I need a bigger prop for my steam tug, it's working fine now but has plenty of torque for more prop, I need either a 3 or 4 blade brass prop with a threaded hole for a 1/8th inch shaft which is a dumas shaft, there 1.75 inch prop is only for 3/16th shaft which the stuffing tube wouldnt fit in the keel of my boat, so if I can find a 1.75 3 blade, or a 1.5-1.75 inch 4 blade for it Id be very happy, the engine is a wilesco dual action and will run either direction at the same speed so rotation is not a concern...a 1.75 4 would be the ideal, it would spin it. during a test run in the tub i could pull it backwards ad a good speed and the engine never slowed...I have the 1.5inch 3 blade at the moment...any help would be greatly appreciated

These seem to be metric threads tho...
http://www.model-dockyard.com/props/4bladem4.asp

Yeah, I found a bunch that are the right diameter, maybe buy the dumas prop for a 3/16th shaft, drill it through, mill the hub down and put a nut on either side of it, not like the steam engine generates enough power that it would ever slip...

still hard to believe no one makes one for a 1/8th shaft...

maybe you can buy a bushing (dumas makes one i think) or have it made from either a machine shop or by using brass tube of different sizes.

Loyalhanna Dockyard - Raboesch Prop, 3 blade, 45MM diameter, 1/8" diameter prop shaft, part number 176-07.

They didn't have any 4 blade props that could use the 1/8" prop shaft.

Their line of Prop Shop Props are made to order so you might could order a 45MM 4 blade prop threaded for a 1/8" prop shaft.

thanks man, really appreciate the help, I'll check into the 4 bladed one being made, that'd be a sweet setup on this boat, just gotta finish a few visual things up yet...It's not gonna be the most scale or detailed thing, but for being a scrath build with no plans it should be a nice boat, the engine is the cool part, and seing steam puff out the stack while its running...

Since steam engines are slow speed and have a lot of torque, you need a prop that has a pitch equal to the diameter ie: 1.75" diameter with a 1.75" pitch. Propshop has a whole list of props available. If you don't see exactly what you need in how they are set up for your shaft, give them a call. They will drill or tap a prop to whatever you need. They have done it for me several times.