Solder Chuck?

[Imechura]

Hello,

I am reading an old book on toolmaking, I am sorry but the title escapes me at the moment. In the first chapter which covered precision locating, the author mentioned something called a "solder chuck" for a lathe. I think in the book this was being used to turn and face metal discs used in precision hole locating.

There where no illustrations or description of this chuck and a google search yielded no mention of this type of tooling.

I am visualizing something like a faceplate. Perhaps with a brass or copper surface that can be machined true after which parts can be attached with solder. It would have to be fairly thick to prevent warpage when heating the face with a small torch. I think this would be useful to face off very flat and very thin parts. Of course this is just what has popped into my head.

Has anyone actually seen or used a solder chuck before? Got any photos or can you describe what it looks like?

 

[L Vanice]

Watchmaker lathes utilized "wax chucks" that were brass rods or discs attached to a collet-shaped arbor. The workpiece was attached with melted hard wax or shellac. Heating was done with a small alcohol lamp. The work was centered by running the lathe while the wax was still warm. After the work was done, the wax was melted and the work was put in a pot of hot alcohol to dissolve the wax.

These days, superglue can be used in a similar way, and removed with acetone. But superglue cannot be temporarily softened for fine position adjustment, so the old wax technique is still useful for watch repair.

Bismuth alloy can be used for fixturing in some cases and has the advantage of low melting point and not adhering to the work.

Larry

 

[sfriedberg]

The technique is sometimes used on the mill, too, with a "solder plate" or "glue plate" grabbed in the vise or clamped to the table. On the mill, it has all the same advantages for holding and stiffening thin, fragile objects without obstructing the front surface with clamps. The precision locating advantages are much less significant on the mill, as you can move the mill table relative to the spindle centerline in ways you cannot move the lathe faceplate.

 

[Scottl]

Haven't actually used a "solder chuck" if such actually exist but I have used a faced off piece of bar stock held in the chuck to make thin washers from brass sheet that way.

 

[Marty Feldman]

Larry's "wax chuck" methods, above, have a long, tried & true history, but I have not acquired the experience to reliably center the work with precision, and rely instead on one of the superglues.

I have turned numbers of small mushroom shaped chucking platforms (from any material to which superglue will stick and which will stand up to acetone) for the purpose described here. The mushroom stem is an arbor that can be positioned in a 4-jaw for centration, and the mushroom head, or platform, is turned to run true and has a series of closely spaced concentric shallow circular grooves to provide tooth for the superglue.

-Marty-

 

[jscpm]

I once read an article in American Machinist in which the author mentions solder chucks as an aside, and he remarks that if a machinist has not learned to use a solder chuck, then he needs to "Tarry at Jerusalem until his beard has grown." That's a direct quote.

In the 19th century brass was widely used as a material for scientific instruments and other precision parts due to it thermal stability. Solder chucks allow the machinist to easily machine thin brass flats because the solder will flow to consistent thickness, allowing for the work to be tightly bound to the chuck in a perfectly parallel way. Generally, the flat is first tinned, then adhered to the brass faceplate. This can be all be done with a simple alcohol lamp, so it is baby's work.

Another important use for solder chucks is driving work between centers with no dogs. Lathe dogs have various disadvantages and undesirable effects on precision work. Therefore, a superior procedure is to use a solder chuck or "slug". To do this, you first turn a brass plug with a taper on one side and a flat on another that matches your work. So, for example if you are turning a 2" rod, you might make a 3" slug. The slug is bored with a shallow recess of 1/8" or so to receive the end of the work which is then soldered into the slug, which is fitted to the spindle by means of the taper. The work will then turn true to the spindle.

Another technique is to solder the work to a chucked slug. The photo and illustration below shows the idea. You solder the disk or other small article to brass bushing which is then mounted in a chuck:



You can also use solder to mount article for milling. There are many situations where thin flats or delicate pieces need to be milled and using a clamp on them would be problematical. Therefore, you solder the pieces (sandwiched if there are many of them) to a flat piece or "platen" in German which is clamped to the bed.

As an alternative to soldering, you can use wax. To do this, you melt together a 50-50 mix of pure beeswax and pine rosin. This substance can then be used to secure flats to a faceplate by using a small torch. It is a good practice to dip the piece in the molten adhesive to achieve a consistent thickness.

 

[Imechura]

I once read an article in American Machinist in which the author mentions solder chucks as an aside, and he remarks that if a machinist has not learned to use a solder chuck, then he needs to "Tarry at Jerusalem until his beard has grown." That's a direct quote.

In the 19th century brass was widely used as a material for scientific instruments and other precision parts due to it thermal stability. Solder chucks allow the machinist to easily machine thin brass flats because the solder will flow to consistent thickness, allowing for the work to be tightly bound to the chuck in a perfectly parallel way. Generally, the flat is first tinned, then adhered to the brass faceplate. This can be all be done with a simple alcohol lamp, so it is baby's work.

Another important use for solder chucks is driving work between centers with no dogs. Lathe dogs have various disadvantages and undesirable effects on precision work. Therefore, a superior procedure is to use a solder chuck or "slug". To do this, you first turn a brass plug with a taper on one side and a flat on another that matches your work. So, for example if you are turning a 2" rod, you might make a 3" slug. The slug is bored with a shallow recess of 1/8" or so to receive the end of the work which is then soldered into the slug, which is fitted to the spindle by means of the taper. The work will then turn true to the spindle.

Another technique is to solder the work to a chucked slug. The photo and illustration below shows the idea. You solder the disk or other small article to brass bushing which is then mounted in a chuck:

View attachment 371106

You can also use solder to mount article for milling. There are many situations where thin flats or delicate pieces need to be milled and using a clamp on them would be problematical. Therefore, you solder the pieces (sandwiched if there are many of them) to a flat piece or "platen" in German which is clamped to the bed.

As an alternative to soldering, you can use wax. To do this, you melt together a 50-50 mix of pure beeswax and pine rosin. This substance can then be used to secure flats to a faceplate by using a small torch. It is a good practice to dip the piece in the molten adhesive to achieve a consistent thickness.

jscpm,

Thank you for the comprehensive explanation and for the historical context.