T-Slot extruded aluminium profile joints – sliding clamp

Profile Joints – Part 6

Sliding clamp

In this, our sixth in a series of posts on aluminium profile joints, we talk about a sliding clamp. Although not strictly an Alusic product or a joint type, it is something we developed to use with the Alusic range of extruded aluminium profiles.

Imagine that you have machine frame constructed using aluminium extrusion, and you need a stop for some part of the machine’s function. Now imagine that you need to move that stop on a semi regular basis (eg: a number of times a day). It would be nice to be able to just grab a handle, release the stop, slide it to a new position, and clamp the stop in place. No need to go looking for a spanner or a hex key to undo clamping bolts, etc. etc..

Well, we have just the thing. At least we think we do. You’re free to decide for yourself.

sliding clamp

Sliding clamp

The concept works with any t-slot extruded aluminium profile. In this example we are using an M8x45* lobed knob (1077.36), an M8x25 rectangular nut (084.302.011), a length of 3 slot 40×40 extruded profile (084.102.005), and a piece of 50x50x5 square hollow section.

The crux of the concept though, is the lobed knob and the rectangular nut in the t-slot.  The rectangular nut readily slides in the t-slot of the profile until the knob thread is tightened. Even hand tightening the knob provides enough grip to very effectively clamp the slider in place.

sliding clamp

Lobed knob and rectangular nut


sliding clamp

Sliding clamp assembly


Slider options

The slider component need not be a hollow section like we’ve used in this example. The hollow section is ideal if your application calls for something like a telescoping arm or leg.  The slider could just as easily be a piece of angle as shown below.


sliding clamp

Optional use of angle as slider


One example of an ideal use case for a sliding clamp is as a movable stop on our Portable Saw Bench.  If you already have a saw bench, retro-fitting a sliding stop could be as simple as bolting a length of t-slot profile to your bench.  For example, 18.5×32 (084.101.003) has a single 8mm slot perfect for a rectangular nut.



T-Slot extruded aluminium profile joints – sliding clamp - aluminium extrusionT-Slot extruded aluminium profile joints – sliding clamp - aluminium extrusion


If you want a copy of the Alusic catalogue to view on your own PC, go to our site main page, fill in your name and email address and click the Send button. We will then send you an email with a download link for the PDF file.



T-Slot extruded aluminium profile joints – pawl clamp

Profile Joints – Part 5

Pawl clamp

In this post the focus is on the pawl clamping connector fastener, or ‘pawl clamp’ for short.  This is the fifth in our series of posts on aluminium profile joints.

pawl clamp

Pawl clamping connecting fastener

A joint constructed using a pawl clamp can have the relocatable advantage of a fixing plate, but via a single fixing screw rather than two. This means less stuffing about on those occasions when a joint needs to be moved.

Information about different styles of pawl clamp can be found on pages 2.53 to 2.56 of the Alusic catalogue.


The Alusic catalogue shows a pawl clamp for almost any joint type your application might require. The basic pawl clamp can be used in place of the standard connection to make a simple square joint, whether T or corner.

There are also pawl clamps that can be used to join profile pieces end-to-end, at an angle or straight, as shown in the diagram below.  This type of joint is stronger than the simpler linear joint or angular joint.  As a result, it can be used to construct a joint that can carry a bigger load, in tension, than a linear joint.

pawl clamp

Preparing the joint

Preparing the joint simply involves machining a hole of the correct diameter and depth in the first of the profiles to be joined. Exact dimensions for the holes to suit each pawl clamp are shown in the Alusic catalogue. The number of holes is determined by the number of pawl clamps the joint needs (2 in this example).

pawl clamp

Ready for assembly

pawl clamp

Joint partly assembled
















Assembling the joint

We can use two pawl clamps to join an 18.5×90 (084.101.006) to almost any profile with an 8mm t-slot. In this example we show it joined to an 18.5×32 (084.101.003), a 1 slot 40×40 (084.102.006), and a 6 slot 45×90 (084.101.019).

Start by putting the pawl(s) into the hole(s) machined in the first of the profiles to be joined.

The joint is completed simply by sliding the pawl clamp square nuts into the t-slot of the second of the profiles to be joined. When the required joint location is reached, simply use a hex key to tighten the fixing screws in place.

pawl clamp

18.5×90 joined to 18.5×32

pawl clamp

18.5×90 joined to 40×40

pawl clamp

18.5×90 joined to 45×90










So there you have it.  The pawl clamp; used to construct strong joints in extruded aluminium profiles, can be adapted to a variety of different joining requirements. The pawl clamp is so adaptable that it could readily be used in applications outside the realm of aluminium extrusions.  Use your imagination, almost any joint requirement can be fulfilled using pawl clamps.

