Are They Necessary?
Are rings actually needed? I read somewhere they were used back when shells were steamed for reinforcement.

Needed? No, not really. It is a matter of choice. Now, bearing in mind that Keller six ply shells are on the thin side as far as industry standards are concerned (and not that this is a bad thing, mind you, you might consider them). Rerings do change the fundamental pitch of the shell, so I hear, but not necessarily in a bad way. I chose to apply them because 1) I went with six ply shells and 2) many very good drums have rings on them, DW's included.

In the old days, shells were thinner and didn't stay in round as well as they do today, so the re-ring was used to help maintain roundness. I lot of great sounding drums were made this way.
Modern shells tend to be thicker and stay in round better, so generally they are not needed. So now you can make the choice based on sound rather than drum strength.

Just a note that I have a kit of 6 ply kellers with no re rings that are holdin up great.

Better glue and better construction methods have both improved shell stability. From my personal experience, I would feel the need to re-ring a 6 ply but not necessarily an 8 ply. 6 ply will still flex when you press on the sides, and I just don't like that. It feels and looks cheap imo.

Yup, I know exactly what you mean. Plus, I just like the sound of thinner shells with rerings. And of course, we haven't even touched on the issue of plies not all being the same thickness. But your point is clear enough without going into that area.

I've built 8ply kits, 6ply and even 5ply kellers and have never used re-ring. The 5ply (has a 7ply bass) was the for a buddy and I play that kit every time I'm at his house and it sounds great!!! The 13x16 floor tom sounds killer with the 5ply shell.
Ayotte uses 5ply shells with 3ply re-rings on their toms and those things sing.

How Do You Install Them?
Does anyone have a "How-To" Guide on installing reinforcement rings on drum shells?

HOLD THE PHONE . . . . It's too early in the morning, I think I just found that Drum Foundry answered my question for me . . .

Reinforcement ring stock is for gluing in your own reinforcement ring to a drumshell. Cut the ring with a straight or angled cut and slowly remove material until the ring fits snugly inside the shell with no gap at the joint. Choose from 1" wide, 1 1/4" wide, and 1 1/2" wide. Our rings are sanded dimensionally accurate and flat in our wide-belt sander before shipping.

So, I guess my next question would be . . . .

Has anyone installed their own re-rings, and what type of glue does one use to do it?

Also, do you install the re-rings before you cut the bearing edges for the drum ??

Some people even sand the excess, as opposed to cutting it.
Regular wood glue would appear to work just fine, providing you are using an adequate amount of clamps around the circumference of the shell. You would wait to cut bearing edges until after the ring is applied and dry, as the ring would comprise the inside part of the bearing edge at this point.

I did re-rings on my first build very much the way described above, one of the few things on my first build that actually turned out the way I intended. I did have to use all the clamps I could find, I think about 18, to "snug" up the re-ring. I used excess material cut from the bass shell for the rings, and cut them 2-3 times with 45 degree cuts to lap till they fit tight. So ended up with 8-ply shell with 8-ply 1 1/4" re-rings.

Where Can You Get Them?
Where can one obtain thinner ply rings to use?

For my acoustic kit project, my goal is to take the best of my favorite professional kits and use as many of the techniques/methods into creating my "dream" kit.

In the case of re-rings, I have always loved the way DW drums sound, and (in addition to the shell material and bearing edges), DW utilizes re-rings on the majority of their maple drums. However, when I have looked more closely at DW drums at music stores, the re-rings do not appear all that thick. In other words, it doesn't appear that they simply take a left-over from an 8-ply shell and glue it in there - for what would essentially be a 16-ply rim/edge. Rather, DW's re-rings appear to be only 2 or 3 ply. I've been told that DW shells are 7 ply w/ 3 ply re-rings.

I am no expert, but if you are thinking in terms of an eight ply shell, adding a five ply ring makes 13 plys that will extend at least one inch down. That would seem like some serious thickness at the ends of that shell.
I would consult Andy at drumsupplyhouse or perhaps Eric at Drum Foundry.

Jaye: sells maple re-rings cut to various ply's not listed on their website, but if you call their telephone number or e-mail 'em, they will sell you some.
I have used Gorilla Glue...insane ?....I really like that stuff.

Read the part of this site on glue. There are a number of reasons why Titebond III is the best choice for drum building.

I talked to Andy and was told the cost is 0.40 an inch in diameter (14" drum .40x14=$5.60). He also told me that you have a choice of ply count depending on stock. I am doing a 14"x8" snare w/10 ply rings for a friend and found him very helpful.

From the DW website:

Tom Ply Composition:
8-13" -- 6-ply shell, 3-ply reinforcing hoops
13-18" -- 7-ply shell, 3-ply reinforcing hoops

Bass Drum Ply Composition:
All are 7-ply shell, 3-ply reinforcing hoops

Snare Drum Ply Composition:
10-ply shell, 6-ply reinforcing hoops
6-ply shell, 6-ply reinforcing hoops

...but please don't forget that ply count isn't the real relevance with drumshells - it's overall thickness! For example, Gheeleys 24ply snare shells are thinner than Pearls 10ply ones... and I know which I'd rather have!

make sure you apply all your clamps EVERY TIME you test fit, patience.............

Actually, that is a VERY good point. With the first shell I started on, I kept cutting down the ring until it snapped into place and then tried to clamp. Well, doing it that way, you come to realize that when you clamp the ring to the shell, you have just created a BIG gap in the seam. That one is a do-over for sure. Also, the glue itself adds a big of circumference to the equation, as the glue joint itself does have some thicknes to it.

Also, while I am certainly far from accomplished on this, I would also recommend on bigger shells (say 14" and above) to make sure that, once you have applied the glue to ring and shell, put the ring into place and begin clamping, that you do so in a circular direction, as opposed to beginning clamping at say, 3 o'clock, 6 o'clock, 9 o'clock, etc. The bigger the shell, the more room there is for additional gapping if you don't keep applying the clamps close together.

It is easiest to do re-rings on a band saw or scrolling saw. A table saw is trickier, and don't forget "the danger factor". A decent scrolling saw can be had for about $100. A bench mounted combination belt/disc sander for about the same money. A bench mounted belt sander with an 80 grit belt will make short work of a ring, even if you just do the intial cut to set the angle, and grind down the rest.