Screw Type Anchor Connector Aluminium Profile Hidden Joint Fastener 30 40 mm Series

OEM / ODM Available Free Sample Available ISO 9001:2015 RoHS REACH

Screw type anchor connector for aluminium profile giving a hidden joint with no visible fastener. Fits a tapped end-face hole in 30 and 40 series sections. Machined from bar and electroplated.

Wholesale Price $0.32 - $1.10 / piece per piece

Material	Steel
Alloy Grade	Carbon steel, machined from bar
Temper	custom
Section Size	30 series / 40 series
Slot	Matches the groove of the receiving section
Length	By series, to drawing
Tolerance	End face squareness within 0.2 mm
Surface	Electroplated
MOQ	2000
Lead Time	18-28 days after deposit
Loading Port	Shanghai / Ningbo
Supply Ability	1,000,000 pieces per month
Payment Terms	T/T 30% deposit + 70% before shipment \| L/C at sight
Trade Terms	FOB \| CIF \| EXW
Certifications	ISO 9001:2015 \| RoHS \| REACH

Request a Quote Reply within 24 hours

Connecting · Anchor connector

A screw-type anchor connector is a small cylindrical fastener that joins two profiles from inside the section. One end carries a cross bushing that is pushed into a drilled and tapped hole in the end face of the incoming member; the other end is a set screw that bears on the inside of the groove in the receiving member. Turning the set screw pulls the two members together and locks the joint.

The point of it is that nothing is visible. There is no plate on the outside of the corner, no bolt head standing proud of the surface and no fastener in the groove. That matters on frames that are seen rather than only used: display structures, clean room and food area enclosures, machine guards where a protruding bolt head would catch, and any frame where a client has asked for a clean external face.

Screw type anchor connector: the cross bushing goes into the end face, the set screw locks the joint from inside the groove. Nothing shows outside.

Why the joint can be hidden

Every other way of joining two profiles leaves a mark on the outside. An angle bracket sits on the outer faces. A T-nut and bolt leaves a bolt head in the groove. A die-cast corner bracket is visible by definition. The anchor connector works because both halves of the fastening are inside the material: the cross bushing is below the end face, and the set screw is below the slot opening.

The cost of that is access. Because the fastener is internal, it can only be reached and tightened through the end face of one member before the frame is closed up. That is what dictates the assembly order on an anchor-connector frame, and it is the single thing most often got wrong on a first build.

The four-step installation

Four steps of fitting a screw type anchor connector, from inserting the cross bushing to tightening the set screw — Installation of a screw type anchor connector in four steps, plus the standard, universal, oblique and miter versions of the same family.

Insert the cross bushing The cross bushing goes into the drilled and tapped hole in the end face of the member that will be pulled in. It is a light push fit and should seat fully without being driven, because the aluminium around it is thin and will deform if forced.
Push in the anchor and pretension it The anchor is pushed into the same hole and turned so its thread picks up in the bushing. Pretension by hand at this stage, not with a driver. The purpose is to hold the assembly together while the frame is offered up, not to clamp anything yet.
Push the member in sideways The prepared member is offered to the receiving member and slid in from the side, so the anchor body enters the groove of the receiving section. It has to go in from the side because the anchor cannot pass the slot opening once it is assembled.
Tighten the set screw The set screw is turned to expand the anchor against the inside of the groove and pull the two faces together. Tighten to the specified torque and stop. The joint relies on friction between the anchor and the groove, so over-torque deforms the groove rather than strengthening the joint.

The end face has to be right

An anchor connector is unforgiving about the hole it goes into. The cross bushing has to be concentric with the section, the hole has to be on the centre line of the groove it will bear against, and the end face has to be square to the axis. Get any of those wrong and the anchor either will not enter, or it enters and pulls the joint out of square.

The requirement is not difficult to meet, but it does have to be planned. A frame designed for anchor connectors should be cut on a machine that produces a square end and drilled on a jig, not marked and drilled by hand on site.

Feature	Requirement	Consequence of missing it
End face squareness	Within 0.2 mm across the section	Joint pulls out of square, visible gap at the corner
Hole position	On the groove centre line, within 0.15 mm	Anchor bears on the groove flank, low holding force
Hole depth	Full anchor length plus 2 mm	Anchor bottoms out before the faces meet
Tap condition	Clean, full thread, no swarf	Cross-threading, anchor cannot be pretensioned
Cut finish	Burr-free on the end face and inside the hole	Anchor binds on entry, bushing will not seat

How the connector is made

Production process of anchor connectors, from cleaning and machining through to assembly — Anchor connectors are machined from bar in several operations, polished, plated and then assembled with the cross bushing fitted.

The connector is machined from bar stock rather than cast, because the wall of the anchor has to be thin enough to expand inside the groove and strong enough not to split when the set screw is turned. Machining in several operations keeps the bore concentric with the outside diameter, which is what allows the anchor to expand evenly and grip the full width of the groove.

Plating matters more than it looks. The anchor is a steel part buried inside an aluminium section, and any moisture that reaches it has nowhere to drain. Electroplating with a full passivate is what stops the anchor corroding in place and seizing in the bushing.

Where a hidden joint is worth the extra work

Frames that are seenDisplay stands, exhibition structures, retail fixtures and furniture frames. A clean outer face is the whole reason the frame exists.

Clean and washdown areasFood, pharmaceutical and laboratory enclosures. A hidden joint has no crevice around a bolt head for material to collect in, and the outer face wipes down.

Machine guardsWhere a bolt head standing proud of a guard frame is a snag point or a hazard, a flush joint removes it without changing the guard design.

Frames closed at both endsBecause the fastener is internal and reached through the end face, a member that is capped or joined at both ends must be prepared before it is closed.

Anchor connector or an angle bracket? Use the anchor connector where the outside of the frame has to stay clean and the end faces can be drilled and tapped before assembly. Use an angle bracket where the frame is functional, the joint has to be adjustable, or the frame will be taken apart again. The bracket is faster and reversible; the anchor is cleaner and permanent.

Frequently asked questions

What is a screw type anchor connector?

A cylindrical fastener that joins two profiles from inside the section. A cross bushing goes into a tapped hole in the end face of one member and a set screw expands the anchor against the groove of the other, so no fastener is visible on the outside of the frame.

Which series does it suit?

30 series and 40 series sections are the standard sizes. The anchor must match both the groove it expands into and the end-face hole it is tapped into, so give us the section you are using rather than the thread size alone.

Can I fit it on site with hand tools?

Only if the end faces were drilled and tapped before delivery. The tapping is the part that needs a jig; the assembly itself is a hand operation. Cutting, marking and drilling a frame on site will not hold the tolerance the connector needs.

Does the joint come apart again?

It can be loosened and re-tightened, but it is not designed as a frequently dismantled joint. Each cycle works the cross bushing in the aluminium, and after several cycles the hold falls away. For a frame that is taken apart regularly, use an angle bracket instead.

What torque should the set screw be tightened to?

Tighten to the figure we supply with the connector for your section, and stop there. The anchor grips by friction against the groove; past the specified torque it deforms the groove and the holding force falls rather than rising.

Tell us the section and we will confirm the connector

Send the profile you are using and how you plan to prepare the end face. We will confirm the correct anchor connector, quote the bulk price and supply samples with the hole specification for a trial frame.

Request a Quote