What is it? Set 512

2987 - The end of a safety knife.

"DoN. Nichols" fired this volley in news: snipped-for-privacy@Katana.d-and-d.com:

Don, any two pins that are parallel and pointing in the same direction can always both make contact with a flat surface at the same time... The pins can be different lengths, entirely -- even infinitely different lengths.

They need no 'adjustment' to accomplish that. Two points define a straight line, Don.

Lloyd

I thought maybe the points could be needles, and that it might be used for sewing (canvas, or similar)

Hmm ... infinitely different lengths may put the points too far apart to both contact a given flat surface of finite dimensions.

And I was assuming (granted, I did not state so) a plane at right angles to the axis of the fixture -- a plane parallel to the one defined by the back end of the tool.

And I was coming from thinking about the tool which I mentioned which would have four equally spaced points in a straight line, and which *would* be used vertical to the surface of what is being tested.

Agreed -- though your example of an infinitely different length of the two pins cannot both touch a finite surface like say a 4' diameter table. :-)

And even given an infinite plane, an infinite (or even near infinite) difference in length will wind up with the points approaching on a parallel to the plane, which sort of defeats the purpose of the points to contact a very small area.

But -- if you are mounting the tool in a controlling fixture, it will likely expect to have the surface plane at a right angle to the axis of the tool.

Oh yes -- and someone mentioned the possibility that it is for testing moisture content in wood. I don't think that device shown it would work that way, because there are no provisions for insulating the two pins from the metal holder. And the black screws coming in from the sides are to secure the points in the holder, not to connect wires. (Brass screws would be more likely to be used for electrical connections, and they would still require the insulation of both the pins and the screws from the holder.

Enjoy, DoN.

"DoN. Nichols" fired this volley in news: snipped-for-privacy@Katana.d-and-d.com:

Good grief! At least now I know who to call when I my supply of "rambling" runs low!

Lloyd

You make some good points on this one, the photos were sent in by a visitor of the site so I don't have it in my possession. I think it was marked as being part of a moisture meter when he bought it but I'll pass along your reservations and see what he says.

I think the object in question predates high impact plastic; one would remove the driver and attach connectors to the electrodes.

Here is a modern version:

Kevin Gallimore

What makes you think that the holes for the pins were not insulated? There were many methods of insulating that did not require plastic, mica, some form of cardboard (but not really a cardboard) , nylon, rubber, epoxy , wood...

That sounds like a good way to use it, I was thinking maybe they just made the holes with this tool, and then stuck some electrodes into these holes, but I think I like your idea better.

Thanks, I just added this link to my answer page.

I think it could have been used without insulation. Use the tool to drive the pins in at the right spacing. Loosen the set screws, remove the tool, connect the electrical tester.

2) The picture shows no wires connecting to the electrodes.

Kevin Gallimore

The pic does not show multiple views. So there is no way of telling.

Seems like a slow way of taking a reading to remove it, I envision some insulator and just attaching alligator clips.

But then again, it might very well be used by removing the pins..

About (2983). Is there any form of insulation between the metal body and the pins? And any insulation between the screws which lock the pins in and either the pins, or the body? Otherwise, I can't see it as being used with a meter -- unless the weight of it is used to drive the pins in, and then the body withdrawn, leaving the pins in place.

Enjoy, DoN.

I should have read down-thread before posting to your post about the answers being finally up. :-)

Sorry, DoN.

It shows one which could have the wires directly connected to the pin holders -- but also the small image expands to show a log with several pairs of pins standing in it, plus one pair still in the holder.

Or Bakelite as something which predates epoxy and was commonly used for insulation and structural members. Probably a sleeve and a disc of the Bakelite would work in the holder.

Enjoy, DoN.

EXACTLY.. then all you would need are alligator clips

I mean no disrespect to wood, people who work with it, or people who measure it's moisture content. I googled "wood moisture measurement". As an outsider, I get the impression that measuring wood moisture content is, as described, a crude, inexact process. It is likely that, for most uses of wood, accurate and precise measurements are not needed. The reference process is: Weigh a piece of wood, dry it, weigh it again. That is probably reasonably accurate and precise. The field process seems to be: Make an electrical resistance measurement between a pair of pins driven an unspecified distance into the wood, then look in a table to get and idea of the moisture for the type of wood. Perhaps, use partly insulated pins to measure at some (incompletely) specified depth. There was one google hit for someone who simply drilled a couple of spaced holes in a block, and drove a pair of nails through the holes into the test piece, using the block as a depth stop. Then he simply measured the resistance and looked up the moisture content. As pure water is non-conductive, all the measurements seem to need calibration for the salts/ion concentration of the specific wood. If I were still in the invention business, I'd develop and patent an accurate, precise microwave wood moisture measurement device, but I no longer care.

So... The thing in the picture (2983) holds a couple of pins. The robust device is bashed with a hammer to push the pins into a piece of wood to an unspecified depth. If or when the pins bend or can't be removed, they are replaced. There is probably some insulation on the pin shanks so there is a reasonable chance of measuring the resistance, then pulling the whole thing out and re-using it a few times. It now all makes sense. I'm happy.

Alexander Thesoso fired this volley in news:l2d034$skb$ snipped-for-privacy@dont-email.me:

You assume way too much.

First, the pins will be driven a specific distance into the end-grain of the wood -- into which they will go straight. The operator is trained to do so. The wood is freshly cut square to the grain for 'official' measurements.

Second, the relative conductivity of the salts in various woods is well- known and documented in easy-to-obtain tables. Hell... you can buy very accurate wood moisture meters with such tables in most high-end woodworking supplies.

Third, you are permitted to be happy. You may be even happier to know that microwave ("radar") moisture detectors are already available for wood analysis. But, then, you'd still need to know the specific "dry" moisture level of each type of wood (which varies by species). You'd also have to know the microwave penetration in each species. These are both issues that are handled nicely by plunging electrodes a known, short distance into the very core of the freshly-cut lumber.

I think you belittle too much things with which you don't have first-hand experience.

Lloyd