Ask Experts Questions for FREE Help !
Ask
    woodworm's Avatar
    woodworm Posts: 4, Reputation: 1
    New Member
     
    #1

    Feb 24, 2009, 09:40 PM
    Radius on a slope
    Dear Folks I have a radius of 2440mm on a level surface, now I need to find the new radius for 2440mm on a 32deg slope, please lay out the full formula so I can punch different radius #s and deg from time to time as required Thanks very much (woodworm)
    Perito's Avatar
    Perito Posts: 3,139, Reputation: 150
    Ultra Member
     
    #2

    Feb 25, 2009, 06:12 AM

    I think you need to explain this problem more thoroughly.
    woodworm's Avatar
    woodworm Posts: 4, Reputation: 1
    New Member
     
    #3

    Feb 25, 2009, 03:17 PM
    Known radius on level plain to radius on slope
    Explanation; this concerns curved stairs, I have a known radius of 2440mm on a level plain now the slope of the stringer going down the stairs from one floor down to the lower floor is at 32deg of slope what would the new radius be? I know that it will be bigger radius (say 2800mm etc) so would like to know the full formula to arrive at the new radius without having to make templates then calculating the new radius off the template by math, as sometimes it is not feasible to travel to the job site and do this to make a moulding from edge of stringer to the drywall.many thanks (woodworm)
    woodworm's Avatar
    woodworm Posts: 4, Reputation: 1
    New Member
     
    #4

    Feb 26, 2009, 08:17 AM
    Quote Originally Posted by Perito View Post
    I think you need to explain this problem more thoroughly.
    Perito ,thank you for your reply, this concerns curved strair moldings; we have a radius of 2440mm on the level plain the stair stringer (that holds the treads) goes down to the lower level at 32deg so what is my new radius? I would expect it could be somewhere in the range of say 2800mm but would like you to lay out the key strokes/formula etc Thanking You (woodworm)
    ebaines's Avatar
    ebaines Posts: 12,131, Reputation: 1307
    Expert
     
    #5

    Feb 26, 2009, 11:00 AM

    I looked up "helix radius of curvature" on Google and found this iste:

    helix and radius of curvature

    Which suggests the correct formula is:



    where r is the "flat radius" and the pitch angle is measured at r.

    There is also a site here:
    http://ca.geocities.com/web_sketches...er_radius.html

    which gives the same answer in a different form:



    where h is the height per full 360 degree turn of the stair case. Note that


    For a flat radius of 2.44m and 32 degree pitch both solutions give you R= 3.39m. This assumes that the 32 degree pitch is measured where you want the helical radius (i.e at the outside radius of the tread if that's where the molding is going).
    ebaines's Avatar
    ebaines Posts: 12,131, Reputation: 1307
    Expert
     
    #6

    Feb 26, 2009, 11:03 AM

    See answer here:
    https://www.askmehelpdesk.com/mathem...pe-321718.html

    In the future please don't double post the same question.
    woodworm's Avatar
    woodworm Posts: 4, Reputation: 1
    New Member
     
    #7

    Mar 2, 2009, 07:12 PM
    key strokes to ebaines answer
    Dear Mr ebaines, thank you for your most helpful reply; on the equation
    R= r over cos2 pitch, remember that 2440mm was the flat radius and 32deg was the slope so I put 2440 divided by coscos32=3632 where did I go wrong? Could you please put me straight again thanking you (woodworm)
    ebaines's Avatar
    ebaines Posts: 12,131, Reputation: 1307
    Expert
     
    #8

    Mar 3, 2009, 06:56 AM


    In the future please don't start a new thread if you are following up on a previous question. It makes it very difficult for people to follow the conversation. The previous thread is here:
    https://www.askmehelpdesk.com/mathem...pe-321718.html

    You're trying to calculate:



    Cos(32) = 0.848

    So:

    Curlyben's Avatar
    Curlyben Posts: 18,514, Reputation: 1860
    BossMan
     
    #9

    Mar 3, 2009, 07:27 AM
    >Threads Merged<

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Radius Doubled [ 5 Answers ]

If the radius of a circle is doubled, by what factor will the area change? Thanks

Measurement of a radius. [ 7 Answers ]

Suppose a chord in a circle is 80 centimeters long and it is 30cm from the center of the circle. How could I find the measurements of a radius of the circle.

Calculating slope and change in slope (Mathcad) [ 2 Answers ]

Hello, I have been using mathcad for a only a few weeks, so my knowledge of it is limited. I have a set of data points which I have created some polynomial and cubic splines on a graph. What I want to do is calculate the slopes and change in slope of the curves. Any help on a mathcad...

A radius [ 24 Answers ]

Picture a chair back(bench) 50" wide,25" high(right now its square) I would like to build a radius approx. 2-3' drop on each end,using the full height in the center. Any ideas how I can make a flowing curve like this? Ken

Density, radius and g [ 9 Answers ]

The earth has density rho(p) and radius R. the gravitational field strength at the surface is g. what is the gfs at the surface of a planet of density 2p and radius 2R. A g B 2g C 4g D 16g what is the equation I would use to solve this


View more questions Search