Where can I get a solid wooden block?

I own a book rack! It’s one of my favorite possessions. The problem is that I also have a Roomba. For some reason, the Roomba likes to drive partway up the sloped base of the book rack and decide that it’s “stuck near a cliff.” Something about the shape and possibly the finish of the base just does its li’l robot head in. I have the Roomba run while I’m at work three times a week, so I’m not there to straighten it out. This happens roughly one out of three times the Roomba runs.

The solution I envision is a solid wooden pedestal to set the book rack on. A square block of wood eighteen inches wide, eighteen inches long, and three or four inches high. I cannot seem to find anywhere that sells big solid blocks of wood! I’m handy, but I don’t have tools to produce something of that size. Does anyone know where I could buy something like that? Or does anyone have any alternative solutions?

How about an apple box?

Find a hardwood supplier in your area and they can sell you a block of wood like that, most likely for a ridiculous price. A block of wood glued together from smaller pieces of wood could be constructed by all sorts of people. I’m sure other Dopers will come in with a number of more practical alternate solutions. A picture of the rack and dimensions of the bottom would be helpful. Do you want wood for some reason or just something sturdy?

That’s a thought - I’m concerned about something hollow. It’s a metal book rack full of books, the “book rack” text in my post is a clickable link to a photo. I’d worry that it would be too heavy for a hollow stand and either crush the box or tip over.

See above - and yeah, something sturdy is all I need. No particular attachment to wood, though it would be ideal if the solution looked semi-nice. The round base of the stand is a little over 16 inches in diameter.

Cheap and easy would be 2x6’s cut to 18 inches, Lowes and Home depot will make the cuts for you.

They also sell these.

If you want to get fancy/expensive google 18 inch cutting boards

A 4x4 would be 3.5" thick. There are several options, depending on how you want it to look. If you want it to really look like one solid block from the front and sides, you would have to miter the corners (cut at 45 degrees) so there wouldn’t be any end grain showing. That’s going to require someone with some tools and some skills.

If you don’t care about showing end grain, you might be able to find scraps long enough at a lumber yard to make a square 18" on a side, but they would have to be cut to length. Or you can buy one 8’ length and get enough pieces to make such a square (two 18" pieces, two 11" pieces; or four pieces 14.5"). Many lumber yards will make such cuts for a nominal fee. You could assemble the four pieces with metal corner brackets and screws, which would go on the inside of the square. This would require a powered screwdriver.

Anything made out of a 4x4 post would be well able to support the weight of your book rack.

May not have the aesthetic look you are going for, but how about landscaping blocks/pavers?

A stepping stone. Pretty expensive to ship, but local hardware/home supply stores might have them.

https://www.lowes.com/pl/Natural-stone--Pavers-stepping-stones-Stones-pavers-Pavers-retaining-walls-Lawn-garden/2931858413?refinement=4294760043

Holy crap, that’s perfect. Duh! Thanks very much, I’ll check hardware stores next time I drive into the city.

Find a wooden box just tall enough to clear the bottom rack of books and set the rack inside the box.

Now that’s thinking outside inside the box!

If you’re not too concerned about appearance, you can buy an 18" square cast concrete stepping stone. It only needs to be ~2" tall to have the Roomba hit it, rather than climbing the sloping base of the book rack.

If you’re more excited about appearance, gift wrap the stepping stone in some neutral or floral paper or sew a snug-fitting bag from an old pillowcase.

Here’s an example of an 18x18 item for $10.

If you could get by with 12x12 those are only $2.00 ea.

They also have stone or stone-burger products that are much more decorative, almost furniture tabletop-like. But they’re $20+ each.

The 18-inchers I can find online all seem to be out of stock everywhere (or at least everywhere near me,) but I’m thinking paving-stone is the right solution now. I’ll poke around at various hardware and home supply stores next time I go into town. The idea of wrapping it is cool, too!

Inspiration!
Buy some random coffee-table book at a used bookstore for $1 and use the large-format book cover as your wrapping paper. It’d look totally libra-tastic.

Utterly brilliant. <3²

Or why don’t you just put the rack on top of a few rarely-used coffee table books you already have?

Used bookstore chic!

Other options (which might need customization or spacing items):
cutting boards, lazy susans, serving trays.
For simplicity, a durable plant saucer might work, possibly with a stepping stone inside.

Plant saucer, @Baal_Houtham best idea yet. Super inexpensive and light weight. Easy to find. Shallow enough to clear the bottom of the book rack.

Nice rack btw! d:r

Also, you could forego a physical modification and just spray some robot repellent around the base of the bookcase.