Topics

Coupler Mounting Screws

Wayne Cohen
 
Edited

In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results

The 2-56 screws Kadee is now supplying with #178 (and other?) couplers have a slightly wider and flatter appearing head.  Have any of you tried them?  If so, how have they worked out?

Thanks,

Wayne Cohen

Benjamin Hom
 

Wayne Cohen wrote:
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."

Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.


Ben Hom

Schuyler Larrabee
 

I’ve not bought new Kadees in some time, but quite a while ago, I bought some brass 2-56 screws from McMaster-Carr that have a very flat head, < 1/16” thick.  They are slotted head, unfortunately, but I don’t think this thin a head COULD be done in a cross-point version.

 

They were not expensive at all, and M-C service meant that I had them in my hand second day later.

 

Schuyler

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Wayne Cohen
Sent: Wednesday, July 08, 2020 1:05 PM
To: main@RealSTMFC.groups.io
Subject: [RealSTMFC] Coupler Mounting Screws

 

In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped at off in normal use and I quit using them. Slot or Phillips head - same results

The 2-56 screws Kadee is now supplying with #178 (and other?) couplers have a slightly wider and flatter appearing head.  Have any of you tried them?  If so, how have they worked out?

Thanks,

Wayne Cohen

Mont Switzer
 

Ben,

 

Why I like the Delrin 2-56 screws is I can cut or trim them to the exact length that I want, with ease.  I've done this before and after installation with equal success.

 

Mont Switzer


From: main@RealSTMFC.groups.io [main@RealSTMFC.groups.io] on behalf of Benjamin Hom [b.hom@...]
Sent: Wednesday, July 08, 2020 1:12 PM
To: main@realstmfc.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

Wayne Cohen wrote:
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."

Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.


Ben Hom

Douglas Harding
 

I have an electrician’s wire stripper that also is designed to cut a variety of small screw sizes, including 2-56. Works great on brass screws, gives a nice clean cut, just touch up with a file and I have one any length I want.

 

Doug Harding

www.iowacentralrr.org

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Mont Switzer
Sent: Thursday, July 9, 2020 9:43 PM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

Ben,

 

Why I like the Delrin 2-56 screws is I can cut or trim them to the exact length that I want, with ease.  I've done this before and after installation with equal success.

 

Mont Switzer


From: main@RealSTMFC.groups.io [main@RealSTMFC.groups.io] on behalf of Benjamin Hom [b.hom@...]
Sent: Wednesday, July 08, 2020 1:12 PM
To: main@realstmfc.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

Wayne Cohen wrote:
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."

 

Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.

 

 

Ben Hom

Tony Thompson
 

Mont Switzer wrote:

Why I like the Delrin 2-56 screws is I can cut or trim them to the exact length that I want, with ease.  I've done this before and after installation with equal success.

      Works equally well with brass screws, Mont. Just turn a nut onto the screw above the cut, make the cut, then turn the nut back off, cleans up the thread, then file if needed. Almost as quick as with plastic.

Tony Thompson



Mont Switzer
 

Tony,

 

That is how you cut longer bolts and treaded rod in the real world.  Always works.

 

Montford L. Switzer

President

Switzer Tank Lines, Inc.

Fall Creek Leasing, LLC.

mswitzer@...

(765) 836-2914

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Tony Thompson
Sent: Friday, July 10, 2020 12:05 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

Mont Switzer wrote:



Why I like the Delrin 2-56 screws is I can cut or trim them to the exact length that I want, with ease.  I've done this before and after installation with equal success.

 

      Works equally well with brass screws, Mont. Just turn a nut onto the screw above the cut, make the cut, then turn the nut back off, cleans up the thread, then file if needed. Almost as quick as with plastic.

 

Tony Thompson

 

 

 

Nelson Moyer
 

I used the Kadee plastic screws when I first started building resin kits, and two negatives soon appeared. The first problem was that occasionally a screw would freeze and trying to remove it would strip the head, which required drilling a new hole, filling it with styrene and starting over. The second problem is that the Phillips head on the Kadee screws is large, requiring a #1 Phillips screwdriver instead of the #0 screwdriver I use for metal screws. That can be a problem in tight clearance situations. It’s really quite easy to strip the plastic head, as it’s not deep enough to properly engage the screwdriver tip. I use 1-56 pan Phillips metal machine screws from FMW Fasteners in  ¼ in., 3/16 in., and 5/32 in. lengths. I ordered 500 each online, and they should last a lifetime. These screws have a deep Philips head that perfectly fits a #0 screwdriver, and I’ve ever had one fail.

