Improving A Cheap Set of Forceps/Tweezers

Over at The Whole Garage Catalogue recently, I posted an item about a cheap pair of forceps/tweezers. Here's the post:

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A Pair Of Forceps/Tweezers Of Some Sort

There's no maker's name on them, and they look cheaply constructed. The pivot is a bit sloppy, and the tips align poorly.

With a bit of work, I could improve the thing, and possibly have a useful tool for something-or-other.

I'll stash these in my spare tools drawer against the day that I feel like getting after them.

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Well, I feel like getting after them. So here's what I need to do to improve this tool:

• Strip off and possibly replace that rotten sleeving.
• Reconstruct the sloppy pivot.
• Align the jaws.

Sleeving

That wasn't difficult to scrape off with a utility knife. The tool is reasonably clean now.

I have some red 3/16" heat-shrink tubing on hand that might make excellent replacement sleeving. That can wait until I've dealt with the pivot and the alignment.


The Pivot

The original pivot was a 1/8" diameter rivet. I cut off its end and discarded it.

The pivot holes are slightly oversize -- that accounts for the sloppiness that I observed in the pivot's action.

I can drill out the pivot holes slightly to accommodate a 6-32 screw, but there's a caveat regarding the use of a screw as a pivot pin. It's a very poor practice to have a pivot point operate on a screw thread. You want a pivot point to operate on a full rod/cylinder. So, what I need here is a 6-32 screw that has an unthreaded shank portion that's just the right length to serve as the pivot point, while providing thread enough to be fastened by a Nyloc nut.

I have some 1 3/8" long 6-32 hex socket head cap screws with unthreaded shank portions to them, but the unthreaded portions are too long. So, I threaded one of the screws further, and now I have a screw that should serve nicely as a pivot (once I've cut it down to correct overall length). Here's a view of the screws I've just been on about.

At the left is an unmodified screw. At the right is a screw that I've threaded further. That one's going to be my pivot screw.

The pivot holes need to be enlarged slightly to accept a 6-32 screw, and it's important that I get as close a fit as possible so as to minimize slop in the pivot. Consequently, I didn't just go with the conventional 6-32 clearance drill size of 9/64". I miked the screw's shank, and chose a drill size based on that result.

The screw's shank measured 0.135". The closest clearance drill size is No. 29 (0.136"). So I went with a No. 29 drill, and that gave me just the outcome I was after -- a relatively slop-free pivot. Here's a view of it assembled without a nut.

Now I just have to cut the screw down to correct length, add a Nyloc nut, and my improved pivot will be done.

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And here we are.

A slop-free, reasonably tidy pivot.

All that's left is to lubricate the pivot, align the jaws and add new sleeving.

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Done.

I've got a decent set of forceps/tweezers from what was a piece of offshore junk. Very satisfying.

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Material Is Where You Find It

A house painting outfit came by a while ago and asked my wife if they could plant a promotional sign on our front lawn. They were doing that all over the neighbourhood. My wife let them, and the sign stayed for days. The painting outfit never came back to retrieve the sign, and I finally pulled it up and stashed it under the carport. Today it occurred to me to dispose of the thing. Here's a view of the sign.

It's a 32" x 20" plastic sleeve affair draped over a skinny steel rod frame. Take away the plastic sign and here's what's left.

About 90 linear inches of 4.5mm diameter steel rod (about 23/128" -- just shy of 3/16").^[1]

It's a bit of an odd diameter, but I might find use for it for something-or-other. The price was certainly right.

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Note:

[1] It's undersize for threading 10-24 or 10-32, though I've half a mind to try it and see if I still get a useable result.

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Roadside Find -- A Pole Lamp With No Base

This pole lamp looks pretty decent, but it has no base, and the line cord has been snipped off. On the plus side, the switches and sockets all appear to be in operable condition.

There's no maker's name on it, but it does say "Made in China" on the wattage labels inside the reflectors. (Surprise, surprise.)

I can fabricate a new base for it, but there's a little challenge presented where the base attaches to the pole. Here's a view of that.

The jam nut that's needed to secure a base is missing, and that's an odd size of threaded nipple. It's M12 x 1.0mm pitch. I'm unlikely to ever find a nut to fit that. What I may do is remove that brass ring nut from its current location, Loctite the nipple in place at the end of the pole and use the brass ring nut as a jam nut underneath my fabricated replacement base.

A New Base

It would be nice if I could faceplate-turn a wooden disk for a base, but my woodlathe's swing is only 10", and it doesn't have outboard-turning capability. I'd like the base to be about 12" in diameter, so the lamp won't be at all tippy. I'll have to bandsaw a disk, and disk-sand its edges to smooth roundness on a tablesaw disk-sanding jig.

