minelab 800 coil bolts

[CharlieT84]

I have installed the coil stiffner on my 15" coil but am having real issues with the extended bolt.
I have tried two different sellers on ebay but the bolts are very weak at the threads. I have broke two of them.
It is not that I am tightening them too much; it is a combo of the threads not being quite right and the weakness of the 3d printer material being used. The threads on the bolts were not quite clean and just threading the nut on was enough to break one. And that didn't take much effort. Very disappointed in the quality.
Does anyone know where I can pick up an extended bolt that is of the same quality as the original minelab bolt?

 

[cellrdwellr]

I have installed the coil stiffner on my 15" coil but am having real issues with the extended bolt.
I have tried two different sellers on ebay but the bolts are very weak at the threads. I have broke two of them.
It is not that I am tightening them too much; it is a combo of the threads not being quite right and the weakness of the 3d printer material being used. The threads on the bolts were not quite clean and just threading the nut on was enough to break one. And that didn't take much effort. Very disappointed in the quality.
Does anyone know where I can pick up an extended bolt that is of the same quality as the original minelab bolt?

The local hardware store might have some nylon bolts in the plumbing section. I've used them for aftermarket coils in the past.

 

[CharlieT84]

The local hardware store might have some nylon bolts in the plumbing section. I've used them for aftermarket coils in the past.

Thanks for the response Jeff. So far I have struck out on finding the right size.

 

[TorqueMaster]

Thanks for the response Jeff. So far I have struck out on finding the right size.

Charlie,
If I recall correctly, the stock bolt is metric, a 8mm x 45mm long. You may have better luck finding a nylon 5/16" SAE bolt and matching nylon nut. To allow for stiffener ear thickness, add a bit of length to the bolt, a 2" (~51mm) should work.

I 3D print equinox stiffeners, though not much demand lately -- and agree that 3D printed bolts will be absurdly weak if the printer doesn't get their settings right. It's the layer-to-layer adhesion that is the primary problem. Strength is even worse if they use a hollow infill rather than printing the part solid.

 

[Beachhunt1]

he threads on the bolts were not quite clean and just threading the nut on was enough to break one. And that didn't take much effort. Very disappointed in the quality.
Does anyone know where I can pick up an extended bolt that is of the same quality as the original minelab bolt?

I rounded up in size and now run SAE 5/16 nylon. Double nut. ZERO issues!!!

 

[CharlieT84]

Charlie,
If I recall correctly, the stock bolt is metric, a 8mm x 45mm long. You may have better luck finding a nylon 5/16" SAE bolt and matching nylon nut. To allow for stiffener ear thickness, add a bit of length to the bolt, a 2" (~51mm) should work.

I 3D print equinox stiffeners, though not much demand lately -- and agree that 3D printed bolts will be absurdly weak if the printer doesn't get their settings right. It's the layer-to-layer adhesion that is the primary problem. Strength is even worse if they use a hollow infill rather than printing the part solid.

I rounded up in size and now run SAE 5/16 nylon. Double nut. ZERO issues!!!

Thank you both for the replies! I will try finding the 5/16" nylon bolt. My local hardware and Lowes did not have them when I checked.
TorqueMaster thanks for confirming the 3d printed bolt (and process) is extremely likely to be the culprit.

 

[hoser]

OK , If I'm hearing this right the 3D printed bolt is not working for you. I've been in maintenance forever and have found even factory-made metal bolts have threads jiggered up and need to be chased with a thread die from time to time. Find the right die and thread it on the bolt to clean up any part that keeps you from putting the nut on.