Endmill Basics

Here's a quick primer on endmill types and the jobs they are used for. It covers centercutting and non-centercutting endmills, the different numbers of flutes and their pros and cons, and the various endmill shapes.
Here's the video on feedrates that mention in this video:
• Feedrates For the Mill...
If you like my videos, please consider supporting my channel on Patreon. You'll get access to gag reels and I'll give you a shout out in my videos.
/ stuartdeharo

Пікірлер: 127

  • @kensendelofski3761
    @kensendelofski37615 жыл бұрын

    thank you. Just getting started in milling. at age 60. enjoyed this video.

  • @kk2ak14

    @kk2ak14

    2 жыл бұрын

    Same situation

  • @robinpaine161
    @robinpaine161 Жыл бұрын

    I've just been trying to mill a blind slot using my lathe. I was trying to plunge a non centre cutting end mill and it broke. I realised I was doing something wrong and now I know why. Very informative.

  • @ninjaabcde
    @ninjaabcde2 жыл бұрын

    I'm a young professional and I found this extremely helpful. Thank you for your work!

  • @StuartdeHaro

    @StuartdeHaro

    2 жыл бұрын

    You're very welcome. Thanks for watching!

  • @swamihuman9395
    @swamihuman93954 жыл бұрын

    Great stuff! Well presented. Thx, Stuart.

  • @1stJaytree
    @1stJaytree4 жыл бұрын

    Just getting started at 56 myself in milling and appreciate the video. You have a voice like Bob Newhart. Good for narrating.

  • @StuartdeHaro

    @StuartdeHaro

    4 жыл бұрын

    Hahaha thanks!

  • @DudleyToolwright
    @DudleyToolwright2 жыл бұрын

    Clear and concise as always. Well done.

  • @flewggle
    @flewggle5 жыл бұрын

    I'm a tool designer. I've been in and out of machine shops my entire life. This was a great quick video and I learned somethings I didnt know. Thanks for posting.

  • @thaaiveeduchannel

    @thaaiveeduchannel

    Жыл бұрын

    youtube.com/@thaaiveeduchannel

  • @bobmac9070
    @bobmac9070 Жыл бұрын

    Couple of things, one most ends HSS or Carbide have about a 2-3 deg dish on the end. So if your plunging and you need a “true flat bottom” you have to order them as a semi special. As for double end end mills there going away. Not many manufacturers want to make them and they just aren’t used that much anymore. As for slotting on CNC machine we very successfully have cut slots with 4 & 5 flute carbide end mills. Newer tougher grades of carbide in todays world can handle it. I worked for a major end mill company So much has changed over the past several years in end mill capabilities.

  • @mckeesk
    @mckeesk5 жыл бұрын

    Just used my first roughing end mill today. Yep, leaves a horrible finish. But, it was about .002" over what I needed so could come right back with a finish end mill same geometry. Thanks for the info!

  • @MicahMade
    @MicahMade Жыл бұрын

    Having a hard time in machining/cnc because I started a week late. I think this video caught me up. Thank you!

  • @StuartdeHaro

    @StuartdeHaro

    Жыл бұрын

    You're very welcome. Good luck!

  • @mwont
    @mwont Жыл бұрын

    Really awesome explanation. Thanks.

  • @whc5180
    @whc51804 жыл бұрын

    What a nice introduction!! Thank you.

  • @MyHeap
    @MyHeap6 жыл бұрын

    Great video. Thanks for sharing. Joe

  • @madeddiesman-stylemonsterm6662
    @madeddiesman-stylemonsterm66622 жыл бұрын

    Very detailed and thorough. Thank you!

  • @blackbear92201
    @blackbear922015 жыл бұрын

    Great explanations - thanks for posting!

  • @chrissena3050
    @chrissena30502 жыл бұрын

    Great information & great delivery. Machining, I believe, is as much and art as it is a highly precise technical skill. Thank you!

  • @thaaiveeduchannel

    @thaaiveeduchannel

    Жыл бұрын

    youtube.com/@thaaiveeduchannel

  • @cossiedriverrs
    @cossiedriverrs3 жыл бұрын

    I learned something, thanks! One type you didn't mention was the "right hand cut, left hand flute" end mill, which I use on thin material, where it forces the work back onto the table rather than causing it to try and ride up the flutes.

  • @donaldnaymon3270
    @donaldnaymon32703 жыл бұрын

    Great video. Great info. Thank you for sharing.

  • @KIJs-gc6ux
    @KIJs-gc6ux3 жыл бұрын

    As a newbie, this was very informative, thanks !

  • @woodylakkham4169
    @woodylakkham41695 жыл бұрын

    Very informative. Great show. Thousand thanks.

  • @StuartdeHaro

    @StuartdeHaro

    5 жыл бұрын

    I'm glad it was helpful. Thanks for watching!

  • @divco13
    @divco135 жыл бұрын

    Perfect explanation of ends mills, and there usage. It get's expensive darn Quick with out knowledge. I am sure this has been a big help for those at home machinist's

  • @Tensquaremetreworkshop
    @Tensquaremetreworkshop Жыл бұрын

    You can ramp manually too. Slowly wind in the Z axis as it traverses.

  • @RobinsTools
    @RobinsTools4 жыл бұрын

    Very informative. Thanks for sharing!

  • @metaverseplayer
    @metaverseplayer4 жыл бұрын

    Very informative! Thank you!

  • @dalaffarhan2895
    @dalaffarhan28954 жыл бұрын

    Thanks for the video, very informative.

