Super Quench Formula for Mild Steel

This is used to harden mild steel (up to 45-50 points of carbon) by rapidly quenching it.

We use it for ad hoc tools. This will not work for hot cuts, as the thin edge will temper quickly and lose its hardness. Heavier tools such as fullers and cold tools such as center punches work well. (Though they are not as good as tool steel equivalents.)

Not for use with high carbon/tool steel. This cools the metal so quickly that high carbon steel will shatter.

Ingredients

  • 5 gallons water
  • 5 lbs salt
  • 28oz bottle of Dawn blue dish washing detergent
  • 8oz bottle of JetDry or other rinse aid.

Do NOT reduce the total quantity, you need the heat capacity from using a large bucket.

Store in a sealed container to avoid evaporation. When the mixture turns yellow/green, it is used up and you need to make a new batch.

Instructions

  1. Mix thoroughly, but gently so you don’t form bubbles.
  2. Heat metal to critical temperature
  3. Submerge immediately and keep in constant motion. If the metal doesn’t “scream” it wasn’t hot enough.
  4. Rinse immediately to avoid flash rusting. Then oil if appropriate.
  5. Do not temper. Any tempering at all will remove the hardness.

History

Super Quench was invented by Rob Gunter of Los Alamos Laboratory after they banned the use of sodium hydroxide as a quenchant.

More information: http://www.anvilfire.com/FAQs/quenchants.htm

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Finger (Clamping) Plate

The next project in the book is a “finger plate”, which looks like it would be really useful for drilling holes in round stock.

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If you want the plans hit me up.

Base Plate

First I would like to say that I love cold saws. Spinning at only 57 RPM, it slices through my metal like cold butter leaving only the smallest of burs. They’re big and expensive, but a hell of a lot nicer than the chop saw I use at home. (Also, why the hell is Walmart selling these?)

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Anyways, I learned that you want to keep your digital calipers far, far, far away from the cold saw. See how far it is? Now move another foot away. Otherwise it is going to be soaked in coolant, which is kinda bad for the electronics.

Cutting the Groves

I’m sure there’s a fancy 60-degree end mill specifically for this purpose, but I don’t own one. So instead I used this thing that I happened to find.

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I don’t even know what it’s called, but it’s clamp-shaped, stored in the junk pile near the mill, and did the job. Maybe next time I’ll try to figure out how to dial it in. This time I was happy with “almost parallel” to the lathe. The cut is a bit deeper in the front, but that doesn’t affect its usefulness.

Cutting the Drilling V’s

For the two v-shaped cutouts, which are designed to offer clearance for a drill, I used an angle grinder. It was totally over-kill, but my Dremel was way too small. (If you know of something in-between, well don’t tell me because my wish-list is already too long.)

A strip sander made quick work of cleaning up the mess left by the grinder. It’s no longer a true V, as said sander can make it wider but not deeper. So I’m just going to pretend that I wanted a fancy flat-bottomed cut.

Clamping Plate

This was a failure, though I didn’t know it until I was completely done. My stock was 1/8” of an inch too short, so I figured I would just make the center slot 1/8” longer.

Nope.

The distance between the holes for the elevator screw and the clamping nut are really important. If it isn’t big enough, the two won’t clear each other. This in turn means that the clamping bar doesn’t actually reach the groove, which is kinda important when trying to hole round-stock.

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I’m going to halve to remake this part, paying careful attention to the measurements next time.

I used a cold saw for the basic rectangle, then an angle grinder for all of the angles. A combination of Dremel and belt sander cleaned everything up.

Elevator Screw

This is a bad design for lathe work. After you thread the screw and knurl the end, you need to part it off. That can leave a rough finish, so you would normally turn it around and face it. But you can’t do that because there’s nothing to grab onto. You’ll either mar the knurling or crush the threads, defeating the purpose.

Compare it to this design, which gives you a nice shoulder to grab.

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I understand why they did it. You want to keep the elevator screw short do that you clear the clamping nut. But still, it’s annoying.

Clamping Nut

This has three steps. The lower step helps with clearing the elevator nut, the middle to grab it in the lathe (and aesthetics) and the top is of course knurled.

