Rockwell Rating

Today two customers came into the showroom asking about the knives and hardness. The knifemaker's lady friend ran through the spiel about the source of metal, carbon percentages, blah, blah, blah to which the customers said "But what is the Rockwell Rating?"

What to say? What is this person talking about?  Even the knifemaker's lady friend hadn't come across this to date.

The knifemaker's aunt zipped into the shop for reinforcement. The knifemaker's dad came into the showroom and answered all the questions. Know what the Rockwell Rating is? It turns out the Rockwell Rating is a system of measuring relative hardness of items based on the depth of an indentation an heavy object makes when dropped onto the thing being measured. The actual rating he difference between the indentation a ball makes on an object upon impact and the indentation it makes again after a period of time. [There's more of course, but as a base piece of knowledge it works.] There is a bunch of math involved with the system, which made the knifemaker's aunt go Yikes! 

This is algebra in motion for everyday work! Now she has a valuable reason for why those middle school kiddos need to learn how to calculate differences. Good lesson to learn! Basically, the Rockwell Rating is the difference 

Wow, Rockwell. 

Sewing the Sheaths

The knifemaker has had the nail knife sheaths sown on a machine -- just a straight line, run down the curved edge. Today, the knifemaker's aunt and lady friend are experimenting with hand-sewing the edge of the sheath. The first handful of sheaths sported a running stitch, a whip stitch, and a blanket stitch. Each offered a different look, but the knifemaker's dad said the whip stitch was the way to go.

To make the holes through the leather, the knifemaker's aunt began with a 4-hole leather punch and hammer and pounded the punch through the leather. A few moments of that brought the knifemaker in from the forge to offer a leather hand punch which made the holes on one side of the sheath curve easier but needed much more manual strength than the knifemaker's aunt had. Each line of holes along the curved edge of a sheath required another pass with a needle to force a matching hole on the backside of the sheath. The needle bent doing this.

Luckily, it turns out the knifemaker's lady friend is a hole whisperer and was able to tease the punch to make holes all the way through the sheath layers. Whoa!  Things went much faster after that. The holes were made and the sewing moved along. By the end of the day, 48 sheaths had been sown in preparation for the knives.

Initially, a running stitch was used on some but eventually
all had a back-and-forth whip stitch.

3rd Time Lucky

There is an old saying that goes, third time's the charm, or third time lucky. It is supposed to mean that after attempting something twice, the third time will meet success. Where does that come from? In England, there is a law that anyone who survives hanging three times is set free. Yikes!  Could it be connected to try, try, try again?  There are numerous mentions and connections to 3 in the Bible. Numerology suggests the number 3 is connected to optimism, which leads the knifemaker's aunt to be hopeful for the next forging episode. Now that she's been in the shop for almost two weeks, she has observed people using the force of hammering to get the job done.

Next time the forge is on and the hammer is in her hand, it'll be 3rd time lucky for the knifemaker's aunt!

Another fabulous gif from www.giphy.com!

Rain, Sheath Exploration, 5pm

Rain today, actually, a LOT of rain. In fact, it was a good day to address the nail knife sheaths again since the knifemaker was busy with a build-a-knife class. Throughout the day, the knifemaker's aunt alternated between sweeping up grindings and experimenting with sewing options for the sheaths.  Before she knew it, it was 5pm and everyone was leaving. How did that happen so fast?! 

Source: www.reddit.com

Improved Grinding

The knifemaker's aunt got onto the Grizzly (the belt sander used to take the most material off a forged knife) and profiled more railroad spike knives. A firm and strong hand put railroad spikes to the belt with confidence and force. Clearly, a quick critique and some practice improved the knifemaker's aunt's profiling technique. The butt end of the spikes resulted in right angled edges.

See how the side meet the butt in a clean line, not a beveled edge from the side to the butt.  What's next? Once the knifemaker's dad grinds the blade the handle will get twisted. THAT will be exciting given the terrible time the knifemaker's aunt had trying to twist the handle of the nail knives!

