Flat Head Stainless Steel Machine Screw

Passivated 316 Stainless Steel Machine Screws / Bolts

Most retailers will sell stainless steel machine screws and not name the alloy. “Stainless Steel” encompasses a large variety of alloys, and you’ll often find that an inferior, and cheaper to produce “Stainless Steel” is what’s sold when the alloy goes unnamed. We only carry Type 316, passivated Stainless Steel Machine Screws, and won’t sell you anything less, as it’s not what we would use on our boat.

316 (A4) Stainless Steel is far more corrosion resistant than it’s 304, A2, or 18-8 Stainless Steel counterparts, and should be your go-to alloy in a marine stainless steel application. The additional nickel and molybdenum in 316 stainless as well as the passivation process adds additional corrosion protection that is necessary in a marine or otherwise corrosive environment.

These flat head 316SS machine screws, or machine bolts come in imperial sizes, have a countersunk (CSK) head, and are available in either phillips or slotted drive. They’ll polish up to a mirror finish if desired.

Purchase by the piece, or in large boxes to receive quantity discounts and pricing that will beat any other retailer. Simply enter the quantity you’d like in the “Quantity” box above and your discount will be applied if applicable.

	Head Diameter
Nominal Size	Max.	Min.
#2 #4 #5 #6 #7 #8 #9 #10 #12 1/4″ 5/16″ 3/8″ 1/2″	0.172″ 0.225″ 0.252″ 0.279″ 0.305″ 0.332″ 0.358″ 0.385″ 0.438″ 0.507″ 0.635″ 0.762″ 0.875″	0.147″ 0.195″ 0.220″ 0.244″ 0.268″ 0.292″ 0.316″ 0.340″ 0.389″ 0.452″ 0.568″ 0.685″ 0.775″

What is stainless steel passivation and how does it help keep our stainless marine fasteners corrosion free?

Stainless steel passivation is a chemical process that improves the corrosion resistance of our 316 stainless fasteners by removing any traces of iron from the surface of fastener. This chemical process enhances it’s natural oxide layer, and helps keep any surface rust from forming for years to come.