If you want a copy of the Alusic catalogue to peruse on your PC, go to our site main page.  There is a place where you can enter your email address and click the Send button. We will then send you an email with a download link for the PDF file.


T-Slot extruded aluminium profile joints – Linear joints

Profile Joints – Part 3

Linear joint.

This is the third in our series of posts on aluminium profile joints.  In this one we focus on the linear joint.

A few months ago, we had a customer who was building a display stand to use at various trade shows around the country. The interesting things about this stand were a) the finished height needed to be changeable, b) it needed to be quickly and easily assembled and dismantled, and, c) it needed to be readily packed up for transport to and from venues.

Complying with c) was easy. Extruded aluminium profiles are readily amenable to being stacked and tied down to a pallet for easy handling and transport.

To make the thing quickly and easily assembled and dismantled (requirement b), we decided to use clamping plates for most of the joints. See this blog entry for more information about using clamping plates.

The reason for the changeable height was that some of the venues for these trade shows don’t have the ceiling clearance for their particular rather tall display stand. So we decided to make the top section in two parts. One of which could be left out of the assembly when ceiling height decreed.

Now, there are a number of methods to join aluminium profiles end to end. On this occasion though, the customer wanted to maintain the clean neat lines of the aluminium extrusion.  As a result, we elected to use linear joints in this case.

The linear joint is ideal when the joint is under a compressive axial load, as was the case here.  This joint type is not recommended for high bending load applications such as the middle of a long span beam.

T-Slot extruded aluminium profile joints – Linear joints - aluminium extrusion

As you can see in the diagram above, the joint piece(s) fit neatly inside the t-slot in the extrusion and there are no parts extending beyond the perimeter of the profile.  This diagram shows a 90mm version in the slot 8 series 40 x 40 profile.  The number of linear joint pieces used in any given joint is limited by the number of t-slots in the extrusions being joined.  The number actually used depends more on the strength and rigidity of the joint required.  In many cases, only one or two linear joint pieces are used even though there may be four or even six t-slots in the extrusions.



Joint construction.

T-Slot extruded aluminium profile joints – Linear joints - aluminium extrusion

Linear joint ready for assembly

T-Slot extruded aluminium profile joints – Linear joints - aluminium extrusion

Linear joint partly assembled

T-Slot extruded aluminium profile joints – Linear joints - aluminium extrusion

Linear joint completed









The linear joint is completed by pushing the ends of the extrusions to be joined firmly together, then tightening the grub screws so that their flat ends bare down on the bottom of the t-slot.  This holds the joint piece(s) firmly in place and the two extrusions cleanly together.


T-Slot extruded aluminium profile joints – Linear joints - aluminium extrusion

Linear joint – 90mm & 180mm


Linear joints are available in a number of different sizes for the slot 6, slot 8, and slot 10 series of Alusic extruded aluminium profiles.  Also, they are available in anodised aluminium, zinc plated steel, and stainless steel.


If you want your own copy of the Alusic catalogue, go to our site main page, fill in your name and email address and click the Send button.  We will then send you an email with a download link for the PDF file.


T-Slot extruded aluminium profile joints – Stronger connection

Profile Joints – Part 2

As a person who is regularly building all manner of things using T slot aluminium extrusions, I occasionally come across a situation where a simple joint using a fixing screw just isn’t going to cut it.  Today I am going to introduce you to just a few of the many different methods of joining T slot aluminium profiles using items found in the Fixing Accessories section of the Alusic catalogue.

Late last year I was putting together a batch of custom designed workbenches when the owner announced that they wanted an LED light panel mounted about 1200mm above the main work surface of each workbench.  No problem, I thought.  Just add a pair of upright sections at the back of each workbench, build a frame to hold each panel and attach to the uprights.

That was all fine until it was let slip that some of the workbenches were to be indirectly attached to pieces of equipment that would put some not insignificant vibrations into the workbenches a number of times per day.  I quickly realised that the simple jointed cantilever design I’d thought of would likely not cope with the dynamic loads generated by oscillations, caused by vibrating machinery, of the panel and frame on the uprights.  Even though that simple jointed cantilever design would be fine with the panel as a static load.