 

Nelson Moyer

 

From: main@RealSTMFC.groups.io [mailto:main@RealSTMFC.groups.io] On Behalf Of Mont Switzer
Sent: Friday, July 10, 2020 6:39 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

Tony,

 

That is how you cut longer bolts and treaded rod in the real world.  Always works.

 

Montford L. Switzer

President

Switzer Tank Lines, Inc.

Fall Creek Leasing, LLC.

mswitzer@...

(765) 836-2914

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Tony Thompson
Sent: Friday, July 10, 2020 12:05 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

Mont Switzer wrote:

 

Why I like the Delrin 2-56 screws is I can cut or trim them to the exact length that I want, with ease.  I've done this before and after installation with equal success.

 

      Works equally well with brass screws, Mont. Just turn a nut onto the screw above the cut, make the cut, then turn the nut back off, cleans up the thread, then file if needed. Almost as quick as with plastic.

 

Tony Thompson

 

 

 

Tim O'Connor
 


I use the Kadee screws for cases (hoppers and flats) where the length of the screw causes it to emerge
and become visible - or if it interferes with something inside the car, like a weight. I install it, and then cut it
off flush. If you're snapping them, you're over tightening them. Use a tiny drop of Loctite if you're worried
about them coming out.

Tim O'Connor


On 7/8/2020 1:12 PM, Benjamin Hom wrote:
Wayne Cohen wrote:
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."

Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.


Ben Hom

--
Tim O'Connor
Sterling, Massachusetts

Wayne Cohen
 

Thank you Tim, and all who responded.

I haven’t snapped heads installing them; rather, they snapped in service.  Still, I think Tim is on to something.  I’ll try the new ones on one or two cars - ensuring they are only snug rather than tight - and see how they do.

The latest iteration of the Kadee has a nice appearance: slightly flatter and wider head, and matte finish as compared to the shiny old ones. Rarely any need to paint them either, of course.


Tim O’Connor wrote:
I use the Kadee screws for cases (hoppers and flats) where the length of the screw causes it to emerge
and become visible - or if it interferes with something inside the car, like a weight. I install it, and then cut it
off flush. If you're snapping them, you're over tightening them. Use a tiny drop of Loctite if you're worried
about them coming out.
--
Wayne Cohen

Claus Schlund \(HGM\)
 


Hi List Members,
 
It is exactly for this reason that I prefer brass screws - they are relatively easy to cut to a custom length (much easier than steel screws), but since they are metal they are stronger than plastic screws
 
Claus Schlunnd
 

----- Original Message -----
Sent: Friday, July 10, 2020 8:31 AM
Subject: Re: [RealSTMFC] Coupler Mounting Screws


I use the Kadee screws for cases (hoppers and flats) where the length of the screw causes it to emerge
and become visible - or if it interferes with something inside the car, like a weight. I install it, and then cut it
off flush. If you're snapping them, you're over tightening them. Use a tiny drop of Loctite if you're worried
about them coming out.

Tim O'Connor


On 7/8/2020 1:12 PM, Benjamin Hom wrote:
Wayne Cohen wrote:
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."

Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.


Ben Hom

--
Tim O'Connor
Sterling, Massachusetts

Schuyler Larrabee
 

I keep running into a difficulty of the draft gear box wanting to rotate if the screw isn’t really TIGHT, which can be obviated by making sure there is a continuous contact between the back end of the box and the center sill, or, of course, by some adhesive.  I really prefer the very flat headed screws I mentioned before as it reduces the side profile of the screw head.  They look something like this:

But have an even flatter head

When I got the dozens I have, they were only available with the slotted head.  I see now that there are some which are cross-headed screws.

