Most of the parts we repair and make, such as shafts, pivots, housings and plates, are steel. The grade makes a big difference in how the part cuts and how it performs. Here is how to pick one and what to tell us.
At a glance
- We machine steels and steel alloys at our Reno shop
- Mild steel, 1045, 4130, 4140 and A572 plate
- Choose by load, wear, hardening and welding
- Shafts, pins, plates and housings
- Mill certificates come from the steel supplier
I have used Wolf Machine several times over the past few years for fabricating and repair of parts on my ultralight aircraft. [...] These guys are great to deal with. I wouldn't take my projects anywhere else.
How the common grades differ
The numbering system comes from the SAE and AISI grade lists. The grades below are general education, not the shop's stock. Carbon content and alloys set strength and how hard the steel can be made.
| Grade | What it is | Typical use |
|---|---|---|
| 1018 and mild steel | Low carbon, easy to cut and weld | Brackets, spacers, general parts |
| 1045 | Medium carbon, stronger, can be hardened | Shafts, pins, gears |
| 4130 | Chromoly, strong and weldable | Plates, tubing, frames |
| 4140 | Chromoly, tough, often supplied pre-hardened | Shafts, gears, heavy-duty pins |
| A572 Grade 50 | Structural plate steel, weldable | Plates, frames, brackets |
Choosing a grade for a shaft or a bracket
A shaft turns, carries torque and wears at the bearing and seal areas, so it wants an alloy such as 4140 or a medium-carbon steel like 1045. A bracket mostly needs to be stiff and easy to weld, so mild steel or A572 plate does the job.
Some of the requests we see are for a custom shaft in ASTM A572 Grade 50 or a 4130 plate that has to be ground flat. Both are typical of how a drawing names the metal. If you are matching an existing part, the worn original tells a lot, and a spark test or hardness check helps confirm it.
Certs, welding and what to send
If you need a mill certificate for the steel, that comes from the mill or the steel supplier, so mention the requirement when you ask for the quote.
Steels weld differently depending on carbon and alloy. Higher carbon steels need preheat, covered in the glossary on preheat and interpass temperature. For hardness callouts see Rockwell hardness. Send the drawing or sample, the grade, the quantity and what the part does, through the quote request or by calling (775) 359-5570. For shaft work see shafts, threads and keyways.
Sources
- AISI/SAE steel grades (overview) (2026-10-18)
