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Making a small scriber...

DocsMachine

Well-known member
Joined
Sep 16, 2006
Messages
1,863
A week or two back, we all saw a video from Clickspring, in which he made a card press for a magician friend. The work was amazing and the resulting device looked like something you'd present to an especially picky Tsar or something. :D

While I knew Clickspring has had a whole series of videos, I'm chronically short on TV-watching time, and so had really only seen a bare handful of them. After posting the card-press video, I took the time to check out a few of his other videos, and discovered he'd actually started a second channel, specifically for short videos showing discreet processes- that is, instead of having to watch an entire video about come part, he had a specific video covering individual processes, like gearmaking or heat-bluing.

One of the videos I ran across, was how to make a needle scriber.

Now this I was interested in, as I'm constantly using scribers, but oddly enough, I kind of hate using them. To clarify that particular statement, here are my three most-used scribers:

scriber01.jpg

I say "most used" because I have a fourth, a Starrett, that I love to use, but hate to get dull. And therein lies the problem.

Of the above three, the top one is a Master Mechanic scratch awl. Handy, but the steel is fairly soft, and I've had to resharpen it frequently. Too much of that and the shaft will start running back into the thicker portion, making it harder to sharpen and blunter to use.

The bottom one is a commonly available replacement- a cheap "carbide scriber" off eBay. The carbide tip lasts admittedly forever when used with aluminum, but it's blunt- the shaft is fairly large in diameter, with a short, 'fat' point. I can use it for lots of scribing, but it's nearly useless for tight quarters, the inside of small holes, narrow slots, etc.

The middle one is my favorite. I have no idea who made it, and would love to buy more if a supplier could be found. The shank is nice and long and come down to a needle point that's easily small enough for virtually all the tiny features I might scribe.

The problem is, while the steel is very good quality and I've only had to resharpen it a couple of times, it too is going to eventually "wear out". I could make one just like it, but the big trick is in shaping and hardening the point- I can do it, but it's a lot of labor and we're back the the issue of it eventually wearing out.

Years ago, I read an article by Frank Ford (warnimg, time **** page!) about a scriber he'd made which used old- as in antique- steel phonograph needles. Now, you can buy these by the binload off of Bay (pack of 500 for $22?) and I'd always meant to order a pack or two and whip something like that up.

In fact, years ago, I wound up with a small pill bottle full of such needles, likely from one of the "lots" of machinist tools I'd picked up. The problem there is I don't know what I did with them. :D

Anyway, getting back to the Clickspring video, his solution was simple- use a heavy sewing needle. Simple, durable, sharp, thin, and easily- and cheaply- replaced if and when it gets dull. Why didn't I think of that?

Click's handle is fairly fancy (ish) but I thought I could make do with some aluminum. I checked my racks, and sure enough I had a couple chunks of 3/8" mystery aluminum that I'd bought from the local Homey-Dee.

scriber02.jpg

Click suggests that about 5 inches (I thought he was Australian? ) would feel most comfortable, so I lopped off two 5" lengths in the bandsaw.

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Faced one end...

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And used a small form tool I had laying about to round the end.

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A splash of WD-40 and a bit of green Scotchbrite evens up the finish a little.

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Flipping it around, I faced the other end...

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And then swung the compound around to about 6 degrees. For this kind of turning, I also use a screwdriver and back off the gib a touch, so it's easier to turn.

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Turn a taper leaving a flat spot on the end about 3/16" in diameter.

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A quick lick with a file rounds the blunt end slightly, and another sweep of the Scotchbrite blends and smooths the finish.

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Extend the rod out of the chuck and grip it by the previously-Scotchbrited tail end, and gently condition the rest of the shank.

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Do it all twice and you have a matching pair.

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Then, with an itty-bitty spotting drill, drill a tiny spot at the point of the tapered end.

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Measure the needle...

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Find an appropriate tiny drill bit...

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And very carefully drill the end to about 1/2" deep. Use lube, and "peck" a lot to clear the tiny chips. These little bitty drills load up fast.

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Use a Dremel with an abrasive wheel to chop the eye off a needle...

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Carefully degrease verything, and use a drop of Loctite or super glue to lock the needle in place.

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Like Clickspring says, if you have to replace the needle, a little heat will free it right up. After wiping up the excess Loctite, set 'em aside to let the stuff cure, and they're ready to use.

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I'll be using these a lot in the next week or two, so I'll give you an after-action report in a little while, but I think they'll work just fine. The needles might be a bit too flexy and skinny to use on, say, mill-scaled hot-roll steel, but in that case, the cheap carbide scribers can be used. For the aluminum and occasionally Delrin parts I've been working on, I think they'll be perfect.

Doc.
 
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DocsMachine

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In a previous thread that basically nobody bothered reading, I... borrowed an idea from Clickspring and made myself a couple of needle scribers.

