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WineStream · 11-04-2011, 06:14 PM

This is a specific case to my '77 Argosy moho, but I suppose it could apply to other moho's of similar vintage.

I removed the lock (from the entry door) and the accompanying latch from the door frame for some repair. I've made the repairs and now I'm ready to get everything back together. The lock mechanism went back into the door no problem. The latch on the door frame...this is the problem. There were two bolts of some sort inside the frame. From what I could see before they disappeared into the depths of the frame, they seemed to be silicone-glued in place. However, when I attempted to re-insert the screws to attach the latch, I only succeeded in knocking the remaining glue loose and thus losing the bolts deep below. I am now left with what is shown in the attached picture. It appears as though the holes were rough-drilled with a bit (from the factory???) at some point. There's no way a 1/4-20 nut went through there. The nut would have had to have been glued in place at the factory before door installation when the entire moho was built?!?

Has anyone else removed their lock latch and run into this problem when re-installing? What was your solution? Even if I could get another nut in there, I don't know how I'd hold it in place to get torque on it. The only other hole in the door frame is the equal hole for the second screw to hold the latch. My first idea was to drill a new hole in the frame, maybe 3/4" and in the middle of the two existing holes and the hold a nut in place with a magnet and pray that I catch a thread.

idroba · 11-04-2011, 07:42 PM

Just wondering if a "riv nut" or "nut cert" could be used to do the job. In case you are not familiar with them, they are a threaded insert which is installed with a threaded piece that is held in a pop rivet like gun. Once inserted in the hole (which must be very close in size to the insert) and the pulling device pulled by the tool, the interior of the nut expands and holds things firmly in place, so you have essentially put a threaded insert in from the front. Then you can use it like any threaded hole.

My description is not very good, and I am sending a URL of a photo of the tool used which I had posted on another forum. I know 1/4 -20 ones are available as I have used them. I would advise steel ones however, not the Al ones, as they are considerably stronger especially for the door latch job you are doing.

1491_p17256.jpg - My Photo Gallery

WineStream · 11-04-2011, 08:10 PM

Thanks for the suggestion. I couldn't quite get from the picture / link what a rivnut does, so I googled it. I get it now. It also seems as though these are relatively common items. Some of them don't even need the special install tool. They are available from McMasterCarr, and the co. that I work for seems to use McM as our supply house for everything. I ordered something from McM just earlier today, actually. I will have to ask around in our maintenance dept. I am thinking that we have an installation tool already. I can (hopefully) buy a bag of inserts, borrow the tool, and fix myself up.

If there's other ideas out there, please post, but the rivnut seems like a good solution.

idroba · 11-04-2011, 11:00 PM

You can very often get rivnuts at a well stocked hardware store, such as ACE or True Value. Since you only need a couple it might be a good source for you.

Again, I recommend only the steel ones for this job. Put some anti seeze on the bolts you use to hold the lock latch. Use only the drill size recommended for the rivnut you use, that is quiet critical for a good tight fit. You might want to experiment on a piece of scrap Al to be sure you see how they work and fit prior to drilling out the existing holes.

WineStream · 11-05-2011, 06:34 AM

Actually, I'm concerned that the holes might already be too big for the 1/4-20 thread rivnut. I'd say the existing hole is at least 3/8 in diameter. Obviously drilling new holes higher or lower is not an option since the latch must align with the lock.

I'm going to be traveling for work in the next week so I won't make much progress on the moho, but I should have plenty of down time during travels to seek out larger hardware stores and see if I can find a rivnut and maybe a cheap/simple install tool.

idroba · 11-06-2011, 10:02 AM

They also make a rubber "well nut" that is similar to the riv nut, but is made out of rubber with a brass insert for the threads. When put into the mounting hole, and a bolt put in and tightened, the rubber pulls up against the rear of the hole, and locks things into place. I don't think they are as strong as the riv nut, but may be more forgiving on the mounting hole size.

Another possibility, if the latch plate can mount out just a little, is to mount the latch to another piece of Aluminum and then rivet that to the existing frame. It may not be possible I understand, depending on the clearances you have to work with, but there is a reasonable amount of "slop" in the door and latch position, so it might work out that you have enough room.

Splitrock · 11-06-2011, 10:47 AM

Why not just remove the inside skin to get access?

WineStream · 11-06-2011, 11:52 AM

Quote:

Originally Posted by idroba

They also make a rubber "well nut" that is similar to the riv nut, but is made out of rubber with a brass insert for the threads. When put into the mounting hole, and a bolt put in and tightened, the rubber pulls up against the rear of the hole, and locks things into place. I don't think they are as strong as the riv nut, but may be more forgiving on the mounting hole size.

Ironically, I was looking at these at TSC this morning. Unfortunately, the only 1/4"-20 well nut that they had was 1" long. The current screws aren't long enough to grab the brass insert and I'm not sure that 1" would even fit inside the frame (obviously after compression it would). So, not wanting a half-@^% solution, I abandoned that idea. I think I'd like the more rigid holding of a rivnut anyway.

