These are tips I collected from multiple places.
I am not the originator of most of this information.
Threading
When hand tapping a hole, start tap a thread or two and start lifting up on tap handle as you continue tapping, tap will square itself up to hole.
If you need to grip on a threaded part in a vise or chuck, get a matching hex. nut/s, and hack saw through one side, screw the nut/s on to the matching thread, place in vise or chuck so that the cut section can be squeezed closed when the part is being held, the nut will close enough to hold the part.
If the only reference surface to dial in a part is O.D. threads lean the rigid scale from a machinist’s combination square vertically against the work on the O.D. of the threads and resting on the lathe way. Usually their is a notch along the side of the v-way. Place your indicator tip against the ruler to dial the part in.
Ever had to make a nut to match a thread that you could not remove. I made a spider (cathead) for the back of my lathe but the spindle shaft couldn’t be off. I measured the pitch diameter using my dial calipers and transferred that measurement to the plug I was threading in the chuck. I had it turned to the OD and correct pitch and kept cutting deeper until I got to the desired dimension. Using the dial caliper’s pointy ends in the grooves gave a close enough fit to match the thread on the back side. It was then a simple matter to bore and internal thread the part to attach to the back end. I use this method in lieu of thread wires; it seems to be an alternative and is faster. I would not use it on the higher tolerance threads however.
Drilling
When drilling a hole in stock in the lathe you can run the tool post up against the drill bit when starting the hole. Pushing the bit past center prevents the drill from wobbling around in the absents of a center drill hole. Soon a cone shape will be formed in the stock. Then you back off the tool post and the drill finds center on its own.
When using large drills in lathe; if drill chatters severely when starting hole, this can be alleviated by holding some MS in toolpost & bringing it up to side of drill until you are up to full dia.
When using large drills in a lathe, use a lathe dog on the shank with the leg against the ways or atop the carriage to give a little extra bracing so it doesn’t slip in the chuck or taper.
Put a drill chuck on its arbor to stay: Make sure the arbor and chuck bore are clean and dry. Place the chuck in the oven at 300 degrees and the arbor in the freezer. Wait 20 minutes. Bring each out and give the chuck a quick tap onto the arbor. Handle the chuck with an oven m
When drilling sheet metal, tear off some waste rag, enough to cover the hole size. Place the rag over the pilot hole and drill your hole, presto! one clean hole without any burrs or rough edges and the drill will not tend to grab.
A drill chuck that keeps coming off the arbor. Take some lapping compound (medium grit) and lightly coat the arbor or the drill chuck tapered hole. Chuck up the drill chuck in a lathe and the arbor in the tail stock. Run the lathe at about 450 rpm and lock the tail stock within range of the chuck. Slowly bring the arbor into the drill chuck with your hand on the E-stop. The lapping compound will lap in a new surface to both. When the lapping compound runs out there will be a moment when you hear the metal to metal squeal. Stop immediately before any damage is done.
Reamers
Using reamers. Thicker tapping fluid will provide a smaller hole than thin fluids. Dry reaming may produce an oversize hole.
To hold size better with a reamer ,sometimes the dead spindle retract will work(shut spindle off quickly at bottom of stroke,retract stopped)
Reamer not reaming to size:
An old mold maker I worked for showed me this one. One day I was trying to ream a hole with a rather dull reamer in a Bridgeport. It was a good sized one, say 1″. It got to the point where the reamer squeeled and spun in the collet and I couldn’t finish the hole. So he showed me a quick fix. Took the reamer out and grabbed a dowel pin. He rubbed the pin along the inside of the cutting surface of each flute. (I’ve used HSS also) Put the reamer back in and no squeel and the hole was within tolerance.
For dull reams 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 – To ream a hole slightly OS, do the same. I can get .001 to .002 doing this, but the ream tends to stay that way.
Another way of reaming OS slightly. take a small wood matchstick and fill one flute with matchstick. ream, keep the matchstick in the hole. The “offset’ of the matchstick pressure will help the cut go OS.
Ever reamed a hole for a dowel pin that was just a tad too loose? Take a ball bearing slightly larger than the reamed hole size and place it on the hole. Give it a sharp rap with your ball peen hammer and it will peen the hole just enough so that you get a nice press fit again.
