A few useful tips to know

In the old days,when they had to make do with less,and a special dia. drill was needed,a skilled machinist would learn to grind a drill's lips slightly off center to make it's longer cutting edge swing wide and drill a somewhat larger hole than the nominal size of that drill.

Most of you probably know how to get a lathe cutting tool at the exact height needed: Use a thin steel ruler,or a thread gauge(the kind with "V's" in it for grinding threading tools. Place the ruler or gauge against the shaft you are turning. Bring the cutter right up to the rule,barely touching it. Adjust the height of the cutter till the rule or thread gauge stands vertical between the work and the cutter. Then,you are exactly half way up the height of the shaft where you should be. No fancy little levels needed,nor really wanted by those who use this quick,easy method.

If your lathe cutting tool is not exactly at the proper height as described above,you will not turn a correct,straight cut when turning a taper.

The lathe was the only machine,except perhaps a drill press,in very early machine shops. Lathes were often provided with T slots on the wings of their carriages. Odd pieces needing boring out could be clamped down on the cross slide without the compound in the way,shimmed to the right height,and bored out without having a milling machine to do it. Great use was made of the lathe faceplate for operations we rely on a milling machine for these days. Lincoln milling machines were a popular milling machine in 19th. C. shops. Their vertical adjustment was to laboriously adjust both ends of their arbors,like you do in a horizontal boring mill these days. They also sometimes had to block or shim up the parts to the needed height. Old timers had to be ingenious to deal with these primitive conditions. They determine the necessary height to bore a hole on center by simple means: A rod chucked in the lathe had a blob of clay or putty added to its end which faced the work. A straight pin,or other light pointer was stuck into the clay. The chuck was rotated,watching the pin as it went around the layout line scribed on the work piece. Shims and adjustments were added until the pin stayed exactly on the scribed line all the way around it. This got you within acceptable tolerance to bore the hole first by drilling,then by single point boring with a boring bar that reached,and was supported by the tailstock center. needless to say,these operations took skill. Brits called it a "sticky pin".

I measured the brass cylinder on an 18th. C. microscope in the museum. The cylinder provided adjustment just by sliding in a hole to focus the lens. The cylinder was turned freehand like wood,and the diameter was made constant just by feeling with calipers. This cylinder was not even .001" out of the same diameter along it's 6"+ length. The museum had bought a POS repro microscope made in England for the Apothecary shop. It constantly slipped out of focus. It must have been made from brass bed tubing,which was grossly out of round,with poor tolerances. It looked o.k.,but was in reality not well made at all. Do not think that those early machinists could not do accurate work. I was taught to "feel a thousandth" with calipers when I was young,and taking a machine shop course by an old,retired Navy machinist's mate. I've made use of this many times over the years.

Real early milling cutters were more like coarse files.The only way they could be sharpened was to anneal them to soft,and re chisel their teeth back on,then re harden and draw them. Must have been SLOW going!! Plus,everything was plain carbon steel without nearly the wear resistance of later tool steels like Mushet steel,and later HSS,etc.

Pressures for sintering carbide was first done in the breeches of large old Naval guns,buried vertically in concrete. Only they could stand the pressures needed at the time.

I knew an old,but inventive machinist who had to mill some trunnion grooves for large spot lights. They were circular arcs too large for the swing of any of his lathes to do. He strapped the head and ram of a Bridgeport down tightly on a good rotary table,got the swing he wanted adjusted by mallets,laid this assembly over the metal to be milled,and succeeded in milling the circular trunnion grooves needed. He also had invented the remote mechanical hands used when handling radioactive material,or dangerous biological samples.

I knew an old,retired,very intelligent machinist back in the 60's who made himself an extra $300.00 a week just putting long allen head bolts in his 10" South Bend lathe,and threading them all the way up. These longer bolts are only made threaded part of the way up,and some customer needed them threaded all the way. He first center drilled them,then threaded them. Then,he'd drill a 1/8" hole and put in a nylon locking plug. He made these by the 5 gallon bucket full. Today,that income would be nearly $3000.00 a week. He also got bronze submarine propeller nuts cast somewhere and threaded their holes on the 10" lathe. I guess those nuts were about 6" in diameter,but it's been many years ago to recall. He went to government auctions and bought all kinds of equipment and machines and sold them. I visited him often,picking up many tips of information. He died buffing large monel metal bolts. His hands were greasy enough to provide insulation from static,until he touched one of them wrong and got a shock that stopped his old heart. It was a big loss to those of us who knew him. Many machine shops would come to him to get solutions for knotty problem jobs. He always had an answer.

