If both the headstock and tailstock (and all of the indexing gears) for the mill's M1-200 Horizontal Indexer are present, that's typically a $200-$300 set if sold by itself. My MFA came with the set and I figured the cost as $150.
Background on the Atlas mills.
The mill was first offered in 1940. There were three models, the basic M1 (not Mi, although that is a common error), which was the basic mill with manual table feed, the MF which added power feed for the table, and the MH, which still had hand wheel and feed screw drive to the IN-OUT saddle but had lever feed on the table and the lift. This were all 16 speed machines.with 4-step countershaft and spindle pulleys, plus 2-speed motor drive and 2-speed back gears (4 x 2 x 2 = 16). The second models, made from about late 1942 through late 1944 were M1A, M1F and M1H with 12 speeds (3-step pulleys on the countershaft and spindle). The third models were M1B, MFB and MHB, made 1945 until maybe 1947. And the fourth and final models were M1C, MFC and MHC. These last six were all 8 speed, with 2-step countershaft and spindle pulleys. The C models were made up until about 1960. There are several differences between the B and C models but the only readily apparent one is that the C models have an auxiliary arbor support bar on the front of the machine and not having the cutter guard on top of the arbor support rod or bar.
If the mill that you are looking at has M1 stamped on the name plate, it may be either an M1 or an M1A, depending upon serial number. Atlas didn't start calling them A-models until they came out with the B model. They can usually be ID'd by having 3-step pulleys or by the serial number being between 1345 and 5465. Although there have been two reports of MF's with serial numbers below 1345 having 3-step pulleys. It is assumed that these were probably converted for some reason, maybe parts availability.
In the next paragraph "*" means any of the four model letter suffixes (blank through C).
The main purpose of writing all of the above was to get around saying that the M1 through M1C are generally valued at about 2/3 of what the MF through MFC are. Although the original price of the M!* was lower than that of the MF*, Atlas must have sold far more MF*'s than M1*'s or MH*'s as the majority of machines that turn up are MF*s. Although an M1* can be converted into an MF* by adding the missing parts, about the only way it would be practical would be to find an MF* of the same model letter suffix (blank through C) that had most or all of the necessary parts but was for some reason cheap.
