What are these parts (for an IKEA INGOLF kitchen chair)

I used to buy my appliance parts at Amre Supply, and never bought anywhere else, so this is only one data point. But one time I was flirting with the checkout girl and she said "you know, if you make a business account you'll get about a 40% discount on nearly everything". All it took was an online application and a business card, which I had for my computer software business. I just checked the "other" box on the "what kind of business" question.

After that, I just identified by business name and got the discount.

And lest you think it was my James Bond Socializing Skills that got me a business account, I just printed the application online and brought it in, about a month later, where it was handled by a 67 year old retired plumber.

So maybe you just need to pick one place and ask if they have business accounts. Ya never know.

"Siding Corner Caps" Or often just tin caps. They should be available. Or you could have some fabricated, or perhaps adapt some intended for other siding materials.

Install by running a thin bead of caulk along the end of each clapboard, slide the top under the upper course and press into the caulk. Nail underneath at each corner with a small corrosion resistant ring shank nail.

Alternately, for a different look, take them all off, trim the clapboards back a bit and install a vertical wooden lapped corner.