When The Screw... Screws You!
Added 2024-08-01 14:00:14 +0000 UTCI knew there was a reason I've been avoiding hardening my parts. But that doesn't mean I'm going down without a fight. We WILL find a way!
Enjoy!
Comments
Your “failures” are better than most of our successes! Plus, Box of Shame was getting hungry.
Allen Guindon
2024-08-08 15:23:31 +0000 UTCIt probably had a hard working life. Now in a hobby shop it will last forever. Could be the second nut as well. Or the original shaft wasn’t heat treated at all. So many variables.
Geoff Williams
2024-08-04 02:01:30 +0000 UTCThis is what I thought, but strange then that the existing leadscrew has wear while the much softer nut is fine. My worry would be of there was grinding dust or similar embedded in the soft metal of the nut (in which case a new nut will help much more than a hardened leadscrew).
hollo
2024-08-03 06:21:18 +0000 UTCThis hurt to watch 😭😭😭 side projects always cheer me up. You seemed to be avoiding them this time. Maybe you thrive with side projects 🤔
Anthony Rutherford II
2024-08-03 04:54:47 +0000 UTCI was sitting here wondering “When did Brandon stop being an Engineer?” Metallurgy is LIFE for us man and you go drop the ball spectacularly 😂. Great effort, and clearly blindsided by task overload taking on the practical of something you likely know pretty well but haven’t done much of. But I have to raise an eyebrow at the sheer optimism in induction heating straight into quench and doing it by hand. 🤔 Might be my 2 decades of Army/diving/flying coming out but I like to visual the process and mentally rehearse several times, even if it’s just dropping in on a dive I like to run through gear rigging and kit tests. Visualise the material and its deformations, just like the Aha! moment on the lathe. I’m just glad you didn’t grab a fistful of ball-pein hammer and take a whack to straighten it. 🤣 💣 Totally annealed this would likely give service beyond your lifespan and usage rate. I’d outsource the heat treat unless you want to invest big on the kit to do this job.
Geoff Williams
2024-08-03 04:08:00 +0000 UTC[Didn't expect "enter" to post and can't edit!]. That got me wondering why the thread wore so much worse than the nut in the first place. The only time I've heard of the harder material abrading faster is when abrasive dust (grinding, lapping paste, etc.) gets into the joint, embeds in the soft material, and abrades the harder. If that's the case then making a new nut regardless, and using an unhardenered shaft, might be the answer.
hollo
2024-08-02 21:01:44 +0000 UTCI've been wondering how fast it would wear if not hardened: I'd have thought very slowly, especially if bearing against a nut made of a much softer material (brass/bronze), hardening might not help that much.
hollo
2024-08-02 20:58:21 +0000 UTCThis makes me cream
James
2024-08-02 10:37:28 +0000 UTCI was watching a guy restore a watch makers lathe and he remade the leadscrew in a similar fashion to how you made yours, the heat treatment process he did however may help you in your next attempt so here's the link to the video; https://youtu.be/TytvJXlbPl8?si=kwSiOxrDNRl1PA1V
troublogaMing
2024-08-02 07:17:04 +0000 UTCGet yourself some CBN Inserts and a already hardened shaft. Might be a little expensive, but you wouldn't get a banana.
Gasch
2024-08-01 17:58:53 +0000 UTCOuch…I’ve been there a hundred times where my excitement outpaces my intelligence. And as you’ve shown, it happens to the best of us 😂
legendary.jerry@gmail.com
2024-08-01 17:33:55 +0000 UTChttp://talbotsfineaccessories.com/books.html Feel free to tell him I said hi, I hope he'd remember me (and kindly). Nobody else I know still has a business presence, apparently, so I can't just post contact information. If Doug doesn't pan out for any reason, I can run through my personal contacts and ask them to contact you privately if you'd like. Let me know.