One “remedy” I’ve used when accidentally reaming oversized holes near the common fractional sizes, is to take an old tap and grind the cutting face of the flutes back to a negative rake angle, essentially, ruining the tap for anything except cold forming. Since the taps are maybe .005 over the nominal bolt OD, they will still displace a little bit of metal if the reamed hole is maybe a thousandth or two oversize. Wind the tap into the hole and it will displace a bit of a groove, and makes an excellent press fit for a dowel pin.
I’ve found that reamers will ream about .0005″ smaller if you use WD40 instead of tapping fluid or oil.
Work Holding
To level up a workpiece whose underside is irregular (slightly or very – this should work even for a casting):
Roll up some balls of that two part epoxy putty (comes in a bicoloured coaxial rod and sets underwater, you can get it in most hardware stores these days).
Lay out as many of them as you need on the machine bed, on (big! if the workpiece is heavy) squares of baking paper.
Put another paper square on top of each, then lower your workpiece vertically into position.
Use the quill of the machine and the z axis readout to push the datum face as level as you want, squashing the balls of putty. Check by tramming.
Leave the putty mounds to set (can take a couple of hours if it’s cold).
Clamp the usual way, adjacent to each wad of putty.
Fastest way to dial in a 4-jaw:
1. After rough aligning to the chuck rings, using a dial indicator on the work-piece, rotate the spindle through one complete revolution noting the highest and lowest indicator readings.
2. Continue rotating the spindle and halt at exactly Midway between the above two readings, then zero the indicator bezel to the needle.
3. Rotate the spindle to bring jaw #1 ‘on plunger’ and adjust jaws #1 and #3 to re-zero the indicator.
4. Rotate the spindle 90 degrees and adjust jaws #2 and #4 to zero the indicator once again.
Done!
When setting up in the 4 jaw, put a centre punch mark in the middle of the job, the set the job roughly in the chuck, next put a tailstock centre in the tailstock and a second one between the taistock and the work (with the point in the centr punch dimple) and the coutersink on the other end over the tailstock centre so it is sandwiched between the tailstock and the work.
If you ever have trouble getting enough friction between vise grips, vise or other gripping tool and a part thats case hardend wrap a sheet of silicon carbide wet or dry around the part then crush it under your tool jaws, it will at least triple the friction.
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.
Chuck up a piece of bar in your lathe, and turn the OD to clean up (actual diameter doesn’t matter). Set your height gage on the cross slide, and measure to the top of the bar. Subtract half of the bar diameter from your height gage reading and write that number in a convenient place. Now you can set your tools on, above or below center with your height gage. Some lathes have a flat surface on the carriage where the follow rest mounts that is more convenient for boring tools. For upside down tools, threading ect., mount the tip of your height gage upside down, and zero it out on the surface plate with an appropriate size block.
A trick to get a 3 jaw to run closer.Indicate piece and use a brass or lead hammer and tap on the high jaw.Will work on wore chucks.Never hammered on a good one.
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
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.)
Centering / Locating
To set the lathe tool on center when you have a large bore in the part int he lathe chuck, stick a piece of 2″ masking tape over the bore. Then lightly hold a pencil to the tape while the lathe runs. it will find center naturally, and you can then set your tool height off of the mark.
When finding the center of a hole with a dial indicator: I always work with two opposite points in the hole, say north and south. And I always swing the indicator from north to south on the same side, say the west side, without touching the west side. Using only the Y axis I find zero north & south. Then I simply move the X axis until I get zero on the west side. At this point it is very close to zero all around and close enough for most, but with a little trimming I can be wthin 2tenths with a 50 millonths (.00005) indicator in under two minutes.
Centering the tailstock.
Install a dead center in headstock and tailstock.
Bring the tailstock up to where the centers almost touch (tailstock retracted most of the way), but be careful not to bang the centers together.
Clamp the tailstock down.
Hold a single edge razor blade vertically between centers and spin the tailstock out until the razor blade is caught gently between centers.
If the centers are off the razor blade will be at an angle and it’s easy to see which way to go.
If they’re right on, the razor blade will be oriented square between the centers.
Square defined as 90 degrees to the ways both vertically and transversely.
Also a quick and easy way to set a radius on a flycutter or boring head would be to edgefind say the side of your vise or the jaw.Preset your offset and move out to the desired radius.Then move out the tool or dial the boring head out while sweeping the vise.Once you feel the slightest bit of drag,,,you’re there.You can also move out a couple of thou past your radius and use a .002 shim.
To locate the center of a large diameter on a vertical mill, mount a dowel pin in a drill chuck or collet holder, lower the pin nearly to the uppermost surface of the part,using a scale measure the distance from side to side and front to back, adjusting the respective axis until the measurements are equal. Mount your test indicator and finish the alignment. With practice, using a scale, one can roughly locate a large diameter with in the range of a test type indicator quickly.
