Easy Radius Turning On The Lathe With No Special Tools! Other complex curves too!

[@Blondihacks]

Hey everyone- some heavy repetition in the comments on this one, so let me save you all some typing: 1) Stepping over less than one full parting blade width is a little dicey because the blade wants to deflect. That’s why I don’t do that. 2) Yes you can do this with partial steps on a thicker tool or a turning tool from the right, but I show this method because it works on concave surfaces and more complex shapes, as shown at the end. There- now hopefully no need to keep saying all those same things over and over. I appreciate the algorithm engagement and all, but save your thumbs. You may want to hitchhike some day and you’ll need them.

[@nocturnhabeo]

Thanks for all the awesome info

[@stacysimon8864]

@@brianhaygood183 Agreed.

[@michaelandersen7535]

Saved me a comment, thanks for the FAQ :-)

[@tlange5091]

And if you do, dont forget your towel. Sorry

[@warrenjones744]

@@vendter That is where I saw it in print, it was quite some time ago. I have used this method, it was taught to me in shop class way back in the 70's. Apparently I have had no reason to turn a radius as I have not used it since!

[@michaelwest4325]

One of the best things shown is how to maximize the work on the rather minimal tools many hobbyists have, a true treasure of instruction where skills can leverage the equipment.

[@0623kaboom]

tbh I dont know anyone in my city who owns their own C & C machine ... let alone 3 or 4 lathes a drill press 2 different bench sanders and 12 3d printers etc ... most people I know are lucky if they have a full box of hand tools and a drill that doesnt zap them from time to time lol

[@VincenzOmaha]

Traveling on business and sitting in the hotel refreshing KZbin waiting for my Saturday to become official. Yahtzee!

[@SethKotta]

This will help me loads when it comes to machining my own hip replacement in the near future.

[@TheBiggerNoise]

Be sure to follow up the file with emery paper. You wouldn't want your new hip to chatter

[@ronmccabe7164]

True story! I worked with a graduate student in orthopedics. His father was a machinist for GM, and of course had his own shop at home. He had some kind of surgery in his pelvis (don't remember exactly what). One day his orthopod told him that one of the screws in his pelvis was migrating IN!. Well the dad went home and designed a tool to extract the screw, built it, took it the next time to said orthopod. The doc looked at him like he was nuts! And hemmed and hawed and politely said that was pretty cool, but no thanks. Well the screw kept migrating and the doc wound (no pun intended) up using said tool.

[@SethKotta]

@@ronmccabe7164 Hot damn. That's the coolest thing I heard all week. You think he could've gotten a patent on it?

[@AHustleIsLikeASideOfFries]

@@TheBiggerNoise I did the same thing when making my false teeth

[@ronmccabe7164]

@@SethKotta Hi, I'm not sure, from what I understand it was kind of a one off deal - may not have been a general tool.

[@rustyshackleford928]

Mind Blown! Thank you. I didn't even know this method existed. Keep up the good work. You are such a positive and humorous creator, I never miss a chance to see what you are doing. I think people underestimate the amount of work that goes in to your videos. I do not. Thank you again, and I look forward to the next one.

[@GratuitousSets]

I just wanted to say, "thank you." I'm pretty new to the machine lathe and this series was super helpful and went really far in helping me feel more comfortable. Danke schoen!

[@springwoodcottage4248]

How super interesting & useful. It reminded me of being taught integration by dividing the curve down by smaller & smaller rectangles till the curve was accurately described & then one found the area by multiplying width x height for each rectangle then summed all the rectangles areas together. Thanks for sharing!

[@jaggederest]

integration by limits, as width approaches 0 of each rectangle, your approximation will be arbitrarily close to the continuous integral. There's a lot of polar math that goes into lathe work, really, helps to know your trig and geometry for sure.

[@StevenPaulBland]

... as the width of the parting blade approaches 0😂

[@tinkeringaround6241]

Another way to center your cutting tool on something round is get a steel rule and put it between your work piece and insert and move the tool in until it’s holding the rule , if the insert is too high the rule will lean away and too low it’ll lean toward you. Straight up and down is perfect. Blew my mind when I learned this in my apprenticeship.