Here's what I have on hand for a base blank.

It's pretty wretched. It's a salvaged motor/grinder mount from an antique grinder that outlived its usefulness. But its thickness is good at 1 1/8", and it's nice and flat. It will have to do.

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And here's my bandsawn blank.

Now I have to rig a circle-sanding jig on my table saw so I can more-or-less 'perfect' the blank's edges.

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And here's a view of the just-completed edge sanding job on my tablesaw.

That's a rude, crude arrangement if ever there was one, but it did the job.

Remaining to be done are the following:

• Round over the upper edge of the disc to 3/8" radius.
• Round over the lower edge of the disc to 1/4" radius.
• Bore through the centre of the disc 15/32" to accept the 12mm nipple.
• Fill all the holes and surface defects and sand the thing.
• Come up with a set of 'feet' to elevate the bottom face of the disc up off the floor. That will provide clearance for the bottom end of the nipple, and the emergence of the line cord.
• Prime and paint the disc flat black. 

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And here we are with some progress made.

Here's a view of the fastening underneath.

(Note the oversize flat washers both top and bottom. Those are absolutely essential to achieving a firm, reliable wood-to-metal attachment of the pole to the base.)

Next up is to make a set of eight feet for it. I was hoping that Canadian Tire might have suitable ones made of black plastic, but I came up empty there. Making plastic feet would be an ideal job for a 3D printer, but I don't have one of those. I'll have to fabricate feet out of hardwood on the lathe.

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Feet

This won't be easy. As a trial effort, I made one sample of what I'm after, like so.

That was turned from a short length of 3/4" dowel held in a chuck on the wood lathe. After turning the taper, I bored it through and counter-bored it for a fastening screw. Then I parted it off. And that's where a snag arises.

Parting off multiple pieces to an exact, consistent length is not easy. I could make eight feet by the same method, but I'd be unlikely to succeed at getting them all parted off to exactly the same 5/8" length. A different approach is called for. Here's how it'll have to go:

• Set up a length registration jig on the table saw to cut eight pieces of dowel to the same length.
• Bore through each dowel piece on the metal lathe 9/64" -- clearance diameter for a No. 6 fastening screw.
• Counterbore each dowel piece on the metal lathe 5/16" for the heads of the fastening screws.
• Fabricate a mandrel that will allow me to mount each dowel piece on the wood lathe for turning the taper.

Here's my length registration setup.

It's just a scrap board clamped to the saw's table the right distance from the blade. Note that the board is positioned so that the work leaves the board before it enters the saw blade. The board must not be positioned so that the work could get pinched between the board and the blade.

And here are my equal-length foot blanks.

I cut one extra one in case I happen to botch one.

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And here they are bored and counterbored.

Next up is the challenging part -- to create a suitable mandrel so I can turn a taper on those feet between centres.

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Here's my mandrel.

Now we'll see what sort of result I can wring out of this.

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And here we are.

Eight tapered feet, all the same length.

I can't say that I did a superb job of that. My mandrel fixture left a bit to be desired, and I wasn't trying all that hard for perfection, but the result is acceptable for the purpose.

I'll do a trial installation of those feet on the lamp's base. Then I'll attend to the lamp's line cord, and complete a trial assembly of the entire lamp. Once all that has been done, I can dismantle the thing and carry on with sanding the base, and priming and painting it.

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And here's the completed lamp, ready for service.

That's not exactly its natural habitat, but it was the best place I could find to photograph it.

Here's a close-up view of the base.

The base is not absolutely flawless; if you look closely enough, its 'chunk-of-wood' origin does show through a little. But from the distance it's normally seen from, it's a perfectly acceptable lamp base -- a good example of what can be wrought from some pretty wretched salvaged material.

And here's a view of the finished underside, with the feet attached, and the line cord's emergence dealt with

Note the following:

• The feet are attached with No. 6 x 1" round-head wood screws. It's a very firm attachment that's not going to work loose.
• The M12 jam nut is very firmly tightened.
• The line cord is sleeved with some tough, clear plastic sleeving where it exits the nipple.
• The line cord is secured to the base by a cable clamp for strain-relief.
•  The 5/8" height of the feet provides more-than-enough clearance for the nipple attachment, and the line cord's emergence and strain-relief.

All-in-all, I appear to have done a pretty decent job of getting this discard back into useable, reliable condition.