I prefer to only use single edge countersinks,or what some call "O" flute countersinks as they do not make the countersunk hole 6 sided. It is easy to make single edge countersinks,and I've made several,some with special angles. Turn your blank countersink and mill or grind one side flat to 1/2 the diameter. Then,file a relief angle behind the cutting edge. Harden and draw to a light brown color when using common W1 or 01 drill rod. 01 is better.

You can made a slightly undersize reamer cut a bit larger by drawing a HSS lathe tool fairly hard across the face of one of the flutes (not the top edge of the flute!!) This will raise a small burr that will enable the reamer to ream a few more holes,but slightly larger.

You only need to grind the angled front leading edges of a reamer to sharpen it. That is where the reamer cuts.

If you want to lacquer polished brass,you MUST,MUST thoroughly clean off the brass. Stoddard solvent(dry cleaner's solution) is the best thing to use. It is a refined paint thinner. It is very surprising how much black crud will ooze out of a polished brass surface. Keep rubbing the solvent on till the black stuff stops oozing out. Use a very soft cloth to keep from scratching the polished brass as you go. If you do not do this,lacquer will strip off the brass like Saran wrap when it is dry. When I made the surveyor's compass I have posted here,I had to keep applying Stoddard solvent to it for quite a while. Black stuff kept on oozing out of the surfaces for a long time. I had to be careful to use a soft cloth to not scratch the finely HAND polished surface that I spent days producing. Machine buffing would have smeared the engraving.

Packing a reamer with lard will make it cut a round hole,rather than a hole full of angles.
 
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360 alloy brass hates lead based solder,but does fine with lead free soft solder,and silver solder.

Wrapping a cylinder you are boring with snug strips of rubber inner tube can help prevent the tube from resonating while being bored with a single point boring tool,producing an undesirable surface. Press on the boring bar with the eraser end of a pencil until it quiets down any resonating the bar is making while cutting. Look for the right spot to press upon. Changing the cutting angles of the cutter also helps a lot.

The post just above has been added on to.
 
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Don't worry about turning HSS blue. It is tempered at very high temperatures in the red hot range. Do not quench them in really cold water. Don't even quench water hardening tools in real cold water. It stresses HSS way,way,way too much. HSS is an AIR hardening steel,which hardens in the air by cooling VERY SLOWLY. Water can crack it. If you must dip the tool in water at the grinder,dip it and withdraw quickly. Wait a second and re dip. This slows the quenching down some. Many do not quench at all,but I get away with it on small lathe tools. Larger tools like horizontal milling cutters should not be quenched.

See to it that your quench water is only at room temperature,as too cold water will even warp and crack W1(water hardening steel). Brass can,and WILL split open when quenched too soon after being heated red hot from silver soldering. I've had it happen!!

Blacksmiths heat their quench water up some on cold mornings by heating a steel bar red hot and putting it into the tub. Water should not be WARM,just more like room temperature,or a LITTLE cool,not cold.

Brass need not be quenched after heating red hot to anneal it. It will still be annealed the same by letting it air cool,and it will be safer,too,avoiding cracking. At least let it cool well below red hot before quenching.

If you need a STRONG joint in brass,but have no silver solder,lead based solder will be just as strong by heating the joint red hot. The lead alloys into the brass. If you pull the joint apart while it is red hot,big "stalagmites" of brass will appear because the lead has alloyed into the brass. You'll find the joint difficult to pull apart,even at red heat.

DON'T BREATHE the fumes from overheating lead if you do the above high temperature lead soldering. And,DON'T quench the brass when it is red hot. I practically can guarantee it will split open,or distort.

Some brass alloys wil not take lead solder. 260 will just fine,but 360 must be soft soldered with lead free solder. Both alloys will silver solder o.k.. ROUND bars of brass are likely all 360 alloy,or possibly something else. I haven't found 260 alloy in round bar stock,so don't try lead soldering round bar brass.

