In my experience, finding any complete treadle lathe, scroll saw, table saw, etc., is fairly hard and getting more so every day.
Barnes was the largest mfg of foot powered machinery and the 4 1/2 was their smallest true screw cutting metal lathe. It went for about $65 with tooling (no chuck) when it was introduced in 1900. It has a 9 in swing and could be obtained in both treadle and velocipede versions. Barnes said it could reach a high enough speed to be good for turing wood and actually offered a specail tool rest for wood turing. It was also offered in a bench top version as well as standard floor mounted version that could be driven via a line shaft. Transporting it was not that big of a problem especailly when the flywheel is removed. It is the lathe that shows up the most. Think all of this lead to its popularity.
The lathe without the foot powered parts is not of much use unless you need a part like a leg or bed especially if there are no change gears. Reproduction parts are expensive especially when you consider the machining cost, transportation and the trouble you have to go to get them cast. (been there and done that) And of course, the parts that are typically missing are the change gears and the foot powered parts. From my experience, I see several or more that are missing the foot powered parts for every one I see complete and I don't see many of them at all.
Yes, you may stumble on one that has been in somebody's basement or garage but the odds of it being complete and not broken are fairly slim at least in my experience.
If you are looking for one that is complete, no cracks or welds, has the change gears, steady rest, no missing gear teeth, you are probably looking at about $1500 as Barnes seems to be the most sought after foot powered metal lathe.
I have plans for a website dedicated entirely to footpowered machinery as soon as my son gets the basic software loaded. Plan to show a number of foot powered metal lathes as well as a wide selection of scroll saws, etc. Will post the address when it has something other than a welcome page available.
I just love foot powered machinery..
Thanks Ed
PS.. Always looking for an old, open frame bandsaw where the lower wheel is much heavier than the top wheel or simply a true foot powered bandsaw. Parks made them for Sears as well as other companies like Crescent.
PPS.. I have seen one of the #13's that was true treadle (not velocipede) that had the riser blocks that took it to a 17 in swing as I remember. She was a sweet running machine but very, very heavy. Think the flywheel alone was heavier than the entire 4 1/2. Took two people to put it off an on.