24 September 2013

My Favorite Engraving Vise

Maybe someone can help me identify this vise. I acquired it several years ago on eBay. When I placed my bid, I thought this was some version of a Stehman vise, because the profile is similar. But it's not the same vise at all.

It wasn't until I had it in my hands that I realized just what a special vise this is. I have taken a series of photos so you can check it out. I would love to know who built it, but there are no maker's marks of any kind anywhere, in or out, that would identify it. I don't know how old it is, though there are clues that might help date it.

In these photos, I disassemble the base to give a sense of how beautifully overbuilt this vise is. The precision of the machining is instrument-like. Yet it has the character and subtle flaws of a one-off piece. As I said, it is a lovely tool.

My only complaint is a practical one: it doesn't have a drag adjustment. Since the top spins on ball bearings - and very smoothly at that - a light touch is all that is needed to rotate the work. To resolve the drag issue when the job calls for it, I wrap an elastic/fabric band around the waist to brake the pedestal.

The narrow light band around the waist is not a seam. It's just a reflection. The machining tolerances are so tight that the seams are nearly invisible.

Here the seam between the base and the spindle is somewhat visible, about 2/3 up the waist. It's so tight that it's work to get a piece of paper into the seam. Note the knurled pattern on the spindle edge. The exterior plating is still beautiful.
A view of the top. The jaws are hand scraped! Unfortunately, a bit of rust accumulated on the exterior edges of the jaws (under someone else's watch...). But it's fairly minor. Note the machine screws in the brass crown beneath the jaws.
Closeup of the jaws. The scraped texture is more evident in this shot (as is the tragic staining, alas...).
A truly beautiful jaw screw.
The wrench/key, which is mostly nickel-plated brass, with a steel business end. Beautifully made, heavy, a delight to use.
Now it's time to take this baby apart and see some of why it's such a special tool. It took me a long time to figure out how to disassemble this vise because the assembly is inscrutable. There is no hole or screw at the bottom of the ball end as with other vises, so for a long time I was perplexed about how it was built. It was clear to me that as smooth as this vise was, it had to be running on ball bearings. Turned out I was right, but I didn't have proof until after it had sat in my shop for months.

So one day, holding the base, I gave the waist a hard twist, and it gave way, but not where I thought it would. It was like leaning on a bookcase in an old haunted house - a total surprise! In the photo - this is what it looks like as the top is unscrewed from the base.

Top: the top part of the vise, resting upside down. Bottom: the bottom half of the vise, resting right side up. The four screw holes are threaded but serve no purpose. I assume their job was to secure the base when it was turned on a lathe.
Unscrewing the four screws to remove the base plate from the top portion of the vise. The imperfections are probably gaps created during casting. None of this shows on the exterior. Probably the biggest "flaw" in the vise.
I unscrew the four anchor screws. The only mark on the vise is in the lower left hand side of the photo: a red "K" marked with a grease pencil or crayon.
Another view of the underside of the top plate.

The top side of the top plate. The four screw heads visible here anchor the large center screw shown in the photo above this one.
With the top plate removed, here's what's left of the pedestal or spindle.
Removing the lock nut.

Taking off the cover yields more screws. They're brass, so I'll be gentle.
Brass screws removed, and I pull out the spindle/bearing assembly.

That's why it runs so smoothly! A ball bearing cassette.
Spindle top, showing knurled pattern, brass crown and vise jaws.
There it is. It's a remarkable vise, precision made (and I didn't even take apart the top, but I did it once, and don't want to mess with it again!), built so that it could be serviced and even repaired. It's no cliche to say that they don't make them like this anymore. Hope you enjoyed the tour. If you can tell me anything about my vise, I'd love to hear from you.

13 May 2013

Bicycle Chain Bracelet - Sprint to the Finish

Nearly done. Here's a look at the final stretch to finishing this amazing bracelet.

The assembly process begins. The copper wires temporarily hold everything together until the chain is riveted together.

Each outer link plate has its holes chamfered to hold the rivet. I use a tapered reamer.

All the plates have been kept in pairs the entire time. Here, a pair of plates is separated to be attached to the chain.

Starting to look like a chain.

One of the great things about this chain is the clasp mechanism. It allows construction of a chain that is visually seamless.

 After the chain is temporarily linked using copper wire, each pin is riveted by hand using a conical punch and a hammer. When the riveting is completed, I use a rubberized abrasive wheel to remove excess material from the tube rivets, as seen below.

Grinding off excess material from the rivet faces.
The chain is ready to polish, and after polishing, it is complete and ready to wear!

09 May 2013

More on Making Tools

Sometimes parts are too small to be worked in the usual fashion (that is, hold the workpiece, and bring the tool against the workpiece).

You have to think backwards, or at least differently, in order to solve the problem before you.

So you have to find a way to hold the tool instead, and bring the workpiece against it.

In this case, the culprits were the tiny, bead-like cylinders that would become bushings and rollers in a bicycle chain bracelet I was making for a client. Holding them is difficult, and getting a nice, even chamfer, or relief edge around the "corners," while no fun, is easy enough on on or two, but achieving this on dozens amounts to a real pain.

The culprits (show here already finished).

What to do?

Think like a machinist, and turn my flexible shaft tool into a lathe.

Since the exterior of my parts is what I was most concerned with, I wanted to chuck them (hold them) from the inside, not the outside (where holding them would likely leave unsightly tool marks).

