Spectrum JR Module Improvement

The latest Spectrum modules for JR conversions are a now a one piece plug in block complete with integral aerial


Or if your version has the long wire and clumsy protruding plug, you can get a conversion kit. This provides a new case and aerial and you transfer the guts from your module. They were available free with newly purchased old style modules earlier this year.


part No SPM 6817E "Integrated Module Case for JR"

Apologies if it has it been presented in RDMFC forum already

I still have two old style Spectrum JR modules. So I've now invested in upgrade cases (c/o hobby corner).

The holes in the pillars for the new 4x 2-56 screws (same as old) are moulded as tap drill size but not tapped. To try and force them in seemed a recipe for disaster, yet this is exactly what Horizon UK suggested to me.
(The old cases must have been tapped because each hole still has swarf/shavings/turnings in the bottom)
Reading the States Horizon web pages, one review customer suggested tapping the holes 2-56 and avoid the risk of breaking the tap or the pillars..
So the first thing to do was to check the bolt thread really is 2-56. Yes it it is !
These American Size taps are like "HensTeeth" to get over here at reasonable prices. £22.50 taper, second, bottom EACH plus post -from -Modelfixings !!!!
However, I did find MG Sharp models of Sheffield and they had a Kadee tap and drill set for £6. The tap is "Trapezoidal" (3 sided). Anyway it did the trick. It was intended to be used for HO guage American model railway couplings.

See below two pics
One of the tap

and the other the tap in the case top (shown in the old one cos the new ones are all fastened up now.

Paul, it's quite normal when designing plastic moulded casings to leave any holes destined to have threaded fasteners inserted in, at their tap drill size (or ever so slightly larger). This is normally only done when using plastics that have a low fill content (e.g. glass filled/carbon filled etc). The use of screws that will tap their own threads in plastics is a good thing because they effectively "lock" themselves due to the forces acting on the plastic as the screw is inserted. Of course, if the post has been designed without enough material, or a hole that is too small (i.e. smaller than the tap drill size) it could be liable to cracking. The posts on that case look to be slightly on the small side, although with a 2-56 screw, there should be enough material there to resist any cracking. The see through plastic also indicates it is not a filled plastic, and therefore will be surprisingly ductile.

Oh, and the plastic shavings at the bottom of the existing holes will be from when the screw is first inserted and it "cuts" its own thread.

Tapping the holes out properly is normally not done for several reasons, the main one being cost (the tooling cost to mould threads in blind holes is eyewateringly big). Manually tapping the holes also increases the part cost due to the time taken to perform that operation during manufacture.

Incidentally, if you do need to tap threads in plastic, cheap taps can be made by grinding a couple of longitudinal slots down a normal machine screw (use a cut of disc in a dremel) and grind a bit of a taper on the end of the screw to guide it into the hole.

Andy (who has spent far too long designing plastic enclosures and cases for a living)...

That's very similar to the tupperware modules, see I said Futaba got it right first time, I think JR/Spektrum are on about the third go

Live at the Apollo next week Rich

Brian Colclough wrote:Live at the Apollo next week Rich

Some sort of joke Brian ??

Don't get it please explain.

By the way did you see the pheasant commit suicide on my car windscreen as we passed the field entrance just as you were waiting to come out ?

It was Rich's joke, so I was asking if he's "Live at the Apollo" next week, it's a stand up comedy gig on BBC 1 Saturday nights.
No didn't see the pheasant or I'd have picked it up took it home and plucked it me being a "Pheasant Plucker"

Thanks Andy for imparting your wisdom.
I'll continue using the tap if I do any more. These boxes are 15 quid each and it could be embarrasing and expensive if wrecking one belonging to someone else.

I don't really see how cutting accurate longitudinal grooves on a 2.2 mm daimeter thread is practical. Well in my case, being an old fart, it really is a case of "I don't see. Full Stop" The ready made tap is a much better route to success for me.

Inwood had the new Spectrum one piece modules on view at the Nats. They have the same case as the upgrade kits. Also a tiny label v2.2 (like some of the originals).
Some old modules [mine] were marked only internally V1.2 but I have no idea what the difference was except the v2.2 also has an internal label 20.4 dB.
However, the 4 screws holding it all together are different and are now small torx headed type with course self tapping threads.
price
119.99 gbp for the module in a box, a 9 channel receiver and binding plug