Hard maple glues fine, I've never had issues with yellow glue. Biscuits will definitely give a better and stronger joint, plus they'll aid a bit during alignment and glue-up.

Watch your grain. If flat sawn, it can help to alternate "smiles" and "frowns" when you look at the grain pattern on the ends of the boards. If vertical grain, not a worry.

Treat the bottom of the countertop as you will the top; If urethaning, urethane the bottom too. Were you to just urethane the top and leave the bottom as raw wood, the bottom face could absorb seasonal moisture and cup the entire top. Or at least the slab would try to cup. Which leads to...

Fastening. I attach wood counter tops from below. I'll have one row of screws that are somewhat tight. That row is sometimes at the front of the countertop (near the overhang) or sometimes at the rear (by the backsplash). Depends on where I want the movement to occur. The remainder of the fasteners will be slightly loose, perhaps using fender washers or the equivalent. The fender washers will prevent the top from lifting, but the oversized holes allow lateral movement. That'll allow the slab to expand and contract as needed during seasonal swings.

Agree with everything mongoct said with one difference.

Splines instead of biscuits. I love and use biscuits a lot, but in edge gluing long pieces, splines hold better, reduce glueup movement, and make a much better joint. You can even use splines made of the same maple used for the countertop.

How do you do splines? Is that where youd cut the edge to fit into the edge of the other board. Can that be done with a router.

Thnx

Splines are simply a long biscuit. You can route grooves in each joining edge with a straight bit. It is best done on a router table with a fence. But, it is possible with a handheld router and an edge guide. You simply center the bit to the edge.

Let's use 3/8" for a start, but you could use 1/4" or 1/2" bits. Then set the depth on the router to 3/16" deep. You route the groove the entire length of each joining edge(Stopping for exposed ends---which actually should get breadboard end treatments).

You now have two grooves that form a 3/8" square ho;e a;omg the joined edges of two boards.

All you have to do is cut as many 3/8" square splines(the strips to fit the groves) as necessary. The splines can be one piece or several in one groove.

Lots of glue. Clamp every 6"-10" along the length and use cauls to keep the glueup flat.

A couple of other factoids:

Hard maple is easy to burn / glaze with a dull blade, pinching, or slow router movement. Not a big deal, but just something to be aware of.

Maple is very cohesive and sometimes jointing or planing will tend to produce chip-out in areas where the grain does not cooperate. Running a damp sponge over the wood just before jointing / planing often helps, and watching the feed direction can be critical.

Being so dense, it can be work to sand it out. A sharp plane or cabinet scraper can help get closer first.

Splines, according to USPL, may actually reduce the strength of an edge glued joint. Your joint should be plenty strong, enough to tolerate this. The major advantage, if done carefully is alignment. If not done carefully it's dis-alignment.

Here is a link that might be useful: See p. 9-18

I'm confused. The link you provided seems to be a construction related source. And all I can find on the USPL is it is plastic lumber.

What I have learned about woodworking and furniture making is much different than what I learned about construction.

In furniture making, which the OP's countertop is closer to, splines are one of the strongest joints as they effectively eliminate wood movement and actually increase glue surface.

I will agree when using normal construction or composite lumber, splined joints will be weaker.

Maple is not hard to work with and it glues up just fine as long as you mill a good joint, just like any other wood.

Splines and biscuits are an aligment aid in face gran joints.

They do not add appreciably to the strength, if at all.

A solid glue joint is already stronger than the wood itself.

Splines and biscuits ARE needed if you are trying to glue end grain. Either a direct end grain to end grain joint or end grain to long grain.

These are weaker joints and every little bit helps.

Hard Maple is only difficult to route with a profile bit. It is very prone to splintering and tear-out. I alwasy use spiral bits for flush trimming. But if you are doing a profile- like a bullnose edge or an ogee, this takes some practice and patience. Many woodworkers make several passes, lowering the router bit a little more each time. I like to run the router backwards for the first passes, but this is dangerous if you don't have a strong grip on the router, since the cutter pulls in the same direction you are pushing. After the cut is made, go back in the right direction to clean up the edge. Done correctly this will eliminate splintering and tear out.

Also be extremely careful hand sanding the finished piece of Maple. The splintering can really catch you by surprise. I've gotten Maple splinters over an inch long embedded in my palm. Not fun.

Purchased a 22' shuffleboard,it was damaged when removed.A 1" deep x 1/2" wide x4" piece was chipped off edge. I was going to router and glue a new piece of maple, but was wondering if I should dowel it and put screws in it. I would also like to know which type of glue would be suitable and what kind of maple is generaly used so I can match the woods up.