A Ruff Business

Since there are two full build-a-knife students in the shop today, the knifemaker's aunt cannot get to the belt sanding to repair yesterday's mis-grinds or continue with the bucket of forged railroad spikes. She has spent time in the showroom with the knifemaker's dog sorting through leather for more sheaths until she gets her turn on the equipment again.

The knifemaker's dog fell asleep in the air conditioning - a pe
rfect summer afternoon activity.

It's a ruff business.

A Fault in the Grinding

The knifemaker's dad pointed out a fault in the aunt's railroad spike grinding duties...an over-zealous edge on the butt end of the spike. At the place where the butt had been ground around the whole of the end, the knifemaker's aunt had beveled the edge. This left horizontal grind marks around the edge, vertical marks across the butt end, and diagonal grind marks where the edges and butt overlap.

The knifemaker's aunt is too artistic for her own good. There should be a right angle edge there the side all around meets the butt end.

Back to the belt sander!

Joking in the Knifemaker's Shop

Because metalworking moves along in stages, there are moments of relaxed levity, Three jokes or riddles passed around:

The knifemaker asks What do you call instant mashed potatoes?  The answer, Imitators!

The knifemaker's lady friend asks What do you call a cow without legs?  The answer, Ground Beef!

The knifemaker's aunt tells A couple friends walk into a bar. Luckily the 3rd one ducked.

Source: wifflegif.com

Railroad Spikes

The railroad spikes were addressed today. The knifemaker's aunt was directed to the bucket of forged spikes - a remote location under one of the benches. Yikes! There must be more than 300 spikes in that bucket! Since metalworking in done in stages, these were probably done a while ago in wait for the time when someone could do the profiling. Today, the knifemaker's aunt was the someone. Done very much like the nails were done, the job did not seem so daunting: establish the blade edge, the spline edge, cut in a finger notch, and then make sure the edges are at right angle to the belt sander. With the railroad spikes, however, the head of the spike is ground as well as the blade and spline. Much like the image of the forged and profiled nails in the earlier post shows, the forged spike is rough, and the profiled one begins to show metal that has a shape. 

The knifemaker's aunt selected 12 spikes and watched carefully as the knifemaker's dad walked her through the way he profiles railroad spikes. It was clear to the knifemaker's aunt, right from the start, the move from a nail to a spike involves more strength, more force, and not dust but metal filings. The metal friction sparks flying off the belt sander were bigger and could be felt...not painfully so, but definitely she could feel the occasional ping ping against her skin. The dust accumulating on her shoes, pants, floor, and arms were actual filings that could be picked off and rolled between fingers. Once done with the first batch, the knifemaker's aunt made a point of using a whisk broom to brush herself off (which was done easily). 

The pile of profiled spikes went to the knifemaker's dad's station for grinding before going back to the forge for the handles to be twisted and the blades heat treated. This is the point with metalworking: everything is done in stages and if one stage is completed then that is the success for the day, not trying to complete all stages in one day. Learning that rhythm and being pleased with success in stages make all the difference.

Patience and pacing are critical...a valuable lesson.

July 4th Knife News

Andrew Jackson, the seventh president of the United States, had a couple nicknames based on his strong personal traits. His tough, ruthless, negotiating skills earned him the nickname Sharp Knife...a good bit of news to know for knifemakers. Sharp of tongue and sharp of mind can go as far as a sharp knife as is demonstrated by this Andrew Jackson quote, "It is a damn poor mind indeed which can't think of at least two ways to spell any word." What's not to like about a mind that can come up with that kind of sharp thinking?

Final Grind before Polishing

Once the nails were heat treated, the blackened surface discolorations and grime are ground off. The knifemaker's aunt spent time today grinding the blade and spine edges again as well as the sides and butt of the handle.
They are ready for the knifemaker's dad to polish and buff them to a blistering sharp edge. When the knifemaker's aunt asked why she couldn't polish and buff the nails, the knifemaker's dad raised a sinister eyebrow of disbelief and said "No, those are the two most dangerous machines in the shop and only I operate them." So, there you go. The knifemaker's aunt is relieved of what is probably a most dangerous part of the process.

