While putting together the Colosseum, reader JdV noticed that the black Technic pins joining together parts of the base were not the same as the Black Technic friction pins that he had come to know and love over the past 30 or so years. He then asked me what I knew about it?

Nothing. so I took a closer look at the element, and saw that it had some definite differences in design.

But is it significantly different? Is it functionally different? And can we fathom why it has been introduced? I dove headfirst into the Brickset database, pulled out my trusty Macro Lens and Digital Micrometer, and set about my investigations…

I went back to where the initial query began building the Colosseum:

I took a look at the inventory for the Colosseum. The element ID for the Technic pin (Connector Peg w. Friction) is given as 6279875, allegedly introduced in 2017. Looking further at this element in Brickset, I see that it has only been included in 26 sets to date.

This is plainly not the connector peg (w/ friction) that I have known for the last 20 or so years, since I was given the Dark Side Developer kit as part of a celebration. So, I took a moment to compare the image with the ‘classic’ peg that we were used to.

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Both elements feature a pair of slots at each end. In the newer version, you can see from the middle pictures above, the slot is shorter and wider. There are also ridges close to the slots. These ridges are slightly longer in the new version, and feature are more round at the end.

There is a circumferential thickening, interupted by 2 longitudinal slots on the old version, with another 4 ridges, similar to those lining up on the end. The new element has only 3 sets of ridges near the central thickening. This ring has definitely flattening on one side, and what almost appears to be a divot on the other. The new element also has a visible ‘© LEGO‘ as well as the Design ID, 61332, on the outside.

Where does it appear?

Post publication edit: It would appear that I have committed a systematic error in the original version of this paragraph: The Brickset inventory actually includes the elements listed in the replacement parts service, rather than the elements included in the set’s original release (as you might find in the back of the Building Instructions). As such, if an element is superseded, it might be replaced by a functionally equivalent element in the inventory. On the advice of reader JD (See the comments below) I have gone back to set inventory, listed in the building instructions. This confirms that the older pin was used for the initial retail releases of 42070, 70260, the Mack Anthem and Nijago City Docks. No instructions and therefore ‘original’ inventory is available for the First LEGO League sets or the Spike Prime set, so the first ‘Regular’ consumer set to feature the element will be 10276 Colosseum, released in 2020. It has subsequently appeared in Creator3in1; Creator Expert, the Marvel Mechs, Spider Man’s Monster truck, Ninjago Legacy sets and Minecraft. Oh yes, also some of the 2020 Technic sets (but interestingly, not all of them.)

As such, it would appear that only some sets are having the replacement part inventory updated at this time, and the element likely only first appeared in 2020.

The new pin, 6279875, made its debut in 2017’s 42070 6×6 All terrain towing transport, as well as 70260 Ninjago City. It has subsequently appeared in a total of 26 sets to date, although only 5 of them have specifically been Technic sets, so far. The others have been across the range: Creator, Creator Expert, Architecture, Minecraft, LEGO City, Ninjago and LEGO Super Mario, First LEGO League and Marvel Super Heroes. There is no doubt that they are becoming more frequently used:

Elements	2017	2018	2019	2020	2021 (first wave of sets)
6279875 (Introduced 2017 2020)	2	5	0	3	16
4121715(Introduced 1993)	161	161	137	152	18…

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Functionally, have I noticed any difference?

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I might have noticed, subconsciously, that the new Police Station Modular attached to the next model slightly more easily than I had expected it to, based on my past experience with modular street connections I certainly have not noticed in any of the other sets I have put together: the 3 Marvel Mechs, and Spider Man’s Monster Truck; 71382 Piranha Plant Puzzling challenge (Super Mario).

If I am perceiving a difference in the effort required to plug the modulars together, is this a reduction in friction? Or flexibility of the pins?

On taking the elements, in an unblinded fashion, I feel as though there is a more peceptable ‘click’ with putting the pin in place with the more established design, and that the new pin feels slightly softer.

An Investigation

I set about designing an experiment to establish whether there was a qualitative difference in friction demonstrated between the two types of Technic Pin. While lacking a dynamometer to measure the force required to extract each pin, I can probably do an experiment that demonstrated the resistance that the pin has to rotation.

After constructing a wall out of Technic Bricks, used a lift arm as a lever, and attached a variable weight to one end. I gathered 10 control pins (‘traditional’ pins of various ages.) I also took 8 pins from Creator 3-in-1 set 311111 Cyberdrone. This set contains the new design.

After drawing a pin at random, I inserted it at the proximal hole of an 11 module lift arm, and fashioned a freely rotating weight, consiting of a 5 module long bar, 2 stoppers and 1×2 bricks – 2 with technic hols. The bottom was stabilised using a 2×3 plate.

