Mysterious bottom bracket format...
 

I'm trying to overhaul the bottom bracket on my 80's Ross, but the bracket doesn't look like any other example I can find on the internet. It's made by Hatta, and has 2 large square notches that are flush with the spindle. I imagine I'll need to buy some sort of special tool, but Park Tools doesn't have one on their website that appears to be made for this; just the pin wrench which appears to be too small to get firm leverage. Any idea how this should be removed?

pics might help

It's called a cottered bottom bracket. Common on low end bikes of the time.

I've never worked on one, but try following this:
http://sheldonbrown.com/tooltips/cotters.html

http://www.flickr.com/photos/22990696@N07/3631043114/

There's an image of the bracket, apologies for the glare.

That's the adjustable cup of a cup and cone bottom bracket. A pin spanner will do the trick for removing, installing, and adjusting it. It looks like you're missing the lock ring, unless you took that off before. Here are instructions for maintenance on that type of bottom bracket.

There are special tools for these but on the adjustable side you can get away with using the pin spanner as Cuevelo said. It might take a bit of trial and error to get it adjusted just right since you might not be able to hold it completely still while you tighten the lock ring but it is manageable.

The slots look they may be the same as one of the old free-wheel removal tools such as Regina (Park Tool FR-2)

If you can't find the proper tool, it shouldn't be too hard to whang the cup off with a screwdriver and mallet, then replace with a modern sealed model.

I use a hammer and drift on those.
Its fairly easy to hold it still with a screwdriver while tightening the lock ring.

The VAR #311 tool was designed for that cup. I've never had much luck with a pin spanner; the slots are too wide to allow the pins to grip well. If there's any corrosion the pins won't stay in the slots.

You guys've been a great help, thanks for all the insight. I picked up a pin spanner, and as JohnDThomspon said, it was a big, slippery fail. I ended up using a blunt-tipped screwdriver and hammer to loosen it, until it was loose enough for the pin spanner to turn without problems. The reason I was pulling it off was because the spindle couldn't be turned by hand without the leverage of a crank arm, and had a bad grinding feel; luckily, it was just too tight, and the insides weren't that dirty or gritty.

It never ceases to amaze me when newbies don't know what a cottered crank is. I mean no offense to you, Josh, and you should not take any.

The thing is, there was a time, not so long ago, when that was basically the only way to attach a crank. It was just about all anyone had. They were as common as dirt. It just goes to prove how innovative and important the Campagnolo Record gear, including their crank set, really was. Now, a cotter is an anomaly and a crank bolt is as common as dirt.

Perhaps if Josh HAD a cottered crank he would recognize it. But as his question was regarding a BB with a nutted, square tapered spindle, we'll never know.

LOL!

I was reacting to Garthr's post:

A lot of cottered cranks have BB-cups similar to what the OP posted. Big needle-nose pliers work for me. Or in tough cases, screwdriver and hammer is the irresistible force...

Why? Cottered cranks disappeared from inexpensive bikes around 1980. That was before a lot of newbies were even born.

Hell, I wouldn't be amazed if you don't remember when cottered cranks were standard on first-rate bikes.

More LOL! I do.

I always thought steel chainrings were the way to go. Too bad everyone switched to aluminum. A replacement ring costs about $100 for me. Sometimes older things aren't so great.

I have had many a newb mechanic come in and be totally baffled by cottered cranks and had a few people tell me I should upgrade the cottered crank on my '55 Raleigh and '57 Peugeot.

I just don't see that happening.

As it happens, there's a VAR #311 on eBay right now. Probably a a little expensive for a one-off repair job, but if you plan on doing a lot of these types it may be worthwhile.

[N.B. no relation to seller; I just happened to notice it]