pitot hardware help

Hey all-

Garmin Pitot tube calls for #6-32 fasteners about 1/4" long. Nylon patch recommended.

Does anybody know off the top of their head what a good part number and source might be for something like that with a 100 degree countersink and a nylon patch on the threads? Maybe with an Allen head?

If such a creature doesn't exist, my fall back plan will just be some AN507s with red lock tite, unless somebody tells me that's a bad idea on a heated pitot.

Thanks,

Terr

Desert Rat said:

Hey all-

Garmin Pitot tube calls for #6-32 fasteners about 1/4" long. Nylon patch recommended.

Does anybody know off the top of their head what a good part number and source might be for something like that with a 100 degree countersink and a nylon patch on the threads? Maybe with an Allen head?

If such a creature doesn't exist, my fall back plan will just be some AN507s with red lock tite, unless somebody tells me that's a bad idea on a heated pitot.

Thanks,

Terr

Click to expand...

I buy my hard to find parts like that locally at a store called ET Fasteners. There should be some kind of store like that in your neck of the woods with another name.

Desert Rat said:

Hey all-

Garmin Pitot tube calls for #6-32 fasteners about 1/4" long. Nylon patch recommended.

Does anybody know off the top of their head what a good part number and source might be for something like that with a 100 degree countersink and a nylon patch on the threads? Maybe with an Allen head?

If such a creature doesn't exist, my fall back plan will just be some AN507s with red lock tite, unless somebody tells me that's a bad idea on a heated pitot.

Thanks,

Terr

Click to expand...

Don't think I'd use red Loctite...you may (will) have to remove it at some point in the future. Blue Loctite should suffice.

Just done 2 Dynon pitot's on Gretz mounts and just shortened a#6 screw and used blue Loctite.

After a little more measuring and head scratching, I see that the wall thickness on the steel mast that I inherited with this project is about .050. The countersink on a AN507 (#6 machine screw) is about .090. In other words, it's a no go with a countersunk #6 unless I can find something with a smaller head i.e shallower countersink.

How are people dealing with this? Just using a pan head screw, shouldered countersink? or what?

I've seen people using pop rivets to hold the pitot tube inside the housing mast. I am thinking of just using the pop-rivet dimpling tool on the mast and use the CS4 pop rivets. This is what I am planning to do in the next few months.

I just used round head screws, why do you need to countersink 4 screws? Drag speed loss of 0.0005 knots?

Yup, pretty much- but I'm about to accept defeat and just use pan head #6 and try to find that .0005 kts somewhere else

PhatRV said:

I've seen people using pop rivets to hold the pitot tube inside the housing mast. I am thinking of just using the pop-rivet dimpling tool on the mast and use the CS4 pop rivets. This is what I am planning to do in the next few months.

Click to expand...

For me, I see a couple of potential problems with this.

On my setup, the back side of a dimple would prevent the tube base from sliding into the mast. Pretty sure you'd have to countersink it regardless.

Second, my pitot is a garmin and it comes with mounting holes already drilled and tapped for a #6, but the hole is only about 1/4" deep so I don't have a high level of confidence that I could get a rivet short enough to fit in there, that would still swell up enough to fill a #6 hole.

Plus it seems like it would be a bear to get it apart again if the need ever arose.

As I said above, I think I'll likely just give up on this one, use pan head #6's and move on. The other alternative would be to find a flush head fastener that is less than .050 deep, which probably isn't worth the effort at this point.

Desert Rat said:

Yup, pretty much- but I'm about to accept defeat and just use pan head #6 and try to find that .0005 kts somewhere else

Click to expand...

Exactly what I did. Use regular screws and move on. Use the time saved searching for and finding other things I can remove to save weight and therefore get more speed with less fuel use.