Tool Projects at georgesbasement

"Projects" at georgesbasement.com

Every so often, I get it into my head to start some project, usually involving machining. Given that most of the folks who preceded me on this planet who were familiar with what's done in a machining task have either died or never got around to using the Internet, and in the hope that you might pick up something, I've begun taking explanatory pictures. The projects are:

1. Rusby Breast Pad. 2. Haeberle & Schmidt Corner Brace. 3. Archie England's Bell Systems Brace. 4. Adrian Mariano's PEXTO brace. 5. Taylor-Patent Brace. 6. Archie England's G-P drill.
6. Replacement LRRCW Assemblies. 7. Refurbishing a factory second No.2 drill.

Rusby Breast Pad

This started out as a project to make a new breast pad for an incomplete Rusby breast drill that was intended as a Christmas present for a friend. I successfully copied the old breast pad from another Rusby drill by welding the flat portion onto the end of a piece of pipe after appropriate shaping & machining of each part.

Then I was faced with the dilemma that the old breast pad was bent long ago by some former user.

Being a graduate metallurgist, I correctly reasoned that the original breast pad must be malleable iron, as it would simply have broken rather than bending if it had been made of grey iron. Therefore, I reasoned, if it bent once, I ought to be able to bend it again in order to return it to its former shape.

Being somewhat cautious, I also reasoned that I really ought to preheat the breast pad before bashing it into straightness, as I could not reliably determine whether its ductile-brittle transition temperature was below or above room temperature. "It ought to be less brittle at red heat" was my next reasoned step.

The new breast pad is at left, which you can tell by the machined inside bevel in the pipe. The old breast pad at right has no bevels, just rounded edges.

Oh yeah - the other reason that so many Rusby drills have lost their pads is because they're so easy to remove.

The bending process is summarized below:


Above: Bent old Rusby breast pad.	Breast pad lying on vise jaws; wood block and large hammer at the ready; propane torch about to be lit.	Breast pad at red heat - really bad picture, as there was insufficient light from the barely red breast pad.	I did not quite have the nerve to hit the breast pad so hard that it would overbend - the malleable iron is not all that ductile, so it's not yet perfectly straight. Straight enough !

Haeberle & Schmidt Corner Brace


Basically what I started with (not the actual eBay image).	US Pat No. 859,059 - all together.	Here's what I was missing.	The final result.

The first step was to reproduce the thumb nut that holds the removable piece down by the chuck. This wasn't easy, because I did not want to remove the existing thumb nut from its place. I had to guess at some of the dimensions, such as the pitch of the threads and the best "tap drill" diameter. Then, that's a blind tapped hole in the thumb nut. At least, the threads are right-handed. You will note that I had to modify my estimates as I went along ... and make a plug gauge to check the progress of my threading.

I do not have any means of knurling, so I used the lathe as a shaper and chased the grooves one at a time, using the lathe's bull gear as a divider.

My "new" removable piece was donated by an old, decrepit Stanley Rule & Level corner brace, where the end was smaller than it should be, and threaded 7/16-22 to boot. Therefore, I had to make an adapter to fit the smooth interior of the socket into which the removable piece had to fit, and it had to have a key to prevent rotation of the universal-joint housing. The adapter's internal thread is almost as large as its external diameter, and it had to be a tight fit on the end of the removable piece.


The original patent's latch was flimsy ...	I had to design my own arrangement.	Here the latch is in the locked position.	There's a spring & ball to hold the latch.

There are several sleeves and packing pieces to take up the slack in the very sloppy fits of the original brace's various pieces. They're bronze, salvaged from old tensile specimens.

US Patent 859,059, July 20, 1906

The pieces go togther now quite nicely, and the brace is fully operational in either configuration - as a straight brace or as a corner brace. If there's one nagging flaw, it's that the split screw over which one or the other of the two thumb nuts fits is insecurely attached to the universal joint housing and falls off relentlessly during any changeover. The patinas of the two portions match pretty well, except for the freshly made pieces, of course, and the wood handles are good matches for each other. Maybe the original removable piece was also made by Stanley ...

Archie England's Bell Systems Brace.


Archie's brace was missing the ratchet cover, etc.	Fine threads ! 32 per inch ...	The change-gear setup.	Aligning slug in the four-jaw chuck.	An old ratchet cover fits OK.

Above, second from right: I used the four-jaw chuck (stiffer than a three-jaw) because the slug was too large to fit my Jacobs Rubber-Flex collet chuck.


The blind hole required me to thread to the stop.	After many test trials, the gauge finally fits !	So does an old ratchet body ... whew.	Final cover with chased knurling.

