The International Cessna 170 Association

What length flush camloc fasteners do I need to secure the cowling latches on my 52 B? EC

I am also having trouble with this, all the research so far seems there is not one long enough to work. I may be a wrong.

I'd encourage you guys to review the various post on the subject of these latches. In the series of pictures Josh posted he showed that even with the bottom part of the latch secure it is still possible for the upper portion of the latch to come loose. In this post I referenced the L-19 p/n 0652070 which is a "U"-shaped piece of metal that Cessna used on the L-19 to secure the upper portion of the latch. In my opinion adding that part or going to the Dip Davis Latch are the best options for securing the upper cowling.

That being said, here is the information y'all are looking for. You need five parts: the stud, grommet, grommet retaining ring , split ring retainer for stud and receptacle. Camloc makes the heavy duty 4002 series studs and the light duty 2700 series flush studs. While the 2700 series studs would be adequate from a strength standpoint I havn’t found them for sale in the length required. Because of the play in the lower latch the dimension varies but on my NOS latch I measured 0.540" grip length with the latch fully depressed. Add to this 0.026" for the plus flush grommet, p/n 4002-N, and the grip required is 0.566". This requires stud p/n 40S5-18 which is available from Pegasus. Because the width of the lower latch is 0.650" I would not use the flush style grommet as that would require countersinking into the radius of the latch. So use the "Plus Flush" grommet, p/n 4002N.

The bottom picture is a cheaper (and uglier) alternative to using Camlocs. The bolt is threaded down to the head and then secured to the latch housing with a nut. It’s similar to what Josh pictured — and just as ineffective.

Gary,
Really good info. Thanks. Securing my latches better is one of the things on my list. One question about the L-19 option though. How is the L-19 U-shaped piece (p/n 0652070) attached to the latch? The L-19 diagram in the thread of your link is hard to see. I can't tell where exactly it's located on the latch or how it's attached.

Gene,
Here’s a picture from my spares stash. I had assumed this was how the retaining "U" clip was mounted on the L-19 but after googling 0652068-1, the L-19 latch assembly part number, I see that I am incorrect. The L-19 latch holds down the bottom rather than the top latch as can be seen below. I think my sample would be a better way to mount the "U" clip. Thinking further on the Camloc modification I’m wondering how much of a misalignment between the stud and the receptical these fasteners can take. As one can see in my earlier picture, with the latch fully depressed, the top and bottom faces are nowhere near parallel. If one could somehow have a stop to only allow the latch to go down to being parallel I think the Camloc would work better. I measured 0.630” with the latch roughly parallel with the base. Starting on page F-1 here I see that Camloc does make longer studs in the 2700 series. 0.630” = 16 mm so a -20 stud would work. The question is who sells studs this long? Does A/C Spruce do special orders?

This might work.

A few days ago I was at an airport with an L-19 Bird Dog on the field and I got permission to photograph the cowl latches on it. So to round out this thread, here are the photos. Sorry I didn't have a tape measure to take measurements, but I don't think they really are necessary. As you can see from the photos, the Bird Dog has two latch safety features not found on the 170's: a dimple and corresponding hole in the top portion of the latch (which I believe Bruce identified in another thread), and the U bracket with pin identified above by Gary around the bottom lever portion of the latch.
The dimple in the upper portion of the latch is just a small rivet with the shop head acting as the dimple. I'm not sure the dimple was intentionally rounded, or just rounded from use.

I have always wondered where the latch safties on my airplane came from.

Now I know. Thanks, Gary/Gene!

A similar "fix" was enabled by a previous owner of 62C, and it appears to work quite well. A very small machine screw was installed installed in the fixed portion of the latch with a corresponding hole drilled in the latch itself. The entire latch was then secured with a screw into a nutplate. I do need to remove the screws from both latches every time I preflight, but that 30 seconds of time is a non-issue and the latches are completely secured from coming loose during flight.

Thanks, I tried to upload the pictures I have but the file was to large. I tried to reduce it and then it was the wrong size. Anyway, I ordered what I thought should work from Aircraft Spruce a -9 but it's to big. I'll have to send back and try for another size. The -9 had a diameter of .344 I need a .250. If I can figure out the photo problem I'll post them.

Thanks, Don