Quote:

Another possibility, if the latch plate can mount out just a little, is to mount the latch to another piece of Aluminum and then rivet that to the existing frame. It may not be possible I understand, depending on the clearances you have to work with, but there is a reasonable amount of "slop" in the door and latch position, so it might work out that you have enough room.

The latch plate "interlocks" with the accompanying plate on the lock. Kinda a guillotine type of setup. Adding thickness with an additional plate likely would cause a problem.

Quote:

Originally Posted by Splitrock

Why not just remove the inside skin to get access?

This would be a last resort. In order to accomplish this I would have to completely remove a gaucho and frame for sure. Perhaps also a part of the floor, the overhead locker, etc. If I can spend $50 and 15 minutes, I'll take that long before disassembling half of the moho.

WineStream · 11-06-2011, 12:32 PM

I just ordered the "screwdriver-installed rivet nuts for thin materials" here: McMaster-Carr

If I don't feel they've done a good enough job, then I'll order the tool & insert kit shown here: Rivet Nut Tools | Rivet Nut Tool | Rivet Gun | Rivet Tool | Rivet Pop Gun | Rivet Pneumatic Gun

But, I think the screwdriver-installed ones will likely do fine for my application.

Splitrock · 11-06-2011, 02:43 PM

What's the piece look like that covers the holes?

My trailer is different. It has a strike plate with a hole in the center.

Splitrock · 11-06-2011, 03:29 PM

I might just use cross dowel barrel nuts and hold them from the outside through the access holes. These are used in woodworking all the time for blind right angle connections like bed rail installations. The barrel nuts can be inserted through a drilled hole and held with a removable bolt threaded into the end. The ones you'd use would have threads in the center and threads in the end.

I'm not referring to Marine type barrel nuts with a slot head. I'm referring to cross dowel barrel nuts like picture below.

http://i.ebayimg.com/00/$(KGrHqMOKjU...+HTW!~~0_3.JPG

I'd probably just make my own from roundbar in the shop. I'd make them from mild steel, thread the holes, and then harden the steel and retap. If I had a ready made nut, I'd just drill and tap the end hole for the hold bolt.

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WineStream · 11-06-2011, 04:33 PM

Quote:

Originally Posted by Splitrock

What's the piece look like that covers the holes?

My trailer is different. It has a strike plate with a hole in the center.

Airstream changed things over the years. I am pretty sure that moho's were always different than the trailers. The following pictures are (in order of appearance):

1) me holding the piece that screws on to the frame

2) the opposite end...the lock in the door

3) for comparison, the frame latch on my trailer (not the moho in question). This is not guillotine style.

Splitrock · 11-06-2011, 05:19 PM

Well if all else fails, you can always use the cross dowel barrel nuts.

I was thinking if that strike plate had a solid backing, you could drill a third hole in the center to use for access to hold the nuts in place. I still might do that. A nice square Dremel cut hole wouldn't be a distraction. It'd still be easier to hold the cross dowel barrel nuts, but you'd have those two holes to cover.

Those could be covered different ways.

WineStream · 11-06-2011, 05:34 PM

Quote:

Originally Posted by Splitrock

I was thinking if that strike plate had a solid backing, you could drill a third hole in the center to use for access to hold the nuts in place. I still might do that. A nice square Dremel cut hole wouldn't be a distraction. .

That one one of my brainstorm ideas, too. Drill a big hole right under the middle of the latch plate and then use that to allow for access with a magnet to hold a standard nut in place while I started the screw into it. That might still be plan B if the rivnuts don't hold strong enough. It's not like there's a lot of load on the rivnuts, so hopefully they work. The rivnuts should stay in place for future service, too. My concern with holding anything in place to "get the job done" is the serviceability of it. If I (or a subsequent owner someday) need to remove the latch plate again, I'd like me/them to not have to deal with putting nuts in again like I am now

WineStream · 11-15-2011, 06:42 PM

It appears as though "Jack Nut" is the proper name for what I received from McMaster (1st pic below). There's even a patent number stamped in each one. The bag of 25 came with a holding tool (2nd pic). Installation was pretty easy, although I actually had to drill the hole in the door frame bigger. The suggested hole size is 11.5mm. Unfortunately, the only drills I had in that range were 3/8" and then jumped to 1/2". 3/8" was too small. 1/2" is 12.7mm so I was over 1mm oversize. There was some slop initially, but it clamped down nicely. The primary issue was the flange that sits on the surface of the door frame. This cause the latch plate to be spaced out farther than normal (4th picture). I used a ballpeen hammer to knock the jack nut flanges as flat as possible. This did the trick as the door closes and latches quite tightly, now. A new piece or weatherstrip all the way around and it should be much quieter than before and hopefully retain heat / cool much better, too. I will have to see next camping season if rumbling down the road causes things to loosen or not. If so, a few snug-downs of the screws should eventually pull things just as tight as if a real nut was in the door frame.