Not shown: I parted the budding ratchet cover from the second slug with a cut-off tool ... very carefully. Far right: I cut circumferential grooves to complement the chased lengthwise grooves.
The new ratchet cover is Type 303 stainless steel, whose color isn't far from the chrome-plated Stanley brace's, and it won't rust. The gauge slug also facilitated facing off the ratchet cover.

Adrian Mariano's PEXTO brace.


Adrian's picture of his Smith-patent brace.	Adrian's picture shows his jaws just wired together ...	A PEXTO-style spring was too weak.	My new design next to the old one.	Now the spring will work right.

I found several spring arrangements among my spare PEXTO jaws. Adrian's jaws were designed for the worst arrangement. The extra loops give the spring a greater range of motion.

Taylor-Patent Brace

Originally the pad of this nicely made Taylor-patent brace was extremely loose. There was both radial and longitudinal play. It had been held on with the usual arrangement of a washer peened in place on a reduced-diameter section of the frame. There was no way of adjusting the end play. I took that arrangement apart, annealed the end of the stem, peened it and adusted its end to accept a split collar designed like the retainers used on automotive valves. The first row of images below describes making the split collar and its retaining ring. Not shown is the bronze split sleeve that I slipped over the stem to remove the radial play at the lower end. I fit another bronze sleeve inside the pad at its upper end.


The cross-hole is to make closing the saw kerf easier.	When I closed the saw kerf, I hit it too hard ...	The lathe dog held the three pieces of the split collar in place for the drilling.	I parted off the three pieces successfully without losing any of them !	Here I am parting off the retaining ring that fits down inside the recess in the pad.

Below, there was no way to machine the stem of the frame, so I simply annealed the stem, peened the end to a stronger configuration, and then filed the reduced section to an approximate cylindrical shape to accept the keys made from the split collar. Not shown: The process of making the two bronze sleeves that improved the radial fits.


The pad, stem and other pieces all apart.	I annealed the stem (blue color.)	Here the retaining ring is in place, "keeping" the keys.	The finished pad, smooth-running & solid.

There's more ! The bit latch was utterly missing, probably because its spring had failed ...

Making the bit latch from a chunk of plow steel

I started with a chunk of plow steel.

Trimming for easier clamping.

Reducing the body thickness.

Lots of sawing and filing later ...

Latch in place & finished brace.

While I had originally planned to case harden the latch with Kasenit, my choice of raw material turned out to be a very hard piece of plow steel, judging from the recessed hole for a square-shanked bolt. I made a maximal spring by choosing thick (0.041 inch) spring wire, which necessitated a small (ca. 0.10 inch) arbor around which to wind the spring with a Hjorth spring winder and my Ultra-Rapid geared brace. It now takes about all my thumb strength to depress the latch fully. I drilled a shallow hole inside the recess for the latch to hold the inner end of the spring, which is fully as long as the dimensions of the brace allow; the upper end goes up inside the thumb pad. A taper pin allows the latch to be taken apart for adjustments.

Archie England's Goodell-Pratt drill


The chuck base wouldn't unscrew ...	By removing the spindle from the frame, I could place it between centers.	After some persuading, the thrust bearing came unstuck.

The first task was to clean up the end-most one or two threads which had been distorted by a previous owner's operation of the chuck without a key part. Placing the spindle between centers allowed me to use a triangular file and a single point tool (a lathe threading tool) as a scraper to remove the distortion without affecting the appearance of the threads.

Two sizes of Goodell-Pratt jaws side by side

The base of the chuck contains an element that presses against the bottoms of the jaws when the shell of the chuck is screwed tighter onto the spindle. The hollowed-out end of the spindle presses against the conical small end of the pushing element; the small contact area minimizes the frictional torque between the pusher and the spindle, so the chuck is self-tightening under load.

I also made a new set of springs as described above. The springs have to be a close fit inside the holes in the jaws, and the wire diameter should be large enough to generate sufficient force to make the jaws spread out inside the shell, and yet not become coil-bound when fully tightened.

The knob that was on this drill had been adapted from another drill's side knob and was most insecurely attached. I pulled out its threaded shaft and bored out the knob for a wooden sleeve, then made a new shaft from a handy 5/16-24 Allen head, stainless steel cap screw. The new shaft is held onto the crank by a nut which I cut into two parts in the ratio 1/3 - 2/3. The thinner part became the outside lock nut and the thicker part became a threaded sleeve to fit inside the bored-out knob (3/8 inch inside diameter). In the image at far right, I am turning down the shortened cap screw to fit the 0.205 inch hole inside the mahogany sleeve. The round-nose turning tool left a generous radius at the junction between the shaft and its (still) threaded base. I am taking light cuts because the jam nut and threded sleeve can't be very tight - they're all that are driving the shaft for the turning operation.


