A Guide to Illinois Watch Co. size 12 Watches, Grade 509.
Run.
Date
From
To
Total
H/O
Jls
Adj.
Run.
Date
From
To
Total
H/O
Jls
Adj.
1
1911
2,386,711
2,386,740
30
O
21
5 Pos.
12
1916
2,903,101
2,903,120
20
O
21
5 Pos.
2
1912
2,406,151
2,406,157
7
O
21
5 Pos.
13
1916
2,903,681
2,903,700
20
O
21
5 Pos.
3
1912
2,473,201
2,473,300
100
O
21
5 Pos.
14
1916
2,945,701
2,945,850
150
O
21
5 Pos.
4
1913
2,585,511
2,585,800
290
O
21
5 Pos.
15
1917
3,238,401
3,238,600
200
O
21
5 Pos.
5
1914
2,623,771
2,623,780
10
O
21
5 Pos.
16
1918
3,334,901
3,335,000
100
O
21
5 Pos.
6
1915
2,701,581
2,701,600
20
O
21
5 Pos.
17
1918
3,335,901
3,336,000
100
O
21
5 Pos.
7
1915
2,783,271
2,783,300
30
O
21
5 Pos.
18
1918
3,401,801
3,402,000
200
O
21
5 Pos.
8
1915
2,799,551
2,799,560
10
O
21
5 Pos.
19
1918
3,424,501
3,424,900
400
O
21
5 Pos.
9
1915
2,832,101
2,832,390
290
O
21
5 Pos.
20
1920
3,620,201
3,620,400
200
O
21
5 Pos.
10
1915
2,864,201
2,864,500
300
O
21
5 Pos.
21
1920
3,788,701
3,789,000
300
O
21
5 Pos.
11
1916
2,896,101
2,896,400
300
O
21
5 Pos.
  Total
3,077
 
Name
H/O
Estimate
Name
H/O
Estimate
Ariston USA [made for Marshall Field & Co. Chicago]
21 Jewels O.F.
20
Illinois Watch Co.
21 Jewels O.F.
690
Ariston Rated [made for Marshal Field & Co. Chicago]
21 Jewels O.F.
20
Hallmark [ made for United Jewellers ]
21 Jewels O.F.
1,650
Illinois  [The Springfield Watch]
21 Jewels O.F.
140
Precise
21 Jewels O.F.
50
Serial numbers used on this page by the kind permission of
Russell W Snyder
Grade 509 Movements found to date.
Grade 509 runs.
Last update 12/30/2015.
Grade 509,
21 diamond, ruby and sapphire jewels adjusted 5 positions, manufactured from 1911 to 1920 a total of 3,077 movements in 21 runs make up this
grade. Model 4 size 12/14 open faced; bridge movements of high quality, double roller and patent micrometric regulator.

Observations,
Most movements have a broad striped pattern demaskeening with the majority named Hallmark; Ariston, Ariston rated, Illinois and Illinois Watch Co.
make up the remainder. Precise have a spiral etched pattern. 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 and were cased at the factory. Hallmark watch were made
for United Jewellers, marked The Hallmark Watch on the cuvette. Ariston and Ariston rated watches were made for Marshall Field & Co. Chicago, have
Ariston marked cases with the M F & Co logo. The Illinois watches were advertised as part of "The Springfield Watch" series and have this on the
cuvette. I,m unsure if the Illinois Watch Co. models come under The Springfield Watch.

Variants,
Two types of escapement bridge can be found, the majority have the two fingered bridge, Ariston models have a full plate bridge.

Description,
21 extra quality diamond, ruby and sapphire jewels; gold settings; accurately adjusted to temperature, 5 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.
Image from run 4.