[@LawTaranis]

I was about to start centering my shiny new lathe, and this is going to save me so much time. ❤

[@bbrockert]

Nice to do a video like this around April 15th when a lot of Americans are thinking about filing.

[@moorejl57]

And her method seems fairly easy and not very taxing.

[@athompso99]

This reminds me strongly of one of the first methods they taught me in university calculus for computing the area under a curve. And it is in fact the same essential technique. Neat!

[@johnmcclain3887]

I learned to use the same technique working in aviation electronics my "Marine profession" where I'd been shoved instead of the machine shop I tried to enter through. Now I have the machine shop and am retracing old steps. I got calculus via the electronics, never thought I'd be able to cross it into machine work, but here I am!

[@OtherWorldExplorers]

I don't know when you put the red marking die on it it reminded me of the hats that Devo used to wear.

[@Gl4uc0n]

I love that I'm not the only one with a cat named Sprocket. I subscribed just for that. I stay and watch for the great machining content.

[@johnmcclain3887]

This is a very well demonstrated bit of fine work, I used this method decades ago, minus the layout fluid and I see now, just how powerful that bit of technique truly is. You do some very fine work. Thanks!

[@robertwagner8596]

fat chance youll see this but I been watching your videos for a good part of my day and I would like to say you have taught me alot about lathework.also after watching this I have ta say your and artist.thanks for sharing

[@TyrellKnifeworks]

This was really useful, Quinn, thanks! I typically do radiuses on pommels and quillions for knives but I usually eyeball them so this would be a fun way to get a perfect curve.

[@64t120r]

Besides the techniques, I enjoy your sense of humor. Humor is an important thing.

[@r1mein54]

Thanks for another lathe working tip,,,and Sprocket sure has you trained.

[@AHustleIsLikeASideOfFries]

Ok, yes, another great video by @Blondihacks, but can we address for a moment what an awesome pet name for a machinist's animal?!

[@StevenWeagle]

Your videos are excellent...you are a great instructor, teacher.

[@kurre_kallkvist]

Just the other day I was thinking, wouldn't it be great with a Blondihack video of turning a sphere or a ball! Mindreading is apparently another of your skills! 😁

[@mrsockyman]

Brilliant bit of knowledge to share! Love these little "good to know" gems

[@blfstk1]

An old machinist trick, and I qualify as and old machinist, is to get some side walk chalk and scrape it across your mill bastard file teeth. It fills the voids between the file teeth and keeps swarf from chinking up your file and scarring your work.

[@BeachsideHank]

I score my chalk when cruising my 'hood, seeing kids making a hopscotch board on the road, I tell them mom just called and lunch is ready, when they run inside, I grab up all their chalk and race off down the road. I think I am teaching them a valuable life lesson here as well.

[@robertwalker7457]

Especially when filing aluminum. Thanks for the reminder.

[@blfstk1]

@@robertwalker7457 Pleased to serve.

[@virendrajanakiram2365]

But also makes the file rust if you leave it on for a while.

[@theselectiveluddite]

I've also used charcoal. Thanks for reminding me to do that :)

[@dougtisdale3262]

I enjoy your sense of humor!!

[@davidkaye821]

"Dogs have Masters, Cats have Staff." lol Love your channel Quinn!

[@johnapel2856]

That's very cool! Very handy. Thanks, and a big MEOW back to Sprocket.

[@Raphael_NYC]

I need more than one lifetime to absorb all the amazing info and experience. Thank you for shariing. Great skill, exceptional understanding and a very thoughtful presentation. Raphael nyc

[@reggienone966]

"As you can clearly see right through the transparent bar there." Your smart aleck sense of humor would keep me watching even if I didn't pick up a trick now and then. It is a good thing we don't hang out together, no one could stand to be around both of us at the same time.

[@firebird8600]

Yay! It's Blondihacks time!! [Loved the intro]

[@kevinsochalski4507]

Good job and great presentation. I couldn't help but to subscribe.

[@tomjpt]

Thank you! I'm a hack amateur machinist and this method will really work for me. 😀

[@Cancun771]

For certain standard radii you can actually use roundover bits for wood routers. They have carbide inserts. All that is necessary is making a holder for them, i.e. a small clamp for the round shaft that will fit on the lathe toolpost.

