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Hinge Pin Cutting Edge Photo

Tcheairs

Well Known Member
I would like to make the insertion of my lateral cowling hinge pins easier. The alignment is not perfect and getting them back in is a pain. I have seen several posts where a "cutting" edge was fabricated on the insertion end of a "dummy" pin and used to ream (chucked in drill) the front edges of the hinge eyes so that upon insertion of the lateral pin it would glance off the edge of the hinge eyelet when it hangs up on insertion. I suppose slight "beveling" with a Dremel tool of the front entrance of the hinge bosses might even be a better solution.

Does anyone have a photo of this "cutting" hing pin end? (yes, I use BoShield)
 
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I would like to make the insertion of my lateral cowling hinge pins easier. The alignment is not perfect and getting them back in is a pain. I have seen several posts where a "cutting" edge was fabricated on the insertion end of a "dummy" pin and used to ream (chucked in drill) the front edges of the hinge eyes so that upon insertion of the lateral pin it would glance off the edge of the hinge eyelet when it hangs up on insertion. I suppose slight "beveling" with a Dremel tool of the front entrance of the hinge bosses might even be a better solution.

Does anyone have a photo of this "cutting" hing pin end? (yes, I use BoShield)

Does the pin go in easily if it's only one side of the hinge? If not, then that might be something to fix - perhaps some loops are not aligned right.

Mine were stiff for a while, but now I can install and remove the pins by hand after I aligned all the loops carefully, found one or two that had a bit of epoxy in them, and liberal use of boelube.

I did create a reamer - I just ground one end flat on both sides - nothing complex. That helped get out the bits of epoxy that I had in some of the hinge loops.
 
So, you ground both sides of the end of the pin. I was thinking grounding only one side to a "chisel" type point might cut better, but of course I don't want to damage the loops. Opinion?

Also, what's the difference in Boelube and Boeshield (comes in a spray can)?
 
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I just hit the end of the hinge pin with a hammer. Lay the hinge pin on the flat part of a vice or something and hit the pin to make a little burr about 1/8" from the end. If you bend the pin, just straighten it out. It might take a few hits to get it right.. You don't need much. A littler wiggle at the End of the pin is ok and may even help
If that doesn't do the job, try again.
In my experience, This process doesn't really take anything noticeable off the hinge eyes but it does make them work a lot better.
I also use a piece of scotch rite to clean the hinge pins every time I remove them and lubricate with LPS2 or equivalent.
 
Reaming the eyelets should be your very last resort. Like was already mentioned it is most likely an alignment issue. Try inserting the hinge pin in one half of the hinge at a time. Note any tight spots and bend those eyelets into position and clean them out as needed until the hinge pin goes in and out freely. You would be surprised to find how easy those eyelets get bent and crushed slightly when installing them. Do the same to the other half of the hinge. Did you bevel the eyelets where needed to assist in hinge alignment? Doing that is easiest prior to installing the hinge, but you can still do it using a file or dremel with a cut-off disc. Finally, get a small 1/4" diameter countersink cutter with a long shaft and using a drill motor with a small chuck, put a countersink chamfer on the ends of each eyelet. Run the pin through a couple times to ensure all burs are removed and the eyelets are clean.
Another trick is to grind the hinge pin insertion end into an off-set bullet nose point. This helps with aligning the point into the eyelet on curves simply by twisting the hinge pin to get the point more in-line with the eyelet opening. The eyelet chamfer will also help guide the pin into the eyelet.
Don't overdo the bevel grinding, do just enough so the hinge half go together with no issues. DO NOT REAM, as you are just prematurely wearing the hinges and not correctly fixing the issues.
 
David, How would you be able to squarely align the 1/4" countersink cutter to the front eyelet? There's not that much room between eyelets. Would a dremel conical sanding tip do the same thing? I do have an alignment issue and I will of course first try to correct that.
 
David, How would you be able to squarely align the 1/4" countersink cutter to the front eyelet? There's not that much room between eyelets. Would a dremel conical sanding tip do the same thing? I do have an alignment issue and I will of course first try to correct that.

A Dremel with a conical shaped carbide burr would work great. Get it as close to alignment as possible. All you really want to do is form a funnel to help guide and bend the hinge pin in place. I just went through this the last couple weeks installing the cowling hinges and the plenum hinges. I was surprised to find several eyelets that got bent or slightly crushed when I riveted them on. I also had a few eyelets fill with epoxy around the hinge pins building the plenum. A machinist scribe with one end that has a 90* end worked great for picking out the thin film of cured epoxy and also opening up the ends of the eyelets that were out of round. Clean and lubricate the hinge pins EVERY time you remove them. You will be rewarded with a really nice pull/push pin fastener system if you take the time to do it right now.
 
Reaming the eyelets should be your very last resort. Like was already mentioned it is most likely an alignment issue. Try inserting the hinge pin in one half of the hinge at a time. Note any tight spots and bend those eyelets into position and clean them out as needed until the hinge pin goes in and out freely. You would be surprised to find how easy those eyelets get bent and crushed slightly when installing them. Do the same to the other half of the hinge. Did you bevel the eyelets where needed to assist in hinge alignment? Doing that is easiest prior to installing the hinge, but you can still do it using a file or dremel with a cut-off disc. Finally, get a small 1/4" diameter countersink cutter with a long shaft and using a drill motor with a small chuck, put a countersink chamfer on the ends of each eyelet. Run the pin through a couple times to ensure all burs are removed and the eyelets are clean.
Another trick is to grind the hinge pin insertion end into an off-set bullet nose point. This helps with aligning the point into the eyelet on curves simply by twisting the hinge pin to get the point more in-line with the eyelet opening. The eyelet chamfer will also help guide the pin into the eyelet.
Don't overdo the bevel grinding, do just enough so the hinge half go together with no issues. DO NOT REAM, as you are just prematurely wearing the hinges and not correctly fixing the issues.

I agree with all the above

The two things that are often overlooked, that can improve pin insertion a lot are pre-shaping the pin so that is closely matches the curve of the hinge, and grinding an offset point on the end such that the point is moved off center towards the edge of the pin, in the direction that the pin is curving as it moves through the hinge.
 
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