Full Range of Process Transitions for Original Equipment or Retrofit Powder Bulk Solid: Vessels, Valves, Screeners, Mixers and Piping
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Have you ever been frustrated with process transition fabrication?
It seems easy, but material thickness, flange precision and overall lengths can all affect outcome. Many times the transition isn’t specified properly or the fabricator doesn’t understand the end result that is needed. Roto-Disc has taken all of the hassle out of precision standard transitions that install just as expected, right out of the box.
A process industry first from the “When-All-Else-Fails” valve company.
Now the power bulk engineering industry has a stock selection of process transitions for the installation of new or retrofit equipment. A complete range of square or round flange dimensions and diameters is available.
Flangeless transitions are also included.
Custom sizes, materials and surface finishes.
The following pages outline many sizes, material thicknesses and end types, but they’re only the start of our capacity to customize your specific process transition. Special dimensions, stainless steel and alloys materials, food-grade surface polishes, shot blast or polymer coatings can be added.

Surface Finish Options
- Polishing/Electro-polishing
- Painting/Powder Coating
- Hardfacing
- Coatings, Platings
- Bead blasting
Sanitary Clamp Ferrule Connections

* To indicate duty grade and material preference add the following to the end of each part number: 1) Duty Grade: L = Light; M = Medium; H = Heavy; 2) Material: 304 = CF8; 316 = CF8M; MST = Mild Steel
Part Number Example: RS-F-03-316 = ( Round Stub to Ferrule, 3”, 316 Stainless Steel )
RS-F
Round Stub to Ferrule
Part No |
A Min. |
B |
C |
D |
RS-F-03-XXX |
2.00” |
2.870” |
#16ga (.0598”) |
3.00” |
RS-F-04-XXX |
2.00” |
3.834” |
#14ga (.0747”) |
4.00” |
RS-F-06-XXX |
2.00” |
5.782” |
#11ga (.1196”) |
6.00” |
RS-F-08-XXX |
2.00” |
7.782” |
#11ga (.1196”) |
8.00” |
RS-F-10-XXX |
2.00” |
9.732” |
#11ga (.1196”) |
10.00” |
RS-F-12-XXX |
2.00” |
11.732” |
#11ga (.1196”) |
12.00” |
RF-F
Round Flange to Ferrule
Part No. |
E |
F |
G |
H |
J |
RF-F-03-XXX |
7.50” |
3” |
.75” |
4 |
6.00” |
RF-F-04-XXX |
9.00” |
4” |
.75” |
8 |
7.50” |
RF-F-06-XXX |
11.00” |
6” |
.75” |
8 |
9.50” |
RF-F-08-XXX |
13.50” |
8” |
.75” |
8 |
11.75” |
RF-F-10-XXX |
16.00” |
10” |
1.00” |
12 |
14.25” |
RF-F-12-XXX |
19.00” |
12” |
1.00” |
12 |
17.00” |
Round to Reduced Round Transition (RRR)

