The mini lathe is a great starting point for learning about machine rigidity. I believe your content has helped a lot of folks deal with the short comings of entry level machines as proven in this video. Thanks again for sharing, Cheers
Very impressive to get that much depth of cut out from a mini lathe. I started using the aluminium inserts on my ancient 1930s benchtop lathe and they are so much better then the regular steel cutting inserts. The best thing about them IMO is not how deep you can go, but how shallow a cut you can take; the regular steel cutting inserts just rub the surface if you try a really fine cut.
@@cooperised Yes they are pretty fragile, as he mentioned in the video if you stall the motor (or make the belts slip as my lathe does) there is a very high chance of chipping the cutting edge off.
If you have failed to machine the correct dimension, then you don't keep single-point turning for .001" or 0.025mm or whatever small amount. Just use a lathe file. This video is NOT the best place to come to learn anything. .
@@taxicamel _"If you have failed to machine the correct dimension, "_ Has nothing to do with this. As an "expert" you should be aware that small lathes simply don't have sufficient power (or rigidity) to take deep cuts. That's fine with HSS, but not so much with conventional inserts which is why they aren't well suited to small lathes. The aluminium inserts do work on small lathes however.
i'm glad you finally got round to trying the ally inserts. Ever since I tried them on my lathe, I've neved looked back. Addmitedly, My lathe is the "1 size up" from yours(SC4) and it does have the fine feed feature, which is incredible for it, but they're truly amazing for this kind of work. Awesome video as always.
It's really amazing how much you have gotten out of a Chinese mini lathe. 3 MM cuts are much more than I would ever than I would ever ask out of such a lathe. I would be satisfied with less performance from a Chinese mini lathe. wow I just noticed that I evidently watched this video before.
When you talk about your inserts not breaking propperly when you mess up, simply run it in reverse, does the trick every time :). During my apprenticeship the machine in the shop we had mostly used was exactly the same model as the one in the job-school. The difference was that the switch for the direction on the shop machine was the opposite of the normal setup for that machine so if you turned the one in the job school on with the habit built up in the shop you'd run the machine in revers. Took one guy 2 broken inserts and serious confusion from the teacher before the mistake was found
I had one of these. I made no mods and it showed. It's gone now since we moved house, but I'm up for another one. This time I'll do mods as recommended by this dude. I'd be silly not to if I want good results...
Outstanding stuff! I use the ground inserts more than half the time I am cutting on the lathe. When you are experimenting for best surface finish, take a look at different cutting oils. Every machinist has their own favorites, but I have been surprised by how much performance can change with different types. For steel, my current favorite is made by Rigid, but I would recommend you try several. You will find your own favorites quickly.
This is a very interesting video, because most people say you can't do much machining on steel with these mini lathes. this method seems to work pretty good. it shows that mini lathes can machine steel providing a person is patient. which is really all a person can ask since these lathes are hobbyist grade and not professional grade lathes. something that I noticed, is the cuts seemed to get easier and cleaner. the smaller the diameter the stock got. which makes sense since the smaller the diameter. the easier it would be on the lathe and the cutting tool. for me I think they are very suitable for making bushings and other things like that. however I'm curious how they would do on stainless steel. I'm going to have to watch the other video to see what the outcome is.
I've been using my mini lathe for about 4 years now, and have turned stainless, mild and cold rolled steels, bronze, brass, aluminum, plastic, lead, cast iron, and the only thing I failed on was a mystery metal that broke 3 inserts (turned out it was piece of a hydraulic shaft, that was case hardened). I've never done that depth of cut on mine though.
I tend to use moulded inserts in the manual lathe too. Ground inserts are a bit fragile,. However never a problem in the cnc unless I do something quite daft. The inserts for aluminium certainly make a lathe think it has had a motor transplant. I think if you want the chip to have a chance of breaking, you may need to double the feed and halve the depth of cut. That works for me. Although that long spiral is at least able to be controlled, not like it is a long straight continuous knife edge waiting to bite you.
You can get 8.7”x15.7” lathes for about 800 USD that have 1.5 HP dc motors. With that, along with generally better QC, one of those lathes could really hog material.
I think people worry way too much about "chip breaking" does it even matter for the home machinist? Whenever I get that long curly swarf the cut "feels nice" so surely you're doing something right!? I suppose there is a safety factor to consider. Anyway that's a great DOC for a mini lathe! I did some experimenting with carbide a while ago and my findings match yours, although I didn't dare go all the way to 3mm. It seems carbide likes being pushed, but only if you have the power and rigidity. I was amazed recently at my Cowells lathe taking 1.5mm (total) off a relatively large diameter of steel! Albeit with a very sharp HSS cutter and very slow rate. But still impressive. If you're not familiar with the Cowells lathe it's a tiny micro lathe more suited to watchmaking! Sometimes I wonder if we are too timid with our machines? Great video. 👍
Awesome mate. Im not always too worries about perfect chip breaking, but when this was spitting out 1m long chip strings, that was a bit ridiculous. Cheers
DCMT’s are a finishing tip. I’m a turner by trade but have a hobby machine in the garage which is pretty much gutless compared to professional machinery. We use WNMG’s or CCMT’s for roughing, and occasionally DNMG’s, but these amateur machines wouldn’t stand a chance under load with any of them.