Those scribers came out great, and have been quite useful already, but have also proven to be just a little too light for my needs. The needle is just a little too flexy for certain things, so I've been looking into other options.

In the thread nobody read, several options were offered, one of which was some tips from steel-tip darts. (Soft-tip darts probably don't scribe well, unless you work exclusively in Play-Doh. ) I thought that was an interesting idea, and was looking into buying some off eBay (where you can find grooved tips, laser-engraved, triangular-ground and other sorts of texturing, which again shows that I'm in the wrong line of business) when a chance encounter with a buddy of mine- who happens to be one of the local dart league champs- led to my being bequeathed a set of used tips for the nominal price of free.

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Now, one of the reasons they were free was, of course, that they'd been used. And in use, of course, the dart aficionado would occasionally strike one of the wires that makes up the scoring pattern of the dartboard.

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I hope I'm not getting to technical for you.

That's not a huge issue, because most of the shape is there, it just needs to be refined. That's easy enough to do with something spinny like a drill, and a belt grinder that I just happen to have. The problem is that I'd like to have a nice shallow angle to the grind, and a standard drill would have too big a chuck to let me get a low enough angle.

After many moons of pondering, unanswered letters to various YouTube celebrities, and some leftover hallucinogens, I figured a Dremel would be ideal. Tiny chuck, small diameter body, etc. Except the dart tips are about 0.091", and the standard Dremel collet is 0.125". Luckily enough, rooting through my stash of Dremel parts, I found an undersized collet I think originally intended for the tiny diamond engraving bits (the bits that use diamond to DO the engraving, not bits used to engrave diamonds) which happened to hold the dart thingy just right.

scriber22.jpg

Then, using a 600 grit silicon carbide belt I'd originally gotten to do TIG tungstens (at which it does an amazing job) and working on a slack portion of the belt, I was able to very easily and surprisingly quickly dress down a tip to freakin' dangerously sharp.

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Here's a before and after. I'm pretty sure just the photograph of the one on the right drew blood.

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After that, it was a simple matter of making another handle just like I did before...

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With the added touch of adding in the grippy-grooves as on Clickspring's example.

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Once sufficiently engroovenated, I drilled the pointy end to receive the pointy bit. In this case, the dart tip is about 90 thou, or some three times the diameter of the needle I used originally- and as luck would have it, I had a drill just one and a half thou larger than the tip diameter.

scriber27.jpg

Note the ER-11 collet holder being used. When I drilled the original ones, I noticed that my chuck doesn't hold tiny drills very well- it's a good Jacobs chuck, but is an older piece and likely has lots of miles on it. So, immediately after doing the needle scribers, I ordered an ER-11/Morse 2 holder specifically for the times I need to hold the little tiny bits. (I'm also thinking of picking up a couple, complete with single collets, specifically to set up some semi-permanent centerdrills.)

Anyway, just like last time, all that was left was to blow out and degrease the hole and the tip, and stick 'em together with a drop of Loctite.

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After it had a chance to cure, I tried it out, and I'm pretty sure this is now my favorite scriber.

scriber29.jpg

It's nice and rigid, the point works even in close quarters, and I'm surprised how natural it feels to hold and use. I think I can call this little project solidly done. This one tip should last me several years, and I have two more ready to go- and of course even more replacement tips, if ever necessary, can be had cheaply and ubiquitously.

Doc.
 

Com_VC

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Oct 7, 2005
Messages
135
Location
Australia
Nice work, have you thought about using tungsten? I've used them as scribes before and they work well.
 
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DocsMachine

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TIG tungsten is too brittle. It's generally pure tungsten, sintered with a few percent of a dopant to help resist heat or improve conductivity or something.

A cutting tool would be made of tungsten carbide a much harder alloy, and sintered with cobalt as a binder.

Yes, as in the first photo, I have some tungsten-carbide-tipped scribers, but as noted, the point is usually too "fat"- the piece is larger in diameter than I'd like, and the tip angle too blunt. Sure, they last forever when used on aluminum, which is like 90% of my work, but the tip geometry isn't ideal.

Doc.
 
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fiftyv8

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Dec 29, 2018
Messages
237
Location
Perth
Nice work.
I have one that was purchased with a straight point at one end and a bent point at the other.
It is about 80 degrees I would estimate and boy do I use the bent end nearly as much as the straight end.
It is a very handy option when doing stuff in confined spaces or out of eye sight even on occasions.
 
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1970W-30

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Joined
Aug 21, 2009
Messages
86
Location
Denver, CO
If you tap the end of your scribe to 2BA, you can buy a variety of screw in conversion tips for darts. Easy replacement.
 

lilredex

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Joined
Apr 29, 2006
Messages
5,956
Location
Toronto
Or, these guys if you tap 1/4-20 TPI. Can be used for center punch tips also.

Back in the day, school shop teachers used them for that.
 

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