Re: making the case for self-tapping screws


Weelllllll,I just couldn't resist.Model makers?...............With the flood of ready to run cars what's the issue?Are there that many of us model makers left to have to worry about screws? <G>,Armand Premo

----- Original Message -----
From: "Dennis Storzek" <destorzek@...>
To: <STMFC@...>
Sent: Saturday, December 27, 2008 1:32 PM
Subject: [STMFC] Re: making the case for self-tapping screws

> --- In STMFC@..., Denny Anspach <danspach@...> wrote:
>> Truck makers make bushings peculiar to their truck bolsters?
>> Denny
>> Denny S. Anspach, MD
>> Sacramento
> Doc,
> I fail to see why truck makers need to be responsible for other
> manufacturers' poorly designed body bolsters. The de facto standard in
> the hobby for the last forty years has been a clearance hole for a
> 1/8" dia. boss, so the truck doesn't pivot around the threads, and the
> screw can be tightened solid without binding the truck. If it wasn't
> for the fact that Kadee persists in adhering to the outdated and
> obsolete NMRA standard, the available trucks would have matched this
> standard 100%, at least before the recent wave of designed in China
> stuff started diverging again.
> There is no reason why resin kit makers can't mold the boss on their
> parts; I was even able to have it included on white metal parts. The
> fact that it might need to be removed to accommodate a few trucks is
> no excuse; it's easier for the modeler to carve it off rather than
> cobble it up from nothing.
> That being said, If you buy Accurail trucks, you get the added value
> of someone actually giving this some thought during the design
> process. Accurail trucks come with the clearance hole for the 1/8"
> boss, and so will fit most any other injection molded kit. The inside
> diameter of the screw head recess is designed to be a decent running
> fit on the ANSI standard dimensions for the pan head on a #2 screw;
> either a wood screw, type AB thread cutting screw (sheet metal screw)
> or machine screw. So, if you use pan head screws, the O.D. of the head
> should give acceptable results, although the standard for pan heads
> does provide wider tolerances that the molded bosses are usually held
> to. You can even trim the bushing off the ubiquitous Kadee #5 box, and
> you will find that the thickness of the Accurail truck bolster is such
> that the Kadee bushing is the proper length.
> Dennis Storzek
> Accurail, Inc.
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