CNC Arm Chair Replacement

I have an office chair that I sit in and watch my Shapeoko. The arm is some type of cast plastic with a metal insert that holds the arm to the side arm. The right arm has a split in it so I would like to replace it along with the second one.

I designed the chair arm in 2d in CC. I have all the measurements figured to make a 2 dimensional arm but need help with figuring out how to cut out the 3d curves of the arm.

Here are some pictures of the actual arm.

This is the upside down view of the arm

This is the view of the arm sitting like it would on the chair.

I have measured the rise and fall and the block of wood I am going to use is 3"wide x 9.5"long X 2" tall and the inner pocket is .3 at the back end and 1.0 at the front end.

My question is how would you suggest I use the modeling function in CC Pro to replicate the shape of the arm. After I get it cut I will cover it with some foam and some faux leather. The reason I want to make it out of wood is so the staples will hold when I apply the upholstery. Plus it is easier for me to work with wood. I could just sculpt the arm with a grinder and flap wheel but I would like to expand my horizon to more 3d machining. Plus I need to make two identical arms to replace both so they look alike.

My gut reaction would be to suggest using something other than CC Pro. :smiley:
Next thought would be to turn it on it’s side & cut the contour with a profile.

However, if you’re hell-bent on using CC modeling it can probably be done.

First thing I would do is draw a side view & cross section using your measurements.
That way I’d have something to follow while modeling, and a better idea of the strategy to use.

[edit] Playing around with ideas… I drew up your bottom view, then traced your side view image to get the basic shape (1st side view above bottom view). Then I rotated the side view to align with the pocket, then rotated it again to fit in your stock.
I would be inclined to modify the design a bit to make the side view symmetrical if I were going to model it in CC. Make it a constant thickness rather than thicker on the left, thinner on the right.
Make the end radii true radii and balance the part so it sits flat like the “Fit” view.

Or use the “Fit to Stock” view to turn the part on it’s side & profile the shape. Then model just the radii around the side of the part & cut those???
You’ll need a fixture or a sin-plate to tip the part to mill the pocket.

Interesting challenge :smiley:

2 Likes

Tod,

Thanks that is why I posted so get another perspective.

1 Like

This topic was automatically closed after 30 days. New replies are no longer allowed.