Shop Tricks From PM - Part I

To All:

Here are some old shop tricks from a past thread in PM. Most of them are manual tricks so I've crossposted to rcm. I've condensed them here

- so to see the original posts and authors you can go to the thread address given below:


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#1 Reamer cutting undersize:

For dull reamers that tend to cut very slightly undersize, i take a carbide insert and run it against the inside cutting edge of the flute. Kind of like using a "steel" on a good knife. slide it one way only, tip to end (the other way damages the tip cutting edge). This raises a slight cutting edge on each flute. do carefully, for doing too much, and you cut OS

#2 Three jaw chuck that runs out:

Ever get stuck with a lathe that only has a 3 jaw chuck that won't run true but you have a part that needs .001" concentricity? I saw this in the Illinois Railway Museum where they had a large lathe and in the big

3 jaw chuck was a 4 jaw chuck in which the work piece could be indicated in as accurate as needed. Beats the trial and error shim routine.

#3 Another 3-jaw trick:

After measuring TIR, shim the "high" jaw with a shim thickness of 1/3 TIR. (e.g. TOTAL measured runout = .006, use .002 shim in the high jaw.)

#4 Deep hole drilling in a lathe:

Set your starting depth and lock the tailstock in place. Now move the saddle back until it bumps against the tailstock and lock it in place. Start drilling. When you're getting to the point where it takes longer to crank on the hand wheel than you care for, loosen the tailstock, pull it back to clear the chips, shove the tailstock forward until it bumps the saddle, lock the tailstock, and start drilling again. This is faster than doing all of that cranking but you won't lose track of how deep you have drilled.

#5 Skinny parallels:

That strapping that you cut off of skids and throw away, save some. I use it for skinny parallels when I have to drill holes too close to the part edge that it would drill into normal width parallels. (not that I have ever drilled into a parallel).

They also make great springs for keeping parallels against vise jaws. Just bend them to make a snug fit against your parallels and now you can open and close your vise with out those stinking chips getting behind your parallels.

Instead of the piece of spring steel to hold parallels apart in a mill vise, I have used a piece of foam pipe insulation.

#6 Gear method of clamping parts that are out of square:

Years ago we had some odd shaped (out of square) parts to machine and drill holes in. The "old guy" in the shop went over to his tool box and pulled out a couple of gear sections. What he had done was taken a flat gear 6" dia. or so and about 3/4" thick then cut it in half. Machined the flats down about an inch on each side. Then when you mesh the teeth together the two flats become adjustable. Just put the good side of the part against the fixed jaw of your vice and the meshed gear on the other and it will adjust to your part. Will work on some pretty severe angles, just take it easy on the cutting.

Collect business cards printed on regular white paper. I use them to shim not quite square pieces in the mill vise and to protect delicate parts from scratching both in the mill vise and bench vise. They can be folded to thicken up and make good mini note pads for jotting down a measurement when your memory is as bad as mine.

#7 Rack gear for clamping out of square parts:

Maybe a piece of rack gear and half of another gear would work even better, especially if you bolted the rack to the back jaw.

#8 Ball method for clamping that are out of square parts in two planes:

I use a steel ball bearing and a couple of aluminum Vee jaws cut with a band saw to hold irregular shaped objects on my mill. The pressure exerted by the vise indents the aluminum and keeps the ball in place. The benefit of this method is that stock can be out of square in two planes and still be held securely.

#9 Drill mod for brass:

When drilling brass or bronze, remove the helical rake angle inside the flute of your twist drill to eliminate the tendency for the tool to hog in to the work. Just grind a little flat along the inside edge of the flute, to try to make the cutting face at 90 degrees to the drill axis.

#10 Easier Loc-Line coolant nozzle installation:

If you ever used the "loc-line" coolant nozzles, they can be a pain in the but to add more pieces to it

put a cup of water in the microwave, and boil the add your "loc-line" pieces in the water for about a minute..take them out and now its much easier to add length or put different nozzles on...

#11 Lathe radius cutting:

For cutting a radius on the end of a part in the lathe, like say a handle for something, i often use a 4 flute corner rounding end mill held in a boring bar holder.