* To indicate duty grade and material preference add the following to the end of each part number: 1) Duty Grade: L = Light; M = Medium; H = Heavy; 2) Material: 304 = CF8; 316 = CF8M; MST = Mild Steel
Part Number Example: RRR-SE-03-L-316 = (Round to Reduced Round, Stub End, 3”, Light Duty, 316 Stainless Steel)
RRR-SE
Round to Reduced Round, Stub Ends
Part No |
A Min. |
B |
C |
RRR-SE-03-XXX |
2.25” |
3.00” |
2.00” |
RRR-SE-04-XXX |
3.00” |
4.00” |
3.00” |
RRR-SE-06-XXX |
4.50” |
6.00” |
4.00” |
RRR-SE-08-XXX |
6.00” |
8.00” |
6.00” |
RRR-SE-10-XXX |
7.50” |
10.00” |
8.00” |
RRR-SE-12-XXX |
9.00” |
12.00” |
10.00” |
RRR-SF
Round to Reduced Round, Small Flange
Part No. |
D |
E |
F |
G |
H |
RRR-SF-03-XXX |
6.00” |
2” |
.75” |
4 |
4.75” |
RRR-SF-04-XXX |
7.50” |
3” |
.75” |
4 |
6.00” |
RRR-SF-06-XXX |
9.00” |
4” |
.75” |
8 |
7.50” |
RRR-SF-08-XXX |
11.00” |
6” |
.75” |
8 |
9.50” |
RRR-SF-10-XXX |
13.50” |
8” |
.75” |
8 |
11.75” |
RRR-SF-12-XXX |
16.00” |
10” |
1.00” |
12 |
14.25” |
RRR-LF
Round to Reduced Round, Large Flange
Part No. |
J |
K |
L |
M |
N |
RRR-LF-03-XXX |
7.50” |
3” |
.75” |
4 |
6.00” |
RRR-LF-04-XXX |
9.00” |
4” |
.75” |
8 |
7.50” |
RRR-LF-06-XXX |
11.00” |
6” |
.75” |
8 |
9.50” |
RRR-LF-08-XXX |
13.50” |
8” |
.75” |
8 |
11.75” |
RRR-LF-10-XXX |
16.00” |
10” |
1.00” |
12 |
14.25” |
RRR-LF-12-XXX |
19.00” |
12” |
1.00” |
12 |
17.00” |
RRR-BF
Both Flanges
Part No. |
RRR-BF-03-XXX |
RRR-BF-04-XXX |
RRR-BF-06-XXX |
RRR-BF-08-XXX |
RRR-BF-10-XXX |
RRR-BF-12-XXX |
Material Thickness: Light: #14ga = .0747” Medium: #11ga = .1196” Heavy: #7ga = .1793”
Square to Reduced Square Transition (SRS)

* To indicate duty grade and material preference add the following to the end of each part number: 1) Duty Grade: L = Light; M = Medium; H = Heavy; 2) Material: 304 = CF8; 316 = CF8M; MST = Mild Steel
Part Number Example: SRS-SE-03-L-316 = (Square to Reduced Square, Stub End, 3”, Light Duty, 316 Stainless Steel)
SRS – SE
Square to Reduced Square, Stub Ends
Part No |
A Min. |
B |
C |
SRS-SE-03-XXX |
2.25” |
3.00” |
2.00” |
SRS-SE-04-XXX |
3.00” |
4.00” |
3.00” |
SRS-SE-06-XXX |
4.50” |
6.00” |
4.00” |
SRS-SE-08-XXX |
6.00” |
8.00” |
6.00 |
SRS-SE-10-XXX |
7.50” |
10.00” |
8.00” |
SRS-SE-12-XXX |
9.00” |
12.00” |
10.00” |
SRS-LF
Square to Reduced Square, Large Flange
Part No. |
D |
E |
F |
G |
SRS-LF-03-XXX |
6.00 |
2.62” |
.44” |
8 |
SRS-LF-04-XXX |
7.00” |
3.12” |
.44” |
8 |
SRS-LF-06-XXX |
9.00” |
4.00” |
.44” |
8 |
SRS-LF-08-XXX |
12.00” |
3.62” |
.62” |
12 |
SRS-LF-10-XXX |
14.00” |
4.25” |
.62” |
12 |
SRS-LF-12-XXX |
17.00” |
5.12” |
.62” |
12 |
SRS-SF
Square to Reduced Square, Small Flange
Part No. |
J |
K |
L |
M |
SRS-SF-03-XXX |
4.00” |
1.62” |
.31” |
8 |
SRS-SF-04-XXX |
6.00” |
2.62” |
.44” |
8 |
SRS-SF-06-XXX |
7.00” |
3.12” |
.44” |
8 |
SRS-SF-08-XXX |
9.00” |
4.00” |
.44” |
8 |
SRS-SF-10-XXX |
12.00” |
3.62” |
.62” |
12 |
SRS-SF-12-XXX |
14.00” |
4.25” |
.62” |
12 |
SRS-BF
Both Flanges
Part No. |
SRS-BF-03-XXX |
SRS-BF-04-XXX |
SRS-BF-06-XXX |
SRS-BF-08-XXX |
SRS-BF-10-XXX |
SRS-BF-12-XXX |
Material Thickness: Light: #14ga = .0747” Medium: #11ga = .1196” Heavy: #7ga = .1793”
Round to Reduced Square Transition (RRS)