[@koharaisevo3666]

As stated the problem is not the lack of tools but small lathe can't handle big form cut.

[@Cancun771]

@@koharaisevo3666 Works perfectly fine, maybe just mount a fixed toolpost instead of the top slide. It gives a lot more rigidity. Compare Robin Rinzetti / Stefan Gotteswinter videos. Also nobody is stopping you from pre-cutting steps before using any kind of form tools of course, which also helps.

[@FEM2008]

It's not just the toolpost on these small lathes-- I wish it was. The ways flex as well. There is not enough rigidity in the lathe bed on a hobby level 100 - 200 lb lathe. And unfortunately, the longer the bed, the more flexible it its. The machinists you talk about have lathes that most hobbyists can't afford.

[@Cancun771]

@@FEM2008 Clickspring uses a fairly small one and uses form tools all the time, even with the top slide on. My own Emco Compact 8V is also not that big, basically one size up from the minilathe which is an Emco Compact 5 clone. Stefan Gotteswinter used a Chinese lathe about the same size as hers for many years before he got the Emco.

[@nerd1000ify]

​@@Cancun771 Important to note here that clickspring typically uses those tools on free machining brass. That stuff is designed to machine well with form tools, as would be typical when making small fittings on a screw machine. If he tried the same thing on 304 or 316 stainless steel he'd have rather a lot more difficulty... Broadly on small lathes you can probably make good use of form tools on cast iron, free machining steels (e.g. 1213, 12L14), leaded brass or bronze (C360 brass, LG2 bronze, etc), free machining aluminium (Grade 2011 T3 or T6) and the assorted non-metals you might find yourself turning e.g. wood and plastics. Smaller forms will also work on mild or low alloy steels, but bigger forms will probably chatter. And stainless (except maybe grade 303, the free machining stainless) or highly alloyed steels are right out.

[@JacobFrazier]

I learn soooo much from this channel!

[@ron827]

Great tutorial on a valuable technique and you did nothing wrong. I have used a spreadsheet with sine and cosine functions rather than CAD to generate my X and Y values. I do it in 10 increments which makes file massaging easier. Rather than a cut off tool, I use a turning tool and proceed all the way to the right with each Y increment. Then I back up to the next X value and dial in the matching Y value. We are both doing step turning, only with different approaches.

[@garbs1917]

Still don't understand how to come up with the depth of cut measurement. Don't have CAD and not sure how the sine and cosine formulas are being used?

[@mike202444]

I cant even spell trig. Can you tell me how I can determine the cuts and depths for a 1", 1/2" and a 0.754" (size of my stock). Can you post for others as well?

[@metalshopwithtroy5755]

I understood what you were putting out there and yes enjoyed watching too. Thank you quinn for your efforts good video Thank you

[@chip3man]

Thank you love the video. Old tool maker's talked about this . It's nice to see it demonstrated.

[@lintelle2382]

your drawings reminded me of my first (and quite enjoyable) exposure to calculus. And now I know how to make a little Devo hat...

[@dobrzpe]

that is a super-legit technique! i like it.

[@ypaulbrown]

Happy Easter Quinn....best wishes, from Florida, Paul

[@Frank.B.Crafts]

This is the exact method I used in High School to make a ball peen hammer for my dad. My machine shop teacher was the best. He taught us many old school methods.

[@twotone3070]

Please tell me the hammer still exists.

[@Frank.B.Crafts]

@@twotone3070 It does indeed, my dad owned an auto repair shop until he retired 10 years ago. He kept the tools i made for him in a separate tool box in his car, which was a very good thing as the shop was burgled one night just before he retired and all the snap on and craftsman tools were stolen. He still uses the stuff i made for him.

[@johnmcclain3887]

I took one machine shop course in about 74 or 75, made a very nice C-clamp out of three quarter inch plate, and have made a career out of mechanic work fed by machine work. This has been one of Quinn's delightful demonstrations of techniques. I still use that clamp daily, I just wish I'd gotten substantially more in school. I'd hoped to fulfill this dream, but never expected I would. I'm retired now, "with a full machine shop" and have learned much out of the young machinists, showing ideas I'd never seen before.

[@engineer_cat]

Red Sharpie! This season's colour 😊

[@stoopsartsunlimited]

Sprocket! Good kitty!

