half the thickness of the hip off the plate line.

    So all you need to do when you make the plumbcut mark where your length is, just come in half the thickness of the hip towards the top and make the same H.A.P. cut as the common rafter.

    It doesn't change anything. If you use a 2x hip, then you just come in 3/4".

    In this drawing you will see the 3/4" run and the rise in the triangle.
    Attached Images Attached Images
    Joe Carola

  3. #3
    Join Date
    Jun 2004
    Location
    Lake Placid, NY
    Posts
    1,113

    Default Re: dropping the hip -lose the pitch?

    A dropped hip is simply an unbacked one, that has been moved in the Z direction so that its arrises are in plane with all the adjacent jacks or commons.

    Backing is the process by which those proud arrises are gotten out of the way.

    How 'bout that? Just another arrishole spoutin' more of those funny words.

  4. #4
    Join Date
    Jun 2004
    Location
    Maywood, New Jersey
    Posts
    36

    Default Re: dropping the hip -lose the pitch?

    Where's Chippy when ya need him ;)
    Common sense is a gift from God that cannot be taught.

  5. #5
    Join Date
    Jun 2004
    Location
    Staten Island, NY
    Posts
    534

    Default Re: dropping the hip -lose the pitch?

    Maybe he's "crock" hunting. . .

  6. #6
    Join Date
    Jun 2004
    Location
    Staten Island, NY
    Posts
    534

    Default Re: dropping the hip -lose the pitch?

    OldJeff,

    What Joe C. said is a variation of the "Birch Method" talked about for years here. By cutting the plumbline in you move the hip in(along the x/y plane) as to the standard hip drop of moving it down (z plane) as Bob states. Doing so changes it's position, but not it's pitch.

    Regardless of what method you use, it will still adjust the hip.
    Last edited by Joe Fusco; 09-23-2007 at 09:22 AM.

  7. #7
    Join Date
    Jun 2004
    Location
    Port Orchard, WA
    Posts
    2,639

    Default Re: dropping the hip -lose the pitch?

    Quote Originally Posted by oldjeff View Post
    I am really confused. I know that backing the hip does take a bit more work but the height above plate and the pitch of the top center line of the hip rafter are correct.

    I dont undestand how those relationships are kept when you drop the hip buy cutting a deeper seat cut.

    Seems like when you cut the deeper seat cut that the height above plate would be lower and also the pitch would become steeper.

    Please help me understand.

    Thanks
    Jeff
    The way I think of it, is that the outside edges of the hip need to have the same HAP as the commons. So taking a bit more out of the seatcut lowers the entire hip, not just at the seatcut.

  8. #8
    Join Date
    Jun 2004
    Location
    Staten Island, NY
    Posts
    534

    Default Re: dropping the hip -lose the pitch?

    This picture is a good example of what Tim says although it's at the ridge where you can see it better.
    Attached Images Attached Images

  9. #9
    Join Date
    Jun 2004
    Location
    Caldwell, NJ
    Posts
    3,153

    Default Re: dropping the hip -lose the pitch?

    Here's the little triangle in Joe's picture that I'm talking about. You see the little run and rise. No matter who cuts a hip and what way who cuts it, it still gets adjusted to plane in at the plate line.
    Attached Images Attached Images
    Last edited by Joe Carola; 09-23-2007 at 11:19 AM.
    Joe Carola

  10. #10
    Join Date
    Jan 2006
    Location
    Houston,Texas
    Posts
    644

    Default Re: dropping the hip -lose the pitch?

    The picture Joe F. posted shows it all. You drop the entire hip by lowering the seat cut.The edges plane with the commons, so the center of the hip doesn't plane to the ridge, though if it was backed it would.

  11. #11
    Join Date
    Jun 2004
    Location
    San Antonio, Texas
    Posts
    753

    Default Re: dropping the hip -lose the pitch?

    I have done a step-by-step photo essay of a model hip being cut without using the “Hip Drop” corrective adjustment. Notice the inverted diamond cut at the heel. It shows that the marks made on the hip really represent parallel cheek cuts. But it is much simpler to just cut a little extra out for clearance at the heel,(Like a loose fitting common/square heel cut). The original HAP lines line up on the walls too, just like the commons.