For quick and dirty locating an odd part in the four jaw for a boring operation. Locate and center drill your starting mark. Place the part against the face of the chuck with the jaws wide open. Bring up the tail stock with a center, and hold the part against the face of the chuck with the tails stock while you tighten the jaws around the part. Should be good to within a few thou.
When indicating something round for center and to big to swing indicator, use edgefinder.
Step 1) Start at roughly 9:00 find edge then move to center.
Step-2 ) move over in y axis to 6:00 do not move x axis find edge and then move back to center.
Go back to step one and start over. Do this 4 times and you will be on center. Actually in most cases three times and you get there.
Centering rectangular section stock in the 4-jaw:
Put a nicely faced square bar in the tool post and feed it up to the work
When touching, move saddle to right (out of the way), flip the chuck 180 deg and move the saddle back.
Adjust jaws so the toolpost bar just slides along each side
Repeat for opposite pair of sides.
I reckon it’s as good a way as any….
Angles / Tapers
Setting up precision angles on manual lathes?
I’ve got to cut several precision angles on a manual lathe using the compound, these angles call for +/- 2 Min. accuracy, I’ve never tried to cut any angles this close and was wondering the best way to set them up? The lathes are equipped with DRO’s and I have a sine bar too if that can be used. Oh and we don’t have a CMM to check these but our customer does!!! These are pump parts going to a nuclear plant so they are very picky about them being correct!!
The angle you are cutting is the hypotenuse of a triangle that has a segment of the lathe centerline as the base. As such, using a unit triangle with a base of 1 calculate the length of the hypotenuse (secant of angle) for the angle in question. Set the compound to slightly less than the correct angle, make it too shallow. Face off a piece of bar for a reference plane. If the angle is to be cut toward the tailstock then make a facing cut on an inside shoulder that faces the chuck.
Wind the top slide back enough so that it can be wound forward the amount of the hypotenuse. Install an indicator on the tool holder. Touch the indicator to the face created and zero the DRO. To meet the required spec this will require an indicator that can show a touch off with .0001 resolution. Back off the tool using the carriage by 1 unit on the DRO. Wind the top slide to traverse the tool toward the face. If it contacts the face before the calculated distance is reached the angle is too shallow, which is what we expect. Steepen the angle until the indicator show a touch at the calculated distance. Given a resolution of .0001″ over a distance of 1″ this will provide a sensitivity of better than 1 part in 10000 depending on the angle. Done correctly it will put you inside the tolerance band.
I’ve got to cut several precision angles on a manual lathe using the compound, these angles call for +/- 2 Min. accuracy, I’ve never tried to cut any angles this close and was wondering the best way to set them up? The lathes are equipped with DRO’s and I have a sine bar too if that can be used. Oh and we don’t have a CMM to check these but our customer does!!! These are pump parts going to a nuclear plant so they are very picky about them being correct!!
This might be straight forward … but if you need to set something up on a compound angle, clamp a milling vice in another milling vice (can’t be a cast bottom vice, has to be a ground vice) and mount a test indicator in the spindle… tap the block for one angle, and tap the vice for the other angle. Putting a piece of round stock underneath the top vice helps for a pivot too.
Measuring the Angles of Tapered Holes
When performing routine maintenance or repair work on tooling & when orig prints are not available, the following formula can be helpful in meas the angle of a tapered hole accurately. 1-drop a ball bearing of radius r into the hole so it touches both sides of hole w/o touching bottom. 2-drop a larger ball bearing of radius R into the hole below the surface of the hole but not too close to the smaller ball bearing. 3-Using a depth mic, find the distance from the top of one ball bearing to the other & call this B. 4-Find the center distance from one ball bearing to the other & call this E. 5-Subtract the small radius from the larger Radius & call this F. Then the Tan of the angle on one side of the hole = F/E. Find this angle in a list of tangents & double it to give you the included angle of the tapered hole.
Setting an Accurate Angle in the Lathe
When setting the lathe compound for an accurate angle I have successfuly used the following procedure. Set the compound as close as you can & leave it snug but NOT tight so it can be lightly tapped into a finished position. Place work in a chuck & mount a dial indicator w/ a straight stem (not a test indicator) normal to the axis. Start at the right end of workpiece & note a reading. Move your compound slide exactly 1″ & note the final indicator reading. Take the difference between both readings & this will be the SINE of the angle. Keep tapping the compound & taking readings until the difference between both readings gives you the SINE of the angle you want. Tighten your compound & you are ready to go. This method works well especially w/ smaller angles.