[@MI-vf5zs]

I watched this yesterday and it got me thinking of radius turning. Today was a slow day at work so I tried a bit of a different technique for corner radiusing with quite impressive results. First I turned and faced a straight piece with an od that matched the radius I wanted to turn. Then I clamped that vertically to the bed of the lathe and used a dial test indicator mounted on the cross slide to follow it's od. I roughed the radius out with straight turning in z direction by going nearly to zero on the dti on every x step and finished it by alternating x and z, turning to zero with z then backing off x until the dti showed I was 0,05mm away and going to zero with z again. Rinse and repeat. turning a 20mm hemisphere took about 15 minutes. This technique is kind of like linear interpolation on a cnc lathe, except it involves no math, no cad/cam and is quite easy to setup. If anyone wants to try this for themselves I'd suggest picking a tool which has the same nose radius as the radius of your dti tip and angling your dti so that it contacts your form in a way that keeps it as square to the form as possible, in the case of the outside radius I did I angled the dti at roughly 135 degrees relative to z axis. This is quite complicated to put into words and english isn't my first language so sorry if this is hard to follow.

[@itsagoodlife4453]

I like it! I’m planning on going out to the shop later this day and trying it.

[@paul_domici]

This is great! I need to make a sphere at work and don't have a ball tuner! Thank you!

[@FEM2008]

Quinn always shows good and reliable techniques using hobby level tools and there are not many on-line that do it as effectively. You can check out making a sphere on a more rigid lathe with no special tools on wonderful channel called Swap Lamp.

[@ValhallaIronworks]

On this episode, Quinn makes miniature Devo hats. Whip it. Whip it good!

[@randywl8925]

Most expensive concrete form stake ever. 😁 Never thought about the accuracy of a handheld file. I was expecting some sort of fancy radius making tool holder. That was neato! 👍

[@TomTribley]

Don’t know how I missed this episode until now! It might have been that I was spending a lot of time trying to catch the perv that keeps stealing my kids sidewalk chalk! Lol Grest episode Quinn! Thanks!

[@mikewilly62]

You are so amazing love you're videos !!!!!

[@kevinmartin7760]

This method (more or less) was described in Guy Lautard's "The Machinist's Bedside Reader" series of books. As I recall he used a spreadsheet to calculate the cut dimensions, and did the step turning using a regular tool rather than a cutoff blade.

[@stacysimon8864]

Your right Kevin. I remember doing this 20 years ago. Also, putting layout fluid in the steps makes filing to them easier.

[@zippy1981dotnet]

Why did I not know about the existence of "a Machinist's bedside reader" before now

[@stacysimon8864]

@@zippy1981dotnet You should try to find a set of them. I think there are 3. Tons of old school tricks.

[@noelhenderson7337]

Marc L'Ecuyer, that lazy machinist, has a video using this technique as well. He uses a radiused tool some fraction of the final ball size in diameter to cut the steps.

[@ronmccabe7164]

Yes. I was thinking about mentioning this. He actually had 3 Bedside Reader books and a couple of really nice story books. I think I saw the books available on Amazon not too long ago. I had email conversations with him in the early 2000's. And sent him some pictures of some ideas I had, and make. He was working on a forth book, but it never came out. I've hunted all over the internet for him and can find no trace of him except for his website. He must be dead. Lived in the Vancouver area.

[@bfeitell]

It's not a round ziggurat, it's a Devo Energy Dome! You came so close to perfecting it with that red marker.

[@JBLewis]

Came her to make a similar comment

[@Menthol_ballroom]

We’re all DEVO

[@jackdelancey248]

Nicely done

[@benjaminshaw80]

I had a really good time building my radius cutter. It’s super simple and it works great. I can cut a nice ball of stainless for knobs.

[@notsonominal]

Very generous of Sprocket to let you finish in time for our regular fix;)

[@Tammy-un3ql]

great episode!👍👍👌👌

[@AmateurRedneckWorkshop]

Great tip. I made a stainless steel hitch ball back in the 70's by just turning the tool post in a circle around the metal.

