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Sprite Science

5/16-18 Threaded Inserts for Wood 15mm Length Furniture Screw in Threaded Insert Nuts 40 Pieces

Based on 2,010 reviews
Condition: New
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$7.99
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Availability: Only 8 left in stock, order soon!
Fulfilled by Amazon
Arrives Tuesday, Nov 17
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At a glance

Condition
New
Size
5/16-18 x 15mm*40pcs
Model
S-40-5/16-18WOOD
Color
White
Material
Wood
Fastener Type
Insert
Thread Size
5/16"-18

Features 5

  • Pack of 40 5/16-18 threaded inserts for wood working applications, 15mm length, 8mm Allen key included.
  • Threaded insert head : 0.545" / 13.8mm, body : 0.385" / 9.8mm, threads : 0.500" / 12.8mm.
  • Threaded inserts are easy to install, simply drill the appropriately sized hole and Install the inserts with hex key provided or other optional drive tools you have.
  • 5/16-18 threaded inserts are ideal solution for soft woods, plywood, MDF, and composition board.

Description

Wood Threaded Inserts are insert nuts that go into a predrilled hole in wood and has internal threads. Threaded Inserts are best for composite materials, soft wood, plywood and hardwood, you just need to drill a hole that the size of the body into the wood for the threaded insert. 40-Piece of 5/16-18 x 15mm Length Threaded Inserts for Wood Nutsert Screw in Nut Insert for Furniture + 8mm Hex Key. Hex Drive Threaded Insert with 5/16-18 Internal Thread Size, the hexagon drive allows for easy installation. Body diameter: 0.385" / 9.8mm. Threads diameter: 0.500" / 12.8mm. Drilling hole for SOFT wood: 29/64" (11.5mm), if it is small, please try 15/32" (12mm). Drilling hole for HARD wood: 15/32" (12mm), if small, please try 31/64". *PLEASE NOTE THAT Drilling Advice is guidance only, as best practice varies between Different Materials, please choose the proper drill bit according to the hardness of your material. *WE SUGGEST Doing A Trial on a piece of wood Then Adjust the drilling size. *PLEASE KEEP your bolts and threaded inserts Straight and Perpendicular While Threading or Screwing.

Specs 24

Material Wood
Fastener Type Insert
Thread Size 5/16"-18
Color White
Brand Sprite Science
Thread Type Unified National Coarse (Unc)
Inside Thread Size M12.8
Thread Style Right Hand

Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Nov 17

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

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View our full returns policy here.

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Top Amazon Reviews

Very handy and easy to install
Size: 1/4-20 x 15mm*40pcs
Great little inserts, perfect for assembling panels that you may want to disassemble some day. Used in plywood without any issues. They seem to be die cast metal, but hold well. I wouldn't use them for high torque applications, but for most light to medium duty applications they should work great.
Reviewed in the United States on January 27, 2026 by tgtech
How buying hardware should be
Size: 1/4-20 x 15mm*40pcs
Review Image by MLBrub
I used these when building a crib. They go in easy and look great. I was impressed by the quality and the attention to detail the sellers had. The bag had all the size information and drilling requirements. I used 24 of them and they each performed well. They even included an allen wrench. I have plenty of them, but it is nice to keep everything in the same spot. Now when I store them and use them later, the directions and the allen wrench will be in the same bag. Great job, this is how buying hardware should be. ... show more
Reviewed in the United States on May 8, 2025 by MLBrub
They Worked Equal to or Better than Expected
Size: 1/4-20 x 15mm*40pcs
Great product. Worked as they should. As a note, as I was setting these units in aged, very hard, dense hickory I was concerned about stripping the hex head. Especially as I was concerned about the treads pulling out of the wood so I drilled the pilot hole for soft wood. To help reduce friction, I applied some bar soap to the external threads prior to threading them into the wood. The inserts went in easily and I had no issues with stripping the hex heads. ... show more
Reviewed in the United States on February 20, 2024 by Fallswine
Good price, quality inserts.
Size: 1/4-20 x 20mm*40pcs
Used these when making a kid’s bed. These inserts work fantastic. Had no problem with them; just make sure you drill the correct size pilot hole.
Reviewed in the United States on May 10, 2024 by JAmidon
Works well
Size: 1/4-20 x 10/15/20mm*60pcs
Arrived promptly and well packaged. Works well for wood working and furniture making
Reviewed in the United States on April 10, 2026 by LisaK
Like them a lot
Size: 1/4-20 x 20mm*40pcs
Well made, will take the load. Been using inserts for over 50 years, the info about testing hole sizes would have been helpful back in the day. A 6mm hex point on a low torque impact driver is the most efficient way to install. Will look for this brand again when I need more.
Reviewed in the United States on January 24, 2026 by Emerson
Very good quality
Size: 1/4-20 x 10/15/20mm*60pcs
These are excellent inserts, sharp deep defined threads screw and hold into wood very well, nicely machined. Use with a 3/8" pilot hole. Comes with a nice plastic container, allen key; and instruction card.
Reviewed in the United States on December 20, 2025 by Redbadboy
Easy to install; great directions
Size: 5/16-18 x 15mm*40pcs
Review Image by F. Kerby
Review Image by F. Kerby
Review Image by F. Kerby
I wanted to install these to attach some locking swivel casters on the base for my router table. The directions provided were very helpful. I ended up assembling an installation and removal tool. The coupling nut opposite the threaded insert is installed loosely in the drill press chuck. By "loosely" I mean that the chuck jaws hold the nut in alignment but the nut is loose enough to slip. The insert is installed by tightening the nut next to the insert. If the hole for the insert is the correct size (tight, but not TOO tight). the installation tool can be remove by loosening the nut closest to the insert. If the hole isn't snug enough, the tool can be removed by holding the shaft and using a wrench to remove the lower nut. These inserts worked great. They were just what I needed to get a great looking caster installation. ... show more
Reviewed in the United States on February 24, 2023 by F. Kerby
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