You need a base for it, like the bottom on the bent wood cases. Model 66 doesn't have anything to stand on under the base, and the moving parts under the feed dogs and bobbin case will be straight on the table. There are more or less fancy bases for the old machines, and you can have one made. A brand new
nice one cost a bit, it's up to the standard of the old Singer bases. You can make a good one your self too, or if you know someone who as the tools. The most cost efficient is to keep the treadle table, it works very well and gives a very good works space in line with the flat bed of the machine. Finding another 66 or 15 in a case with motor and light will probably be just as good an option.