So, a quick design review later.  It was decided to use fixing angles (084.305.033) for the main joints and make braces for the uprights using some joint angles (084.305.011).

fixing angle 43 x 86  joint angle for 40 x 40 profile


The fixing angles made the joints very much stronger than they would have been otherwise.  Using joint angles to make braces for the uprights stiffened the structure enough to almost eliminate oscillations that would be generated by the vibrating machinery.  Thinking about it now, just the braces may have been adequate to keep oscillations, and hence joint loads, down enough for the original simple joint design to cope.  Oh well … I think there is a saying in the engineering world that has something to do with “belts and braces”.

A few months after that, the same owner said they wanted some more workbenches (different design of course) also with the LED light panels.  This time though, they wanted to be able to adjust the braces up or down a little for operator head clearance.

At first that seemed a bit complex, not to mention costly.  A stock of different length braces to be removed and replaced by maintenance people as and when required.  I could see there would be no way to guarantee that adequate length braces would not all soon be replaced by the shortest braces, or even removed completely.  Not a viable option in my view.

Then the Alusic catalogue came to the rescue.  Instead of using a joint angle at the end of each brace and making different size braces it was decided to use a screw swivel joint (084.311.010) at the end of each brace.  That would ensure every LED panel support would be adequately braced as well as have a small amount of adjustment using just a hex key.

brace using screw swivel joints

To get your own PDF of the Alusic catalogue, fill in your name and email address on our site main page https://gapengineering.com.au/ and we will send an email with the download link.










T-Slot extruded aluminium profile joints – Standard connection

Standard Connection

The standard connection is the simplest and most cost effective joint for Alusic aluminium T slot profiles.  It is a perpendicular (or square) joint using a single socket head screw (fixing screw) without the use of any fancy accessories.

In this simple joint the hole in the middle of the first profile piece to be joined is tapped with a thread to suit the fixing screw to be used.  The second profile piece has a hole drilled perpendicularly through at the desired location of the joint.  The hole is to allow a hex key to be used to tighten the fixing screw.

T-Slot extruded aluminium profile joints - Standard connection - aluminium extrusion



Details of how to make one of these joints are at this blog post.

Since this joint type is the simplest and most cost effective, it is by far the most commonly used in light, medium, and some heavy duty applications.  For more heavy duty and not so simple applications, other solutions are available.

The standard connection joint type is not limited to use with square profiles either.  It can be used to join rectangular profiles to square profiles as well as rectangular profiles to rectangular profiles.

Probably the only drawback of this simple joint is that it is not readily re-located along the second profile piece should the need arise.  Another hole needs to be drilled to suit the hex key at the desired new location.  Admittedly, this situation doesn’t often crop up, but it does occasionally.  For details of one of many alternative solutions, see this blog post; what are clamping plates.



Full Body Joint

One variation of the standard connection is known as a full body joint.  A full body joint can be used where slightly heavier duty demands.  The main difference in this joint variation is that the drilled perpendicular hole is to suit the fixing screw rather than the hex key.  This adds a small amount of complexity, and hence time, to preparing the joint, but it remains a very cost effective joint.


T-Slot extruded aluminium profile joints - Standard connection - aluminium extrusion                            T-Slot extruded aluminium profile joints - Standard connection - aluminium extrusion

Diagrams from the Alusic catalogue showing two forms of a full body joint.


Joining the other size aluminium profiles

This basic type of T slot connection is not only cost effective it is also incredibly versatile. All of our profiles can be connected this way without the use of any accessories and different size profiles can be joined in this way.



Technical Specifications of T-Slot Aluminium Profile

Extruded Aluminium T slot  profiles

Our extruded T slot Aluminium profiles generally come in one of the 3 standard slots as shown below. Please contact us if you need more information

6 mm Slot – 30 & 60 Series

Aluminium profile extrusion with 6 mm Tslot

6 mm T slot Aluminium Profile

8 mm Slot – 40 & 80 Series


 Aluminium profile extrusion with 8 mm T Slot

8 mm T slot Aluminium profile

8 mm Slot – 45 & 90 Series

Aluminium Profile Extrusion with 8 mm T Slot

8 mm T Slot Aluminium Profile

Technical Data for Alusic Aluminium Profile

All extruded aluminium profiles are manufactured by Alusic SRL (Italy) using a primary aluminium alloy EN AW-6060 (AlMgSi  0.5) – EN AW6063 (AlMgSi1). The metalurgic composition of aluminium profile bars is T6 (solution heat treated and artificially aged). The dimensional tolerances for aluminium profile extrusion are in compliance with the requirements for precision extrusion EB12020-1.

