Sheet Metal – Metric Gage Substitutions for Imperial Gage Sheets

In Europe and Asia, sheet metal stock is more commonly available in metric gage rather than imperial (used widely in the USA).  With the globalization of manufacturing, supply chain can span between multiple regions where availability of raw stock may be exclusively one type vs the other. This may present a particular challenge when components for a single assembly come from different regions.

With fabrications, designers may be able to allow “either/or” selection of raw stock, thus opening up the manufacturing options to all efficient regions of the world.  The following table is handy for designers and engineers who build manufacturing flexibility into their designs.

Imperial Gauge Imperial in mm Metric Sheet mm
10 3.25 3.0
12 2.64 2.5
14 2.03 2.0
16 1.63 1.5
18 1.22 1.2
20 0.91 0.9
22 0.71 0.7
24 0.56 0.6
26 0.46 0.5

Carbon Steel Grades Cross Index (Commercial Designations)

The following table is a list of carbon steels commonly used in industry, along with their alternate names and designations in their worldwide commercial use.

Material Code and Material Name Worldwide Commercial/Alternate Designations
1103, Carbon Steel T-1 T-1; T-1 Type A; T-1 Type B; USS T-1, T-1 Type A, T-1 Type B
1201, High Strength Steel 4130 4130; AISI 4130; SAE 4130; 4130H; UNS G41300, H41300
1203, High Strength Steel 4140 4140; AISI 4140; SAE 4140; 4140H; UNS G41400, J14046
1204, High Strength Steel 4330V 4330V; 4330; 4330 Mod; 4330V Mod; 4330V (Mod+Si); UNS J23260, K23080
1205, High Strength Steel 4335V Mod 4335V Mod; 4335 Mod; UNS K33517
1206, High Strength Steel 4340 4340; AISI 4340; SAE 4340; E 4340; 4340 H; UNS G43400
1207, High Strength Steel 52100 52100; E 52100; Teton (Allegheny-Ludlum)
1208, High Strength Steel 8630 8630; AISI 8630; SAE 8630; 8630H; UNS J13042, J13050, G86300
1209, High Strength Steel E9310 E 9310; SAE 9310; AISI E 9310 H; AMS 6260 E; UNS G93106
1210, High Strength Steel 17-22A(S) 17-22A(S); 17-22A(V); Uniloy 14 MV (Universal Cyclops designation for 17-22A(S))
1213, High Strength Steel D6A D6A; D6AC; UNS K24728, K24729
1214, High Strength Steel Hy-Tuf Hy-Tuf; UNS K32550
1215, High Strength Steel Nitralloy 135 Mod Nitralloy 135 Mod, Type G Mod; AMS 6470 Nitriding Steel; SAE 7140; UNS K24065
1216, High Strength Steel Hy-130/140 HY 130, 5Ni-Cr-Mo-V Steel; UNS K51255
1217, High Strength Steel 300M 300M; Tricent; 4340 Mod; UNS K44220, K44540
1218, High Strength Steel H-11 Mod H-11 Mod; AISI Type H-11; SAE Type H-11; UNS T20811; Al Tech Potomac A
1218, High Strength Steel H-11 Mod Carpenter No. 882; Chromo-V; Gutrel H-11; Hot Form No. 2
1220, High Strength Steel 18Ni (250) Maraging 18Ni 250 Grade Maraging Steel; UNS K92890, K92940; Almar 18 250; Marvac 250
1220, High Strength Steel 18Ni (250) Maraging Nimark 250; Udimar B-250; Vascomax 250
1221, High Strength Steel 9Ni-4Co 9Ni-4Co; HP-9-4-20; HP-9-4-30; UNS K91283
1223, High Strength Steel 18Ni (200) Maraging 18 Ni Maraging Steel; 18Ni-Co-Mo; 18Ni (200) Maraging; 18-8-3; Vascomax 200 CVM
1223, High Strength Steel 18Ni (200) Maraging RSM 200; Almar 18
1224, High Strength Steel AF1410 Unimach 1410; AF 1410
1225, High Strength Steel 18Ni (300) Maraging 18Ni Maraging Steel; 18Ni-Co-Mo; 18-9-5; Vascomax 300 CVM; RSM 300; Almar 18
1225, High Strength Steel 18Ni (300) Maraging Marvac 300; 18Ni (300) Maraging Steel; 300 Grade Maraging Steel
1225, High Strength Steel 18Ni (300) Maraging 18 percent Nickel Precipiation-Hardening Steel; Grade C-MAR-18-300
1226, High Strength Steel 9Ni Steel 9 Ni Steel
1227, High Strength Steel M50/M50NiL Steels M50: AISI M50; Carpenter VIM-VAR M-50 Bearing Steel
1227, High Strength Steel M50/M50NiL Steels M50: Latrobe CM-50 High Speed Steel; Latrobe Lescalloy M50 VIM-VAR Bearing Steel
1227, High Strength Steel M50/M50NiL Steels M50: Vasco M-50 High Speed Tool Steel; UNS T11350 (K88165)
1227, High Strength Steel M50/M50NiL Steels M50NiL: Latrobe CBS-50NiL VIM-VAR Carburizing Bearing and Gear Steel
1228, High Strength Steel Maraging T-250 Maraging T-250; Maraging MS 250; Maraging Free-Co
1229, High Strength Steel AerMet 100 AerMet 100; UNS K92580
1230, High Strength Steel H-13 H-13; H13; AISI H-13; Premium AISI H-13; ASTM H-13; SAE H-13; Material No. 1.2344
1230, High Strength Steel H-13 40CrMoV5; Cast Grade CH-13; GX40CrMoV5-1; X40CrMoV5; ESR H-13
1230, High Strength Steel H-13 8407 SUPREME, 8407 2M (Assab); Nu-Die V, Nu-Die XL, Nu-Die ESR (Crucible)
1230, High Strength Steel H-13 Orvar Superior, Orvar 2M, W302 SUPERIOR, ISOBLOC (Bohler-Uddeholm)
1230, High Strength Steel H-13 No. 883, Extendo-Die, Pyrotough 78 (Carpenter)
1230, High Strength Steel H-13 DH2F (International Mold Steel); MTEK T90813 (MetalTek)
1230, High Strength Steel H-13 THYROTHERM 2344 EFS, 2344 EFS SUPRA (ThyssenKrupp)
1230, High Strength Steel H-13 THYROTHERM 2367 SUPRA ESR, 2344 ESR MAGNUM (ThyssenKrupp)
1230, High Strength Steel H-13 VDC H-13, TLS H-13 PQ, LSS H-13, LSS H-13 PQ (Latrobe)

