According to Bricklink, there are three versions of the part 4265:

  • 4265a with teeth and tight-fit axle hole
  • 4265b with teeth and loose axle hole
  • 4265c without teeth and loose axle hole

Looking at the release dates it seems like B superseded A and C superseded B, although there were long overlap periods. My guess is B was introduced to reduce the amount of plastic used per-part and possibly to make it easier to slide it on an axle. Then C removed teeth because they're fragile and tend to break off.

Is my theory correct? If not, then why was that part redesigned?

  • I suppose that you're right about the teeth being fragile, but it's also worth pointing out that they are quite useless. I bet they were intended to prevent the part from unintentionally spinning on the axle, but the way that they designed the hole in the part already did the job. Also, I think they are called "bushes." Commented May 1, 2020 at 12:04
  • Also, they might have made the clutch tighter since it was quite pointless and annoying for the bushes to occasionally slip off. Commented May 1, 2020 at 12:35
  • 1
    If you check sets each version was available in, you'll spot there isn't much of an overlap. Yeah, some sets still had older version, while newer one was already introduced, but is more of an exception (or error while inventorying a set) rather than a rule. A version had its end in 1993, B version began to appear in 1992 and ended in 1997 (with few odd sets released afterward), just where newest, C version, was introduced.
    – Alex
    Commented May 1, 2020 at 14:42
  • 2
    Part A & B were fragile, to the point where enough teeth fell off you ended up with your own version of Part C. :-)
    – LarsTech
    Commented May 1, 2020 at 20:04

1 Answer 1


I'll speak from my experience with these items as I don't have any formation backed by TLG.

The teeth themselves, found on A and B version of the 4265, while looking fragile, weren't the cause of the redesign I think. These could bend or deform but still be gripping with Technic plates with toothed ends as well as toothed pin axle connectors (which I think was the primary reason teeth existed on half bushes at first).

First two versions seem to be quite weak since they tend to crack quite often. Especially with aging, when clutch strength increases (perhaps parts shrink a little over time?). Don't know the reason behind designing version B, but it looks like the issue with cracking was observed and TLG tried to remediate this.

As for version C, I cannot really tell if supplemental sets released in 1993 really had this version included. It looks like the actual year C version was used is 1997, being part of several sets. You'll also notice this is also the year modern Technic connectors (like 32016) were introduced. These new connectors have the same angles you could construct from toothed pin axle connectors with busing of A or B type and are much stronger. Due to this there's no need for half-bushing to have teeth, thus it can have a little more plastic to make it stronger. In fact, I cannot really remember if any of modern 1/2 bushing I have got cracked or broken.

As seen on this picture from Rebrickable C version (represented here as 32123a and 32123b) had minor mould change over its production as well. Bricklink doesn't distinguish these variations and use 4265c part number for both.

enter image description here

  • 1
    Oh! I knew the teeth could be interlocked with another bush but I completely forgot about those plates with toothed ends - even though just yesterday I assembled an old Technic set that had those. And I think I still have one of those axle connectors. As a side note I remember quite a few of the old bushes breaking or losing single teeth but I indeed can't remember any modern being damaged. But that could have something to do with the fact the old ones were used by me and my brothers, while the new ones only by me.
    – Maurycy
    Commented May 1, 2020 at 13:09
  • Since those teeth pin axle connectors caused so many teeth to fail, I assumed they just replaced them with angled version, which also made the bush version less necessary. Big improvement, in my opinion.
    – LarsTech
    Commented May 1, 2020 at 20:12
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    I never had a tooth break on one of the old-style bushings, but more than half of the ones in my collection, including nearly all of the "a"-style ones, have split down the body of the bushing.
    – Mark
    Commented May 1, 2020 at 20:48
  • Indeed the interlocking of the teeth with plates or toothed pin axle connectors was rarely used, but it did happen: it is for example used in set 8480 (Space Shuttle) to give the cockpit ceiling the right angle. Without the teeth, the cockpit ceiling will move around its axes and never take a nice position. The angled connectors are much more robust, but also take up much more space, so I have trouble considering them as a straight replacement for the old system. Commented Jul 27, 2020 at 13:49

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