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    Default chuck key size

    I have Cushman and Skinner chucks for my South Bends and Monarch that I just made a chuck key for at .305 flat to flat. There is no way a 5/16 would work, and the square recesses are too big to be wallowed out 1/4. However, I have not been able to find any key size around .3 inch. Was there ever an inch size between 1/4 and 5/16 or did they just expect a 1/4 inch key to wobble around?

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    TTC 9/32" Lathe Chuck Safety Wrench | eBay

    9/32" (7MM) SQUARE STANDARD CHUCK T-WRENCH (3900-4863) | eBay

    Flexbar 15470 9/32" Square Lathe Chuck Safety Wrench | eBay

    Yes, there are keys between 1/4 and 5/16 inch, but they are smaller than .305. Some businesses make using peculiar sizes of what might otherwise be standard products to drive repair parts need back to themselves.

    Larry

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    Quote Originally Posted by bll230 View Post
    I have Cushman and Skinner chucks for my South Bends and Monarch that I just made a chuck key for at .305 flat to flat. There is no way a 5/16 would work, and the square recesses are too big to be wallowed out 1/4. However, I have not been able to find any key size around .3 inch. Was there ever an inch size between 1/4 and 5/16 or did they just expect a 1/4 inch key to wobble around?
    Did the one you made have decent corner relief? Or sharpish?

    Most of the female sockets have slightly rounded corners, so even if the flats-across is correct, they'll not go in.

    Page Two:

    More of my chucks than a few are made to METRIC specifications.

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    I have a Cushman 4-jaw that has an odd ball square size in the screw. Do what I did make a chuck wrench to fit the square needed. I've taken used chuck wrenches that the square was rounded off and re-cut a square on the end to make the wrench new again. Chuck wrenches in general are not harden that hard. Only in the 28-36 HRC range, maybe a tad harder on some. A couple I have are not even that hard! I do have a old Cushman chuck catalog back home that shows dimensions for the square for different size chucks that Cushman made back in the days. There are a couple of oddball squares in there!

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    When making what you want, make the shank (with the square) some round number size.

    Then you can acquire a spin index that takes 5C collets

    Then you can make what you want in no time at all - square wise - assuming that there is a mill or surface grinder (or even a shaper) waiting to help you

    Holding still for things that don't work is a giant waste of the minutes you been given

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    Quote Originally Posted by johnoder View Post
    Holding still for things that don't work is a giant waste of the minutes you been given
    Amen!

    "improvement" is not complicated. I've "adjusted" two in the last four days with a common hand file, Mark One Eyeball.

    I should go and pick-up one of those El Cheapo combo belt / disk sanders. Before I buy a Burr-King I don't need even a few times in two or three years.

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    About 35 years ago, I needed a key for the 4 jaw chuck that came with my Southbend Heavy 10" lathe. I grabbed a piece of Dwydag rock bolt rod and some rebar on a hydroelectric jobsite where I was working at that time. The Dwydag rod stock and the rebar are both essentially re-rolled railroad rail steel, and have enough carbon to "take hardness". I turned the body of the chuck key a bit larger than the square drive section, reducing to it and turning to the approximate diameter "across the points" (1.414 x length on one side of a square = diagonal or "across the points" distance). I transitioned from the larger body diameter to the "across the points" diameter with a steeply angled shoulder. To create the square section, I heated the "across the points" diameter to a good orange heat and forged it on my anvil to form the square. I forged the square section a bit oversize, maybe 1/16" . Leaving things soft, I then filed the square section to a good fit in the chuck's key sockets. I finished turning the body of the key, and then heated it back up to an orange-red heat and oil-quenched it. I drew the temper to a light bluish, so the squared section and body of the key are fairly hard. I made the tee handle out of rebar turned to form round stock. The top of the chuck key body is drilled to take this handle and tapped for a setscrew to keep the handle in place. I made that key over 35 years ago, use it very frequently, and have never had a problem with it.