* To indicate duty grade and material preference add the following to the end of each part number: 1) Duty Grade: L = Light; M = Medium; H = Heavy; 2) Material: 304 = CF8; 316 = CF8M; MST = Mild Steel
Part Number Example: RRS-SE-03-L-316 = (Round to Reduced Square, Stub End, 3”, Light Duty, 316 Stainless Steel)
RRS-SE
Round to Reduced Square, Stub Ends
Part No |
A Min. |
B |
C |
RRS-SE-03-XXX |
2.25” |
2.00” |
3.00” |
RRS-SE-04-XXX |
3.00” |
3.00” |
4.00” |
RRS-SE-06-XXX |
4.50” |
4.00” |
6.00” |
RRS-SE-08-XXX |
6.00” |
6.00” |
8.00” |
RRS-SE-10-XXX |
7.50” |
8.00” |
10.00” |
RRS-SE-12-XXX |
9.00” |
10.00” |
12.00” |
RRS-RF
Round to Reduced Square, Round Flange
Part No. |
D |
E |
F |
G |
H |
RRS-RF-03-XXX |
7.50” |
3” |
.75” |
4 |
6.00” |
RRS-RF-04-XXX |
9.00” |
4” |
.75” |
8 |
7.50” |
RRS-RF-06-XXX |
11.00” |
6” |
.75” |
8 |
9.50” |
RRS-RF-08-XXX |
13.50” |
8” |
.75” |
8 |
11.75” |
RRS-RF-10-XXX |
16.00” |
10” |
1.00” |
12 |
14.25” |
RRS-RF-12-XXX |
19.00” |
12” |
1.00” |
12 |
17.00” |
RRS-SF
Round to Reduced Square, Square Flange
Part No. |
J |
K |
L |
M |
RRS-SF-03-XXX |
4.00” |
1.62” |
.31” |
8 |
RRS-SF-04-XXX |
6.00” |
2.62” |
.44” |
8 |
RRS-SF-06-XXX |
9.00” |
4.00” |
.44” |
8 |
RRS-SF-08-XXX |
12.00” |
3.62” |
.44” |
8 |
RRS-SF-10-XXX |
14.00” |
4.25” |
.62” |
12 |
RRS-SF-12-XXX |
17.00” |
5.12” |
.62” |
12 |
RRS-BF
Both Flanges
Part No. |
RRS-BF-03-XXX |
RRS-BF-04-XXX |
RRS-BF-06-XXX |
RRS-BF-08-XXX |
RRS-BF-10-XXX |
RRS-BF-12-XXX |
Material Thickness: Light: #14ga = .0747” Medium: #11ga = .1196” Heavy: #7ga = .1793”
Square to Reduced Round Transition (SRR)