Chemical composition of alloys:

 Alloy  Cu  Fe  Mn  Mg  Si  Zn  Cr  Ti  Al
 6060  0.10  0.1 – 0.3  0.10  0.35 – 0.6  0.3 – 0.6  0.15  0.05  0.10  Rest.
 6063  0.10  0.35  0.10  0.45 – 0.9  0.2 – 0.6  0.10  0.10  0.10  Rest

The mechanical characteristics obtained after heat treatment at which they are submitted are:

 Alloy  Maximum Stress
(N / mm2)
  Yield Stress
(N / mm2)
 6060 215 160  12 70
 6063 245  200  9 80

Characteristics for the design of aluminium structures:

Young modulus 69000 N/ mm2
Electric resistivity 0.033 Ω mm2/ m
Thermal conductivity 210 W/ mK
Casting temperature 615 – 655 oC
Coefficient of thermal expansion 25 x 10 -6 K-1

In addition to a guarantee of high quality and dependability of the aluminium profiles and accessories for solar installations, ALUSIC is certified to a quality system UNI EN ISO 9001:2000 that provides confirmation of its continuous quality control of raw materials and processed materials and that demonstrates continuous improvement  of its products.

Further information, including R&D advice can be obtained in collaboration with Profilium and Alusic’s technical and commercial departments. Please CONTACT US for more information.

Need more information?

If you want more information on how to use our profiles, the benefits of using the Alusic profile system or you simply want a brochure or catalogue, then go to the Alusic Downloads page.

Alusic aluminium profile and accessories – faster, more cost effective assembly


A simple, yet strong joint can be achieved by using both
an Allen head screw and square washer screwed into theCONNECTION.JPG

core hole of the profile (see image on right). A small pilot hole is drilled opposite where the joining profile is to be located so that the screw can be tightened. This is the standard joint for the Alusic range and is a very cost effective outcome.
⇒ The cost per Alusic connection as shown is $0.34 using an M8x20 bolt (084.301.003) and 13×13 square washer (084.303.001).
⇒ Achieves an extremely simple, yet strong connection in under 1 minute.
A leading competitor’s equivalent connection costs $3.35 each and takes 3 times longer to achieve
In some applications you may also add our anti twist
device that replaces the square washer in the standard
connection. The twin tabs on the anti twist device go
into the slots of the connecting profile and stop any
twisting in the joint – a simple and effective solution.


The total time taken to complete a standard Competitor’s connection is 2-3 minutes depending on available tooling; with the cost of the competitor’s connection being up to 300% greater in labour costs alone, let alone the higher material cost of the connectors. With a competitors connection. the distance from the profile end, to the centre of the cross bush is critical to ensure the connector works effectively; if this is not achieved accurately this length of profile is left unusable whereas with the Alusic connection system the pilot hole is simply re-drilled and the adjoining profile tapped accordingly.


The distance of the pilot hole with Alusic profile is predetermined by the drilling jig with several millimetres of adjustment from side to side. With the Alusic connecting system there is also the option of self tapping the screw into the adjoining profile as opposed to pre-tapping to ensure the connector has the best possible fit and to eliminate any possibility of vibration affecting the joint. The potential for a loose join can also be eliminated with the use of thread locking products like LocTite although this is not essential as the connection is extremely effective without this process.


To demonstrate some of the labour cost savings that can be achieved using the Alusic system we have performed a cost comparison exercise. On the structure shown below, we conducted a time and motion study and have estimated the labour saving that could be achieved using the Alusic aluminium system when compared to a comparable, high quality European competitor’s profile.

There are 350 individual connection points on this frame with a saving of between 300% to 500% in labour costs using Alusic standard connectors. In other words, if using a competitor’s connector that takes up to 3 minutes per connection point, you would require 1,050 minutes or 17.5 hours just to complete the connections on this structure and cost it would cost $1,172.50* for the connectors. Using the Alusic connector it takes less than 1 minute per connection point, and you would complete the connections in 5.8 hours and it would only cost $119.00* for the connectors! That is 3 times faster than the competitor and an enormous cost saving in labour costs alone. That is a saving of 11.7 hours per structure and $1053.50* in parts!!