#12 Feeler gages as shim stock.

Get a set of flat feeler gauges and take it apart for use as shim stock.

#13 Silly putty centering pin:

This is the handy "sticky pin" - sometimes you want to pick up a scribed line on a work piece, but you don't want to remove your cutter

- stick the plasticine to the end of the cutter with the pin (or needle actually) pointing down. Now you can start the spindle and get the pin running true for picking up scribed center lines, or just leave the spindle switched off if you want to move the workpiece around while running the pin back and forth down a scribed line.

#14 CD lathe spacers:

I have a use for all of those used CD's we don't know what to do with. I needed to turn a piece on the lathe about .3 thick so my cutter was getting very close to the jaws on the chuck. Take a CD and cut it to shim the part out a little. They are very good tolerance and easy to cut up. They even have a hole in the middle if you need to drill thru.

#15 Turning small or long diameters:

When turning small to medium diameters of plastic bar, tool "push" can be a real problem. The solution is to use a very sharp HSS tool and take it all off in one pass.

#16 Coolant magnet:

Put a big magnet in a plastic bag and drop it in the coolant tank near the pump. It'll attract the chips away. Pull it out and clean it once a week.

#17 Cutting oil can magnet:

Ever spill a can of cutting oil? I used to. Now I bought some plastic beakers and some ceramic cup magnets. put the magnet in the bottom of the beaker and pour in cutting oil. ============================================================

That's enough typing for me. I'll go through the rest some other time.

Do you have any personal tooling or setup tricks you'd like to add?

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Thanx for posting it over there. Not much going on other than a spammer that uses A in his forged addresses.


Reply to


You're very welcome.

You know, I'm getting that as well. Usually Earthlink is pretty good about filtering that kind of spam out. Perhaps they cut back on too many employees.

I'm sure you must have a machining or troubleshooting trick or two up your sleeve that we could all appreciate.

Reply to

I used a hot-air gun, rather than hot water, to put some of this back together on my scroll saw, where it has a thin plastic tube inside, and can't be easily detached from the machine.

Reply to
James Waldby

There are special snap pliers for loc line, both for attaching and detaching. Really, well, a snap.

Reply to
Proctologically Violated©®

Proctologically Violated©® wrote: (...)


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Dats dem!

I believe these pliers are a loc-line product, not aftermarket, but I could be wrong. I think I paid around $10-20, years ago.

I cain't imagine using locline without these -- like changing cat40 spring collets without a holder or spanner! Altho, I spose, iffin you don't have these pliers, hot water/hot air and strong teeth certainly would help. :)

Reply to
Proctologically Violated©®

When machining material that is a similar density as your coolant, there is a tendency for it to suspend and clog up your sump. Acrylic fines for example. That pitiful little screen in front of the pump can become blocked pretty quickly.

An easy way to address this is to build some kind of dam across your sump (most already have some kind of divider that will work), put a pickup tube on the dirty side, a pump rated to transfer solids, and a filter bag going into the "clean side" of the sump. If the pump you choose can outpace your coolant pump, your dam doesn't need to be perfect because the filtered coolant will back flush around it. And large filter bags are only a few bucks, and hold several pounds of gunk, so you can just discard them when they're full. No more clogged coolant lines or starved coolant pump etc. Also, this pump can be turned on for a little while with the machine off to keep the coolant aerated on an idle machine.

Reply to
Polymer Man


Reply to
Proctologically Violated©®

I have a lathe programming trick that comes to mind. Everyone has turned a shaft more than 5 diameters long at one time or another. Due to deflection the front of the part will measure larger than the part at the chuck. The standard fix is to program this deflection out by starting your X diameter smaller by the amount of taper and then add a U or X finish diameter on the finish Z line. Now the front of the part and the chuck side of the part measure the same. The problem now is the middle of the part will measure undersize from the front and back. What I do to get rid of that is use the length of the shaft as the chord (C) and the difference in the middle hieght (H) and calculate the radius value (R); (((Csq)+(4*(Hsq)))/(8*H)). Lets say I have a shaft 1. diameter and 5. long. It measures 1. at the front and back but .998 in the middle. C = 5., H = .001, R = 3125. The start point in X at Z0 is .996 the next line is G3 X1. Z-5. R3125. You can check the shaft with a blade micrometer from front to back and be within .001.