[@AmateurRedneckWorkshop]

@@somebodyelse6673 my lathe has a lantern tool post. You remove the tool holder and insert a hss tool bit in it's place. You are now far enough back to make a 2" or larger ball just rotating the compound on its mount.

[@utidjian]

@@AmateurRedneckWorkshop I can't wrap my head around what you are describing (see what I did there?) Seems to me that in order to create a *convex* curve (a ball) the tip of your tool needs to be pointing *in* towards the pivot point of your tool holder. Seems impossible to do with a lantern tool post while using the lantern tool post as the pivot point. All that said... you certainly can position the point of the tool *in* towards *a* pivot point if you use the compound as the pivot point. All depends on how you can positionn the tool post in the compound T-slot. Perhaps this is what you are describing?

[@AmateurRedneckWorkshop]

@@somebodyelse6673 you just described the action. The compound is lower than the work piece and the center point of rotation is under the work piece. Making a concave surface like this is limited to larger sizes. I saw someone do this on youtube once but I do not remember the channel. However I did this back in the 1970's.

[@AmateurRedneckWorkshop]

@@utidjian yes that is what I am describing. You are limited to how large the work piece can be since the center of rotation of the compound must be under the work piece. You can also make a concave surface like this but I have not tried that.

[@RelentlessHomesteading]

That was great for the few times one might need such a feature. Thankyou

[@tinkeringaround6241]

Great tip thanks for sharing!

[@stevedaenginerd]

Sprockets!!! 😻😜

[@gagasmancave8859]

Nice one Quinn

[@billbryant1288]

I'm glad to see you using a rounded handle on your file. Folks who use a file without a handle are asking for the file to impale their wrist if something goes sideways.

[@andrewscottbaron]

Yes! There ARE round ziggurats! I just compared a crown-stressed spiral clock mainspring in an article for Horological Times entitled "Don't Overlook the Obvious".

[@paulthomas3782]

Great tip Quinn thanks for sharing Cheers.

[@henrydando]

if you have a DRO usually it has a feature that lets you cut the behive thing

[@CTXSLPR]

I used the related Mill version of this to make an almost round pocket where it was well beyond the ability of my benchtop mill to plunge directly and I don't have a rotary table. Divided up the pocket into steps of the endmill radius in X and the walk it in on Y each time. Now I had to overdo it since I can't file the pocket but it worked great!

[@goldridgedesign9069]

This is great, thanks!

[@drd1924]

very cool trick

[@paulmorrey733]

Thanks Quinn

[@ValiRossi]

That 3 jaw looks nice and clean.

[@rickhand8228]

I use an online bolt circle calculator and take smaller "bites" which means less filing. I start the bolt circle at 3:00 o'clock and end at 6:00 o'clock. If making a near 360 degree ball, making the switch at 6:00 o'clock in tool postion is important. Good job! Thanks!

[@deeiks12]

This is an excellent technique and i've used it many times for some complex shapes. I have a cheap chinese DRO and it has some features like this built in. It can help you calculate the positions for some simple shapes like triangles and balls.

[@HeidiLandRover]

Ooh lovely! I believe that particular shape of beehive is called a skep.

[@richardepps8500]

Awesome intro. Couldn't have done it better myself

[@Eluderatnight]

Technique i have be using is to turn it free hand with saddle and carraige hand fed at the same time, mark with blue then put it up to refference to check, hit those spots and repeat, finishing with emory.

[@TheBipolarBear]

To the audience members who had not guessed it already: This is how curves are approximated in computer graphics, sans cutting any material of course. If one magnifies a computer screen enough, one can actually see the rectangular shapes (pixel columns) which make up seemingly curved edges.

[@johnsushchyk7933]

Thank you for sharing this A great help for me Nice work

[@DavidKutzler]

A very useful technique. Mark Presling used this exact technique to reproduce the distinctive profile of the handle on the handwheel of a South Bend milling machine he was restoring.

[@stevenlitkey9354]

Awesome little technique 👌 A little time consuming but hey, we're hobbyists 😊

[@angrygnome4779]

Good info. Now I just have to figure out trig.

[@julianp.1713]

Looks good, interesting.

[@kevinwantstoshred]

Could you do twice as many steps by moving the parting tool only half of its width or do parting tools only work properly when they're running full?