Michael Faragher
2024-08-01 17:33:43 +0000 UTCYou know me, not a professional, just an enthusiastic amateur. I have some thoughts. First, sorry Mrs. IM, both for toy and cost . . . they made FLIR brand thermal cameras for cell phones. I suggest the external devices, as the CAT branded phones which have them are trash. Seeing not just the point temperature, but the overall part temperature, is well worth it for many applications. There's a learning curve and it's low resolution, but I've used it for everything from baking to electronics, and it's saved me from "is this hot?" burns more than once. For heat treatment, or even just to get an idea of how much heat an operation generates, it's probably worth considering. There's an art to preventing warping, and much of it revolves around packing parts. Sometimes this overlaps with case hardening, but it's a rabbit hole. I am not the man to ask about that, I simply know it exists. I highly suggest you pose questions to the general blacksmithing, armoring, and blademaking communities. Modern equipment is great and all, but unless you want someone to just suggest a *bigger* induction heater, you need to go classic. Propane fired blade furnaces are a DIY-friendly tool that is designed to do exactly what you want: heat a long piece of metal uniformly and quickly. Maybe not to the tolerances you require, but better than a hand torch. And this is a community that started with hardwood charcoal in a forge made from a truck's brake drum. I also suggest a test run for tempering. Try powers of two for time at the same temperature (15 min, 30 min, 60 min, 2 hours, etc.) to see if you can draw the hardness down within your maximum temperature to the levels you want. IIRC, it works. I knew a guy who tempered SAE 1050 armor in his kitchen stove just by soaking it for hours and hours. Sadly, neither the Midwest Armorer's Guild nor the Armour Research Society appear to exist anymore, and I'm far out of the game, but I suggest contacting Doug Strong at Talbot's Fine Accessories, and ask who to talk to about heat treating steel. Man's a fine armorer on his own right, as well as a historian. If anyone knows who to talk to, it's him. I have other options, but he's my go-to who knows everyone else I'd suggest (Brian Rainey, Chuck Davis, Robert MacPhearson, Patrick Thaden, Ugo Serrano, etc.) and I promise you'll find a community you'd love. Mac was in love with clocks, last I saw him, so that puts you in good company. I assume Patreon will hate the length of this message already so . . . good hunting, man!
Michael Faragher
2024-08-01 17:27:15 +0000 UTCThe clay was usually applied across the entire blade, just of differential thickness (at least in my reading). The thin clay, like all thin insulators, actually increased cooling speed (increased surface area had more effect than insulation had) while the thick clay slowed things down considerably. It also allowed for things such as thicker clay in bands down the blade, providing the same anti-crack propagation as ripstop nylon, and the decorative hamon seen on most blades. But it's a complicated topic, since tahamagane (the steel mixture used) isn't homogeneous, even on the macro level, with many blades using a lower average carbon core with higher average carbon working surfaces. Also, they could change the genera curve post heat treatment using a red hot block, which really wouldn't help a screw, but I got lost in the weeds. :D I wish I remembered the book I had, it was orange, but when I mentioned it to Tony Bryant of Sengoku Daimyo fame, he said it was a solid book. (Miss you, Tony) As you mention with blades, there's usually final grinding to bring things down to size and shape, which unfortunately doesn't appear to be an option here. Still, amazing information and great ideas! The air hardening steel idea never occurred to me. And the heat treat oven is a great idea.
Michael Faragher
2024-08-01 17:11:47 +0000 UTCHeat treat oven to get a more uniform heat treat? Use it to normalize the steel blank before starting..
Jeffrey Britton
2024-08-01 17:08:55 +0000 UTCAh man, as soon as I saw you put it in the hydraulic press, I knew what was coming 😟 It's not much of a take away, but I applaud you for even approaching this. To my understanding, a lot of professionally made acme leadscrews are made by grinding the threads profiles on a CNC cylindrical grinder, so the fact that you got this far with just a lathe is impressive. In terms of what to do next - I think a huge part of the problem with the warping is the fact that the heating uneven, and above else - a large portion of the heat is going out to heating the workshop rather than the part. You can actually see the bar moving as you were heating it. An ideal case would be something like an induction furnace, where the heat it applied to the entire area around the part. With all that said, I'm extremely far from an expert on this subject, and some comments here have much better experience and knowledge to back the info up. Great video as always, Brandon. Don't let this get you down. Knowledge gained through failure and all that.