    FWIW: as a young fellow starting out in machine shop work, I had to file a cube 2" x 2" x 2" from a chunk of round cast iron, getting it within a few thousandths of an inch. At Brooklyn Technical HS, I also had to file an octagon from round stock, and got a grade of 100& on it when the teacher miked it across the flats and found it was parallel along the flats aside from having the same dimension no matter where he put his micrometer. Making a chuck key is a fairly straightforward exercise, and one does not need a milling machine, grinders, belt sanders, or similar. A little patience, a few files (one of which should have a "safe edge" to avoid filing into the shoulder), a vernier caliper (which is all we had back "in the day", no dial calipers or digitals, or we used mikes) and a vise along with a good eye can make a perfectly good chuck key. I chose to forge the one I made as I like incorporating a bit of forging, and heat treating made perfect sense.

    I twist that chuck key quite hard at times, chucking rough forged pieces of axle steel for some jobs. That key has been as good as a "factory made" key.

    On another of my lathes, I had no key for a 10" Oneida 4 jaw chuck. It has 1/2" square male ends on the jaw screws (OLD chuck). I cheated on that one. I took a Craftsman US made 1/2" square drive extension bar and cut it off with an abrasive cutoff wheel. I took off the chrome plating on the cut area of the round shank, and fitted it to a "tee handle". I made the body of the tee handle from a chunk of Ford F 350 axle steel, and bored it for a good fit on the round shank of the 1/2" extension. I welded the two parts together with one of those all purpose miracle repair electrodes called MG 600. Quite pricey, but will weld mystery metals (steels of unknown alloys) together, including tool steels and 5160 spring steel. I made the handle for that chuck key out of rebar turned to diameter. That chuck key has resisted my best efforts to twist it to death.

    I know I can go and order new steel of known composition, and do that on jobs where it is specified, or where it is critical. Every now and then, probably for sheer orneriness, or because I worked overseas years ago, I make parts and tools out of salvaged truck axles, tie rods, and similar. I worked overseas in South America and saw how the people there make-do and use everything a few times over. No piece of steel was simply discarded. I saw the South American mechanics soften up axles and tranny shafts in forge fires, then make tools and parts from them, often with next to no tools or shop at hand. The result is I like to use my imagination, working with what's at hand, as well as using the basic skills and keep myself sharp as far as my eye and manual skills like forging and filing.

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    If I tried to file a square or hex to perfect size, it would look like crap!!! There would be nothing parallel about it!!! Thanks for sharing Joe.

    Received a chuck wrench with an wore out lathe I received many years ago that was made of a old tap brazed to a steel bar. The square end of the tap was a near perfect fit to the chuck screws in the worn out chuck. I don't recommend doing this as the tap could snapp off effortly.

    Ken

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    Quote Originally Posted by 4GSR View Post
    If I tried to file a square or hex to perfect size, it would look like crap!!! There would be nothing parallel about it!!! Thanks for sharing Joe.
    Just cheat.

    Hold it in a vise instead of free-handing it. Vise is "parallel" enough... if it is any good atall.

    Ga-ron-tee any Old Skewl craftsman with a hot fire , hammer, and anvil COULD (and we routinely DID) "freehand" a damned close square and file-finish it with low effort.

    Stronger when hot-forged, they are as well.

    I need to get me an anvil...

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    Quote Originally Posted by thermite View Post
    Amen!

    "improvement" is not complicated. I've "adjusted" two in the last four days with a common hand file, Mark One Eyeball.

    I should go and pick-up one of those El Cheapo combo belt / disk sanders. Before I buy a Burr-King I don't need even a few times in two or three years.
    I own a burr king, and I used it to make the chuck key....buy a cheap import key, mark one eyeball
    to scale it, 15 minutes later done....
    And yes, put generous chamfers on the corners.

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    Quote Originally Posted by digger doug View Post
    I own a burr king, and I used it to make the chuck key....buy a cheap import key, mark one eyeball
    to scale it, 15 minutes later done....
    And yes, put generous chamfers on the corners.
    Damned good job I had NOT invested in a belt sander, then.

    Given all I had was hand files, chose to "freehand" right next to the lathe to make trial fits faster, it was only about four minutes.

    Mind - all I had to do was adjust store-bought from US 1/4" to wotever metrifuckated substitute the poor disadvantaged French were limited to. About ten-thou or so to remove?


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    Quote Originally Posted by thermite View Post
    Damned good job I had NOT invested in a belt sander, then.

    Given all I had was hand files, chose to "freehand" right next to the lathe to make trial fits faster, it was only about four minutes.

    Mind - all I had to do was adjust store-bought from US 1/4" to wotever metrifuckated substitute the poor disadvantaged French were limited to. About ten-thou or so to remove?