[@johnelrick8945]

Have a thumbs up from a fellow enthusiast for sesquipedalianism!

[@carlwilson1772]

Very impressive.

[@David-hm9ic]

You're awesome as usual! I'm a year late here but also just in time. I was just asked if I could make some knobs that look a lot like one end of your drawing at 11:00, about 2-1/4 to 2-1/2" max diameter. We're restoring some 3" Naval guns for a battleship and some of the knobs are missing. Thinking about using an as-manufactured 3/8" cobalt HSS steel bit instead of a cutoff tool. That would pretty much eliminate side deflection.

[@georgebell7103]

Well done, thanks

[@kmet2000]

Hi Quinn, I think it now time to invest in DRO? 😁 Great video again. Straight and simple.

[@andrewdolinskiatcarpathian]

A neat and tidy solution. 👏👏👍😀

[@SW-qr8qe]

Very y handy - thanks!

[@TSYRR350]

Very nice.

[@prodoverjeff2876]

Maybe aggressive was what I wanted, but a file card is a personal favorite. After a few card swipes, the first few strokes feel so machinisty!

[@parkershaw8529]

I appreciate the lesson you taught and I don't even have a lathe yet. :-)

[@MichaelLangdon-en5cw]

Great video 💙🇺🇸

[@IanSlothieRolfe]

I thought at first you were going to show the free turning tool that Prezzo has been using lately, which would be a good investment if you do this kind of thing a lot, but this is the way to do it for zero margin cost, I recall being shown at school a very similar technique but using a roughing bit (The school was paranoid about breaking parting bits, largely because we were so good at breaking them!). Using the parting bit is better though for shapes more complex than rounded ends as you show at the end.

[@SamCyanide]

Is there anything like this for internal radii? Maybe there's an insert with a squared off edge or something. Because what I'm thinking is you could maybe use it on a boring bar

[@leighmackay7486]

You had me with ziggurat. 😎❤️

[@StevenPaulBland]

Reminds me of my Calculus 1 class❤

[@JanBinnendijk]

I once had to machine a couple of Hemispheres on a conventional lathe, i used a tool with a round insert and i calulated the X, Z positions with Sine and Cosine (sine (angle)*radius and cosine (angle*radius) with small radii, you can increment the angle with like 10°, while on bigger radii, you might want to go to 5° or smaller to get a smoother surface.. On my CNC machine, i have all these calculations written in the cycles, so the machine does the math for me If you have a rounded tool (like with a round insert), and you're using CAD, you also can get a smoother surface.. and you can take smaller cuts, as a tool with a round insert will not deflect like a parting blade does.

[@TheHailacopter]

Pausing voiceover to play with kitty: priorities in right place.

[@mattiaarnio9249]

Ah the memories... In last century I did a tool surface (steel plate) in 0.1 mm (1/254 inch) steps and curvature of about 4 meters. This tool diameter was about 0.3 meters (1 feet), and the excess was left there because this tool was a (rough) shaped lapping plate that abraded to final dimension during the use.

[@chieftalltrees8970]

may i inquire further about your cad drawing?? how did you get your dimensions for the size of the hemisphere you made? like how did you know how far to move the groove on the z and how deep to cut on x? how did you approach your drawing to get your accurate hemisphere?? and how does it different in can from hand drawn?

[@johnmcclain3887]

The size of the steps is relative to the size of the ball and the accuracy one needs. Smaller steps more accurate, more labor intense. Using a radius gauge is perhaps the best part, as one can rather accurately profile to fit. My first attempt was using the thickness of the parting tool to choose the steps, and while fast, leaves much to "quality of filing technique".

[@steelcannibal]

A thin piece of brass, or a squashed mouth of a spent rifle casing/bullet shell(.308 or 30-06 or something of similar size) pressed into the teeth of a file works great for cleaning single cut files, especially if you're filing aluminum.

[@trackerdan1]

Great technique - thank you! If the key to the whole process is calculating the plunge depths for each step-over, it might have been good to provide a simple example of how to do that manually. I know every situation is going to be different, though.

[@mike202444]

@trackie1957 I cant even spell trig. Can you tell me how I can determine the cuts and depths for a 1", 1/2" and a 0.754" (size of my stock). Can you post for others as well?