The load was increased, by a 2×3 brick at a time until the arm was unable to resist gravity.

The number of 2×3 bricks added, to cause it to collapse was recorded.

Sometimes, with both types of pin, the system would collapse as soon as the weight was connected. In this situation, pressure was applied across the fulcrum, to ensure that the pin was properly ‘clicked in’ place. The weight was then reapplied. This was seen to happen with both types of pin.

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Results

A total of 10 ‘older’ and 8 of the newer pins were tested using this methodology. The number of bricks required to overcome friction was recorded, and charted as a frequency histogram.

You can see a skew towards the left (lower weights required) for the newer pin, compared to the right. I calcularted the median weight for each pin type: the Older design – 4.5, the newer pin: 3.

Similar differences were seen using the mean and mode as measures of central tendency. The sample size was too small to be able to make any reasonable assumptions as to whether or not the data is normally distributed, and I don’t think any statistical analysis would stand up to a lot of scrutiny… but the vibe is there, and measures of central tendency imply a likely reduction in force required to overcome friction with the new pin design. Just for fun, however, I ran a 2tailed, unpaired t-test over the results, and found a p value of 0.0302. This suggests that there is a statistically significant difference between the two groups.

Part of the reason can be attibuted to the reduced number of ridges near the equatorial thickening, in the new peg comapared with the old. But are there any other, more subtle differences between the two pegs?

How did it measure up?

I pulled out my trusty micrometer vernier callipers to see if there was any major difference in any of the measurements of the new connectors, compared to the old. I took measurements from 4 connector pins of each type.

I compared length, external diameter at the ends; internal diameter at the ends, diameter at the equator, width and lengths of the end slots. A paired Student t test was applied. P<0.05 was taken as being a statistically significant difference.

	Old Connector 4121715	New Connector 6279875	P	Sig?
Length (mm)	15.96	15.71	0.27	N
External diameter (mm)	5.17	5.11	0.02	Y
Internal Diameter (mm)	3.16	3.13	.41	N
Central Diameter (mm)	5.85	5.88	0.02	Y
Slot Length(mm)	3.5	2.98	.000084	Y
Slot Width (mm)	1	1.09	0.90	N

So: We see that the new connector is slightly narrower at the opening, has a slightly wider central cuff, as well as a shorter slot. These measurements were all taken by hand, and as much care as possible was taken. Unfortunately, I do not own scales sensitive enought to compare the weight of the pins.

Why the change?

There could be two justifications for considering a change in mold for this functionally common element:

• a perceived problem with the existing element
• an attempt to reduce the consumption of raw materials.

Now, According to BrickArchitect.com, in his annual survey of LEGO part element counts, the black Technic Friction pin was the 4th most commonly used element in LEGO sets in 2020. Certainly, if there is the possibility to reduce the amount of raw material used, it has the potential to make a significant impact on the companies bottom line, as well as environmental impact.

Otherwise, what could be the issues with the old pin?

• Too sticky? hard to remove with pliers in some situations, when a brick seperator or a axle cannot reach?
• Difficult to line up two or more, for example when putting together a modular street – joining the buildings up with a Technic pin? I was suspicious that something was afoot earlier this year, when I placed the police station next to the Spring Lantern Festival – it felt a lot easier to join them up than I typically remembered.
• Difficult to pull apart when 2 or more are used to hold to bricks/beams together.

And why so gradual? I suppose so there was an opportunity for some post release surveillence, looking for evidence that the new element was functioning as intended. In 2017 and 2018, the only Technic sets that it was released in were the flagship models, as well as other sets, where the dependence on the pins were not integral to the entire model.

I presume we are now entering a phase where more and more sets will feature the new pin, rather than the old. I find it interesting that there are two Monster Jam trucks in the Technic lineup next year, and only one features the new pin.

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After a few years of testing in the market place, and doing what it says in the name, I am left thinking that this element is ready for prime time. I presume, in general, that the LEGO group have decided that it should be considered functionally equivalent to the older pin, even though it may not offer as much resistance to rotational movement as the older version. This newer pin has not had the original time in the market place that I had thought. It would appear that is it being phased in this year, included in around half the sets requiring a technic pin w/ friction, across multiple themes, while the older 4121715 is also still being distributed, and is available in a similar number of sets in the first quarter’s sets.

If it were not functionally equivalent, then I would like to think it would have been manufactured in a different colour, to make it easier to distinguish from the older version.

Have you been aware of the fact that this element has been trickling into our parts drawers over the last few months? Have you noticed any problems with it?

Why not leave you comments below, and until next time,

Play Well.