I’m really happy with the knurling job. I paid close attention to the vertical alignment of the wheels and gave it a lot of initial pressure, both of which paid off.

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Drilling

The tail stock starts at 1/4”. (Why? If it won’t hold anything in the Morse taper unless it is extended to 1/4”, why not just mark that as 0.00 on the tail stick?)

The total of all three steps is 0.78”. I want some extra for safety, so drill it to 1.00” right?

Yea, ‘cause 0.25 + .78 + extra totally equals 1.00.

New Trick: Back of the Jaws

So after parting I needed to make the hole a wee bit deeper. If I wanted any chance of getting this concentric I needed to continue the existing hole rather than make a new one on the back side. But holding it normally would crush my knurling, and I’m not going to ruin my best knurl to date.

So what I did was use the back of the jaws to grab the middle step with the knurling towards the chuck. The internal clearance of the chuck is 5/8”, which is plenty of room. After fixing the hole, just flip it around a tap as normal.

Threading

Or not.

Don’t try to thread the entire nut. Thread about halfway and drill a clearance hole for the rest. Seriously, it’s not with trying to break a tap over this. (I wasn’t successful at my attempt to break the tap, my tap has a bit of a shoulder that stopped me from going any deeper.)

Since I was tapping from the top, I had to turn it around and use the back of the jaws again to drill out the clearance hole. Then I retapped from the top to clean the threads.

Stud

I didn’t have any 1/4” studding so I parted off a bolt in the lathe, partially crushing the threads in the process. I wasted a lot of time chasing that with a nut to clean it up. Someday I need to learn the correct way to cut down threaded rod.

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Building a Micrometer Stand Part 2

Here’s the completed project.

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Holding Screw

The instructions call for the holding screw to be machined from a piece of brass or plastic so as to not mar the micrometer. What I ended up doing as making it a steel knurled nut instead. I threaded the center, then ran a nylon screw through the center.

My original plan was to melt the nylon screw into the nut so they would become one piece. I envisioned cutting a couple of groves on the top to make this happen. In the end that wasn’t necessary, as it works just find by hand-tightening the plastic screw then using the nut to lock it into place.

Knurling on the Mini Lathe

The mini-lathe has trouble dealing with the forces involved in knurling steel. I had to replace the lever on my quick change tool post with a nut that I could crank down hard using a long wrench.

The last time I knurled something was over a decade ago so I’m sure that I’m forgetting a step or seven, but it worked out well enough to be usable.

Tilt Adjusting Screw

I made this out of a single piece of 1/2” cold rolled steel. The plans call for 3/4”, but I already have 1/2” chucked up from the previous part. And really, 3/4” seems overly large.

In theory I could have used a piece of threaded rod that was glued into place, but that’s kinda cheesy. So I did turn it down to the correct screw diameter. Actually I went a thou or two under on the theory that if my cheap digital calipers were off it was better to err on the low side. (No, I don’t actually own a micrometer. The stand is a gift.)

Cutting the Threads

The first attempt was a dismal failure and I bent the part. Not willing to start over, I straightened the shaft using repeated blows from a lead-filled, rawhide mallet.

That taken care of, I tapered the end so I would actually stand a fighting chance. I normally don’t like doing it because changing the angle on the compound slide it a pain in the ass. But after doing so, the threads were easy to cut.

I used a die holder from Little Machine Shop so I didn’t need to remove the part from the lath. This has always proven to be much more reliable for me than using a hand-held die holder.

Swivel Screw

I’m not entirely sure why I needed to make this screw (besides the learning experience). It seems to me that a normal set screw would have done the job equally well. Is there really any advantage from only threading half of the screw?

Parting Off

Trying to part this off using the lathe’s parting tool was silly. It snapped long before I got close to finishing the cut.

Thankfully I had a small vise. So I racked it up and finished the parting operation using a Dremel’s cutoff wheel. Then I cut the slot for the screw driver using the same tool.

Finishing

I used Birchwood Casey Gun Super Blue to add a protective finish. It’s always worked well for me so I haven’t tried anything else.