For this, I used a split mandrel, (basically a steel rod with a slot cut through a portion of it, lengthwise).

Split Mandrel. Since I grabbed this beautiful shot from www.bursforcarving.com, please, go buy yours from them!

Here's how they're usually used:

Or, just wrap the sandpaper in a spiral and remove the paper as it wears out.  (Again, apologies to www.bursforcarving.com)
Anyway, the tension on the two sides (halves) of the split mandrel makes it a perfect inside chuck. File away (with the mandrel chucked into a handpiece) just enough material from the mandrel so that it will fit snugly into whatever tubing you need to finish.
Here, the filed-away portion is clearly visible. The diameter has been reduced just enough so that it will snugly hold the rollers of the chain for finishing.
Here is a narrower split mandrel, with one arrow showing the filed-down section, and the other arrow pointing to the bushing it will hold.

There. Time to get to work. Holding the tool (in this case a fine file), and bringing the work to it. Almost magic!

08 May 2013

Back to the Links (Making a Bicycle Chain Bracelet, Continued...)

Using a rotary file, excess material is trimmed from the side plates. Tubular pins keep the pairs of plates aligned (so they'll match) during the entire process.
A rubberized abrasive cleans up the coarse file marks, leaving a satiny, pre-polish finish. As with every other procedure on this chain, I then do the same to another twenty links.

I could probably devote several posts to the topic of toolmaking, but here's a quick example of how building a tool can make a job easier. Using various brass scraps, I constructed a holding tool to securely grasp the side plates for sanding/finishing the flat sides. The two protruding pins facing to the left hold each plate by inserting into the two holes on each plate. Using this tool I can confidently sand the plates using the Wolf Sander pictured above without burning my fingers off or having the sander accidentally launch the plates to Mars.
Again, using my plate holder, I finish each plate on several grades of sanding/finishing paper to obtain a bright, lustrous finish.
Sometimes I make tools that are quite useful, but not at all fancy. I strung all the hollow pins, bushings and rollers on wire or rod, like this one, to polish the little bits en masse. Just fold the wire ends over sharply, and those little guys will all stay in place during the rigors of polishing.
There. Shinier now.

Basic chain components, prepped and ready to assemble.

26 April 2013

Chain Saw (Building a Bicycle Chain Bracelet, continued)

OK, so a chain saw might be a little too much for this project. The jeweler's saw is slow going, but about as fast as I would want to have it go in order to produce consistent, accurate cuts. Below are a few shots of the progress.

Sawing away. I use a brass bench pin I made just for delicate piercing operations like this one.

Now the reasoning behind the silver sandwich is apparent. Lots of sawing ahead.

I remove excess material from the edges. Since it's easier to work with a large chunk of material, I carefully cut out the links in stages so I'm always holding the larger chunk and removing link plates one (pair) at a time.

I carefully arranged the links so that they are spaced together as tightly as possible to conserve metal. The spacing must account for the kerf (width of the path) of the saw blade, with a little left over for "user error." But they're tight enough that I have to pay attention to what I'm doing. No daydreaming permitted.

One by one, links are cut out (top, left). What you don't see is the pile of dust and scrap below.

I inserted the pins to keep the pairs of plates together. I keep the links in pairs throughout the process to ensure perfect alignment of the chain.

25 April 2013

Taking Sides...(Another in a series on the making of a bicycle chain bracelet)

Next, it's time to make the plates for the chain. I begin with two sheets of sterling silver, which I sandwich together.

Two sheets of silver, a 3x5 card and a bottle of white craft glue. I some glue all over both sheets of silver with a gluey sheet of paper between them (in this case, 3x5 card), then sandwich them together overnight until everything is dry.

Once the sandwich is dry, the two sheets of silver can be handled as one unit. The glue trick, which I first learned in Alan Revere's Professional Goldsmithing, is a surprisingly durable way to laminate metal together for work.

The benefits of this are many. All the plates, which will be made from these sheets of silver, will be created in pairs. This helps ensure precision (what I do to one link I'm also doing to its mate), and it also reduces labor because when I drill a hole or saw out a link, I'm getting nearly twice the work done. And given the number of pieces I'm working with and the enormity of this project, any time saver is a big help.

The first hole is drilled. The "L" shaped wire pin will help me accurately position the master or pattern link.
With the master link anchored to the silver sandwich, I'm ready to drill the second hole.
I use a drill press for this project because making holes at right angles to the plates is vital for the chain to work properly. For scale, that drill bit is .7mm.

With one end of the link pinned to the silver, when I drill the second hole, I know the pitch (distance between the holes) will be right on, and the same for each link.

Once I have two holes drilled, I secure the link with two pins and then, using a scribe, I trace the outline of the link using the master link. The pins, which fit snugly in the holes, ensure that everything is locked down for perfect alignment.

The precision drill press that helps me get the job done. Once the pilot holes are drilled, I re-drill each hole several times with successively larger drill bits to accurately expand the holes.

All the link plates are traced and the pilot holes drilled. The four "L" pins provide extra security (to keep the sandwich sandwiched) while I re-drill to expand the holes. The "L" pins are secured with super glue.

Using successively larger drill bits and burs, the holes approach their final size.

Finally, using a clock maker's reamer, the diameter of each hole is expanded just enough to accommodate the tubular link pins. The holes will be large enough to push the pins in easily, yet tight enough so that they will not fall out.