 

Schuyler

 

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Claus Schlund \(HGM\)
Sent: Friday, July 10, 2020 10:13 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

Hi List Members,

 

It is exactly for this reason that I prefer brass screws - they are relatively easy to cut to a custom length (much easier than steel screws), but since they are metal they are stronger than plastic screws

 

Claus Schlunnd

 

----- Original Message -----

Sent: Friday, July 10, 2020 8:31 AM

Subject: Re: [RealSTMFC] Coupler Mounting Screws

 


I use the Kadee screws for cases (hoppers and flats) where the length of the screw causes it to emerge
and become visible - or if it interferes with something inside the car, like a weight. I install it, and then cut it
off flush. If you're snapping them, you're over tightening them. Use a tiny drop of Loctite if you're worried
about them coming out.

Tim O'Connor


On 7/8/2020 1:12 PM, Benjamin Hom wrote:

Wayne Cohen wrote:
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."

 

Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.

 

 

Ben Hom


--
Tim O'Connor
Sterling, Massachusetts

Daniel A. Mitchell
 

What you illustrate is called a “binder-head” screw. They have the thinnest head among the common screw types. Due to the shallow head few have Phillips or cross-head driving recesses. They were developed to hold wires to terminals, called “binding”. They are commonly found in the electronics industry, especially on barrier-type terminal strips.

Slightly thicker and more rounded are “pan-head” screws. The thicker head allows, in addition the common slot, use of Phillips or cross-head driving recesses.

Next up in head thickness is the common “round-head” screw where the head is nearly hemispherical.

There are many other types. The more common include:

“stove-head” screws (sometimes called" truss-head”) that have a larger diameter thin head. The name comes from their original use in assembling sheet metal heating and cooking stoves.

“fillister-head” screws (sometimes called “cheese-head”) have a thick cylindrical head, usually with a slightly convex top surface. These are found mostly in machine assembly. Some of the Kadee plastic screws have this head.

Most of the thicker head styles are also available with “Allen” (hex socket) driving recesses, and nowadays “”Torx” or similar star-shaped recesses.

Complicating the issue is that every make uses slightly different shape and proportions, plus many commercial large-scale users specify their own designs.

Dan Mitchell
==========


On Jul 10, 2020, at 11:47 AM, Schuyler Larrabee via groups.io <schuyler.larrabee@...> wrote:

I keep running into a difficulty of the draft gear box wanting to rotate if the screw isn’t really TIGHT, which can be obviated by making sure there is a continuous contact between the back end of the box and the center sill, or, of course, by some adhesive.  I really prefer the very flat headed screws I mentioned before as it reduces the side profile of the screw head.  They look something like this:
<image003.jpg>
But have an even flatter head
When I got the dozens I have, they were only available with the slotted head.  I see now that there are some which are cross-headed screws.
 
Schuyler
 
 
From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Claus Schlund \(HGM\)
Sent: Friday, July 10, 2020 10:13 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws
 
Hi List Members,
 
It is exactly for this reason that I prefer brass screws - they are relatively easy to cut to a custom length (much easier than steel screws), but since they are metal they are stronger than plastic screws
 
Claus Schlunnd
 
----- Original Message ----- 
Sent: Friday, July 10, 2020 8:31 AM
Subject: Re: [RealSTMFC] Coupler Mounting Screws
 

I use the Kadee screws for cases (hoppers and flats) where the length of the screw causes it to emerge
and become visible - or if it interferes with something inside the car, like a weight. I install it, and then cut it
off flush. If you're snapping them, you're over tightening them. Use a tiny drop of Loctite if you're worried
about them coming out.

Tim O'Connor


On 7/8/2020 1:12 PM, Benjamin Hom wrote:
Wayne Cohen wrote: 
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."
 
Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.
 
 
Ben Hom

-- 
Tim O'Connor
Sterling, Massachusetts


Matt Goodman
 

Interesting. I’ve seen 4-40 shears on wire strippers, but not 2-56. The former works, but requires cleanup. Ironically, my full size strippers will cut down to the 4-40, whereas the smaller strippers that will do 30 gauge wire only goes down to 6’s.

Matt Goodman
Columbus, Ohio, US

On Jul 9, 2020, at 10:57 PM, Douglas Harding <iowacentralrr@...> wrote:

I have an electrician’s wire stripper that also is designed to cut a variety of small screw sizes, including 2-56. Works great on brass screws, gives a nice clean cut, just touch up with a file and I have one any length I want.
 
