Frank in Thailand
making mistakes so you don't have to...
I have a problem.
Due several changes in my setup almost all threads are lost.
Hardest hit are my 152Ah cells, I used the bolts that where delivered with the cells at start..
Now I know: Only threaded rods!
Still, with threaded rods, 4Nm is a lot of force.
I've cleaned all recognisable threads and used epoxy to give them a tat more strength.
That works, sometimes.
For those who are stripped, I went to 8mm.
Drilling is easy, I took out the tip of the drill, it's not needed when making a hole bigger.
This prevents to drill too deep.
6.5mm isn't much material to work with.
And while I epoxied all the M8 rods out of precaution, some of them aren't strong.
I have 3 taps to use, last one should go to the bottom, it doesn't.
2.5mm isn't threaded...
2 rounds are tapered, not straight.
M8 is 1.25, so 2.5mm not used.
add that manually tap will wiggle some, especially at start.
you lose a mm there.
that leaves 2.5mm usable thread..
not a lot :-(
Perhaps adjust a normal M8 tap?
They are flute, but can be cut halfway, then its full threaded.
It really sucks.
I can feel if/when it goes wrong.
A good thread feels like iron on iron, massive hold.
A bad one feels like it has a spring under it, you are tighten it, but the torque doesn't really increase the way you expect with that 1/4 or 1/2 turn.
When they are above 4.x Nm, I let them be. 4Nm is enough for the connection. (Is the terminal and bus-bar are clean, free from oxidation)
So what's next for solutions??
Go to M9?
Or M10?
Probem stays the 6.5mm material,that only become a larger problem with the thicker stud size.
Helicoil could be an option if there are helicoil bottoming taps available in Thailand, on-line.
I have helicoil for M6.
The Incerts are to long, that's fixable. (10mm)
The thread cutter I have for my helicoil is through hole (flute), not a blind one!!
Blind hole/ straight taps are a real problem.
I know Thailand is somewhat third country left behind with many engineering tools.
I even needed to get the ox-guard from US...
Living off grid with no power isn't fun.
I need a locally available solution.
China / USA takes too long time.
options please!!
Due several changes in my setup almost all threads are lost.
Hardest hit are my 152Ah cells, I used the bolts that where delivered with the cells at start..
Now I know: Only threaded rods!
Still, with threaded rods, 4Nm is a lot of force.
I've cleaned all recognisable threads and used epoxy to give them a tat more strength.
That works, sometimes.
For those who are stripped, I went to 8mm.
Drilling is easy, I took out the tip of the drill, it's not needed when making a hole bigger.
This prevents to drill too deep.
6.5mm isn't much material to work with.
And while I epoxied all the M8 rods out of precaution, some of them aren't strong.
I have 3 taps to use, last one should go to the bottom, it doesn't.
2.5mm isn't threaded...
2 rounds are tapered, not straight.
M8 is 1.25, so 2.5mm not used.
add that manually tap will wiggle some, especially at start.
you lose a mm there.
that leaves 2.5mm usable thread..
not a lot :-(
Perhaps adjust a normal M8 tap?
They are flute, but can be cut halfway, then its full threaded.
It really sucks.
I can feel if/when it goes wrong.
A good thread feels like iron on iron, massive hold.
A bad one feels like it has a spring under it, you are tighten it, but the torque doesn't really increase the way you expect with that 1/4 or 1/2 turn.
When they are above 4.x Nm, I let them be. 4Nm is enough for the connection. (Is the terminal and bus-bar are clean, free from oxidation)
So what's next for solutions??
Go to M9?
Or M10?
Probem stays the 6.5mm material,that only become a larger problem with the thicker stud size.
Helicoil could be an option if there are helicoil bottoming taps available in Thailand, on-line.
I have helicoil for M6.
The Incerts are to long, that's fixable. (10mm)
The thread cutter I have for my helicoil is through hole (flute), not a blind one!!
Blind hole/ straight taps are a real problem.
I know Thailand is somewhat third country left behind with many engineering tools.
I even needed to get the ox-guard from US...
Living off grid with no power isn't fun.
I need a locally available solution.
China / USA takes too long time.
options please!!