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Building a Micrometer Stand Part 1

These plans were inspired by Useful Machine Shop Tools to Make for Home Shop Machinists by Stan Bray. Unfortunately the plans and instructions in that book are woefully incomplete, often missing key steps and measurements. Furthermore, they use British screw sizes that are not available in the US. So while the book is useful, I think this will help beginners like myself.

Where appropriate I’m including links to my local hardware store. Even if you don’t buy from them, you at least know what to look for.

Micrometer Stand

Micrometer Stand Plans PDF
Micrometer Stand Plans Fusion 360

Conversion Notes

When I originally did my conversions, I did a direct mapping between British BA sizes and US numbered sizes. Then I realized that some numbers sizes such as #5 and #12 don’t actually exist. Yes, you can buy tap and die sets for those sizes and make your own screws. But they are hard to find and not worth the effort. So I went back and only used #4, 6, 8, 10, and 1/4”.

My next mistake was using UNF or fine-threaded screws. In my defense, these are closer to the TPI used by British BA screws. And I already had the necessary taps and dies in my starter set. But UNF screws are hard to come by. Apparently UNC or coarse-threaded is considered the “general purpose” screw design and UNF is only used when vibration is a concern.

Beyond that I had to guess at some measurements. Thankfully the book is printed almost 1:1, so I should be pretty close to the original.

Body

Ideally the body is milled from a single piece of metal. If you don’t have access to a mill, or don’t want to waste the metal, it could be constructed from three pieces that are bolted together.

Milling

Set the part on parallels that are high enough that you won’t cut the vise when cutting the bottom of the U-shape. This doesn’t leave much metal to grab, so center it in the vise and crank it down hard.

Start at one edge and cut thin slices forward and back until you reach the correct depth. I used a 1/2 end mill for this. Lock the X-axis while performing these cuts so the table doesn’t move.

Once the right depth is reached, lock the table height. This is important because you want the bottom to be even all the way across. (Though honestly, nothing touches it so it isn’t really that important.)

Unlock the x-axis, move the cutter over a bit, then relock it. Take off a slice using the the side of the end mill by cranking on the Y-axis handle. Make sure this is a conventional cut, not a climbing cut, or you could yank the part out of the machine.

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Repeat until you’ve reached the other end of the part.

Holes

The holes on the bottom are counter-sunk at 82 degrees to match the US flat-headed machine screws. If you don’t have a counter-sink, it’s not important. There’s enough clearance for pan-headed screws.

The holes on either end are critical. If you accidentally drill one of them off-center, move the other one over by the same amount so that they are lined up with each other. (If I had a long enough drill bit, I would have drilled both holes at the same time. These are called “aircraft” drill bits.)

Cleanup

A belt sander is really useful for rounding over the sharp corners. If you have a narrow strip sander, it can do the inside as well. Otherwise there are always files.

Base

The recommended size is 3” x 1.25” x 1/2” thick. Really it can be any piece of scrap that is wide enough to lend stability to the stand.

Transfer the holes from the base to the body. Transfer punches can help with this. Note that the cheap Harbor Freight set won’t mark steel very well, if at all. But if you are using wood or aluminum then it should be just fine.

If you are 100% perfect in the placement of the holes in the body, the transfer punches aren’t necessary. (But if you are that good, why the hell are you reading my blog?)

The body is supposed to be centered on the base. Unfortunately I drilled one of the holes too big, so I had to move it over a bit. Then I broke a tap and had to move the holes over a second time. Now I have a convenient place to stamp my initials or attach a clamp.\

Slightly counter-sink the holes, it will make starting the tap easier. You may also want to use a slightly larger drill. This will reduce the “thread engagement”, weakening the holding power but also lessening the torque needed to tap it.

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Support

The support is the piece that actually holds the micrometer. Again this could be constructed from 3 parts but it is better to mill it from a single block.

Milling

Setup is easy since you are cutting parallel to the vise. I’m not sure what the best setup for this is, so I made the top of the part flush with the top of the vise.

Rather than following the plans exactly, I chose an end mill that the was slightly wider than my micrometer and ran it straight down the middle, leaving a shallow slot. Raise the table, then repeat until the correct depth is reached.

While doing this you’ll want to lock the Y axis. This is a pretty easy cut, but there is no sense taking chances that the table will shift.