 
From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Mont Switzer
Sent: Thursday, July 9, 2020 9:43 PM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws
 

Ben,

 

Why I like the Delrin 2-56 screws is I can cut or trim them to the exact length that I want, with ease.  I've done this before and after installation with equal success.

 

Mont Switzer


From: main@RealSTMFC.groups.io [main@RealSTMFC.groups.io] on behalf of Benjamin Hom [b.hom@...]
Sent: Wednesday, July 08, 2020 1:12 PM
To: main@realstmfc.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

Wayne Cohen wrote: 
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."
 
Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.
 
 

Ben Hom


John Monrad
 


Dimensions per McMaster-Carr for 2-56 screw heads, 18-8 ss:

Type    Diameter (in)   Height (in)   /100 (1/4in)
Truss       0.194              0.053             $4.96
Binding*  0.181              0.050             $4.69
Pan          0.167              0.063             $4.49

*Slotted only

John Monrad

Schuyler Larrabee
 

Actually, binder head screws are used in conjunction with binder posts, a T-shaped internally-threaded post which fits in standard punched holes in paper.  The posts and the screws are used to >>bind<< booklets and to get to topic, freight car diagram books.  Having caused the ELHS to republish freight, passenger and locomotive diagram books, I am quite familiar with them.

 

Schuyler

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Daniel A. Mitchell
Sent: Friday, July 10, 2020 4:27 PM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

What you illustrate is called a “binder-head” screw. They have the thinnest head among the common screw types. Due to the shallow head few have Phillips or cross-head driving recesses. They were developed to hold wires to terminals, called “binding”. They are commonly found in the electronics industry, especially on barrier-type terminal strips.

 

Slightly thicker and more rounded are “pan-head” screws. The thicker head allows, in addition the common slot, use of Phillips or cross-head driving recesses.

 

Next up in head thickness is the common “round-head” screw where the head is nearly hemispherical.

 

There are many other types. The more common include:

 

“stove-head” screws (sometimes called" truss-head”) that have a larger diameter thin head. The name comes from their original use in assembling sheet metal heating and cooking stoves.

 

“fillister-head” screws (sometimes called “cheese-head”) have a thick cylindrical head, usually with a slightly convex top surface. These are found mostly in machine assembly. Some of the Kadee plastic screws have this head.



Most of the thicker head styles are also available with “Allen” (hex socket) driving recesses, and nowadays “”Torx” or similar star-shaped recesses.



Complicating the issue is that every make uses slightly different shape and proportions, plus many commercial large-scale users specify their own designs.



Dan Mitchell

==========

 



On Jul 10, 2020, at 11:47 AM, Schuyler Larrabee via groups.io <schuyler.larrabee@...> wrote:

 

I keep running into a difficulty of the draft gear box wanting to rotate if the screw isn’t really TIGHT, which can be obviated by making sure there is a continuous contact between the back end of the box and the center sill, or, of course, by some adhesive.  I really prefer the very flat headed screws I mentioned before as it reduces the side profile of the screw head.  They look something like this:

<image003.jpg>

But have an even flatter head

When I got the dozens I have, they were only available with the slotted head.  I see now that there are some which are cross-headed screws.

 

Schuyler

 

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Claus Schlund \(HGM\)
Sent: Friday, July 10, 2020 10:13 AM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

Hi List Members,

 

It is exactly for this reason that I prefer brass screws - they are relatively easy to cut to a custom length (much easier than steel screws), but since they are metal they are stronger than plastic screws

 

Claus Schlunnd

 

----- Original Message ----- 

Sent: Friday, July 10, 2020 8:31 AM

Subject: Re: [RealSTMFC] Coupler Mounting Screws

 


I use the Kadee screws for cases (hoppers and flats) where the length of the screw causes it to emerge
and become visible - or if it interferes with something inside the car, like a weight. I install it, and then cut it
off flush. If you're snapping them, you're over tightening them. Use a tiny drop of Loctite if you're worried
about them coming out.

Tim O'Connor


On 7/8/2020 1:12 PM, Benjamin Hom wrote:

Wayne Cohen wrote: 
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."