Sheet Metal Thickness Tolerances

What range of tolerances can we expect from standard steel sheet stock used in sheet metal fabrication? The main cause of variability in sheet stock thickness: during the rolling process that produces the sheet stock, a certain amount of “bowing” occurs in the rollers. This results in the sheet being slightly thinner at the edges than at the center of the sheet.

Gage Nominal Max Min 36” sheet 48” sheet
10 0.1345 0.1405 0.1285 0.006 0.009
11 0.1196 0.1256 0.1136 0.005 0.007
12 0.1046 0.1106 0.0986 0.004 0.006
14 0.0747 0.0797 0.0697 0.004 0.0055
16 0.0598 0.0648 0.0548 0.0035 0.005
18 0.0478 0.0518 0.0438 0.003 0.004
20 0.0359 0.0389 0.0329 0.002 0.003
22 0.0299 0.0329 0.0269 0.002 0.003
24 0.0239 0.0269 0.0209 0.0015 0.002
26 0.0179 0.0199 0.0159 0.0015 0.002
28 0.0149 0.0169 0.0129 0.0015 0.002

Depending on the requirements of the design and intended functionality, this variation can have significant impact on the quality, consistency, and acceptability of the part being fabricated.

Checklist for Info. Required in your Castings RFQ

In order for us to provide you with complete and comprehensive quotes, we appreciate you provide us with the following information in your Castings RFQ packet:

  1. Drawings by Operation (if available): most of our customers provide us with separate drawings for castings and machining for each component. This is very beneficial for all parties and eliminates confusion. For complex parts larger than 3 inches, we recommend you provide a casting drawing based on ISO GD&T, a separate drawing for machining, (and if necessary in some cases) a third drawing for finishing.
  2. Volume and/or Weight: in order for us to quote, we need to know the volume of the part, or weight.
  3. Material and grade: Please specify clearly the material specifications, and also the grade and class of material that you require for the casting.
  4. Solid Models: It is critical for us to receive solid models of your parts, along with your drawings. The most common format is 3D IGS. We also accept Solidworks, Pro/E, Solidedge, CATIA, UG, and Inventor. If you have other formats, please contact us to discuss.
  5. Tooling Drawings: As part of your design process, if you develop/design tooling drawings for patterns, jigs, fixtures, and/or dies, please forward this to us. This will reduce development time considerably.
  6. Usage in Assembly: For some castings, it may be useful for us to know and understand where the castings will be used in assembly. With this information, we can better comprehend critical dimensions, and also provide feedback to you for improving manufacturability, lowering costs, and enhancing performance.
  7. Quality/Testing Requirement (see below)

Quality Plans

Along with your drawings, we also appreciate you provide your quality plan for the components. This quality plan can list all your requirements and specifications for producing acceptable parts, including

  • Material testing requirements
  • Certifications as needed
  • Tooling requirements, if available
  • Finish requirements, including coatings as needed (specify RA value and depth as required)
  • Destructive test plans
  • Non-destructive test plans, including sample sizes and quantities
  • Inspection requirements, inspection plan, and required reports

With the above information available to us, we can provide you the full quote, and guarantee that the parts that we supply to you will meet your requirements, consistently. With incomplete information, we are forced to make assumptions that may lead to confusion down the road.

Gear Quality Number (Q-Number)

SANDMARK can manufacture and supply high quality gears, up to Gear Quality Number AGMA 14 (or DIN 3, or ISO 3).  The Gear Quality Number is also known as the Q-Number or the Gear Quality Grade.  The Q-Number for a gear is a measure of the geometric accuracy level of teeth on the gear.

While the standard used in the USA is set by AGMA (American Gear Manufacturer’s Association) ; other regions of the world use different standards for gear teeth quality. The following table provides a general cross-reference between different standards (JGMA – Japanese Gear Manufacturers Association , ISO – International Organization for Standardization , and DIN – Deutsche Industrial Normen). However, note that there is no direct and full conversion between the standards. The cross-reference table below notes the ‘likeness’ of the Q-Numbers in each standard.


Higher the Q-Number in AGMA, the higher the quality of the gear.  Inversely, a lower Q-Number in ISO/DIN indicates higher quality.

A typical Gear Quality Measurement Report from SANDMARK is shown below.  The gear being measured here has been manufactured to a Q-Number of ISO/DIN 6-7, or AGMA 10-11.