Erik D. Radzius
2024-08-01 16:46:52 +0000 UTCI'd temper it below 60 HRC to be honest ^^
Christoph Fuchs
2024-08-01 16:33:30 +0000 UTCI'm guessing your sponsor this video is myheritage.com? Your closed captions starting around 1:53 are for your sponsor, and it then offset by the spot length for the rest of the video. It'll probably only be an issue here on Patreon. Quinn over at Blondihacks talked in one of her recent videos about how to stress relieve material before milling it. I'm guessing that her method would also work for this.
neal richard
2024-08-01 16:29:29 +0000 UTCOoooouchh! Painful as that was to watch it was semi inevitable, imho. To me the best thing to do based on your last machining method would be to send it out for HT or find someone with a ramp and soak oven big enough and support it well in the oven. Personally, I believe quenching it horizontally is better for the the simple reason of getting the whole thing in oil quicker, hence less banafication. Kyle's Idea of using A2 is also good point as well as his oven thoughts. Katana quenching is a very purposeful process to banana the full length, create the cutting hardness and spine toughness and clay is the trick. Another choice would be 4140 (will give you 58HRC after HT) and have it nitrided to get your 62HRC. Overall to get something fitting for your fine gift lathe, I'd send it out for HT. Nice machining btw, sans a few bobbles. Hat Tip, ~PJ
PJ
2024-08-01 16:26:25 +0000 UTCHow heartbreaking Brandon. It happens to us all but given the great lengths you go to provide us with in my opinion, the best machining content available, it broke my heart to see it end the way it did. Keep the fantastic content coming!
Jeffrey Spoor
2024-08-01 16:10:37 +0000 UTCThe BOS is pleased 😈
James Riordan
2024-08-01 16:06:38 +0000 UTCThere is also the option of a custom induction heater coil. One long enough to fit the entire shaft into so you can still use your "hot rod" to heat up the part. The main take away is trying to apply the heat as evenly as possible to reduce expansion at different rates. Dare i say, differential expansion. This is all with the assumption that after machining, if your shaft bananas again, you can straighten it out before hardening ever takes place, and then focus on the heat treat not adding any warping.
Kyle Wellman
2024-08-01 15:37:26 +0000 UTCI may actually be able to help you for once instead of you teaching me all the time :D So a while back i made a ring mandrel for a friend in the jewelry buis. It was about 15" long with a 1° taper, and 3" of handle for a total of 18". Hopefully thats in the ball park of what you're lead screw is for an accurate comparison. Long story short, i wanted to harden it aferwards for longer use life. I was also worried about making it into a banana using a torch to heat it up as its impossible to apply even heating causing irregular warping to contort the atoms in a whacky way. Lucky for me my neighbor and good friend in our tiny village is a knife making blacksmith with a very long heat treat oven. Using his oven allowed for even heating across the entire piece resulting in equal expansion and no warping. My other recommendation is using A2 tool steel so you can harden it without having to quench as quenching is the reverse problem. Insuring you bring that temp down quickly and evenly is nigh impossible. Going in vertical like you did is the best method, but even then one side is dropping in temp rapidly before you even get the piece all the way submerged. This doesn't really bother knife makers as much because their parts are so thin relative to a lead screw that the warping is far less severe and often times if they are quick it wont happen at all. Even if it does they can bend back a lot easier. Samurai swords are quenched horizontally with a clay mixture on one side to intentionally introduce the signature curve and also keep the sharpened side hard while keeping the spine softer for toughness. I experimented once with using a very thin layer of clay on one side of a hydraulic cylinder shaft that would enter the quench first in hopes that it would more evenly cool across the entire piece as it entered the quench. It did keep it relatively straight, very minor warping, but i had enough meat left on purpose to grind it back in straight. In otherwords, it would take an awful lot of testing to get it dialed perfectly. Which leads to my recommendation to remove the need for quenching at all by using A2 air hardening steel :D
Kyle Wellman
2024-08-01 15:26:10 +0000 UTCOn material, instead of tool steel, how about 4140 pre hard instead?
Seta
2024-08-01 15:22:11 +0000 UTCWow! Just wow! Sorry this happened! I was looking forward to the success then heart shattering conclusion (your own game of thrones saga!) In my humble opinion just two things with the hindsight advantage: - do the hardening after bending it straight. -leave the shaft longer to avoid crashing the live center, then parting to length Bonus for the shop boss on roasting the shirt: we call them “Extra-Medium” size in my neck of the woods 🤣 🤣 🤣
Seta
2024-08-01 14:58:20 +0000 UTC
