Thread: 4th Arm holder for electronics

Never seen those before, look much better than those horrible third hand holders from Altronics etc.

Originally Posted by bueller

Never seen those before, look much better than those horrible third hand holders from Altronics etc.

These are the hoses used for coolant on lathes etc. A bit of searching and you should be able to find a source of the hose only without the little valve on the end. Also very handy for directing an airflow from a compressor onto a scroll saw etc. to clear the dust away (directed towards the dust extractor!)

Alan...


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Originally Posted by Uncle Al

These are the hoses used for coolant on lathes etc. A bit of searching and you should be able to find a source of the hose only without the little valve on the end. Also very handy for directing an airflow from a compressor onto a scroll saw etc. to clear the dust away (directed towards the dust extractor!)

Alan...

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Yes I already have one of these on my MW lathe but I got mine on eBay where a half dozen of those hoses cost half the price of a single one at H&F
6 PCS 1 4" Round Nozzle Plastic Flexible Water OIL Coolant Pipe Hose 30cm Switch | eBay

Thanks for the info. Little hoses are on order.

I got my little hoses on Friday and managed to knock this up the morning.

It also gives me somewhere to locate my old "helping hands" gizmo, which I still find useful.

HelpHands2.jpg

6mm Al plate with edges rounded over using a router.

The red squirty ends of the hoses take a 4mm tap and the alligator clips have 4mm threaded pieces soldered onto them.
Using only first 1/3rd of a starting tap on the quirky end means there is enough friction between the threads for the alligator clips to be rotated so they stay in position although a locking wingnut could also be used if needed.

The other end of the hoses have a plastic 1/2" UNF thread but the plastic mould lines are quite prominent and prevent them screwing into the al plate even under some force.
I ran a 1/2" UNF die over the thread but it grabbed too easily and I managed to cross thread the die on the feisty one then I remembered the trick of using light machine oil as a lube and the die went on dead easy.

I backed https://www.kickstarter.com/projects...ile-third-hand on Kickstarter, also now available from Hobby Creek

I have since found out there is an "Instructable" web page Third Hand++: A multi-use helping hand for electronics and other delicate work. with 348k views and a 9 year history on building these things.

If these interest you it's worth having a look through the photos in the Instructable comments because other persons have come up with many different variations and uses.

Since making mine I have found out that the thread on the base of the coolant nozzle hoses is 1/4" BSP (19 TPI, 0D 13.16mm) while I thought they were 1/2" UNF (20 TPI, OD 12.7mm) which is probably why I had trouble getting the threads in to begin with. Although I have both sizes of taps and dies, if all you have are the UNF taps and dies then running a 1/2" UNF over the plastic thread with a drop of machine oil will easily re-size the thread.

Of course it's not necessary to use Al for the base, wood would work and the coolant nozzles could be just screwed into a tight fitting hole.