I mean yes it can be done, but there are a few things to consider here. 1214 is a free machining steel, which machines like butter compared to 4140. While the mini lathe is managing that depth of cut, the feed rate is really slow and you would be better off taking smaller depths of cut at a faster feedrate. I know my 650kg hobby lathe will happily do 3-4mm DOC at 0.2mm/rev in 1214. A “fullsize” lathe wont just do a 2mm depth of cut, it will go much more. The inserts you are using aren’t brittle per se, they are the same carbide just with super high positive rake and razor sharp edge for machining soft materials. They just don’t hold up because both of those things lead to highly reduced edge strength.
I am aware of this, and material removed wasn't really what I was aiming to demonstrate. I just wanted to see how far I could push the lathe, in light of the new mods and the new insert. I just thought it was neat what this little lathe could do. I even said in the video that this was best case scenario
High Speed Steel calls for lower cutting speeds and heavier depth of cuts. I prefer tangential HS tools on my lathe. Originally my lathe came with a 550 W single phase motor, but I bought a three phase 1.5 kW motor and a one - to three phase frequency converter after I discovered the motor to stall when turning with carbide inserts. Since then I've only had a few occasions with belt slipping instead and only turning with HS steel. Downside is an inferior surface finish.
Good stuff, you really pushed that there, I can do 1.5 and that’s pushing it. But I prefer carbide myself but sometime need that odd shape HSS so got a load of them for when needed. Good video.
That was a good assessment of what your tool is capable of doing although there are a couple of factors I think you didn't consider. number one volume of material removed in cubic centimeters per minute the larger the diameter the more material you remove per minute stated in cubic centimeters. Such as 1 mm deep cut on a 50 mm diameter removes more material than a 1mm deep cut removes on a 25mm diameter for the same length of cut. Number two the absence of coolant. Coolant can greatly increase the efficiency of a tool by putting a barrier between the tool in the material also the coolant causes the chip to take the heat of the cut and the chip reacts differently when it's hot rather than when it's cool try these and tell me what you think. my best wishes
Good stuff to think about. I'd love to install a coolant set up one day with this lathe. I use a bit of mineral cutting oil when stuff heats up but its always a bit of a bugger to use when I have the cameras set up. Cheers :)
I'd recommend an AC servo motor, 1 to 1.8 KW. You can get some that go up to 3000 RPM, which would be plenty I feel like for a lathe like this, especially with gearing.
Really appreciate these videos! Gives a good perspective on what can be achieved with these little machines. Any chance of a link to the inserts you use? Cheers lad.
Nice! -but 0.5HP seems to be almost more than what the rigidty of the machine really handles. You'd need better main bearings, a better chuck and a stiffer bed to push it further.... I'd work on that in stead of putting time and money into upgrading the motor :)
I use ccmt aluminium inserts on my little lathe, they cut a lot better than normal inserts. But yes, crash the machine and the insert is stuffed. But the maximum depth of cut i can get is 0.4mm, and those blondilocks chips is the best I can do. At least they are contrallable rather than a rats nest. But all my cutting is on 4140, dont know how it would go on mild steel. Oh - and I let the magic smoke out of my motor trying to do deeper than 0.4mm cut.
There is a video somewhere on youtube where a guy takes a 25mm depth of cut with a mini lathe if I remember correctly. He’s done loads of modifications to the machine to stack everything in his favour and it did work. However when comparing cuts, depth of cut is far from the only metric. If you want to see how quickly you remove material you should calculate volume of material removed per unit of time. (Inch^3/minute or mm^3/second). Comparing depth of cut while slowing down the spindle and feed is usually not faster than regular roughing strategies because of the compromises involved. Edit: I found the video and I see you found it as well about a month ago. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-1z7WctFry9U.html
I am aware of this, and material removed wasn't really what I was aiming to demonstrate. I just wanted to see how far I could push the lathe, in light of the new mods and the new insert. I just thought it was neat what this little lathe could do. Cheers
@@artisanmakes They are indeed a very good option to use on small lathes. But even on larger ones like the +-300kg lathe I'm using them often on parts that cant be (easily) set up rigidly.
I would recommend using uncoated inserts if possible instead of the yellow coated ones you use. The coating on most carbide inserts makes the cutting edge slightly duller, and the performance benefits from using coatings are not beneficial at the performance level of small machines.
