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JB Weld versus Loctite for grubscrews

Since your M6 bolt has 10 1mm threads,
I'm not sure, because I used a grub screw in the end. The "logic" behind even attempting to drill to ~10mm was because that was the depth of the threads on the bolts sent with the battery. I don't recommend drilling to this depth unless your cell is in almost irreparable already, and sacrificing a battery cell is acceptable to you.

EDIT: I don't recommend this ever.
 
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I encourage this, too, but it's too late for me. Did you?
The smallest M6 Helicoil is 6 turns (6mm when threaded), while the stock Helicoil bottoming tap tapers for 6mm.

So if you drill to 7mm and tap with a bottoming bit, you should be able to thread a stock 6turn Helicoil fully without needing to trim it and engage at least 5 M6 threads.
 
4 helicoil threads is stronger than new. The screw doesn't have threads all the way to the bottom and you don't screw it all the way to the bottom anyway
 
Did you see hightechlab spear one? It gets red hot inside and releases a bunch of vapor that can burn.
You probably wouldn't puncture anything but I wouldn't do it. You might just burn your face off
 
A drill stop, a piece of copper tubing slipped over the drill, would be a good idea.
Don't know about you guys, but I tend to plunge the drill through my workpiece, or it bites and pulls itself through.
Although drilling with a square-bottom drill in an existing hole makes it much easier to stop at the bottom.

I'll second the safety hazard, and suggest PPE.
 
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4 helicoil threads is stronger than new. The screw doesn't have threads all the way to the bottom and you don't screw it all the way to the bottom anyway
Are saying 4 Helicoil threads engaged into the terminal will be able to handle 35 inch-lbs (and possibly 45 inch-lbs)?
 
Are saying 4 Helicoil threads engaged into the terminal will be able to handle 35 inch-lbs (and possibly 45 inch-lbs)?
I'm saying it will handle 60 inch pounds because I tried it. It tore out at 80 inch pounds.
I would have tried 70 but I thought it would handle 80
 
Then I would want 6 threads for nominal 2x margin. (If I was assembling one of these cells, which I'm not.)

Was that grub screw installed with loctite, cured, and then nut torqued to 60 inch pounds with dry threads?
Lubricated vs. dry makes a big difference.
 
Then I would want 6 threads for nominal 2x margin. (If I was assembling one of these cells, which I'm not.)

Was that grub screw installed with loctite, cured, and then nut torqued to 60 inch pounds with dry threads?
Lubricated vs. dry makes a big difference.
No loctite. I did a practice helicoil on a bad cell. You have to turn the helicoil past the top 1/2 turn.
You're supposed to leave space in the bottom to get the tang out. But you could probably get it out.
I personally think it is fine with 4 threads but if someone successfully gets 6 threads, that is better.
 
What i used to do with aluminum engines is clean the hole with acetone on a ear swab and get a or make a stud.

put a drop of locktite 271 and install the stud all the way. from then on you only have to remove the nut. Jb weld woulw be a insulator and could cause a hot spot under heavy load.




























there is
 
I'm saying it will handle 60 inch pounds because I tried it. It tore out at 80 inch pounds.
I would have tried 70 but I thought it would handle 80
Wow, cool.

So if 4 fully-engaged M6 grubscrew threads in 4 fully-engaged Helicoil threads can withstand 60 inch-lbs only 3 might withstand 45 inch-lbs.

But I’m kind of thinking the ‘easy-peazy’ Helicoil plan may be to get their stock bottoming tap, use their stock drillbit to drill 6mm deep (which means the center should only penetrate ~7.6mm), then to use the stock bottoming tap to tap 4 full threads and 2 tapered threads.

Hopefully the standard 6-turn Helicoil will fully thread (meaning the bottom two could/threads tapered) and an M6 grubscrew will fully engage at least 4 full threads.

I’m still a bit lost as to whether the tab at the bottom may be a problem and/or whether removing is from a blind hole is straightforward, but I suppose the ~1.6mm cone below the center should make that easier...

With your experience dealing with Helicoil and these terminals, would you have any advice as to the easiest way to achieve 45 inch-lbs using stock drill bits, taps, and 6-turn Helicoils?

And if that’s no possible, what about with stock tools working with a trimmed/modified 6-turn Helicoil?
 
What i used to do with aluminum engines is clean the hole with acetone on a ear swab and get a or make a stud.

put a drop of locktite 271 and install the stud all the way. from then on you only have to remove the nut. Jb weld woulw be a insulator and could cause a hot spot under heavy load.
We’ve already been through this. There is little/no conductance through the grubscrew - conductance is hugely dominated by the aluminum surface of the terminal.
 
I’m still a bit lost as to whether the tab at the bottom may be a problem and/or whether removing is from a blind hole is straightforward
I mentioned earlier in the thread that I (erroneously) put the helicoil in the threaded hole upside down (with the tang up). It inserted smoothly and all the way and the tang was very easy to remove. I'm not saying it will work that way every time, but it might.
 
I mentioned earlier in the thread that I (erroneously) put the helicoil in the threaded hole upside down (with the tang up). It inserted smoothly and all the way and the tang was very easy to remove. I'm not saying it will work that way every time, but it might.
Cool, I missed that. So it’s possible to thread the Helicoil ‘upside down’ and then either just remove the tang from above or trim off and Helicoil extending out of the top if it didn’t fully insert.

I’d missed that.

Also, I see that am M6 bottoming tap can be had for not too much denaro: https://www.threadtoolsupply.com/m6x1-hss-sti-bottoming-tap.html

So standard 1/4” drillbit, an $18 bottoming tap and 6-turn Helicoils - sounds like getting at least 4 full M6 threads engaged should be possible...
 
fyi I have never found any of the permanent thread lockers really permanent. I was trying to find something so I could secure a backup generator as part of a system to at least slow down a thief. Nothing actually held if I use my impact wrench with enough patience. It was disappointing....buuut, do you have a product in mind that you have tried? My attempts were just the typical off the shelf consumer grade stuff.
Solder is a pretty solid thread lock.
 
If you go the helicoil rout check your local auto parts supplier they male a kit that comes with everything drill -tap -installer and coils real cheep. The tab end goes in first and when you are done just snap off the tab with a small screw driver.
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If you go the helicoil rout check your local auto parts supplier they male a kit that comes with everything drill -tap -installer and coils real cheep. The tab end goes in first and when you are done just snap off the tab with a small screw driver.
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Just ordered one from Amazon: https://www.amazon.com/gp/aw/d/B082PDTXG4?ref=ppx_pt2_mob_b_prod_image

$14 for 35 threads is almost as inexpensive as JB Weld...

Now I just need to decide if I’m going to attempt my first-ever grinding on this tapered tap or just spend another $18 on a bottoming tap...
 
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