What's with these new 3mm kingpin screws?

[markbt73]

Apparently sometime while I wasn't looking, Tamiya decided it would be a good idea to switch from the round-headed 4mm thread kingpin screws that have been in use since olden times to the little 3mm thread ones that I first saw on TLT axles. The little devils were on the M05 and M06, and now the MF-01X as well.

Those nasty little things with their woefully undersized head slots have to thread into rock-hard plastic uprights, and the square-ended machine threads don't want to start, and when they do, they don't start straight. And then 2 threads before you get the thing all the way in, the head starts to round out. So there's no chance you're getting it out again unless you cut a slot for a flat-bladed screwdriver.

Why, Tamiya, why??? Those four little lumps of pure evil spoil what is otherwise a pleasant build experience, when every TA, TB, TL, WR, WT, and earlier M chassis had the chunky 4mm ones that popped right in. If it's because they need to be smaller, that's fine; make them hex-head so we can get them in place easier. Having to press down while turning a delicate part that you're holding in your other hand is a recipe for disaster.

Does anybody else hate these things? Is there a trick to them I don't know? Do they work better with an actual JIS screwdriver instead of my trusty Philips set that I can get away with on every other screw? Is there a hex or Torx head replacement available anywhere?

[Mokei Kagaku]

I too instantly hated them when I built my first TA04, which was one of the very first to get these kingpins, probably the first (in 2000). Needless to say, I damaged the screw heads. However, to be fair to Tamiya, I made the mistake of using the Tamiya JIS No.1 (medium) screwdriver instead of the No. 2 (large), which would have been correct although the heads are quite small. Meanwhile I've built many models with these kingpins and when using a high quality JIS No.2 (TRF Screwdriver and Tamiya Electric Screwdriver with No.2 bit), they work pretty well, although I don't consider them to be an improvement over the earlier type.

A hex head hop-up version of these kingpins are available from Tamiya too, and I have used them on my most hopped-up MF-01X, M05 and M06 and they are indeed better.

Check 54237 M05 Low Friction King Pin (4 Pcs.).

 

[markbt73]

Excellent! That's what I was looking for. Why on Earth don't they just include that style with the kits?

[Backlash]

Why cant you just use a regular 3mm machine screw or tap to pre-cut the threads into the steering knuckles, and then fit the step screws later??

[Crash Cramer]

3 hours ago, Mokei Kagaku said:

I too instantly hated them when I built my first TA04, which was one of the very first to get these kingpins, probably the first (in 2000). Needless to say, I damaged the screw heads. However, to be fair to Tamiya, I made the mistake of using the Tamiya JIS No.1 (medium) screwdriver instead of the No. 2 (large), which would have been correct although the heads are quite small. Meanwhile I've built many models with these kingpins and when using a high quality JIS No.2 (TRF Screwdriver and Tamiya Electric Screwdriver with No.2 bit), they work pretty well, although I don't consider them to be an improvement over the earlier type.

A hex head hop-up version of these kingpins are available from Tamiya too, and I have used them on my most hopped-up MF-01X, M05 and M06 and they are indeed better.

Check 54237 M05 Low Friction King Pin (4 Pcs.).

 

VERY SEXY, another few extra bucks in Tamiya's pockets, THAT is why they don't include them in the kits.

1 hour ago, Backlash said:

Why cant you just use a regular 3mm machine screw or tap to pre-cut the threads into the steering knuckles, and then fit the step screws later??

That is an old trick, I have a spare part kit for the HotShot for the uprights and they sold them in single upright parts bags included with a rather large looking 4mm machine screw, it was to tap the upright before attempting to screw the ball end onto the upright, it was real fun with a domed shaped, flat head, soft aluminum screw to go into hard plastic, so yes, old trusty trick, get a 3mm screw with real good threads and some steady surface and tap the first mm or two with that, then SLOOOOOWLY remove it to not build up heat, then get the real deal and put it in slowly too, in order to not cross thread. I just recently did that on my M01 chassis since it has TONS of old hard plastic that needed self tappers, so I was real slow and methodical with that rebuild.

 

I will keep my eyes out for some of those new screws and since it is allen head, better choice of tools. On the JIS, I doubt they were an improvement to drive the smaller 3mm kingpins with as I have found that some of the 4mm were also knackering up even with a Tamiya JIS large(#2) driver.

[WillyChang]

gee... 3mm kingpins came out on TA04 knuckles getting on 2 decades now  which got up cycled onto TLT1/HiLift axle, then M03M used them when they updated the c-hub & knuckles for Suzy Swift like 10-12yrs ago.

Rather than buy the 54237 I rather use a flanged sleeve and a plain machinethread screw (as used on later tourers)... I'm often bending kingpins & it's no fun buying another pack of 4 just to replace 1 that's bad... vs plenty of spare M3x10 screws about. 

For thread tapping, for cost of forgoing a beer this is worthwhile investment:-

 

[Crash Cramer]

That is great Willy, but now we need the drill chuck too, that is near the cost of a CASE of beer. You guys sure know how to spend a guy's money fast. I will put this on my wish list someday, but it does seem close to the way the Alu uprights are installed with simple 3x10 screws and a flange, special size flange, but if you are only bending them instead of snapping them off, well then the flange won't go flying off into the brush.

[WillyChang]

hah! I ain't that desperate to send T all my $$$ so soon 

you can use any generic handle/chuck, cheap China does the job

but as pandas are sedentary creatures, i stick thread taps into a mini chuck with hex drive stem driven by cordless screwdriver  just need a slow but torquey unit

they cost less than beernuts  & handy for polishing shafts/hingepins too