The old belt protected the knob.	Three equally thick pieces of soft wood ...	Scrap Honduras mahogany became the sleeve.	Turning down the shaft to 0.203 inch.

Now the next part is serious: This is the method used to attach the pads to old braces - it's permanent, because the sleeve is glued inside the knob.
The washer was peened tightly to the reduced-diameter end of the shaft, so the bearing surfaces are the opposite ends of the mahogany sleeve.


The threaded sleeve is used to adjust the end play of the mahogany sleeve on the shaft after the washer is peened onto the shaft to hold the sleeve in place.	Here's the assembly before I glued the knob on. Thankfully, I thought to put a couple of drops of oil inside the knob - carefully, so as not to spoil the gluing process. I bent the crank plate to improve one's wrist angle.	The drill is now all back together with a free-running ball thrust bearing and a smoothly turning knob ... while not the original crank and knob, its just as useful.

The replacement jaw retainer was potentially a nightmare - if I had tried to make it by bending sheet steel to shape - it wouldn't tolerate repeated adjustments/bends. My solution was to carve the retainer out of the solid metal, as it's not called upon to deflect or to resist much force. The saw cuts greatly sped up the shaping process. Note how delicate its attachment to the jaw is !

Design 1 of the protected-springs chuck - before repair

Unmatched jaws of protected springs chuck

The original chuck had a poorly fitted jaw.

The peened-in pin was hard to get out.

All together now !

Lots of space for the retainer ends.

The jaw tips don't match.

Whoa ! It turns out that there are two protected-springs designs of the Millers Falls chuck. They are not interchangable, as the truncated cone that aligns the springs in the original patent has a pointed tip, a lot like the Goodell-Pratt chuck described above. The alternative design has a smaller, cylindrical extension to fit against the drill spindle. The original patent shows a third way ... The protected-springs chucks that have the patent date imprinted in them are all the coil-spring, original design. None of the chucks with the S-shaped springs has any markings, even though they were used exclusively on Millers Falls drills. These are the size used on the No.2 eggbeater drills with either the LRRCW, two pinions, or both two pinions and the LRRCW.


U.S. Patent 660,121, issued October 23, 1900.	Archie's jaw design in the patent.	An unmarked Millers Falls chuck with S-springs.	The connection to the spindle is different !

Replacement LRRCW Assemblies

Millers Falls No.2 drills have often lost their roller assemblies (LRRCW's in my Millers Falls No.2 Type Study) and so I'm occasionally asked for replacements. As I have no leftover LRRCW's or their associated parts, I've had to reply negatively. I decided to make some replacement assemblies, but I also decided not to make counterfeits. Here's my solution: I am making redesigned LRRCW assemblies that do not require a screwdriver for adjustment. I'm making the rollers themselves from scrap bronze (i.e., broken tensile test specimens) which is a nice way of recycling as well as a way of making use of the work hardened condition of the material, which cannot be heat treated to increase its wear resistance. Rather than just making the offset cams with a screwdriver slot, I'm adding a projection to facilitate grasping the cam in order to adjust it. The normally standard No. 6-32 screw that clamps the assembly will now have a crank shape so that it can be tightened with one's fingers. Rather than trying to develop a heat-treating process for the cams, which are lightly loaded, I'm using drill rod as the raw material, as the carbides in the annealed microstructure will provide some wear resistance. All you need do is remember to oil the assembly every few years !


These three views show the LRRCW assembly.	Normal LRRCW shape, but in bronze.	Properly adjusted LRRCW assembly.	Another drill had its cam hole placed wrong.

The eccentric cam requires some precise machining. I made a holding tool for the blanks by offsetting a piece of 3/8 inch round barstock in the four-jaw chuck so that its axis was 0.048 inch off the center of rotation of the lathe spindle and then drilling and reaming a 0.250 inch through hole. The 0.152 inch diameter part of the eccentric cam has to be tangent to one side of the 0.250 inch body of the cam to maximize the range of adjustment of the LRRCW and yet still allow putting together the main gear and LRRCW assembly. I got it right on the first try !


Saw cut was made with a piece of bar inside.	Rod faced off & ready to machine eccentric.	Another eccentric cam ready to be cut off.	LRRCW reshaped to allow LRRCW adjusting.

