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Thread: Determining the radius on an early curved ornamental cabinet.

  1. #1
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    Determining the radius on an early curved ornamental cabinet.

    I am going putting aside my hesitation of posting details on this forum with the work I am doing to refurbish this early curved ornamental cabinet. Specifically, I am going to cover how I went about working out the original radius used to construct this cabinet. To understand the specifics, I will also include my initial findings when all 3 curved panels were temporarily pinned together.



    The following in black ink pen clearly shows that when compared to a scribed pencil line at 156mm radius, the mating bevels on each of the frame stiles needed to be re-worked to better match the correct radius.



    To then return to how I was able to work the correct radius, I used masking tape to measure the circumference around the cabinet.





    The measurement of 492 (180 degrees) was then multiplied by 2 (=360 degrees) , and the resulting 984mm was imputed into the following formula to give me a radius value of 156mm.
    http://www.rkm.com.au/CALCULATORS/CA...le-sphere.html

    After scribing the 156mm radius on a reference board, and re-working the bevels on each of the frame stiles, I was able to end up with an excellent match.





    Stewie;
    Last edited by Stewie Simpson; 02-15-2017 at 8:03 PM.

  2. #2
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    How did you determine it was originally half a circle and not a smaller segment with a larger radius? By the curve on the individual segments?

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    Was there some reason to not measure from one end point to the other on the 180º arc, then divide by 2 to determine the radius?

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

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    Quote Originally Posted by Jim Belair View Post
    How did you determine it was originally half a circle and not a smaller segment with a larger radius? By the curve on the individual segments?
    Jim; that was confirmed when a compass radius of 156mm was scribed out on the reference board. What was difficult to determine was the original clearances on the hinge and non hinge side of the swing door. After setting my own clearances, I ended up just short of a full 180 degree arc by 1/8". That's not a bad result given I had to pull apart all of the wood joints to use a stronger adhesive, and that the mating surfaces on the stiles that had developed some slight bow and cupping over the years also had to be dressed back.

    Stewie;

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    Quote Originally Posted by Jim Koepke View Post
    Was there some reason to not measure from one end point to the other on the 180º arc, then divide by 2 to determine the radius?

    jtk
    Jim; I was using the circumference measurement of the cabinets 180 degree arc to determine its original radius. We are talking about 2 different approaches.

    Stewie;

  6. #6
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    The base and upper dais were dressed back to a flat surface on both sides, followed by some glue repairs and wood filler. The radius for the frames were was also re calibrated from 156mm to 154mm to pick up a shortfall of 1/8" from a full 180 degrees.

    Frames were then secured to their mounts using 1/2" brass screws. These will be later reinforced with adhesive to strengthen their bonding. The original 2mm ply that was used for shelving will be discarded, and a 9mm mdf used in its place. A timber feature shown when the door is open will also be glued in the maker a neater appearance. The original shelving slots will need to be widened to accommodate that increase in shelving thickness.

    The work done previously to square up each of the frames paid off in dividends when it came to the fit of the door frame. Uniform spacing's all round, with no sign of hinge bind as the door is opened and closed.

    When it came to fitting the upper dais, a chalk transfer fit was used to make sure even contact being made along the top surface of the curved rails. On-ward's to completion.

    If the amount of detail I am providing is overly boring let me know and I will hold of further posts till completion.

    Stewie;



    Last edited by Stewie Simpson; 02-18-2017 at 3:00 AM.

  7. #7
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    Appreciate every detail, Stewie. Look forward to the rest of the restoration.

  8. #8
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    Not sure if you are looking for critique or not but here goes. It looks like it originally had two smaller hinges. I think the three longer ones is a bit much on a small door. And mdf for the shelving- Really?

    Apart from that it's a pretty little cabinet and should look nice when you've got it done. I'm assuming you have a source for curved glass for the doors?

  9. #9
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    The original 3mm ply that was used for shelving will be discarded, and a 9mm mdf used in its place.
    Any possibility to find some glass or plexiglass shelves?

    In trying to imagine 9mm shelves it seems a bit heavy for the cabinet.

    Shelves of clear material will help to illuminate the inside of the cabinet.

    jtk
    Last edited by Jim Koepke; 02-18-2017 at 12:40 PM. Reason: spelling
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

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    Oh golly gosh Jim B. Your post reminds me of why I was so hesitant in posting details on this project. I wasn't after a critique but lets put that comment aside. Yes, there were 2 hinges. And the spacing in between did not prevent the thin walled hinge stile from bowing out on the door frame. By reducing the distance between the hinges (ala 3rd hinge) the door stile should remain straight from now on. Yes mdf for the shelving. Why. Because mdf doesn't expand or contract like natural wood does. Why would I want to stick with the original design of using 2mm ply that's highly prone to wood movement, let alone seated in slots that were 2 1/2 times greater than the actual shelf thickness. This cabinet is going to be painted when I am finished rebuilding it. With all of the wood repairs that were required so far, its going to be too difficult to colour match everything to clearer finish. Do have a source for the curved glass panels. Yes Jim, its the original curved glass panels.



    Stewie;
    Last edited by Stewie Simpson; 02-18-2017 at 2:59 AM.

  11. #11
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    Quote Originally Posted by Jim Koepke View Post
    Any possibility to find some glass or plexiglass shelfs?

    In trying to imagine 9mm shelves it seems a bit heavy for the cabinet.

    Shelves of clear material will help to illuminate the inside of the cabinet.

    jtk
    Jim K.; sound advise with the look of glass as the shelving material.

    cheers Stewie;
    Last edited by Stewie Simpson; 02-18-2017 at 2:32 AM.

  12. #12
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    Magnificent work, l look forward to seeing the finished display.
    - - - - - - - - - - - - -
    Jim Mackell
    Arundel, ME

  13. #13
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    If you are set on painting it then MDF will work as a light duty shelf but 9 mm does seem thick for this piece - I think though using glass is another nice idea but it all depends on what will be displayed inside the case. With glass there is often a frame in panel approach used where the glass sits into a simple rabbet. That way, in a worst case scenario, the glass can be easily replaced. Of course you will need to build the frame but since its all going to be painted you needn't be concerned with matching the wood species. Glass would be nice with a lighted case also. There are lots of low voltage LED light pucks and strips out there that do a great job of uniform, dimmable lighting.

  14. #14
    Quote Originally Posted by Stewie Simpson View Post

    If the amount of detail I am providing is overly boring let me know and I will hold of further posts till completion.
    Color me intrigued by the entire process.
    After tools, my favorite restoration subjects are houses and furniture.
    (many years ago, cars were at the top of that list)

  15. #15
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    I doubt I will find a use for this cabinet within the home. That's not overly concerning. Its the actual process that I find enjoyable.

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