Originally Posted by 
AK83
				 
			special tool (LR type) is a bar with a 'barrel' type fixture where it bolts up to the HB.
it's a rim shaped barrel tho, where you bolt the four outer rim bolts to the HB, and the centre void allows you to use a socket on the HB bolt to do/undo it.
IIRC the HB bolt, when doing it up, is 90Nm then 90° more to finalise it. And if you don't do it up enough, HB will come loose at some point. 
This coming from experience.
Instead of just getting the tool, or making up a proper tool, I made a weak as peace flat steel angled bar. had a angle cut at the HB side to allow 2(of the 4) bolts onto the HB and the V shape allowed access to the HB bolt.
As I tightened it up for the 90° part of the final install, my weak welding snapped, and HB rotated. I thought I got close enough to the 90° setting, but about 2weeks later HB slowly spun off the crank. 
After that debacle I bought a crank holding tool off ebay ... wasn't stupid expensive like some 'pattern' tools can be, I think just over $100 or so. nice and solid and hasn't broken the 3 times I've used it. 
Nice to have when undoing, but not necessary, as there are many ways to undo the bolt, but (from my experience) requirement to do HB bolt properly without risking issues.
If you're good at welding and have access to materials, you can easily make up a holding tool yourself. 
if you're looking to buy a tool, note that it supposedly fits some Jags too. That's how mine was advertised on ebay.