A Guide to Illinois Watch Co. size 12 Watches, Grade 510.
Run.
Date
From
To
Total
H/O
Jls
Adj.
Run.
Date
From
To
Total
H/O
Jls
Adj.
1
1911
2,386,741
2,386,760
20
O
23
6 Pos.
8
1915
2,832,391
3,832,400
10
O
23
6 Pos
2
1912
2,406,158
2,406,160
3
O
23
6 Pos.
9
1916
2,903,121
2,903,130
10
O
23
5 Pos.
3
1913
2,585,501
2,585,510
10
O
23
6 Pos.
10
1916
2,905,401
2,905,490
90
O
23
6 Pos.
4
1914
2,623,781
2,623,800
20
O
23
6 Pos.
11
1916
2,905,491
2,905,500
10
O
23
6 Pos.
5
1914
2,652,201
2,652,250
50
O
23
6 Pos.
12
1917
3,077,351
3,077,400
50
O
23
6 Pos.
6
1914
2,652,301
2,652,400
100
O
23
6 Pos.
13
1918
3,424,901
3,425,000
100
O
23
6 Pos.
7
1914
2,701,571
2,701,580
10
O
23
6 Pos.
 
Total
483
 
Name
H/O
Estimate
Name
H/O
Estimate
Ariston [Made for Marshall Field & Co. Chicago]
23 Jewels O.F.
30
Illinois  [The Springfield Watch]
23 Jewels O.F.
100
Ariston Rated [Made for Marshall Field & Co. Chicago]
23 Jewels O.F.
10
Illinois Watch Co.
23 Jewels O.F.
50
Hallmark [made for United Jewellers.]
23 Jewels O.F.
250
     
Grade 510 movements found to date.
Grade 510 runs.
Serial numbers used on this page by the kind permission of
Russell W Snyder
Last update 12/30/2015.
Grade 510,
23 diamond, ruby and sapphire jewels adjusted to 5/6 positions, manufactured from 1911 to 1918 a total of 483 movements in 13 runs make up this
grade. Model 4 size 12/14 open faced; bridge movements of the highest quality, with double roller and patent micrometric regulator.

Observations,
The majority of movements have broad striped pattern demaskeening named Hallmark and Ariston. The remainder are crosshatch pattern and named
Illinois and Illinois Watch Co. The size 12/14 movements have a size 12 bridges and size 14 pillar plate and have a stretched enamel dials that are not
recessed into the pillar plate, they require special cases. Hallmark models adjusted 6 positions marked on the pillar plate, with burnished set jewels, found
with Hallmark double sunk metal dials and have The Hallmark Watch on the case cuvette; Ariston USA and Ariston Rated models adjusted 5 & 6 positions
marked on the center bridge with screwed set jewels, Ariston double sunk enamel dials and Ariston marked cases with M F & Co: Illinois models adjusted
6 positions marked on the barrel bridge, with jewelled barrel marked on the pillar plate with screwed set jewels, the cases are marked The Springfield
Watch on the cuvette.

Variants,
Two types of escapement bridges can be found, most of the movements have a two fingered bridge except the Ariston models that have a full plate
escapement.

Description,
23 extra quality diamond, ruby and sapphire jewels; gold settings; accurately adjusted to temperature, five or six positions and isochronism; very carefully
timed; compensating balance having gold screws; steel escape wheel; double roller escapement; red ruby roller and pallet jewels; jeweled barrel; best
quality Breguet hairspring; Phillipe coil; patent micrometric screw regulator and first quality mainspring; unusually large dial is a special feature of the
watch all were factory cased.