Same basic idea, but used to set the tailstock offset.
Move the carriage instead of the top slide.
Move the tail stock X wise instead of rotating the compound.
Use a 1-2-3 block as spacer against the carriage stop.
The ratio x/y is now the Tangent of the andle rather than the Sine.
Use the 2″ or the 3″ side for better acuracy if you have the space.
To get 125 divisions you need three fives (5 X 5 X 5 =125). The forty to one head gives you one five (40 = 2 X 2 X 2 X 5) and a 25 division plate gives you two more (25 = 5 X 5). The extra twos in the 40:1 worm would allow you to multiply that 125 divisions by 2, 4, or 8 for 250, 500, or 1000 divisions. Actually the 1000 divisions are the basic number for this combination of head and plate.
Another thing is you do not have to buy the plate. You can make one that is just as accurate as your head by using a repetitious process. Start off with a 25 division plate that is as accurate as you can lay it out manually. It doesn’t really have to be any particular degree of accuracy, but the better it is, the fewer repetitions you will need. Now use that first, coarse plate with your head to make a second one by using every 40th hole. This second plate will have errors that are only 1/40 of the errors in your first one. So, if you have 1 degree errors on the first plate, the second one will be off by no more than 1/40 degree or about 1 2/3 minutes. Now use the second plate to make a third. It will again be 40 times as accurate as the second or 1600 (40 X 40) times as accurate as the first. The error will now be only 1/1600 of a degree or well within +/- 30 seconds. That should be about as accurate as your head and when you use it on the head, the error in the work, due to the circle, will again be reduced by a factor of 40 so the error from using this home brew circle will be completely negliable.
A dividing head or rotary table is, in effect, an accuracy amplifier. The first plate can easily be layed out by hand and drilled manually on a drill press and yet the third one is very accurate. In theory, this method can be used to make circles for any number of divisions with any dividing head or rotaty table.
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Paul A.
I have an interesting use for 1-2-3 blocks. Say you want to measure the taper of a tool or workpiece.
Lay the 1-2-3 blocks on a surface plate with the 1″ dimension vertical. Put the tapered item between them so the axis of the taper is vertical. Lay your calipers flat on the upper surface of the blocks and measure the diameter of the tapered item. Call this dimension d1.
Now repeat this process with the 2″ dimension of the blocks vertical. Call the measured dimension d2.
You now have two part diameters measured exactly one inch apart. The half-angle of the taper can be found from:
angle = arcsin [(d2-d1)/2]
Double this angle to find the included taper angle.
Since the blocks provide a nice flat support for the calipers, it’s easy to get accurate diameters spaced a known amount.
Since I make mostly smaller models, I’ve made myself a set of half-size blocks – 0.5-1-1.5 inches. They’re as handy, at least to me, as the full-size blocks.
To turn a morse taper, one simple way is to put a spare centre or other tool with the required morse taper on the end between centres in the lathe. The way you mount the taper will determine which way you will cut your taper. (large end or small end towards the headstock).
Set your dti exactly on centre height, adjust the taper turning attachment (TTA) as Tin suggested and wind the carriage back and forth along the full length of the floating centre. You will probably see runout on the clock as you wind. With the clock at one end of the taper, turn the TTA until you halve the error. Try again. Keep adjusting the angle on the TTA until there is no runout. It will now be set for the correct taper.
Unless you have a micrometer or vernier adjustment on your TTA, this will probably be a more accurate method than trying to set up by reading an angle on the TTA.
When you think you have completed turning the taper, wipe some Prussian blue (not too much) – or a soft lead pencil – down the length of the taper in one broad line, not all the way round. Insert your new taper lightly into the socket and rotate it. If the taper is correct, you should see an even smearing of the blue down the length of the taper. If one end of the line remains untouched, the taper is not correct. If it is only intact or smeared near the middle, it means your cutting tool is not on centre height.
Dave
The Emerald Isle
Setting a taper for thickies part 1
Sorry no pics so I’ll do my best to describe it.
First get a parallel bar and put between centres or in a chuck and support on a centre in the tailstock.
Set the top slide to zero and lock it. Then using a piece of square bar or shank of a lathe tool set it up sticking out like a boring bar, wind in so the bar touches the parallel bar all along it’s length.
