Had a quick measure. Small disc is 230mm bolt centres and 260mm on the big ones. Looks like its 280 over all on the smaller disc and the 257 could be bolt centres on the larger one. Confusion??
Like i said the oval disc does not really work on the older utilitys. The later utilities with the power torque had the handle mounts extened forward past the front of the engine so that the blade disc would miss them.
Ive tried trimming a power torque disc (because i only had short blades at the time) and im sure it would have worked if id had a way to ballance the disc.
I fished these out of the scrap pile and took a pic
Then went back out grabbed a couple more and some blades and took another pic.
(had to upload on image shack as the site loader was not working, messed about for ages with no joy, if we could fix that this might make a good stick post) ((now the code wont show it, click the link to see the pic)
http://imageshack.us/photo/my-images/222/blades004.jpg/ [img]
http://imageshack.us/photo/my-images/222/blades004.jpg/[/img]
Top Left ive no idea, one only got the one, only ever seen the one and its had it. Stupid design, i can see by looking at it why its got those great big holes in it.
Top centre and right. Old style disc. These crack at the bottom of the step down at the back of the recess for the blades to swing back into. The ones with the vane/lip on the top are not so bad but they still do it. Bad design.
Centre right is the small utiliy disc that takes the long blades. These also crack inwards behind the blade. Need to be checked when changine blades. Id say age might have something to do with it.
Centre is the oval Power torque. Same bolt/blade spacing as the 3 discs at the top. Good design, never seen a cracked one.
Centre left is a masport disc, can be bought as a universal type. These are bigger than the large Victa disc so you need the propper 18" masport blades to use the disc on a Victa. Just so happens that baby bob blades are pretty easy to get and you can put 4 of them on.
Bottom left i think its a jetfast or similar same diameter as the masport/universal. Not sure what blades you would use, not very common blades.
Bottom right, early Victa, Blades sit on top, has blade bolts with a big square head. Not sure if there were utility type blades for this disc. I think there were as some versions of this disc had two blades top and two flat blades mounted underneath.
The blades sitting on the Power torque disc left to right, older utility, power torque utility (same length as the common victa rear catcher blades), baby bob.
Im not sure if the long utility blades are the same length as the 19" Victa ones.
Rear catcher baldes do not work very well on utiltiys anyway.
Dont think ive missed any.
All in all its not that complicated, well not as bad as the rovers.
Bob.