Lamps

The labels inside the reflectors call for 60 watt maximum R20 bulbs. At the dollar store, I found 50 watt halogen PAR20s for $2.00 each. (By the way, here's a good explanation of what 'R20' and 'PAR20' are all about.)

LED equivalents are now widely available, and the prices, though still rather high, are within reason. The halogen bulbs do have the advantage of being dimmable; that could be a very attractive feature, depending on how this lamp ends up being put to use.

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Waxed Paper 'Washers' For Finish Protection

If you attach anything securely to a painted or varnished surface, the attached thing is likely to 'weld' itself to the surface tenaciously, no matter how well hardened the finished surface appears to be. Future removal of the attached thing will result in damage to the surface underneath. That may or may not matter to you, but if you'd rather preclude such damage, install waxed paper 'washers' at the interface of the attached thing, and the painted or varnished surface.

I recently removed the mechanic's vise from my workbench, so I could refinish the workbench's hardboard surface with polyurethane. Where the vise base's mounting washers had been in contact with the bench, the washers had bonded themselves to the bench with a vengeance. The washers came away with great shards of hardboard stuck to them, like so.

I filled in the damaged spots on the benchtop, refinished the bench's surface and cut three waxed paper washers for the reinstallation of the vise.

And here we are with the vise's base bolted back in place.

The reason for placing washers underneath the vise's swivel-base mounting ears is to preclude breakage of  the swivel-base casting. Tightening down a cast swivel base directly onto a benchtop's surface is unwise -- irregularities in the surface, and/or the casting, can result in stresses that may break the casting. I've seen it happen. The washers serve to concentrate all the attachment force directly at the ears, isolating the rest of the casting from untoward forces.

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On Salvaging Old Gear

On the face of it, salvaging old gear of any kind seems like a paying proposition. Retail prices of anything new these days are sky high, and are unlikely to ever come down. But are there really savings to be had in salvage?

Much as I'd like there to be, and much as this blog has often featured salvage projects as subject matter, I'm not so sure that salvage effort is always, or even often, worthwhile.

Over my years of servicing laser and impact printers, and working closely with printer subassembly remanufacturing operations, it dawned on me that there seems to be nothing quite like factory 'newness'. No matter how meticulously an old mechanism is refurbished, its service life and reliability are unlikely to equal those of new replacements.

Anyway, for want of anything better to do, I thought I'd refurbish an old water supply shut-off valve, and test it out to see if it could still be trusted to give leak-free service. Here's a view of the valve.

It's a common 1/2" copper pipe to 3/8" compression fitting shut-off valve, as is typically installed for a faucet's water supply. This one appears to have been installed by a DIYer -- there's evidence of some sort of sealant having been applied to places where there ought to be no need for sealant. DIYers are notorious for gratuitous application of sealant.

I'll clean it up nicely, and devise a test fixture. If it doesn't leak at its valve stem when fully opened, I'll consider my refurbishment to have been a success.

Following are a few noteworthy points:

Washer

The washer in this type of valve is not replaceable. Water supply shut-off valves are so seldom closed that washer wear is not an issue. An embrittled, cracked washer would spell the end of a valve's usefulness, unless one wanted to undertake the machining necessary to make the washer replaceable.

The Valve Seat

Like the washer, the valve seat is not replaceable. A corroded valve seat (unlikely) might be salvageable by reaming and/or burnishing with valve-grinding compound. See this post.


Valve Stem

The valve stem ought to be cleaned with fine steel wool prior to removal of the gland nut and seal. One wants nothing to abrade the lip of the valve stem's seal as the seal is removed.

The 1/2" Copper Pipe Socket

I've been meaning to acquire a 5/8" reamer to help me salvage 1/2" copper pipe fittings, but the price has been scaring me off. Meanwhile, I've been making do with an X-Acto knife and steel wool.

The socket must be clean, and must easily accept a pipe end to the full depth of the socket.

The Valve Stem Seal

There are two parts to the seal -- a thrust washer, and the ring-seal itself.

The thrust washer is concave; the concave side goes outboard. The ring-seal is asymmetrical face-to-face; note its orientation as you remove it.

The ring-seal must be resilient and undamaged, else the valve is a write-off. The seal pictured here looks a bit distorted on one side; it remains to be seen whether that will be detrimental.

Note the discolouration of the valve stem near the stem's thread. That's evidence of slight corrosion that may cause stem sealing to be iffy.

The Test

I assembled the cleaned up valve, using silicone grease on the valve's threads, and all its stem-sealing surfaces. I rigged a test fixture that allows me to install the valve onto a faucet that has a 3/4" hose-fitting thread on it. Here's a view of the valve in 'operation'.