Adjust by moving the square bar in to tool post or rotating the tool post.
All you are doing at this point is getting the square setting bar parallel to the parallel bar in the chuck, once this is done do not touch the toolpost or square bar.
Now replace the parallel bar with your master taper, old drill, chuck arbor etc and again support with a centre.
Now slack the top slide off and wind the setting bar in using the cross slide and as it makes contact with the taper it will spin round, nip the top slide and check using the MKI eyeball and a sheet of white paper underneath that it contacts over the whole length, then tighten to top slide.
The top slide is now set to the exact angle required. You don’t need any tables, hell you don’t even need to know the angle, no dial gauges – nothing but a sheet of paper and an eyeball.
Try it and see, takes longer to write about it than do it and once you have done it that experience is there for life.
John S.
Chatter
To prevent chatter with a countersink when all else fails, say in a severely work hardening material like cold-rolled stainless angle, take a smallish square of tough rag, (denim is good), fold it in half and then quarter. Slurp some neat cutting oil onto it, then invert it onto the hole, trapping it with the bit. Use heavy feed pressure and slow speed to countersink through the pad you’ve made. This trick works even when doing site work with a hand drill gun.
If you are getting chatter when boring on a lathe, Try clamping a c-clamp to the end. This with dampen the vibration in many cases.
if you have trouble with chatter in turning or on parting on a lathe turn the tool upside down and reverse the spindle rotation so that your pulling against the dove tail instead of pushing against it.
Cutter Chatter on Thin Wall Parts
When you are machining thin wall parts chatter is often an issue.
Chatter occurs when a resonant value is reached. Sometimes changing the speed or increasing the feed will eliminate that factor of resonance. Sometimes it will not…
In those cases there are still options available. If you are turning an OD, a rolled up section or rubber, wet rag or paper stuffed into the bore should eliminate the ringing and chatter.
The same holds true for a bore. Rubber, wet rag or paper wired to the OD will dampen the effects of
resonance and the bore will cut cleaner.
This is one of those tips that HAS to be used with COMMON SCENE!
If you pack a bore with wet cloth or paper and that material is extending out of that bore, flopping around with every revolution…
Need I say more?
Chatter on thin wall parts CAN be resolved, but NEVER at a risk.
Rick
Removing Broke or Stuck Parts
Something I learned from a Helicopter mechanic that I worked with. I keep a small film canister of dry valve grinding compound in my tool box. If I ever have a screw that has a stripped head just dip the tip of the screw driver in the dry valve grinding compound and that extra grit/traction walks that screw right out. works great for those pain in a** philips screws that have been miss treated.
A few times a year I’ll use my little variable speed electric engraver to remove broken bolt or stud threads. It works especially well on small fine threads. Some times the rapid hammer action of the tilted hardened pin is all it takes, whereas using a punch and hammer will only make things worse.
If you have a steel screw “frozen or rusted” in a piece of brass, just mix a solution of ALUM – saturated to the point of some ALUM settling in the bottom of the container. Submerge the brass part with the rusted screw and forget it. It is a long process but can be speeded up, somewhat, if you can drill a small hole in the steel screw. You will have your piece of brass and no damaged to the internal threads on the brass-unless your drill slips.
Regarding set screws that grip a shaft — for pulleys, knobs, handwheels, etc. If they get loose and slip, and can’t be tightened enough to prevent it, drop a piece of lead shot or a short clipping of solid copper wire down into the hole. The soft metal will deform and grip both the shaft and then tip of the set screw, preventing it from backing off. The 2 best parts of this which make it superior to Loctite are that a) it doesn’t creep under the pulley, locking it to the shaft, and b) the set screws are easy to remove, preventing damage to the head.
We quite often have people come into our shop asking to help remove a flat head cap screw that has had the head stripped. We tell the mechanics they should take a small punch, small enough to fit inside the socket end of the screw and give it a sharp tap before they strip the head. These screws are quite often just well seated against the angles of the flathead and the workpiece. The sharp tap does the same thing as a tap to the top of your drawbar on a mill it breaks the taper lock. Once you have tapped the punch the screw is usually easy to remove. This is much more convenient than drill the head of
Removing broken center dril point from workpiece.
If you break a center drill point off in a workpiece, don’t throw the rest of the center drill away.
