TR-21 mounting screws

The TR-21 comes with long (1.25 inch) black flathead screws (4-40).
These screws are the countersink type and do not work well with my
fiberglass instrument panel. They have a small head.

I'm looking for a source for machine screws, 4-40 x 1.25", in a black
non-metallic material. Any suggestions would be appreciated.

Raul Boerner

On Mar 24, 3:03*pm, wrote:
The TR-21 comes with long (1.25 inch) black flathead screws (4-40).
These screws are the countersink type and do not work well with my
fiberglass instrument panel. They have a small head.

I'm looking for a source for machine screws, 4-40 x 1.25", in a black
non-metallic material. Any suggestions would be appreciated.

Raul Boerner

"non-metallic material" or non-magnetic? Most mounting hardware is
brass or nylon (very low strength)and the heads are painted with black
prior to installation.

Try fastenal:


http://www.fastenal.com/web/products...0181675&ucst=t

On Mar 24, 2:03*pm, wrote:
The TR-21 comes with long (1.25 inch) black flathead screws (4-40).
These screws are the countersink type and do not work well with my
fiberglass instrument panel. They have a small head.

I'm looking for a source for machine screws, 4-40 x 1.25", in a black
non-metallic material. Any suggestions would be appreciated.

Raul Boerner

Part 2 of this game is guess what a TR-21 is and guess which country
you are in.

You mean a Trig TT-21 transponder?

In the USA lots of places sell different instrument panel screws.
Often available in brass or aluminum with a black coating. Aircraft
Spruce, I think Cumulus Soaring and I assume many others. You might
have a problem with 4-40 but look at those places.

Darryl

On 3/24/2010 5:03 PM, wrote:
The TR-21 comes with long (1.25 inch) black flathead screws (4-40).
These screws are the countersink type and do not work well with my
fiberglass instrument panel. They have a small head.

I'm looking for a source for machine screws, 4-40 x 1.25", in a black
non-metallic material. Any suggestions would be appreciated.

Raul Boerner

When it comes to hardware, mcmaster.com is a great resource.

--
Mike Schumann

On Mar 24, 3:35*pm, Darryl Ramm wrote:
On Mar 24, 2:03*pm, wrote:

The TR-21 comes with long (1.25 inch) black flathead screws (4-40).
These screws are the countersink type and do not work well with my
fiberglass instrument panel. They have a small head.

I'm looking for a source for machine screws, 4-40 x 1.25", in a black
non-metallic material. Any suggestions would be appreciated.

Raul Boerner

Part 2 of this game is guess what a TR-21 is and guess which country
you are in.

You mean a Trig TT-21 transponder?

In the USA lots of places sell different instrument panel screws.
Often available in brass or aluminum with a black coating. Aircraft
Spruce, I think Cumulus Soaring and I assume many others. You might
have a problem with 4-40 but look at those places.

Darryl

Darryl,

Indeed, my error. I am installing a Trig TT-21. Another error is that
the machine screw is 1.5" long instead of the slightly shorter version
posted. The 4-40 in 1.5 iches, panhead and black, is a problem.

Raul Boerner

Hi,

I don't have exactly what you need, but I have recently started stocking up
on a variety of "glider panel screws". I stock them both in black oxided
stainless steel (nearly non-magnetic) and brass with black oxide. The sizes
I stock are listed below. I found it was easy to get black stainless steel
screws at McMaster Carr, but black brass was tough. I had to have the
screws treated locally in a large batch.

The stainless steel screws don't seem to affect compasses - even when a box
of screws is near the compass.

In stock in both brass with black oxide and stainless steel with black oxide
- M3 x 8 mm - pan head
- M4 x 10 mm - pan head
- M4 x 10 mm - pan head
- M4 x 12 mm - pan head

I also stock the following screws for use in a variety of U.S. made small
instruments: 6-32 x 1/2" black stainless steel.

I also stock 8-32 x 1/2" in black brass

I also stock 8-32 x 3/4" and 8-32 x 5/8" in flat head black stainless steel
and 8-32 x 5/8" in pan head black stainless steel.

I think that is most everything. I'll add them all to my web site soon.

Note: Winter used to supply aluminum M4 screw that were black, but they
can't get them anymore. They now supply black treated brass screws. I have
a few of the aluminum ones remaining in stock.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

wrote in message
...
On Mar 24, 3:35 pm, Darryl Ramm wrote:
On Mar 24, 2:03 pm, wrote:

The TR-21 comes with long (1.25 inch) black flathead screws (4-40).
These screws are the countersink type and do not work well with my
fiberglass instrument panel. They have a small head.

I'm looking for a source for machine screws, 4-40 x 1.25", in a black
non-metallic material. Any suggestions would be appreciated.

Raul Boerner

Part 2 of this game is guess what a TR-21 is and guess which country
you are in.

You mean a Trig TT-21 transponder?

In the USA lots of places sell different instrument panel screws.
Often available in brass or aluminum with a black coating. Aircraft
Spruce, I think Cumulus Soaring and I assume many others. You might
have a problem with 4-40 but look at those places.

Darryl

Darryl,

Indeed, my error. I am installing a Trig TT-21. Another error is that
the machine screw is 1.5" long instead of the slightly shorter version
posted. The 4-40 in 1.5 iches, panhead and black, is a problem.

Raul Boerner

On Mar 24, 9:03*pm, wrote:
The TR-21 comes with long (1.25 inch) black flathead screws (4-40).
These screws are the countersink type and do not work well with my
fiberglass instrument panel. They have a small head.

I'm looking for a source for machine screws, 4-40 x 1.25", in a black
non-metallic material. Any suggestions would be appreciated.

Raul Boerner


4-40 screws in that length are hard to come by. Your best bet would be
to use the screws supplied with the TT21 and use countersink finishing
washers. These effectively turn the countersink screw into a pan head
screw and are available in various materials and colours. I have seen
this done successfully on several panels.

Neil

"Neil" wrote in message
...
On Mar 24, 9:03 pm, wrote:
The TR-21 comes with long (1.25 inch) black flathead screws (4-40).
These screws are the countersink type and do not work well with my
fiberglass instrument panel. They have a small head.

I'm looking for a source for machine screws, 4-40 x 1.25", in a black
non-metallic material. Any suggestions would be appreciated.

Raul Boerner


4-40 screws in that length are hard to come by. Your best bet would be
to use the screws supplied with the TT21 and use countersink finishing
washers. These effectively turn the countersink screw into a pan head
screw and are available in various materials and colours. I have seen
this done successfully on several panels.

Neil

Are you *sure* they are 4-40? Considering source of TR21 they may be metric.

Hartley Falbaum

On Mar 25, 5:30*am, "HL Falbaum" wrote:
Are you *sure* they are 4-40? Considering source of TR21 they may be metric.

I wondered the same thing too so I checked the TT-21 installation
manual. It says 4-40.

Andy (GY)

On Mar 25, 8:52*am, Andy wrote:
On Mar 25, 5:30*am, "HL Falbaum" wrote:

Are you *sure* they are 4-40? Considering source of TR21 they may be metric.

I wondered the same thing too so I checked the TT-21 installation
manual. *It says 4-40.

Andy (GY)


I've gone to http://www.smallparts.com for hard to find fasteners.