Front Chain Guard: Inspection Plate Thread Repair

[Reddawg]

Looking for some advice on how to fix the stripped threads for one of the 12-24 Oval Head screws that hold one of the inspection plates on the front chain guard of a '42 WLA. The metal isn't thick enough to put in a Heli-Coil. I could tap it out to 1/4" which is the next biggest size but I can't find a comparable domed oval head slotted screw that I could parkerize to make it look right. (I could come up with a flat oval head screw though.) Weld it up and re-tap it to correct size? Got some time to fix this while the bike is down. Any advice?

Inspection Plate.JPG

Thanks,

Steve

[Rubone]

Weld it up and re-tap or weld a 12-24 nut on the backside of it. The nuts on the speedo mount bolts are thin and would work fine.

[Reddawg]

Weld it up and re-tap or weld a 12-24 nut on the backside of it. The nuts on the speedo mount bolts are thin and would work fine.

That's an interesting idea. Thanks.

[Tomsan]

You might try Fastenal for a plain steel slot head machine screw.

they have stainless which at a glance look like cadmium. Plain steel can be Parkerized. I find it helpful calling the local branch, but here’s a link to a brief search I did for a 1/2” long 1/4-20, slotted with flat head.

search came up with stainless and brass. With a bit more effort you might find plain street.

I don’t have access to welding so retapping in 1/4

https://www.fastenal.com/product/fas...gregation=Head

Good luck
Tom

[ChiefTwoKicks]

Here's a couple of ideas... I don't know how many threads you have to work with, but this stuff might be worth a look.

You might try a product made by LOCTITE "Thread Repair Kit" or "FormaA_Thread". There several stock numbers, various prices. I've used this product in several different applications.
AS long as you aren't tightening the fastener too tight, it works pretty well. Not for stressed bolts, but I have used it for a transmission bolt, about 6-7 threads, and so far, so good.

Also a "Nut-Sert", or as my son calls them a "riv-nut". Some come with a small die and nut to attach the fastener. Others require a larger tool similar to a pop rivet tool, with the various dies for the correct thread. Various sizes, although I'm not sure about the 10-24 you need for correctness.

I think both items are worth having in the shop. The thread repair for light load fasteners, and the nut-sert for various blind nut applications.

C2K

[T. Cotten]

Here's a couple of ideas... Also a "Nut-Sert", or as my son calls them a "riv-nut".

I've used "riv-nuts", C2K!

And I'd vote for them for thin sheet metal, even though I have a torch.

(They are certainly cheaper.)

....Cotten

[ChiefTwoKicks]

I was wondering if anyone else had used the "riv-nuts" on anything motorcycle related. I've used them alot, not so much on M/C's, but in a variety of other applications.

For example, as blind fasteners for the acrylic windshield on my bass boat. As flush mount, blind nuts on the deck of the boat for removable rod holders. My son used them on the interior of his Sprinter Van.

I thought about using them as blind nuts to secure a cast iron luggage rack on my '45 EU Chief.

The two main issues with them is they must be mounted on something flat and quite firm (fiberglass gel coat works pretty well), and the "riv-nuts" require the drill hole size to be precise, so that the crush of the rivet catches the underside evenly. The underside of the rivet crushes similar to a regular pop rivet, but unlike a pop rivet, where you can put a washer spacer on the underside making the alignment correct, the whole idea of the blind nut is not having the backside available to insure the gripping factor. Thus, you must be sure the parent surface is firm, flat, and thin enough to allow for the crush factor.

I've seen the "blind nuts" made of aluminum and stainless, some of a thicker guage, but most are a lighter duty. I have been told some are made of a hard plastic, but I've not found them yet.
Available from HarborFreight.com, for $24.99, the FASTEN-PRO, Threaded Insert Riveter Kit, the contains 45 pieces. Rivet set tool, 4 nose pieces (dies), 6-32; 8-22; 10-24; 1/4-20 inserts (10 of each), instructions, if you need them. maximum 1/4" depth rivets. I have seen deeper rivets at finer hardware speciality stores.

Nearly as indispensable as a pop rivet tool, I can't imagine not having one of these tools in my tool box.

C2K