 

Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.

 

 

Ben Hom


-- 
Tim O'Connor
Sterling, Massachusetts

 

Douglas Harding
 

Matt you are right. Mine are 4-40, but I have used them to cut brass 2-56 screws.

 

Doug Harding

www.iowacentralrr.org

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Matt Goodman via groups.io
Sent: Friday, July 10, 2020 3:52 PM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

Interesting. I’ve seen 4-40 shears on wire strippers, but not 2-56. The former works, but requires cleanup. Ironically, my full size strippers will cut down to the 4-40, whereas the smaller strippers that will do 30 gauge wire only goes down to 6’s.

 

Matt Goodman

Columbus, Ohio, US

 

On Jul 9, 2020, at 10:57 PM, Douglas Harding <iowacentralrr@...> wrote:

 

I have an electrician’s wire stripper that also is designed to cut a variety of small screw sizes, including 2-56. Works great on brass screws, gives a nice clean cut, just touch up with a file and I have one any length I want.

 

 

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> On Behalf Of Mont Switzer
Sent: Thursday, July 9, 2020 9:43 PM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

 

Ben,

 

Why I like the Delrin 2-56 screws is I can cut or trim them to the exact length that I want, with ease.  I've done this before and after installation with equal success.

 

Mont Switzer


From: main@RealSTMFC.groups.io [main@RealSTMFC.groups.io] on behalf of Benjamin Hom [b.hom@...]
Sent: Wednesday, July 08, 2020 1:12 PM
To: main@realstmfc.groups.io
Subject: Re: [RealSTMFC] Coupler Mounting Screws

Wayne Cohen wrote: 
"In the distant past, I tried Kadee’s 2-56 Delrin screws to mount couplers.  Many of the heads snapped off in normal use and I quit using them. Slot or Phillips head - same results."

 

Slot or Phillips is irrelevant - why use plastic screws if electrical shorts are not an issue?  Use metal screws instead.

 

 

Ben Hom

 

Bud Rindfleisch
 

I've found "button head" screws from Micro Fasteners to be very low profile.I bought them in 2-56 and 0-80. They use a small allen wrench of which the size escapes me right now. I like the way they look compared to a phillips cross slot when underbody detailing is important.
     The attached pic is on my S scale scratchbuilt underframe for an LV caboose I'm converting to scale from Am Flyer. I use the 0-80 with the Kadee 802 couplers.
      Bud Rindfleisch

Paul Catapano
 

I found a surplus hardware store in Burbank, Ca. (Joe Factor Hardware now Luky’s Hardware) that sold assorted 2-56 screws for $1 a POUND (Know how many 2-56 x 3/16 pan head screws are in a pound? A whole lot!)
I bought every type, version, and length of 2-56 screw they had;
Brass, steel, stainless steel, pan head, counter sunk, round head, etc.
They also had washers for these screws, thin enough to use for minor coupler height adjustment.
Check on line for surplus hardware stores near you, or try screw and bolt suppliers and buy in bulk.
I know McMaster-Carr carries a wide variety.



Paul Catapano
Winchester, Va.

Daniel A. Mitchell
 

The Allen “button-head” is typically similar to a Pan-head, but maybe just a tad thinner. One nice thing about them is that they are almost always blackened. They’re also a higher strength screw, but I can’t imagine that being a major factor in model railroading.

The one downside is that they are steel, and thus magnetic. This can cause problems with Kadee-type couplers. An alternative is to get Stainless-steel Allen heads screws ... these are minimally magnetic and have the same profile … they do need to be painted however.

Dan Mitchell
==========

On Jul 11, 2020, at 12:42 PM, Bud Rindfleisch <BlackDiamondRR@...> wrote:

I've found "button head" screws from Micro Fasteners to be very low profile.I bought them in 2-56 and 0-80. They use a small allen wrench of which the size escapes me right now. I like the way they look compared to a phillips cross slot when underbody detailing is important.
     The attached pic is on my S scale scratchbuilt underframe for an LV caboose I'm converting to scale from Am Flyer. I use the 0-80 with the Kadee 802 couplers.
      Bud Rindfleisch
<LV AM Flyer caboose project 7-5-15 002.jpg>