Holes

The holes on either end are critical. They must be lined up perfectly with each other or the part won’t rotate correctly. Drill them deeper than the plan calls for and you’ll be less likely to break a tap.

Speaking of which, be really careful tapping these holes. The #6 tap is easy to break and you can’t simply move the holes like you did with the base. (So yea, I did have to make a second support. Also, #6 taps are cheap so buy several when you do break it.)

Technically speaking you should use a taper tap to start, then finish the blind holes with a bottoming tap. But again, I drilled the holes deeper than necessary and just used a generic plug tap. Use plenty of tapping fluid, it will help to wash away the chips.

The location of the hole on the side isn’t critical. You can even have multiple if you want to hold things other than a micrometer.

Part 1 Completed

From top to bottom is the support, body, and base. In my next post I’ll talk about machining the custom screws.

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BA to UNC (US) Screw Conversion Chart

For converting British small screws (BA) into equivalent US screw sizes.

BA Screw

Closest US Screw

Clearance Hole

Size

TPI OD (in) Size
OD (in)
Tap Drill
(in)
Close Fit
(in)

Free Fi
(in)

BA0 25.40 0.236 ¼-20
0.250
7
0.201
F
.2570
H
.2660
BA1 28.22 0.209
BA2 31.36 0.185 #10-24
0.190
25
0.150
9
.1960
7
.2010
BA3 34.79 0.161 #8-32
0.164
29
0.136
18
.1695
16
.1770
BA4 38.48 0.142 #6-32
0.138
36
0.107
27
.1440
25
.1495
BA5 43.05 0.126
BA6 47.92 0.110 #4-40
0.112
44
0.086
32
.1160
30
.1285
BA7 52.92 0.098
BA8 59.07 0.087 #2-56
0.086
50
0.070
43
.0890
41
.0960
BA9 65.13 0.074
BA10 72.57 0.067
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Fabris – Drills for Plate 24

This play is essentially the same as plate 23, but it starts on the outside.

Plate 24 – Common Fencer 1a

  • Both fencers start in 3rd on the outside.
  • The agent provokes a response by beginning to constrains the patient by turning the wrist into fourth
  • With a step, the patient disengages to the inside and attacks in fourth.

Plate 24 – Common Fencer 1b

  • Both fencers start in 3rd on the outside.
  • The agent provokes a response by beginning to constrains the patient by turning the wrist into fourth
  • With a step, the patient disengages to the inside and constrains in second. This puts him in narrow measure

Plate 24 – Fabris 1

  • Both fencers start in 3rd on the outside.
  • The agent provokes a response by beginning to constrains the patient by turning the wrist into fourth
  • With a step, the patient attempts to disengage to the inside
  • Agent lowers the body to collect the patient’s point on his hilt while thrusting in third under the sword.

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Plate 24 – Fabris 2

Use this if the patient allows the original constraint to be completed.

  • Both fencers start in 3rd on the outside.
  • The agent constrains the patient in fourth.
  • The patient tries to free his sword using a disengage
  • The agent steps into narrow measure, constraining on the inside in second.
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Fabris – Drills for Plate 23

This play specifically says the fencers are in misura larga or wide measure. Loosely speaking, this is the range in which you can attack with a single step.

Plate 23 – Common Fencer

This drill will work better for the patient if the agent is an angled third. Any actions of the point take longer because it has so much further to travel. You can make it even worse by standing upright as shown in this illustration from L’Ange.

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  • Both fencers start in 3rd on the inside.
  • The agent constrains the patient by turning the wrist into second
  • Patient attacks below the agent’s sword by lowering the point [If he doesn’t react, see Plate 22 Fabris 1a]
  • Agent lowers his own point, turning his hand into fourth.

Plate 23 – Fabris

Using the extended third of Fabris allows the agent to make a smaller motion for both the constraint and the counter-thrust.

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  • Both fencers start in 3rd on the inside.
  • The agent constrains the patient by turning the wrist into second
  • Patient attacks below the agent’s sword by lowering the point [If he doesn’t react, see Plate 22 Fabris 1a]
  • Agent lowers his own point, turning his hand into fourth.

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