* To indicate duty grade and material preference add the following to the end of each part number: 1) Duty Grade: L = Light; M = Medium; H = Heavy; 2) Material: 304 = CF8; 316 = CF8M; MST = Mild Steel
Part Number Example: SRR-SE-03-L-316 = (Square to Reduced Round, Stub End, 3”, Light Duty, 316 Stainless Steel)
SRR – SE
Square to Reduced Round, Stub Ends
Part No |
A Min. |
B |
C |
SRR-SE-03-XXX |
2.25” |
3.00” |
2.00” |
SRR-SE-04-XXX |
3.00” |
4.00” |
3.00” |
SRR-SE-06-XXX |
4.50” |
6.00” |
4.00” |
SRR-SE-08-XXX |
6.00” |
8.00” |
6.00” |
SRR-SE-10-XXX |
7.50” |
10.00” |
8.00” |
SRR-SE-12-XXX |
9.00” |
12.00” |
10.00” |
SRR-RF
Square to Reduced Round, Round Flange/Sq Flange
Part No. |
D |
E |
F |
G |
H |
SRR-RF-03-XXX |
6.00” |
2” |
.75” |
4 |
4.75” |
SRR-RF-04-XXX |
7.50” |
3” |
.75” |
4 |
6.00” |
SRR-RF-06-XXX |
9.00” |
4” |
.75” |
8 |
7.50” |
SRR-RF-08-XXX |
11.00” |
6” |
.75” |
8 |
9.50” |
SRR-RF-10-XXX |
13.50” |
8” |
.75” |
8 |
11.75” |
SRR-RF-12-XXX |
16.00” |
10” |
1.00” |
12 |
14.25” |
SRR-SF
Square to Reduced Round, Both Flanges
Part No. |
J |
K |
L |
M |
SRR-SF-03-XXX |
6.00” |
2.62” |
.44” |
4 |
SRR-SF-04-XXX |
7.00” |
3.12” |
.44” |
8 |
SRR-SF-06-XXX |
9.00” |
4.00” |
.44” |
8 |
SRR-SF-08-XXX |
12.00” |
3.62” |
.62” |
12 |
SRR-SF-10-XXX |
14.00” |
4.25” |
.62” |
12 |
SRR-SF-12-XXX |
17.00” |
5.12” |
.62” |
12 |
SRR-BF
Both Flanges
Part No. |
SRR-BF-03-XXX |
SRR-BF-04-XXX |
SRR-BF-06-XXX |
SRR-BF-08-XXX |
SRR-BF-10-XXX |
SRR-BF-12-XXX |
Material Thickness: Light: #14ga = .0747” Medium: #11ga = .1196” Heavy: #7ga = .1793”
Square to Round Transition (RS)

* To indicate duty grade and material preference add the following to the end of each part number: 1) Duty Grade: L = Light; M = Medium; H = Heavy; 2) Material: 304 = CF8; 316 = CF8M; MST = Mild Steel
Part Number Example: RS-SE-03-L-316 = (Round to Square, Stub End, 3”, Light Duty, 316 Stainless Steel)
RS-SE
Round to Square, Stub Ends
Part No |
A Min. |
B |
C |
RS-SE-03-XXX |
2.25” |
2.00” |
2.00” |
RS-SE-04-XXX |
3.00” |
3.00” |
4.00” |
RS-SE-06-XXX |
4.50” |
4.00” |
6.00” |
RS-SE-08-XXX |
6.00” |
6.00” |
8.00” |
RS-SE-10-XXX |
7.50” |
8.00” |
10.00” |
RS-SE-12-XXX |
9.00” |
10.00” |
12.00” |
RS-RF
Round to Square, Round Flange
Part No. |
D |
E |
F |
G |
H |
RS-RF-03-XXX |
7.50” |
3” |
.75” |
4 |
6.00” |
RS-RF-04-XXX |
9.00” |
4” |
.75” |
8 |
7.50” |
RS-RF-06-XXX |
11.00” |
6” |
.75” |
8 |
9.50” |
RS-RF-08-XXX |
13.50” |
8” |
.75” |
8 |
11.75” |
RS-RF-10-XXX |
16.00” |
10” |
1.00” |
12 |
14.25” |
RS-RF-12-XXX |
19.00” |
12” |
1.00” |
12 |
17.00” |
RS-SF
Round to Square, Square Flange
Part No. |
J |
K |
L |
M |
RS-SF-03-XXX |
6.00” |
2.62” |
.44” |
8 |
RS-SF-04-XXX |
7.00” |
3.12” |
.44” |
8 |
RS-SF-06-XXX |
9.00” |
4.00” |
.44” |
8 |
RS-SF-08-XXX |
12.00” |
3.62” |
.62” |
12 |
RS-SF-10-XXX |
14.00” |
4.25” |
.62” |
12 |
RS-SF-12-XXX |
17.00” |
5.12” |
.62” |
12 |
RS-BF
Both Flanges
Part No. |
RS-BF-03-XXX |
RS-BF-04-XXX |
RS-BF-06-XXX |
RS-BF-08-XXX |
RS-BF-10-XXX |
RS-BF-12-XXX |
Material Thickness: Light: #14ga = .0747” Medium: #11ga = .1196” Heavy: #7ga = .1793”