hammerscale

Amateur Machinists' Tools, Techniques and Materials

Caswell Plating

Posted by hammerscale on July 28, 2014

Caswell Plating offers an extensive line of plating, anodizing and other surface treatments for metals and plastics. Here’s a few pieces plated with their electro-less nickel plating system.

nickelplated

The company is in Canada (their USA distribution center is right over the border in upstate NY) and there sometimes is a loss in the translation of English in the instruction book. For instance, they refer to “SP” cleaner/degreaser for prep prior to immersion in the plating solution.

Here’s the sequence I use for cleaning parts:

1 – Degrease parts in mineral spirits, for gross removal of cutting oil and metal particles.

2 – Degrease again in a clean bath of a fast drying solvent such as Naphtha or acetone, to remove the heavy oily film left by mineral spirits .

3 – Immediately before immersion in plating bath, degrease again in a solution of TSP (Tri Sodium Phosphate) and almost boiling water (distilled water)
TSP is what I believe they refer to as “SP Degreaser”. If you can’t find it locally, you can order if from McMaster-Carr, etc. You will be impressed by the amount of still-clinging metal fragments released in this step.

4 – (optional) clean off any residue with a quick rinse bath in clean, hot, distilled water.

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Taking pleasure in measure

Posted by hammerscale on February 13, 2014

Some measuring credos and observations on machining tolerances.

1: Measure with a micrometer, not a caliper.

2: The machining feed and speed should be the same. (in other words, dont take a measurement off a roughing cut.)

3: Make sure the micrometer is zeroed correctly. Use a known standard, or for a 0 to 1 inch micrometer, bring the anvil to a close.

4: Use the same feel and pressure when taking a measurement. It’s your fingers, get a consistent feel for how the mic closes.

5: Make sure both work piece and micrometer anvils are clean. Use your finger tips to feel for grit, contrary to pop opinion (a.k.a. old man foolishness) you do not need to clean the micro with a folded hundred dollar bill or any other nonsense, your finger tips are fine. The human finger can detect inconsistencies smaller than 1/10,000 of an inch.

6: Take multiple readings. With round work travel slowly across the diameter of the work piece. Gently wiggle the micrometer as you take a reading to fight any tendency of the anvil faces to skew instead of lay flat

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The Good Old Days

Posted by hammerscale on January 10, 2014

A brief history of the Henry Ford Trade School, started 1916.

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Welding video

Posted by hammerscale on December 27, 2013

A good intro into the basic theory of the smoky art;

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Drill Doctor

Posted by hammerscale on November 22, 2013

I’ve owned a Drill Doctor for a while and find it quite an asset to the shop. Recently, after sharpening a fairly large diameter bit with the DD I found it rubbing instead of cutting. I recognized this immediately as negative relief. In other words, the cutting edge, though sharp, was lower than the following edge. I had never had this issue grinding small bits, and a few attempts at fiddling with the DD settings proved fruitless. As much as I hate to admit it, I had misplaced the user guide, so off to the www.

My search brought me to the following video;

 

This addressed directly the issue at hand, and the girl with the French manicure pointed me towards the solution.  First, I followed the directions to grind completely (spark out) which seemed to help, but only minutely. I then adjusted for greater relief as instructed, choosing the maximum setting.  After grinding, the bit was just beginning to cut, and I could see some small chips lifting off, but the bit still rubbed when pushed.

As I had adjusted the bit’s maximum relief in the DD chuck, the third attempt I set using ” seat of my pants” adjustment. I rotated the bit manually just a small amount further in the chuck, maybe 1/8 of a turn.  This did the trick, as after grinding the drill bit cut thru steel like butter.

This adds a little trial and error for setting up a bit in the DD, just something to be aware of.

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Another good Youtube channel

Posted by hammerscale on October 29, 2013

I like the growing selection of machining videos on Youtube. The following is under username Abom79

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Small engines and me

Posted by hammerscale on September 14, 2013

Some might have a love-hate relationship with something in their lives, but it seems I have a hate-hate relationship with small engines. I hate them and they certainly hate me. Or vex me. Air, spark, gas, – what can go wrong? About everything apparently, but far less apparent is the cause/solution.

Case in point was the pressure washer, 5.5 horse Honda engine GX160. It worked fine for years, then, about a month ago decides to not work. Runs great for several seconds, then quits. I, of course, check out the universal trouble-shooting guide, AKA Google. That leads me to a few Youtube videos about cleaning and rebuilding the carburetor. I took the carburetor off twice, and as expected, squirting carb cleaner randomly around in a vain hope of “cleaning” whatever it is you’re supposed to clean, only resulted in growing frustration in the” take it off/clean it/put it back on/fiddle with several linkages/get a quart of gasoline over your hands/and then try firing up the engine again” cycle of repeating events.

It was a little gummy, and I thought I had some success getting the float bowl to make a “moving around sound” Still, after the second try, the problem persisted. I ordered a new carb. $16.00

I installed the new carb today (another quart of gas down my sleeves) and fired the engine up. It ran a little bit longer, but still quit after about 30 seconds. I could hear the engine try to keep firing, but then quit.

The only thing really left was the spark plug. How often can spark plugs fail? Cars and trucks go for 75,000 miles before the recommended replacing, and I only put about 10 hours on this pressure washer each season. But, then I considered the machine is about 20 years old, so maybe……?

