Male to Female Thread Adapters And Reducers.

What are Male to Female Thread Adapters And Reducers?

Male to female thread adapters, also known as male to female screw adapters or thread converters, are part of Accu's thread adapters and reducers range, turning an existing tapped hole into a different thread while keeping the same male-to-female arrangement. Each male to female hex thread adapter is a single machined hexagonal body with a threaded stud projecting from one end face and a tapped bore in the other, so it looks like a long hex nut with a bolt shank fixed to one end. Screw the stud into the hole you have and the bore presents the thread you need, so a metric screw can go into an imperial hole, or the reverse, without retapping anything.

External threads are cut to class 2A on imperial and 6g on metric, with internal threads to 2B and 6H, the general-purpose fit classes for unified and ISO metric threads, so both ends work with standard screws and tapped holes from any supplier. That makes them a common sight in laboratory, photonics and test equipment, as well as machine building and tooling, wherever imported hardware has to meet a threaded surface that cannot be changed.

How Male to Female Thread Adapters Work.

The stud is threaded into the existing hole until the hex body seats against the surface, then tightened with a spanner on the flats so the shoulder clamps down and the adapter cannot rock. From that point the bore at the top behaves as a new tapped hole. The mating screw threads into it and its load passes through the hex body into the stud, then into the original thread below. Because a male to female screw adapter is threaded in rather than bonded, it comes out again with the same spanner and leaves the original hole exactly as it was. The body also sits proud of the surface by its own length, so every adapter raises the joint slightly as it converts it, which is worth allowing for when heights or clearances are tight.

Picture an optical table drilled and tapped with 1/4-20 UNC holes on a one-inch grid and a set of European post holders and mounts designed around M6 hardware. A 1/4-20 UNC to M6 (1 mm Coarse) male to female thread adapter screws into a table hole and presents an M6 tapped bore on a 1/2" hex, so each metric post holder bolts straight down with its own M6 screw. The 3/4" body lifts the mount by the same amount, so beam height is set with that in mind. Without the adapters, the options are retapping a precision table surface, which cannot be undone, or buying a second set of imperial mounts for a single bench.

Materials Male to Female Thread Adapters Are Made From

Accu's range of male to female thread adapters is machined from engineering metals selected for accurate thread form on both the stud and the bore, corrosion resistance and, where it matters, low mass:

• Aluminium: The lightest option at roughly a third of the weight of the equivalent stainless adapter, with natural corrosion resistance that suits portable rigs and lightweight fixtures where every raised adapter adds mass.
• Stainless Steel - (303): A free-machining austenitic stainless steel to SS 303 / ASTM A582 that cuts clean external and internal threads and resists corrosion in indoor, laboratory and general industrial conditions.
• Stainless Steel - Marine (A4): Specified to SS 316 / ASTM A276, this molybdenum-bearing grade gives the highest corrosion resistance in the range, standing up to salt water, washdown and cleaning chemicals.

Every adapter in the range is supplied in a Natural, uncoated finish.

Sizes & Types of Male to Female Thread Adapters Available

Accu's range of male to female thread adapters spans more than 400 thread pairings across every combination of imperial and metric:

• Male Thread Specification: 2-56 UNC to 1/2-28 UNEF and M3 (0.35 mm Fine) to M12 (1.75 mm Coarse).
• Female Thread Specification: 2-56 UNC to 1/2-28 UNEF, 1/8" NPT and M2.5 (0.45 mm Coarse) to M12 (1.75 mm Coarse).
• Thread Specification: UNC, UNF or UNEF paired with metric coarse, fine or extra fine in either direction; imperial to imperial; metric to metric.
• Thread Type: Imperial to Imperial, Imperial to Metric, Metric to Imperial and Metric to Metric.
• Thread Class: 2A / 2B, 2A / 6H, 6 g / 2B and 6 g / 6H.
• Socket Size (J): 1/4" to 7/8" and 10 mm to 22.2 mm.
• Nut Thickness (T): 1/2" to 1-1/2" and 12 mm to 38.1 mm.

Not every pairing comes in every material. Aluminium starts at 1/4-20 UNC and M6, so everything smaller, down to 2-56 UNC and M2.5, is stainless only. Imperial to imperial adapters and the single 3/8-24 UNF to 1/8" NPT adapter are made in Stainless Steel - (303) only. At the top end, the largest threads in every direction are the 1/2" imperial sizes and M12.

If you're unsure which threads you're working with, Accu's guide on how to measure a screw will help you identify the size and pitch. For a pairing outside the standard range, Accu's custom manufacture service can produce one to your specification. Where the thread already matches and you only need height, browse Accu's range of threaded standoffs, a simpler alternative for spacing a component off a surface without changing the thread.

FAQ

Q: How do I read the sizes on a male to female thread adaptor?

A: The first thread in the name is the male stud, which must match the tapped hole you already have, and the second is the female bore, which must match the screw you want to fit. A 1/4-20 UNC to M6 (1 mm Coarse) adapter screws into a 1/4-20 UNC hole and accepts an M6 x 1 screw. Adaptor and adapter are interchangeable spellings for the same part.

Q: How do I stop a male to female thread adapter unscrewing with the screw?

A: Seat the adapter fully with a spanner on the hex and apply a medium-strength, removable thread-locking compound to the male stud before fitting it. The adapter then stays put when the screw in its bore is taken out, which matters on fixtures that are reconfigured often, while still coming out with a spanner when it needs to.

Q: Can a male to female thread adapter be used as an extension?

A: Yes. The hex body raises the joint by its Nut Thickness (T), from 12 mm to 1-1/2" depending on size, so an adapter can clear a raised feature or bring a fixing up to a new height while converting the thread. Same-thread versions in 1/2-13 UNC and M6 (1 mm Coarse), both in Stainless Steel - (303), extend a thread without changing it.

Q: Is there a male to female adapter for an NPT pipe thread?

A: Yes, a 3/8-24 UNF to 1/8" NPT male to female thread adapter in Stainless Steel - (303). It lets a fitting with a 1/8" NPT tapered pipe thread, such as a small gauge or pressure sensor, mount into a 3/8-24 UNF tapped hole, sealed with a suitable thread sealant.

Bespoke Male to Female Thread Adapters And Reducers Manufacture.

High precision, bespoke manufacture of Male to Female Thread Adapters And Reducers to customer specification. State of the art facilities specializing in both small batch prototyping and large scale manufacture.