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Top 10 “Tech Tips” for Choosing the Best Sealing Screw

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If your equipment is exposed to harsh environments then your equipment is best served and protected by using sealing screws and fasteners. ZAGO’s line of self-sealing screws, bolts, and nuts offers you unsurpassable fastening and sealing power.

Here are a few tips to consider when choosing sealing screws for your next project:

Tech Tip #1:
Choose the right screw material and o-ring material. When considering the choice of material there are 5 important criteria: Mechanical Properties, Corrosion Resistance, Fabrication Operations, Total Cost and Material availability. When choosing an O-ring factors that should be considered are the application for which the O-ring is to be used; the media to be sealed; the size of the fastener to be sealed; and the temperature and pressure to which the O-ring will be subjected.

Tech Tip #2:
Use a clearance hole. We recommend an oversized clearance hole be machined on the mating part in order to prevent the o-ring from being damaged. Machining a clearance hole forms a “squeezing” area for the O-ring to sit and fill the gap between the o-ring groove and the plating surface avoiding excessive twisting, nibbling or cutting of the O-ring.

Tech Tip #3:
Use an Over-sized Head. If your application requires a large opening to be sealed, try ZAGO’s oversized head sealing screws for complete metal-to-metal contact with 360 degree sealing power.

Tech Tip #4:
Use a Socket Button Washer Head Seal Screw. If your application requires sealing of a large opening we recommend using the socket button washer head sealing screw as the larger head accommodates a larger surface to accomplish metal-to metal contact with the advantage of a low projection head.

Tech Tip #5:
Provide a Print. If you have an application that requires a special seal screw or a non-standard machine screw, just email us a print to We can manufacture to your exact specifications.

Tech Tip #6:
Use a Socket Cap Screw. The 6 flat surfaces within the recess allows for high torquing without damaging the head and require no side clearance restrictions. Ideal for assemblies with close tolerances.

Tech Tip #7:
Need help choosing a product? ZAGO’s technical engineering team is always available to provide assistance in choosing the right sealing product. You can also visit us at to view ZAGO’s capabilities for producing “special” sealing products.

Tech Tip#8:
Save time. ZAGO is now offering non-standard machine screws without a sealing element. If your application requires sealing or non-sealing machine screws ZAGO is your one-stop-shop due to our fully equipped in-house machine shop.

Tech Tip #9:
Don’t be afraid to ask. If you need a fastener with dimensions outside the standard range, ZAGO is your best source for unusual lengths and head sizes. We can modify to your exact specifications.

Tech Tip #10:
Advise if quick turn-around is needed. Our ISO certified in-house machining process helps us provide you with the best lead times and the highest quality products.

Did You Know?

ZAGO is a purpose-driven company that is committed to the triple bottom line strategy of "People. Planet. Profit."