The photo shows the valve pressurized and fully opened. The valve's output end is closed, as it would be if it were supplying a closed faucet.

It looks good. There's not a hint of weeping at the valve stem.

So, that turned out well. It would be safe to put that valve in operation in an actual faucet installation.

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Lexicon -- Rule/Ruler

In my junior high school years (grades seven and eight), we had excellent metalworking and woodworking shops. I can't recall the man's name, but one of the woodworking teacher's pet peeves was the use of the word 'ruler' for 'rule'. Whenever a student would call a 'rule' a 'ruler', the teacher would point out to him that, "The Queen of England is a ruler; the measuring tool is a rule."

LittleMachineShop.com has a good article on steel rules and their use. Note that they consistently abstain from use of the word 'ruler' -- the tool is called a 'rule'.

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Miele S2 Momentum Vacuum Cleaner Service Note

The Miele S2 Momentum is a fine piece of high-tech machinery; that is to say that it's largely unrepairable by conventional means in a home workshop. If the machine's electronics or motor develop a problem, you'll be out of luck -- you'll have to take it to a shop that's equipped to deal with the machine's architecture. However, it's still worthwhile to check out a dead machine's fundamentals -- even sophisticated machines are prone to simple failures.

Our unit died on us recently, and the trouble turned out to be an open circuit condition due to a line cord plug defect. Here's a view of what I discovered within the line cord plug.

The plug's neutral tine had fractured within the plug's encapsulation. When I cut and filed away the plug's encapsulation, the neutral tine came away with just a nudge. A conventional, screw-terminal Leviton plug from Canadian Tire made for a neat repair, like so.

The machine is back in business at very little cost. A factory-authorized repair outlet would no doubt have insisted on replacing the entire cord reel assembly to effect a repair -- easily a $100.00 repair job, more than likely.

I had to open up the machine in order to do a continuity test on the line cord. The casing has some concealed claws that make access a bit of a challenge, but once you know about them, it's not too difficult to get the machine opened up. Proceed as follows to open up the machine.

Filter Bag and Filters

Remove the filter bag.

Remove the exhaust filter. (The rectangular filter up on top.)

The remaining rectangular filter in the rear wall of the filter bag compartment can stay in place. (It's the motor pre-filter.)

Lid Removal

Spread the lid at its hinged pivot-points to free the lid from its hinge pins.

Upper Shell Fasteners

There are seven obvious screws to be removed. You'll need a T20 Torx driver. The screws are all the same length.

Foot Switch Cap

This is the tricky part. It's pretty much impossible to show by way of a photograph how this item is fastened. There are four concealed claws at the rear that must be unlatched -- two that keep the foot pedals from flipping up, and two that retain the entire cap.

Start by forcefully raising the front of the foot switch cap with your thumbs. It will snap free upward, getting you to here.

Note that the cap is now tipped up at the front by about one inch from its normal, seated position.

Near the centre-rear of the two 'pedals', there are two claws that keep the pedals down in place. Trip those two claws with a small screwdriver, and you'll get to here.

Now, looking down into the rear of the machine, you'll be able to see the two claws that are holding the rear edge of the cap in place. Trip those claws with a screwdriver, and you'll be able to free the cap completely. Here's what you'll see.

Unlatch the white cover, and you can tip it up to your right, like so.

Free the cable, circuit board and switch from the white cover.

Free the white cover from its hinge pins.

Upper Shell

Down inside a deep well, you'll see one last screw to be removed. With that screw out, pry up the upper shell at the front of the handle to free the front edge of the upper shell. There's also one claw-tower near the rear of the filter bag compartment. Trip that claw, tug the shell forcefully upward and it'll come away. You'll now have full access to the machine's innards, like so.

For the trouble I was having, opening up the machine like this allowed me to do a continuity test on the line cord and its reel. That led me to an unambiguous diagnosis of the problem.

Note the following:

a) The on/off switch is not the power switch for the motor -- it's merely a signalling switch that triggers a solid-state switch.

b) The solid-state motor current switch is embedded in the motor -- it's not a discrete component that's accessible for test or replacement.

c) The circuit board is for motor speed control and, presumably, over-heat detection/shut-off.

Re-assembly Note:

There's a peculiar-looking white flexible shaft associated with the motor speed control knob in the foot switch cap. When reinstalling the foot switch cap, you'll have to take care to guide that shaft so it mates with a potentiometer on the circuit board. Aside from that little detail, re-assembly is reasonably straightforward.

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