I think to get the chip breaker to work your attacking it from the wrong angle.. Rather than going a deeper cut, I think you need a more aggressive step over.. The chip it just to thin to break. With a thicker cut rather than deeper the chip becomes more brittle and less ribbon like
I do it by hand, I have a hand crack that connects to the spindle. That is the one downside with my AC motor, with the gearing I have, the lowest I can get is about 400rpm. Although you can get AC motors with VFD controllers to lower the RPM
You would be better with ground finishing inserts for steel. The aluminium inserts work but dont last long as the rake angle is too steep. DCMT the M stands for molded, look for DCGT (G stands for ground) finishing inserts for steel. Ground inserts are much sharper and finishing inserts allow less D.O.C. Even stainless is pretty simple them. Less tool pressure. They can be more fragile
do u have a suggestion on a quick change tool post for one of the mini lathes 7x14? i got one on amazon an i did get one of the cheaper cause i had just picked the lathe up an dont have a bunch i can dump on accessorys but i didnt expect much from the tool post i got an it will take some work for me to keep it repeatable but my biggest concern is when i was turning some steel in it i noticed the post seems like it was giving alittle but only when cutting, couldn't feel any when not so its not as ridged as the one that came on the lathe so when working with harder materials i'll be switching back to the one that came with the lathe cause it didnt do this but for softer i'll use the quick change post but i really wanted the quick change tool post for adjusting the tool up an down more than for being able to switch them out but since ive gotten it i see the value in being able to just switch between the tools but the little post i got just isnt rigid enough for some of the stuff im going to be doing. mine costed $34 so there was cheaper but also i feel like its a touch smaller that it should be compared to the original post that came on the lathe 175mm is how big the tool post is im not sure how big it should be an it also didnt have a place to engage the little spring loaded catch to help keep the post from turning, i dont know if this is how it suppose to be or if it should have one, this is my first lathe an ive never gotten to mess with one until i got this so i know very little about them but its videos like this that have guided me so far. thanks for sharing.
Thanks, the motor power is the limiting factor in preventing the feedrate increasing here. I've bought some slightly different inserts with a different chilbreaker and that should help. Cheers
I take normally similar depths of cut on my cnc lathe but the feed I'm using for roughing is like 10x yours. 7,5kW motor, 250x500mm lathe, weight 2500kg
well it's a lathe ru-vid.comUgkxN9zrzkkhnjUF5PQbuA_B1gYdsfCu9k6z but it wasn't what i would have anticipated. Headstock, tailstock, carriage apron are manufactured from aluminum now not cast iron. The spindle diameter for the bearings is too small allowing for a few play in the spindle so I am using some blue Loctite to take out the play.
I have used proper seco and kyocera inserts to machine stuff on this lathe they don't perform all that much better, given the limitations of the machine
Is that 1214 or 12L14 ? The chipbreaker is designed for aluminium. I find they break steel chips if you reduce the DOC and increase either feedrate or rpm or both.
Anyone have an idea of the rigidity difference between this lathe and a 9x20 lathe? I have a 9x20, and I've always assumed it was just a bigger heavier 7x14 with similar rigidity, but now I'm thinking it may be quite a bit more rigid. Not that 3mm doc is bad for a mini lathe, it's incredible.
@@MF175mp oh wow, yeah the 9x20 is much heavier than that. Without the base it's probably around 80 or 90 kg, like 200lbs, and the base adds another 20kg probably. I didn't realize the 7x14 was THAT small. Thanks for the info.
A bit late, but one of the risks of a long chip like that is it wrapping around the part - marring the finish - or even getting wrapped around the chuck, spinning around and picking up more long chips like that. A long whip of very thin very sharp steel flying around at hundreds of rpm is dangerous for the operator. If it doesn't pick up like that and instead continuously feeds downward, you may find yourself grabbing sharp steel line when trying to stop your feed too.
I'm feeding it manually, and how much I push it really depends on how much the motor can take. You get a good idea with feeling when the motor is maxing out, so I can't really give you a quantified feed rate. Cheers
Correction. Depth of cut has nothing to do with the amount of material removed. You could be 2mm into the part while removing less material with an edge of the cutter. To make this test anywhere a curate, you have to compare results with a power feed.
Well yes, you could see that the feedrate was suffering quite a bit at the heavier cuts. I wouldn't take this video too seriously, I was just a bit curious to see how far I could push the lathe. Cheers mate
I was taught how to use a lathe, but a lot of the nuances in machining, like turning different materials and fixturing is self taught and is jus learned from experience.
Absolutely, but us hobby users tend to coopt these things even if it's not optimal. And this insert has its advantages over a sharp hss tool. I have seen a few stainless steel inserts that are pretty sharp though :)
I don't understand why people are using these pointy inserts. I understand for small diameters with live center, but in other cases, it should not be used. A square insert would be better.
@@artisanmakes If you look at the proper angles for machining, the square insert is the proper one. It turns the cutting/chip/swarf much better over. That pointy one does not have a rear "wall" to turn over the swarf/chips.
Obviously a bigger lathe can cut better. This channel is about taking a $600 mini lathe and pushing the limits to the next level. Its very cool to see the limitations bypassed!