    Mine IIRC was 3/4" down to 5/8" or less.
    No worries if it was hardened scrap axle parts either.

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    Quote Originally Posted by digger doug View Post
    Mine IIRC was 3/4" down to 5/8" or less.
    No worries if it was hardened scrap axle parts either.
    Lemme tell yah about axles...

    Most have splines or such.

    All have to live long and prosper under severe twisting forces, far too many of them arriving as seriously rude shock loads.

    Not a lot of alloy any BETTER for making a chuck key, actually.

    Some makes just SUCK for hammer heads, though. DAMHIKT!


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    Thermite:

    Your prose and wit takes a bit for an old thick-headed dinosaur such as myself to understand sometimes, but I do appreciate it. Each of us has our writing style, and this 'board is a great place to share what we can bring to the table as well as our writings.

    If your cutting wit could be channelled properly, it could precisely shape steel. I enjoy reading your posts !

    I use axle steel because of my time in South America. Seems a sin to throw away a piece of axle steel. I soften and anneal axles in the firebox of my coal fired heating boiler during the heating season. Wait for a warmer winter day when the firebox is on low draft, bury the chunk of axle steel in the glowing coal/coke bed, and let it soak for maybe 45 minutes to an hour. Pull it out with blacksmith tongs and stand it on end in a steel bucket of coal ash and clinker. Come next day or two, I take the axle steel out of the ashes, up outside the garage, and run over it with the air needle scaler. This knocks off the scale and adhering cinders. I then wire wheel it and inspect for cracks and obvious damage. I keep a few of these chunks of axles around for projects. I always try to take a heavy roughing cut to get thru any surface cracks. Never had a bad piece of axle steel.

    The steam engine at Hanford Mills has the thrust rod in its governor made from a piece of 1970's F-250 rear axle. A few more shafts and odds-and-ends are made from WWII Jeep axle steel.

    I work out twice a week doing Pilates. I recommend a system of regular stretching exercises to anyone, particularly as our numerical age creeps up. I am going to turn 70 in September, but can drop and give about 40 pushups and can do situps until the person holding my ankles gets sick of counting or gets bored. It's a great thing for working around heavy equipment, locomotives, and doing smithing and fabrication work. No cricks, aches, pains, or problems as a rule. One day, while working out, I noticed that my Pilates teacher's equipment needed some modifications and parts made. I offered to make the necessary parts (some non-standard tee nuts, machined washers, and stock threaded aluminum knobs and threaded studs). I had a chunk of a Toyota Camry front axle in the shop with the splines. I softened it up in the boiler firebox and cut off a chunk. I simply polished the OD in the lathe, drilled a hole down the center, and "cut the salami" to make the washers. My Pilates teacher thinks they are great, liking the effect of the splines, and enjoying how well her equipment now works. She maxxes out the springs for me and has me doing advanced exercises, so I get to have my own work used to keep me in shape.

    I use snow plow cutting edge steel (which our town highway department throws in their scrap pile). This is usually a 1060 steel. I anneal it as it is fairly hard and has had a lot of impact loading on the highway trucks scraping along. Once annealed, it machines nicely. It also hardens nicely for things like parallels, setup tooling, vise jaw plates, and similar.

    I use truck and locomotive spring leaves as well. The old locomotive spring leaves are likely a 1090 or something close to it, and the newer truck spring leaves are 5160. I anneal the spring leaves (which are usually busted pieces). My first act is to "slick off the surface" with an angle grinder and finer grit disc. This usually discloses any cracking. Used spring leaves often have hairline transverse cracks. I machine below the cracking before using spring leaf steel. I've made motorcycle parts, wrenches, and kitchen knives from old spring leaves. I forge the tools and knives to shape rather than just cutting away the extra steel. The 1060 and 5160 harden nicely in used vegetable oil left over from frying turkeys.

    For hammer heads, I got hold of some heavy rebar when we were building a power transmission line. We were putting in deep caisson foundations, and the rebar cages were made with rebar a bit over 2" diameter. Sometimes, the foundation contractor would hit rock, and it the rock was deemed competent, we'd issue a change order for a "rock socket". This meant field cutting the rebar to shorten it and grouting the ends into holes drilled in the bedrock. Needless to say, I grabbed a bunch of that large diameter rebar. This was rebar made to a known specification, and is re-rolled railroad rail steel. Makes fine hammer heads and anvil tools, but you better have (or know someone who has) a power hammer to work it down.

