I get my rivets and dies from Hanson Rivets....

http://www.hansonrivet.com/

Generally the rivets used on pinballs are 1/8" diameter, semi-tubular, oval head in varying lengths. There are several materials but I use steel rivets. The sizes I stock (and the Hanson stock numbers) are

3/16" (C-6-ST)
7/32" (C-7-ST)
1/4" (C-8-ST)
9/32" (C-9-ST)
5/16" (C-10-ST)

I purchase these rivets in lots of 100 and they are around $0.06 per rivet.

I have a rivet press but also use a hand held roll over die since the press can't always reach. This hand held (HT-174) could be used for all 1/8" riveting of semi-tubular rivets... Rivet head just needs to be supported on a very hard surface. I have even taken a 3/8" bolt and cupped the bottom to support the rivets while hammered.

The hand held roll over die can be found here...

http://www.hansonrivet.com/tools-machines/solid-rivet-tools-machines/hand-rivet-clinchers/

If you look at some of the stuff that is riveted on pinball machines...notably a ramp for instance...you will see that a hand squeezer will not be able to reach rivets in the bottom of the ramp. I do not own a hand squeezer and see no need to have one. You will be much better off with a rivet press like the one shown here...

http://www.pinrestore.com/Riveting.html

I built my own for around $100 with a Harbor Freight arbor press.

The arbor press and the hand held roll over die can handle pretty much anything on a pinball.

I did leave the "1" off my rivet types in error, but I do not see where they have discontinued any sizes. Did you try calling them?

On the product list they show a red asterisk. You simply add the length there to your order. All lengths are in 1/32"...So a 9/32" length would obviously be a 9... A 1/4" length would be an 8, a 3/16" would be a 6, etc.

Be sure you order some washers as well. Whenever the rolled over portion of a rivet would be in direct contact with plastic, you need to use a washer.

I stock basically 2 sizes of washers:

BUP-4S (Use this one the most)
WS-0808

I don't even use the second half of the die (the die that holds the head of the rivet). In my arbor press I use a 5/16" bolt with the bottom ground into a cup to support the rivet head. When I use the hand held die I put a similar bolt in my vise and then just hammer the rivet. Sometimes I just position the piece I am riveting over one of the vise jaws and hammer away. I posted a short video of me using the hand held roll over die here...

https://pinside.com/pinball/forum/topic/swords-of-fury-custom-ramps/page/8

If you aren't going to do a lot of riveting, the hand held tool could be used for everything.

I do a lot of disassembly of old ramps to put parts onto new ramps. Generally I've seen both nickel plated steel and nickel plated brass. I use steel rivets for what I do. The plated brass rivets require less pressure to crimp and are easier to remove than the steel rivets.