One drill had its 0.250 inch eccentric cam hole drilled in the wrong place, so I had to enlarge the replacement LRRCW so that it could be adjusted properly; this drill probably was a factory second and did not have a LRRCW when I obtained it. The far-right-hand images in the two rows above show the problem and its solution. More to come: making the LRRCW itself.

Histogram of LRRCW diameter distribution

After the above debacle over the center distance and diameter of the LRRCW, I made some measurements of the drills in my Millers Falls No.2 Type Study. I found that the center distance between the main shaft and the hole for the eccentric cam was usually about 0.81 inch, with all the measurements falling between 0.75 and 0.83 inch, but the LRRCW varied in diameter significantly, as shown at left.

Types K through H have LRRCW's that usually measure around 0.31 inch (5/16th inch), but the later Types G through D have smaller LRRCW's, about 0.28 inch (9/32nd inch). Oddballs include a couple of 1/4 inch LRRCW's in the earliest Type K drills, which may have been either worn or replaced. There is one large LRRCW in a Group III, Type G drill that was probably commandeered from an earlier type. Nearly all of these drills were made while the company was still located in Millers Falls, Massachusetts. The histograms were made with PSI-Plot.

			Above: Some of the clamp levers that I made; note that I started with screws that had both a slot and Phillips recess, so I could support the outboard end with a live center. Original at right.
Above: Making the holders for milling the adjusting tab on the cams.	Above: End milling the tab on a cam, held in the cam holders.	Above: Eight of twelve LRRCW-GB cams that I made recently.	Above: The clamp levers are made from modern screws by machining in the lathe & bending.

Finished Product !

The No.2 Millers Falls drill at left with my LRRCW-GB installed. This drill came to me with just a 1/4 inch slug of steel in the hole that was meant to hold the LRRCW cam. It did serve a portion of the original purpose, as the slug had a small flat spot worn into it from rubbbing against the larger gear wheel.

I'm all set to make a bunch of bronze LRRCW's. However, I'm slowing down a little and doing them one at a time for the half dozen or so No.2 drills that I have that are missing the LRRCW assembly or just the LRRCW itself. The statistics are in favor of making the LRRCW's all one size (see the analysis I did above) but I'm still going to work my way through this group and see how they turn out.

I'll make replacement LRRCW-GB assemblies for your drills if you wish - Price $20, plus shipping in a First Class padded enevelope.

These LRRCW-GB assemblies adjust easily to keep the gears meshing on their pitch lines, and without any need to resort to tools - the clamp lever holds the cam securely and won't unscrew and get lost unless you move the main gear wheel out of the way. After unclamping the cam, the tab lets you adjust the position of the bronze LRRCW with your fingers, with visual feedback to simplify the task.

Orders to:

Refurbishing a factory second No.2 drill

This was an otherwise normal 2B drill with hardwood handles, but with a specially adapted Jacobs Model 4364 Rubber Flex chuck, 3/8 inch capacity.

The Jacobs chuck is marked with the U.S. Patent No. 2,346,706 and with a pending patent, which turns out to be No. 2,459,899. Another pertinent patent is No. 2,683,041.

The rod through the handle, hefty at 7/16-18, had an unsightly nut and washer which I cut off flush with the end of the handle. Whoever fitted the chuck also added a larger threaded sleeve over the original drill's 3/8-24 spindle threads. I made a new, larger bronze LRRCW to replace the lost roller and to allow the running clearance of the gears to be properly adjusted. The patent drawing for the body of the chuck matches the outline of the actual chuck, but the rubber spider for the three jaws does not match - one has to infer the design from U.S. Patent No. 2,459,899.


Markings: "[Star] No. 2B, Millers Falls Co., Millers Falls, Mass., U.S.A."	The frame had been tapped and a piece of threaded rod inserted through the handle.	Chuck is marked "Patent 2346706 & Pat. Pend." (U.S. Pat. No. 2,459,899) & "Model 4364."	Patent drawing from U.S. Pat. No. 2,683,041.	Jaws, 2,459,899 & 2,683,041 patents.

Referring to Randy Roeder's fine website, A Millers Falls Home Page, the No.2B drill with LRRCW was only made from 1912 to 1938. The Jacobs chuck was made between about 1944 after the first patent issued and 1949 when the second patent issued. Therefore, the marriage was conducted outside the Millers Falls organization, using a cast-off No.2B drill. I cannot find any other Model 4364 chucks or even any reference to them on the Internet. I have seen some 1/4 inch capacity Rubber Flex chucks on power drills, however.