IF you make something like a brass plane out of 260,and use 360 alloy brass for plugs to hold the plane together,the 360 will look PINKISH against the 260. By itself,360 looks normal. Do not mix the 2 in assembled models if you want the screws(with filed off slots) to be invisible.
 
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You can drill holes even in solid HSS power hacksaw blades(yes,the fully hard,solid HSS ones),with an inexpensive masonry drill. I have done this many times when making kitchen knives from solid HSS blades I sometimes find(most power hacksaw blades are not solid HSS because they can shatter). Run the drill press as fast as it will go,or about 2000 RPM,actually. There will be orange hot shavings whirling about,so wear goggles!! The fast running carbide tipped bit heats up the HSS so hot it softens it and scoops it out.

I have found it necessary to sharpen the bit for every hole,or it shatters the power hacksaw blade in half. This must be done with a diamond wheel,or a diamond hand hone.

I'm talking about holes in the 3/16" -1/4" range. It is also very easy to drill holes in files. I do this also,to attach the files to a wooden block for filing guitar frets.

Be careful to not get the bit too hot,or the brazing will melt and the carbide tip will fall off. You need to buy a few spare bits if you intend to drill several holes,until you get the melting point figured out.

This can also be done with solid carbide straight flute or carbide spade bits,but they cost a lot more than a small masonry bit if your application is not critical,like drilling rivet holes for knives.
 
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Is your lathe worn,or needing leveling up??

On the subject of leveling a lathe or milling machine. I have a 16" South Bend lathe that was new and delivered to the Naval Shipyard in Virginia February 1956 and placed on board a Navy ship. Just how level do you think this machine ever was in its service lifetime?
 
I think the main reason for leveling a lathe is so that, in a non-pitching/rolling world, both ends of the ways are at the same slant. If one end were a bit off from the other one, there would be a twist in the ways. Then, as the carriage moves down the ways, it would be twisting to match its location.

When your lathe was bolted to the machine room deck, I'm betting they made sure it had no such twists. As long as both ends pitched or rolled the same amount the lathe would stay straight. More important than actual level.

Got to respect the man that could keep doing his job around spinning equipment in a moving room. :sailor:
 
Correct. It isn't that a lathe needs to be level,it needs to have the bed straight. That can be adjusted without the lathe being on a rigid platform. Turning a piece between centers and making sure it is the same diameter all over is 1 way,to be brief. Other things must be checked first,but the necessity is for the lathe to turn true. This has been rehashed many times on fora. Ian Bradley in "the Amateur's Workshop" discusses how to set up a lathe without a level. I did it that way for years before I had the money for expensive levels.

Read my first list of tips for how to "level" a lathe without a level. It really is just making the bed straight with itself,not "leveling" in the true sense.
 
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If your lathe cannot cut smoothly with a round nose or other wide type of tool,to smooth out the chatters,try using cutting oil,and with the lathe turned off,drag the chuck around by hand,slowly advancing the cutter till it smooths out the chatter marks. It works for me. I'm not sure if it will work with the little HF type 9" lathes,but it might. I had it work with a 10" Jet many years ago,although the Jet was a decently hefty small lathe. The idea is to impart extremely low RPM to the work,like 1 rpm.

Similarly ,if threading to a shoulder worries you,turn the lathe off and drag the work around those last few turns to get exactly to the shoulder without an accident,or crash. A handle made to fit and expand into the outboard end of the spindle is a great help with this sort of thing. Remove it before starting the motor!!

Really good old time machinists would grind a drill bit to the same angles as a 60º thread. They would drill the hole where the thread would stop,using the lightly scribed thread track previously made as a guide. Then,they would drag the threading tool by hand turning the lathe,stopping the tool in the hole for a super neat thread terminus. You can see this on old blueprint drawings.
 
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Mr. Wilson,
your postings remind me so much of my grandfather's wisdom.
i was a small boy when he passed on, i still remember small things he would tell me from time to time.
one of my favorites was the use of bacon grease mixed with mineral oil
i still use it very frequently, whether drilling or tapping ...it really works well.

thanks for too many nuggets to list, but please keep them coming!
you can never learn too much
:man:
 
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