Another trick for using thread wires. Take a piece of shim stock approx.

1/2" wide x 4." long x .005 thick (all dimensions are reference). Tape one wire to one side and the other two wires to the other side. You can now bend the shim stock into a C shape and pinch your part with one hand and measure with the other.
Reply to

I have a dozen copies of PM's "Shop Notes", ranging from 1938 to the late

50s. Still a lot of usefull info in them.
Reply to
Stupendous Man

The Machinist Bedside Reader Vol I and Vol II has alot of good stuff as well.

Reply to


That's a neat trick.

I've used silly-putty & clay to hold thread wires. A thread mic is even better. LOL

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Bob, we just used a beeswax from one a those stick like you would use to rub against a bandsaw blade.

Reply to
Brother Lightfoot

Only way to go! Have both the 1/4" & 1/2" pliers. Most valuable tools in the shop.


Reply to
Matt Stawicki

I don't smoke, but there is always a package of cigarette papers available. They are handy when you need very thin shims to adjust the position of a work piece.

Steve R.

Reply to
Steve R.

To All:

Here is part III of the shop tricks from PM. The original authors are at the site listed below:


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#33 Chalking a file:

Using a mill file on a part, you?re trying to get that final finish or diameter with a part in a lathe, BUT your file starts hanging chips in the file's teeth and it soils the surface finish you?re trying to get. Cure ...get a big piece of chalk (I use children?s sidewalk chalk ...big bucket full & big pieces ...color don't matter! ?But I kinda like blue! *G*) Now take the chalk and start going up and down on the file's teeth, filling them heavily! Now try filing again, the chalk will "help" prevent chips from hanging up in the file ...not for ever, but extends the filing time!

#34 Fluid containers:

You want to dispense fluids ...oils, mineral spirits, even acetone, & etc. go to a beauty supply store and ask for "lady Clairol dispensers" clear plastic bottles (about 6/8 oz.s) with black plastic cone tops. About a buck ($) each. I fill mine with cutting oils and lacquer thinner (the plastic stands up to them all) very convenient for dispensing small quantities and doesn't break or spill when dropped on the floor!

The sort of barrel shaped plastic containers that Frenches mustard comes in will stand acetone, mineral spirits and any other solvent that I use, plus you get to eat the mustard. After that, they are free.

#35 CCing combustion chamber with clay:

Another modeling clay use is for making a volume measurement of an irregular chamber. It works particularly well for such uses as engine cylinder head chamber volume. Pack the chamber with modeling clay and level with a straightedge. Remove from chamber and form into a shape which will drop into a a suitable graduated cylinder containing enough water to immerse the modeling clay and with enough extra capacity to not overflow. Note the reading on the graduated cylinder, drop in the modeling clay and take the reading. The difference between the two readings is the chamber volume.

#36 File cleaning with brass:

Mash down one end of a piece of brass tube, one that's maybe 5" long. Use it to clean the teeth of a file - just push it parallel to the teeth, and the brass will deform to look like a comb. Works like a file card, but much, much faster. If you want to get fancy, you can put a wooden handle on it. Mine is a spent 20mm cannon shell.

#37 File handles:

Golf balls make good file handles.

I found that 4"-6" foam paint rollers work perfect for file handles. The plastic core grips the tang very well. No more slipping with oily hands, and @ $3 for a pack of 6, makes them fairly disposable.

#38 Simple speed/feed calcs:

The SFM equals RPM at 4" diameter. Or very nearly so that you won't damage anything and you look like a mental giant. Remember, smaller goes faster...bigger slower. Let's try it... Want that 1" drill to run 110SFM? It will be 4X 110 = 440RPM. How about that 6" slug in the lathe at 300sfm? That will be 4/6 X 300 =

200RPM Fun eh? (Corrected original math here BB)

#39 Lining up part in lathe with bearing:

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#40 Multiple dowel pin removing:

If you need to remove alot of dowel pins from something like a die shoe make an adapter for an air chisel to hold an undersize piece of drill rod works way faster than a drive punch and hammer.