    Chunks of old railroad rail also can be made into good tools, aside from the more usual use as small anvils.

    My wife knows I have incredible vision, able to see chunks of scrap steel along the shoulders of roads, even when obscured by fallen leaves or cover of darkness. She also knows that I WILL put that steel to good use. Recently enough, a buddy with a repair garage gave me the tie rod from a mutual friend's Dodge Ram diesel pickup. The tie rod is about 1 1/8" diameter, not full-hardened. It machines beautifully. I've made a few mandrels for running jobs in the lathe out of that tie rod, as well as a couple of parts for the old Airhead BMW motorcycles (centerstand pivot bushings which had worn out after 40 + years).

    I'm slowly designing a steam engine as I go along building it around a cylinder, two crank disc castings, and flywheel casting. The cylinder finished up at 2 7/16" bore x 3" stroke, and the flywheel is about 12" diameter x 2 1/2" face width x 1" bore. I am making the crankshaft from a tow truck rear axle. A neighbor had a repair garage at the foot of our road for many years. Towards the end of his life, he cleared out his iron pile for metal pickup day. I got there first. I grabbed what was useful to me, including a rear axle from his old tow truck (complete with flange plate and studs). He was originally from Haiti, and had a reputation for never throwing anything away and "cobbing cars together" with stuff from his back iron pile or other hoards. He and I got on famously. The neighbor died not long after he put his beloved iron pile out for metal pickup, into his 80's. I figure to memorialize him by using his tow truck axle in the crankshaft of my steam engine. Another chunk of the other tow truck axle will get forged into the connecting rod. I annealed the tow truck axles and have to say they machine nicely and with a properly ground HSS tool bit, give a finish like precision grinding.

    Old timers like myself were taught to spark test steels to determine alloying elements. We were also taught to use our senses, using files or a hammer and center punch, vise/hammer bending, drilling into a sample, or notching a sample with a hacksaw, the heating/quenching and breaking (or bending) to determine roughly what we had. I learned this at Brooklyn Technical HS (1964-68), and then oldtimers in the shops expanded my knowledge. Seems to have stood me in good stead all these years.

    Forging tools is one of those things I picked up along the way, and just enjoy doing. As a kid at Brooklyn Tech, we were acquainted with the grain flow in forgings, and it reminded me of how a tree trunk, when sawn, will show a grain flow and the strength the tree had from it. It also reminded me of the way shipwrights used to look for particularly shaped oak trees to use for the frames of wooden sailing vessels, or how country people would find trees with a "bow" or "crook" to use for the runners on bob sleds (the kind used for hauling loads such as timber). We learned that machining "cuts thru the grain", and in later years in my career, I came to realize that some metals will "self relieve" once the rolling lines in it are cut. Forging seems to give the best stress distribution and better strength, but that's just my oldtime half-baked thinking. The closest this old dinosaur comes to "additive manufacturing" is to buildup a part with welding or brazing. Can't wrap my head around 3-D printing as producing working parts that can handle stresses, pressures, temperatures and erosive environments such as steam or parts of an I/C engine.

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    Quote Originally Posted by Joe Michaels View Post
    Thermite:

    Your prose and wit takes a bit for an old thick-headed dinosaur such as myself to understand sometimes, but I do appreciate it. Each of us has our writing style, and this 'board is a great place to share what we can bring to the table as well as our writings.

    If your cutting wit could be channelled properly, it could precisely shape steel. I enjoy reading your posts !

    It is so channelled.

    It cuts a lot more than matter. Concepts. Curiosity. Barriers to one's OWN success. Not mine.

    All at the hands of others. Of course.

    I don't mind if it is because I show or tell "the way", inspire, annoy, or even seriously PISS OFF the "do-ers". So long as THEY have to "think". Not sit and grow mold on the mind.

    Learn, grow, do it again, better and faster.

    "Others" outnumber me. "BIGTIME". And are serious-good problem-solvers, individually, or in the aggregation.

    I class that a marvelous-grand tactical and strategic ADVANTAGE. To all of us.

    Not the reverse.

    Life's easier when they disagree. Too much like work they agree.

    LazyIyam.


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    Wonderful recounts of experiences. I sit back in awe, knowing what a noobie, i am.


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