Evaluation of loc-line brand "coolant arms"

A project log for Locking ball and socket gooseneck system

3D printed ball and socket joint with a quarter turn twist lock at each joint. Brick shithouse goosenecks!

alex-richAlex Rich 05/23/2015 at 02:450 Comments

Loc-line arms:

My gooseneck:

I recently purchased a set of loc-line brand coolant arms to evaluate and compare with my 3d printable gooseneck system. If you're not familiar with them, these arms are designed to direct flood coolant towards cutting tools on CNC machining equipment. They are extremely vibration proof and do not spring back at all once you have pointed them in a certain direction. Recently these have become insanely popular to use as helping hands or third hands for soldering. Sparkfun sells them and this instructable has hundreds of thousands of views.

I tested a bit and this is what I found:


1. They are cheap, two loc-line arms cost less than $20 with shipping

2. No 3D printer required, only some tools to make a platform to mount the arms on (can be made of metal, wood, plastic, whatever).

3. They hold! Without a doubt, these arms stay exactly where they are aimed until you intentionally move them.

4. No spring back - unlike the metal coil goosenecks, the ball and socket joints have no spring back.


1. Loc-line arms are really, really stiff. This is good if you want your arms to stay put no matter what, but it makes fine adjustments difficult because the force required to move the joints causes the entire arm to "jump" from one position to the other.

2. Loc-line arms are hard to take apart and put back together. The joints just aren't designed for frequent disassembly, they are designed to have excellent holding power. Assembly is difficult enough that they actually make a special plier-like hand tool for this purpose.

Comparison to my 3d printed gooseneck:

Verdict? If you have a 3D printer, try my system before you buy loc-line arms. You might be surprised at how well they work.

*Loc-line coolant arms were purchased at McMaster Carr using part number 10095K11