#41 Dowel pin alignment tool:

I build a lot of gages and use a lot of dowel pins in them. If you are going to press a dowel pin in a hole sometimes its hard to get it started straight, I came up with a trick for this. Take a piece of flat stock about 2 time thicker than your dowel is in dia. Ream a .001 over size hole in it and put the pin in the oversized hole, Hold it over the hole you are going to press the pin into, as you hold down on the tool you have made you can tap the pin in and it will go in straight every time.

#42 Removing broken off dowel pins in blind holes:

"...A good way to remove a dowel pin thats broken off in a blind hole (bad bad design) if you have access to a EDM or hole popper is burn a hole all the way through the center of the pin then make a hook from something like a small nail punch hook the bottom of the pin and use a slide hammer to walk the pin up..."

Another trick, if you have a good tight drill press and don't have and EDM is to run a carbide drill bit down the center of the the dowel pin. Make the hole close to the size of a standard pin punch 3/16 Starrett for example. When the hole is through the dowel and the punch fits nicely. fill the hole with oil, put the punch in and hit it sharply with a hammer. The pin will "hydraulic" out. Sometimes it will "Diesel" and get everybody's attention.

#43 Broken bolt removal:

For a broken bolt or stud in a hole, use a left hand twist drill bit to drill the hole for the easy out. About half the time, the heat and L/H force spins the piece out. You have to drill it anyway, so if it don't work you still have the easy out.

#44 Sharpie spray painting:

I have one very simple but very useful trick that I use much more than I ever thought I would. I call it "painting with a Sharpie". Simply hold a marker in front of an air hose and blow. BE CAREFUL! or you will make a MESS!! but very handy for linking up those hard to reach undercuts and counter bores.

#45 Tap drill size:

Here is a tip for selecting the proper size drill for any straight thread tap without a chart. Works everytime. If you don't believe it, do the math and compare to a chart.

Metric is easy. Subtract the pitch from the OD.

8 - 1.25 = 6.75mm drill Convert to standard by dividing by 25.4 6.75/25.4= .266 17/64 = .266

Standard is a little tougher. Subtract the inverse of the pitch (1/pitch) from the OD. For a 1/4-20 bolt it would be: 1/4 - 1/20 = .25 - .05 = .200 An #7 drill is .201"

3/8" - 16: 3/8- 1/16 = 6/16 - 1/16 = 5/16"

#46 Lathe thread chip catcher:

When tapping a thru hole on the lathe, brass and steel chips always seem to fall out the back end of the hole and get stuck in the chuck jaw scroll. After many parts like this, I always have to remove all the teeth to clean the inside of the chuck so it turns freely again. Sometimes I would put a piece of masking tape in a cone shape covering the back end of the part to catch all the chips, then remove the part from the lathe and thread the tap thru by hand after.

#47 Large OD turning:

For OD turning thin pieces like 10" dia, 1/4" thick flat plates center punch and hold up against the chuck jaws with a live center in the tailstock. Just pressure will hold it there, if you take too deep a cut it will just spin on the chuck jaws.

We call that pressure turning and it works a little better if double sided tape is put on chuck jaws to help hold the part. ============================================================

Any more tips or tricks you wish to add?

Reply to

these are great - the one about dropping a piece of copper down a set screw hole if it doesn't hold - I needed that just today, cut a couple of snips of copper wire, and Poof! - it worked - so thanks

Reply to
Bill Noble


You're very welcome. I'm glad someone found them useful, it makes transcribing them from PM worthwhile.

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There are set screws that are made with brass tips, but unless a guy stocks lots of sizes, there won't be enough of them sometimes.

I've taken old machines apart and have found small brass disks down in the bottom of holes for set screws (especially when the screw hole is over threads).

An easy way to make small brass disks is with a locking split shaft collar (the kind that only has one slit cut in the collar). Take the screw out (often a SHCS socket head cap screw), and thread it into the opposite (threaded) side. Slide a thin piece of brass into the slit, and run the screw in until it punches a disk out the clearance-hole side (usually only a couple of turns with a hex wrench for leverage). The disk material could also be aluminum, brass or thin mild steel.

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