A surprise bonus on this July 4th day.

From the Ashes, Phoenixes Arise

The metalworking insight: Like the phoenix of mythology, where the magical and spectacular bird rises out of the ashes to start a new long life, remarkable knives and metal objects arise out of the metalworking dust and debris that accumulates day to day in the shop. Each forging session, belt sanding session, or bandsaw visit results in grime on the floor, on hands, on machines, in the hair and on the clothes.  You may remember the knifemaker's aunt's toggle upon arrival to the shop on the first day. Now, it looks like she's been a worker!  Routinely, she makes a mid-day visit to the bathroom to wash her hands. It takes 3 passes with soap and washing to get to a point where the water in the sink runs clear. 

The knifemaker's hands shows evidence of the work he does, complete with cuts. The line on the second finger of the left hand was a cut this week when a drill press offered more resistance than anticipated.  You can see his clothes. YET, the floor in the background is swept! The dust and debris is emptied into the trash can with the thought that any dust and grindings swept up is dust that cannot be blown around when a breeze blows through!

Heat Treating

Once the handles were twisted, each nail is held in the forge for several moments until the blade comes to critical temperature. This is called heat treating and the purpose is to bring the metal to a hardened state. The blade is heated to the point when the iron and carbon separate into a molten state while still holding shape.  The final product needs to be hard enough to hold a sharp edge yet flexible enough to withstand the forces of using it without breaking. The knifemaker's aunt keeps an eye on it to know when to take it out. 

When the blade is ready, it is taken out of the forge with a sure hand and plunged into water to cool. It is swirled around a little because the water immediately around the blade and tongs holding it will heat up. Moving it around makes sure the blade is cooled effectively and efficiently. When the molecules reconfigure, a magnet will not stick to the blade.

After about 25 blades, the water became too hot to use and had to be  replaced with another water jug. In all, 40 nails are ready for polishing and buffing.

Twisting the Handle

Twisting metal means heating the metal to critical temperature and, while red hot and pliable, twisting it in two different directions. Once the nails have been ground to acceptable shape, the handles are heated in the forge. When red, they are grabbed out with pliers and, with a locking wrench, the handle is twisted so the end is parallel with the blade.

The knifemaker demonstrated the technique. It looked so easy -- like twisting a thick piece of stale licorice.  When the knifemaker's aunt tried it, Yikes!  The hand strength necessary to twist the hot metal seemed beyond the old girl. She could only make a quarter turn before the metal would cool beyond movement. Bummer. She returned to sweeping until the knifemaker could swing by her station and twist the rest of the nails.

Grinding the Nails

Walking into the shop today, the knifemaker's aunt was met by the knifemaker. While he teaches two horseshoe knife classes, the knifemaker's aunt is going grind, twist and heat treat the nails that have been profiled so far. 

The knifemaker does a demonstration with a couple nails, and the grinding begins. The idea is to grind the metal along the edge of the blade and spine to be at right angle to the body of the knife. The profiled nail is run at a 90 degree angle to the belt sander along the blade's edge and the spine's edge.

The flat side and edge of the blade is the next grinding action. One side is done, then the opposite side. 

Once the blade sides and edge are ground, it is gently rocked against the belt sander to smooth the side from blade edge to spine. Afterward, the knifemaker's aunt asked the knifemaker's dad for critique (the knifemaker was busy with students). About half of the nails needed a re-grind because the rocking action had produced sides that bulged out from the spine to the blade edge. He demonstrated a different way to grind the sides that broke the rocking action into separate steps with much improvement.

As happens, knives drop. Even without polishing and buffing step, the nails are already sharp enough to stick into the floor if dropped.  Note the dust accumulated with just one 1 1/2 hour grinding session.

Once done, the knifemaker's aunt grabbed the broom and dustpan to sweep up. In fact, this has become the fall-back activity while waiting for the next duty or space to accomplish the next task. Dust accumulates each time someone forges, profiles, grinds, polishes, buffs, or cuts handle stock.