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TR4/4A studs for the trailing arms

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alanjohnturner said:
The idea is that if you have a stripped thread or broken stud in a trailing arm then using a Helicoil cuts away rather more alloy than you need.

There is not a lot of metal in a TA and we have seen some Helicoils that break through.
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There is only about .025" (0.6mm) difference in major diameter between 3/8 NC and a 5/16 NC Helicoil. If you are winding up with less than .025" wall thickness, I'd say it's time to either discard the TA, or weld up the area.\\

Is it possible you are thinking of a solid insert, rather than a Helicoil?
 
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tomshobby said:
"Please note that this is for use with KeenSerts" Quote from Bob's site.
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Sorry, Tom, I was replying to Alan's post (and that other thread). You snuck in with the link to Bob's site while I was typing :smile:
 
Hi Randall, just thought a quick read might miss that. Had to re-read it myself to find the reference. My inserts arrived yesterday from McMaster-Carr. 92070A250 Black-Phosphate Steel Key-Lock Insert for Metal, Thin Wall, 5/16"-24 Interior Thread, 7/16"-14 Exterior, 7/16" L 26 https://www.mcmaster.com/

They do also have SS inserts but I have never been a fan of SS fasteners on a car. Worked in a shop rebuilding food processing equipment with an emphasis on cheese making equipment. Nearly everything was SS and some aluminum castings. There was a lot of trouble with SS fasteners galling and seizing making them impossible to tighten or remove. The combination of SS and aluminum led to a corrosion that turned the aluminum into a powdery substance. We had to use the SS fasteners to meet code and even with anti-seize they still would bind.
 
There are a great many different "stainless" steels, and they don't always act the same. I've seen similar issues with other SS fasteners, but never with Helicoils. We used to make satellite navigation units (before the days of GPS) with cast aluminum (alloy) housings that would sometimes get mounted above decks, exposed to salt air (and sometimes even spray). We used Helicoil inserts for all of the threads in the housing and I never saw them bind or gall.

There was even a unit that was recovered from a ship that had burned and sank. We flushed it with fresh water, replaced the burned and melted cords and keyboard, scraped some of the smoke damage off the display, then (more as an advertising gimmick than anything else) showed that the unit still worked. I was there when the lid was removed and the screws came right out.

Wow, I can't believe I found this. There is a picture of one of those units (not the one that burned and sank) on page 14 at
https://www.ion.org/museum/files/TransitBooklet.pdf

I'll spare you the lecture, but the ME who designed that unit explained to me how the Helicoil inserts resulted in threads that were stronger even than using the next larger size bolt directly in the aluminum.
 
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There are several guys on the forums that I would enjoy meeting and swapping stories of life experiences. These forums are good for many things but face to face discussion would be excellent. If you ever get up this way let me know.

I am building a custom steering wheel for my TR6 and am using 17-4PH Stainless Steel rod for the spokes. I chose it for strength and corrosion resistance and am threading it. And probably a 308 or 316 for the hub.
Image5.jpg IMG_1731.JPG
 
TR3driver said:
There is only about .025" (0.6mm) difference in major diameter between 3/8 NC and a 5/16 NC Helicoil. If you are winding up with less than .025" wall thickness, I'd say it's time to either discard the TA, or weld up the area.\\

Is it possible you are thinking of a solid insert, rather than a Helicoil?
Click to expand...

I bought two trailing arms for the sole purpose of restoring them, using the method apparently preferred by some of us on this forum, with keenserts from McMaster, and that tool set from Patton Machine (Danielson Jig or whatever it's called). Is that still seen as a good, sound way to go?

Also, a more minor issue, I can't recall where the new studs are purchased from and whether those are installed with threadlocker, torqued or just bottomed out.

Thoughts on the above?
 
Remember that the tapping size for a normal 3/8in UNC is 5/16in.

So you DON'T need to do any drilling out.
and you DON'T need a Helicoil drill
and you DON'T need a Helicoil or any insert.

You just use any ordinary UNC tap and you leave the maximum metal on the TA.
 
Something not all that unusual has happened to me. I'm lost. I thought the Keenserts were to be used because of their greater strength in holding a stud than could ever be the case in threaded aluminum.
 
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