Metal detection in wood

[DAPPH]

Well no - you just shut the drive that pulls the wood in - unless its manual, in which case you have to have a siren, light, buzzer, whatever. I reckon you will need to make a pre table ahead of the main body - certainly do-able once you have the right shaped pickup coils

The idea I have is all wood is scanned before it enters the bench saw bench cabin, wooden table containing the detector made as a glued & pinned up construct , So a rectangular mouth of say 12 x 5 inches with at least two detector coils in/ around the rectangles a foot or so apart .
Spoke with Fizzy , his suggestion is a detector wand , but the Norbert's at the shed will either not bother using it or swipe it over the wood so quick missing nails/ staples or other ferrous metals etc. ..especially if they don't wear their glasses .

Can you change the planer blade carrier to have small blades like carbide machine tool inserts, a chipped blade then means turning or changing an insert so still machine downtime but if the inserts are cheaper and last for 4 metal strikes ?

Doubt it without a lot of costly precision engineering.
One of the influencers at the shed didn't even want to spend £ 20 or so on a new drive belt for the motor &r a flat rubber one for the thicknesser drive

 

[DAPPH]

Well no - you just shut the drive that pulls the wood in - unless its manual, in which case you have to have a siren, light, buzzer, whatever. I reckon you will need to make a pre table ahead of the main body - certainly do-able once you have the right shaped pickup coils

It's the pick-up / detection coils I'm seeking designs & circuitry for .
Could they be 10 inches tall by 5 inches across be an ovalid pair like a liquorice comfit torpedo .
One or two ,a trio or quad set of carefully hand wound coils even , each separated by say 100 mm gap and using some sort of OP amp circuitry with tuned circuits to make a comparator & amplifier that triggers bright light and sounders if metal is detected . Even a drawing pin minus it's head needs to be detected . Also thinking of a red laser light beam identifying the exact line across the wood the pin is in .

 

[DAPPH]

.....and just how fast is that wood advancing in ? I've run wood planers before in shop class, and I own one.

Try watching the machine, maybe even put some chalk marks on the wood to represent a piece of steel.

See just how fast & attentive the operator has to be to shut down in time.

Usually they get it started, and then turn back to the pile to get another board ready.

That's why I'm suggesting all wood has to be checked and passed fit external to the planers room . Ardy understands th problem of having a number of half blind stubborn or senile geriatrics playing with wood in a Men's Shed set up . honestly the detector has to be mains transformed down to a few volts and the equipment must be totally idiot proof when used .

Would detection coils be better as tennis racquet flat type rings or hundreds of windings over a plastic tube former such as a 25 litre round or rectangular oil drum?

 

[Other Daniel]

That's why I'm suggesting all wood has to be checked and passed fit external to the planers room . Ardy understands th problem of having a number of half blind stubborn or senile geriatrics playing with wood in a Men's Shed set up . honestly the detector has to be mains transformed down to a few volts and the equipment must be totally idiot proof when used .

Would detection coils be better as tennis racquet flat type rings or hundreds of windings over a plastic tube former such as a 25 litre round or rectangular oil drum?

Good luck with that one

 

[GRW]

Surely the easiest way is to have any pre-used timber scanned with a stud finder/metal detector before it's taken anywhere near a planer or other?

Guy I work for has the same issue with felled timber, & metal wrecks Chainsaw chains & all other machine blades pronto. Technically it is virgin wood, but of course lots of the timber was in hedgerows and land borders, so can be riddled with staples & nails, bits of fencing wire etc.

 

[Turbo]

Airport type wands are recommended over on the woodwork forum & only cost £30-£40 on Amazon, find 2 nails & you've saved the price of a set of planer blades.