I took out the spark plug. It could be described as “carboniferous”, but that’s to be expected as I was running the engine rich trying to start it over and over again. The gap looked kind of big. So, one firm tap against the electrode and I declared it gapped properly.
Re-installed, the engine fired up on the first pull and ran fine.

Lesson?

A: It’s always the simplest thing.
B: Replace wear parts on a regular schedule.
C: All the fiddling, fumbling, and Googling and in the world can’t beat a lucky day.
D: All of the above.

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Smallest and best Tool Kit

Posted by hammerscale on August 31, 2013

I can’t count how many things have broken this summer,-  notables are; the air conditioning, lawn tractor, pressure washer, chain saw, and yesterday the washing machine.

I have developed a very basic kit of tools that seemed to be used over and over, as pictured, it leans heavily towards disassembly and cleaning.

photo

A number 2 Phillips, nippers, needle nose, and small wrench for disassembly. Also; a flashlight, knife, cleaning brushes and fine sand paper for polishing contacts, etc. All tucked neatly into an easily replaceable cardboard box.

Not pictured are a nice socket set, nut driver, wire ties, paper towels, and ten thousand other tools standing by to assist.

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A quick primer on knurling

Posted by hammerscale on June 10, 2013

Knurling is often a vexing issue as well as a lathe operation prone to contentious debate.

In no particular order, please take note of the following tips/advice:

We’re talking embossing a pattern on steel, brass, whatever; NOT cutting a knurl pattern. In a typical setup, knurl wheels are either pressed into the piece at 90 degrees to the work piece axis (bump knurling), or better, a scissors type knurl holder is cranked down to emboss a pattern with the knurl wheels 180 opposed from one another.

Diameter is irrelevant. I say again irrelevant. It would make sense to sync the pitch of the knurl pattern with the diameter of the work piece if the knurl wheels where travelling at a constant, predictable speed. However, knurl wheels are free spinning; they can speed up, slow down and even reverse direction depending on what forces they encounter. So it’s pretty easy for a knurl wheel to slip into an existing pattern as it is formed while the wheel travels the perimeter of the piece on the lathe.

Make RPMs slow. Even to the point of using backgear to slow down the spindle. Trying to impart a pattern on a work piece spinning too fast is akin to jumping on a treadmill that’s going 10 mph. Bad things will happen.

Make longitudinal travel fast. Fast travel equals less flaking and less of a tendency for the knurl pattern to wander, especially noticeable on straight knurls.

Use sharp knurl wheels. Sharp as in new,- obviously you can’t sharpen knurl wheels. When they reach a certain level of dullness after prolonged use they must be discarded. I prefer cobalt knurl tooling, as import HSS is probably not that high a quality material.

A “cheat” technique is to tilt the knurl wheels slightly into the work piece, maybe 3 to 5 degrees off the axis. This allows a deeper, surer emboss without excessive pressure. Not applicable with a scissors knurl tool.

Make sure both work and knurl wheels are clean, any chips from previous ops, flaking, etc. can affect the final outcome.

Lubrication. Take care here, often you’ll find advice saying “use alot.” That’s machinists’ speak for “I’m bluffing my way thru this interview.” Use just enough to insure smooth spinning of the knurl tooling. Too much lube tends to accumulate and hold gunk (swarf) which can disrupt a clean knurl from forming.

The biggest problem when knurling is double cutting. That is, not forming the primary knurl pattern, but the pattern skipping and tracking over itself creating a light, fuzzy texture. Solutions: more pressure, slower rpms, or replacing dull knurl tooling. Also consider using a scissors type tool or just taking a break and trying again later !

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Ratios for the lathe compound

Posted by hammerscale on May 25, 2013

This is a popular trick for advancing the tooling in very small increments, but often the ratio to use eludes one’s memory.

Let us review, for today, the relationship between compound angle and its effect on relative movement of the cutting piece into the work.

For this discussion, we will measure degrees as follows:
0 degrees is along (parallel to) the work piece axis.
90 degrees is perpendicular to the work piece axis.
It’s as though a protractor is placed up against the work piece with 0 marking touching the work and 90 degrees marking pointing at your belly button.
The preceding conventions help illustrate what’s going on and also clarify the issue, as different lathe compounds have different protractor angles etched on them.
When the compound is set at an angle other than 90, and you crank the compound handle in, the movement indicated by the micrometer dial is governed by the pesky laws of trigonometry. For instance, at 45 degrees, advancing the compound 1 increment causes a movement that corresponds to a ratio of 1.408 in either the X or Y axis.
So, a movement of 1 thousandth of an inch @ 45 degrees equals 0.71 thousandths in X or Y.
(1 / 1.408 = 0.71)
It’s a right triangle, with 1 as the hypotenuse and 0.71 as either leg. The ratio differs depending on the angle (trigonometry.)
It’s the sine of the angle, (with the above conventions), or could be the cosine if 90 degrees is parallel to the work and 0 degrees @ a right angle to it.

Enough trig. Below are popular ratio’s for using the compound:

1:1 ratio (90 degrees off workpiece)
1:2 ratio (30 degrees off workpiece)
1:5 ratio (11.5 degrees off workpiece)
1:10 ratio (about 6 degrees off workpiece) (5.8, actually, if you can read your compound dial that precisely!)

The following shows kind of what I’m talking about, and shows an example of 30 degrees off the lathe workpiece:
ToolingAngle

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