Grind the remaining portion in such a way as to have the leading most edge of the broken section act as a boring/coring bar. Put it back into the drill chuck and slowly remove the material surrounding the point. You’ll most likely have to pick out the point and redrill with a bigger center drill
Removing a broken drill or tap in
nonferrus metals (brass – aluminum, etc.)
At most any grocery store, buy a box of alum. Select a glass or ceramic container (made for stove top use) or an aluminum pot large enough to place your part in so it can be submerged in water. Remove the part and bring the water up to just below the boiling point of the water. Add alum until no more will disolve, then place your part in the solution. Keep the solution at a simmer and you will soon observe a trail of tiny bubbles coming from the broken drill/tap. Keep the solution at a simmer and add water as needed as long as the trail of bubbles continue. When the bubbles stop, remove the part and let cool for inspection. You should discover that the steel drill or tap has turned to a rusty mud which is easily removed from the hole.
Soldering
If I have to keep solder off of an area, I find that a carpenters lead pencil works well to keep the solder from spreading and sticking. The wide soft flat lead makes fast work of covering an area. The solder will not stick to it, and it cleans up real quick when you are done.
Dale
Unsorted
The bearings in the serpentine belt idlers on my car were complaining rather ominously on a very cold morning and after taking them off and working some WD40 into them they seemed pretty smooth….just dry. Problem…how to oil a sealed bearing without damaging the seal. I took my shop vac and secured the hose end verticaly in the bench vise, held the bearing tight against the soft plastic end of the suction hose, squirted a generous amount of oil on the top side of the bearing (bearing lying horizontal) and turned on the vaccum. In a very short time the suction pulled the oil through the seal and into the bearing. When it starts coming out the bottom side, stop. It’s been quiet as a mouse for over 6 months now!
Making butterfly plates for throttle bodies without a wire cutter or laser cutter (the plate is elliptical) Take a bit of 1″ round cut a bit off about 4″ long with a coldsaw set to the angle you want the butterly to sit at I used 10 degrees, solder a piece of flat such as gauge plate which is a bit bigger than the required butterfly to the angled bar end trying to get it roughly centred. Put the assembly in a lathe and turn to the size of the throttle body. Being an interrupted cut on thin plate I found a sharp hss tool works best.
Making a gasket
Putting all those bolt holes in gasket material can be a real pain unless you’ve got the approporiate hole punch.
Place gasket material over work piece & place a ball bearing over the required hole, tap gently with a hammer.
One size ball does all!
If you need to chamfer the edges of a surface and want to have the same depth all the way around, instead of walking your 45* cutter around the part set it so to the solid jaw on your vise and just rotate the part in the vise without moving the knee or y axis. Another good way to chamfer larger plates is to use a router with a bearing on the end of the bit, this way you can even chamfer contoured profiles.
If your 6 ,8,12” dial calipers can measure from end to movable jaw, (i.e. jaw flush with end) measure the Over All Length of the caliper with something accurate like a height reference gage on a surface plate. Etch that number on the caliper or write it on a label. Now you can use this number and the reading on the caliper for an inside reference measurement, using the end of the caliper against one surface and the depth rod against the other, effectively increasing the range of the caliper by its length. Not good for precision work, but good for reference.
If you need to get an outer race from a bearing out of a blind or semi-blind hole. Hopefully the inner race and balls are gone. Run a bead of weld around the inside of the outer race let it cool and presto it will usually fall right out when turned over. Be careful not to weld the race to the housing.
for cutting a radious 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, it works great. i have also done this with ball end mills when a 1/4 round shape was needed.
my favorite way to cut disks outa aluminum in the lathe is to chuck the blank in a 4 jaw or faceplate, then take and mount a die grinder with a small endmill to the toolpost, with the lathe on the slowest speed i feed the die grinder into it and it works great, i suppose you could also cut deep grooves this way, kinda like using the lathe for a rotary table
Band Saw Savy
If you have a metal cutting band saw, regardless of make or type, sooner or later you will break a blade in the midst of a long cut. Installing a new blade will usually cause a binding problem because the tooth “set” will be wider then the saw kerf made by the old broken blade. Sometimes you can turn the piece around and start a new cut from the other side, and that is a good solution. But sometimes you can’t. So, consider saving an intact but worn old blade for those situations. It won’t cut as fast as a new blade, but it won’t bind up either.
I was taught by my grandfather many years ago that you always use hollow punches on the end of a hardwood block such that when the punch goes through the material it enters the end grain of the timber. I believe that this prolongs the sharpness of the punch as the edge simply separates the wood fibre/grain rather than cutting into it,
Tony