    Pardon the weathered wood; it was all I had laying around the house at the time.

    The first pic (001) shows the Hip marked (I used 12” for the two lengths, hip’s and tail’s) on the top outside edges (which is the point or line of plane) prior to performing any cuts. The only difference between cutting a common rafter and a hip/val rafter is that on the common the cheek cuts are square and parallel and on the H/V the cheek cuts are beveled and parallel. (If you used a beveled heel cheek cut on your hip/val, that is.)

    The second pic (003) shows the first three parallel check cuts performed on the model.
    Attached Images Attached Images
    Last edited by Richard Birch; 09-24-2007 at 07:28 AM.

  12. #12
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    Jun 2004
    Location
    San Antonio, Texas
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    753

    Default Re: dropping the hip -lose the pitch?

    The third pic (004) shows the mirroring bevels performed. These are commonly called “diamond-cuts”. The inverted diamond cut at the heel is shown in the fourth pic (005).
    Attached Images Attached Images
    Last edited by Richard Birch; 09-24-2007 at 07:27 AM.

  13. #13
    Join Date
    Jun 2004
    Location
    San Antonio, Texas
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    753

    Default Re: dropping the hip -lose the pitch?

    The fifth pic (008) shows the heel cut finished. Notice that the dimension of the tail at its centerline is equal to the dim originally marked on its side in the first pic. It is not a common practice to make these mitered heel cuts on hip rafters and was only done here for emphasis about the parallel relationship of the vertical plane of the wall to the vertical plane of the side and end of the ridge.

    The final pic (010) shows the hip as it would be placed on the corner of the building. This method of hip/val rafter cutting requires no additional “Hip Drop” adjustments as the original HAP marks line up properly when placed on the corner.
    Attached Images Attached Images

  14. #14
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    Jun 2004
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    Caldwell, NJ
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    Default Re: dropping the hip -lose the pitch?

    Richard,

    I know we've been through this a million times before. Why can't we just put it to rest. You don't call it a , "Hip Drop" which is fine. Forget the word ever existed. It should just be called, "Hip Adjustment". The problem I have with you is that you always say that you make no adjustments, when you do.

    If you don't cut a diamond cut or extend your heel cut, your hip will not fit.

    I've asked you to do this before and you haven't done it. Since I cut your hip the way you do, can you cut a hip the way I'm asking you now and like I have in the past?

    Measure your hip and mark the top of the plumbcut at the ridge and then measure your hip length and mark the plumbcut at the bottom.

    Now cut the top of the plumbcut like you've always described by cutting that line with the saw set at 45° and then continuing that cut by eyeballing it on the other side creating a diamond cut. Since you do that you've just shortened the top plumbcut by 3/4". So now the original top plumbcut line is gone and the point of the 45° diamond cut is shorter by 3/4" plumb.

    Now go down to the bottom of the hip plumbcut and mark the same H.A.P. cut the same as the common H.A.P. cut and DON'T cut a diamond cut or extend the heel cut and see if your hip fits at the ridge.

    It will not because it will be 3/4" short measuring plumb.

    1)Cutting the diamond cut corrects that and slides the hip 3/4" plumb towards the ridge and IS an adjustment, plain and simple!

    2)Cutting the hip the way you do and I did for you by extending the heel cut slides the hip 3/4" plumb towards the ridge and IS an adjustment, plain and simple!

    If you don't diamond cut or extend your heel cut and also cut your top plumbcut at the ridge 3/4" short plumb, your hip hip will not fit.

    Can you cut this hip the way I've asked first?
    Joe Carola

  15. #15
    Join Date
    Jun 2004
    Location
    Staten Island, NY
    Posts
    534

    Default Re: dropping the hip -lose the pitch?

    It seems that we'll be talking about this for a few more years. . . .

    The simple reality is the hip needs to be adjusted and whether you do it in the z plan of the x/y plan as long as it fits, no one will care.

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