  • @mykedindeal
    @mykedindeal2 жыл бұрын

    Thank you.Great tutorial👍

  • @frankbonsignore.RochesterNY
    @frankbonsignore.RochesterNY3 жыл бұрын

    Excellent presentation

  • @jimm2442
    @jimm24424 жыл бұрын

    Great information, Thank you!

  • @sidekick3rida
    @sidekick3rida4 жыл бұрын

    Super informative. Thanks!

  • @MagnetOnlyMotors
    @MagnetOnlyMotors2 жыл бұрын

    Wonderful info, thanks!

  • @louisroy9348
    @louisroy93486 жыл бұрын

    Nice explanation, Thanks

  • @kevinarnold213
    @kevinarnold213 Жыл бұрын

    informative and I am just learning tyvm sir

  • @muhammedshafi9539
    @muhammedshafi95394 жыл бұрын

    thanks for this tutorial. nice explanation.

  • @thomasherbig
    @thomasherbig4 жыл бұрын

    Excellent video, just like your other ones! As a sequel, could you perhaps address different cutter materials (HSS, Cobalt, Carbide), coatings (bright, TiN, TiAlN, ZrN, etc), and rough guidelines on how to pair cutters with materials?

  • @StuartdeHaro

    @StuartdeHaro

    4 жыл бұрын

    That would be a good one. I'll put it in the queue. Thanks for the idea and for watching!

  • @PppP-gc1df

    @PppP-gc1df

    4 жыл бұрын

    Please make on this.

  • @MERCKXWOOD
    @MERCKXWOOD6 жыл бұрын

    Excellent informative video - Thank You

  • @StuartdeHaro

    @StuartdeHaro

    6 жыл бұрын

    You're very welcome. Thanks for watching!

  • @eddiekulp1241
    @eddiekulp1241 Жыл бұрын

    Sharpened many of those cutters, endmills , roughers on cutter grinders for 31 years, have fun

  • @brianjacobson7820

    @brianjacobson7820

    3 ай бұрын

    Hey, 32 here just got my first knee mill. Also got lucky and bought out a local tool and die shop. Came with a end mill sharpener. Do I need a surface grinder to Sharpen them? Curious about the process if you would care to explain. Id throw ya a PayPal compensation for your time. Just curious, like learning

  • @danielm.7396
    @danielm.73966 жыл бұрын

    Thank you for this. I am beginner machinist, and the school I went to was for shit. This was much needed.

  • @greglaroche1753
    @greglaroche17538 ай бұрын

    Great video. Thanks.

  • @FantasyWeapons
    @FantasyWeapons2 жыл бұрын

    Very useful information 👍🏻

  • @charleskutrufis9612
    @charleskutrufis96124 ай бұрын

    Thank You, much appreciated.

  • @Mia-jp5fk
    @Mia-jp5fk3 жыл бұрын

    Awesome video! just got a student job working partly as a machinist, love it.

  • @StuartdeHaro

    @StuartdeHaro

    3 жыл бұрын

    Fantastic! Good luck with the new job. Watch how people hold workpieces and never be shy about asking questions. Thanks for watching!

  • @hyminlottering7680
    @hyminlottering76804 жыл бұрын

    Thanks this helped a lot

  • @michaelstorm8578
    @michaelstorm85784 жыл бұрын

    Very nice job.

  • @marywager947
    @marywager9476 жыл бұрын

    Fantastic.. very clear and informant

  • @StuartdeHaro

    @StuartdeHaro

    6 жыл бұрын

    I'm glad you liked it. Thanks for watching!

  • @petersmith3703
    @petersmith37035 жыл бұрын

    many thanks for very helpful briefing.

  • @StuartdeHaro

    @StuartdeHaro

    5 жыл бұрын

    You're very welcome. Thanks for watching!

  • @j.davidslaugh5761
    @j.davidslaugh57614 ай бұрын

    Thank You

  • @FretsNirvana
    @FretsNirvana5 жыл бұрын

    Excellent tutorial for a newbie thanks ...

  • @StuartdeHaro

    @StuartdeHaro

    5 жыл бұрын

    You're welcome. Thanks for watching!

  • @mth469
    @mth4693 жыл бұрын

    Thank you sir.

  • @eldiagrama
    @eldiagrama6 жыл бұрын

    very informative, thank you

  • @StuartdeHaro

    @StuartdeHaro

    6 жыл бұрын

    Thanks for watching!

  • @SuperJsToysChannel
    @SuperJsToysChannel3 жыл бұрын

    thanks. very useful

  • @pradipmaheshwari217
    @pradipmaheshwari2175 жыл бұрын

    Great work sir.................

  • @StuartdeHaro

    @StuartdeHaro

    5 жыл бұрын

    Thank you!

  • @bobuk5722
    @bobuk57223 жыл бұрын

    Hi Folks. An advantage of two flute end mills is that they will cut accurate width sized slots. Three sided ones will mill slots slightly wide as two teeth can be engaged on one side and only one on the other - the end mill has unbalanced cutting forces and distorts slightly. BobUK.

  • @genegoodwin8925
    @genegoodwin89252 жыл бұрын

    My first day operating a Cincinnati No.6 mill I made an ashtray and engraved the company's logo in the bottom of it using a ball nose cutter. You are only limited by your own imagination.

  • @spiderbrandt4066
    @spiderbrandt40663 жыл бұрын

    G'day Stuart , it looks like I'm 2 years late , but here goes I'm a Fitter and Turner and I like very thing you say but for one , the first 2 flute mill , we call a Slot drill which we mostly use for cutting Keyways . keep up the good work

  • @StuartdeHaro

    @StuartdeHaro

    3 жыл бұрын

    Yes. I've had this conversation with a few other people from around the world. It appears to be a nomenclature issue between countries, similar to the different names for parts of automobiles. Hood and bonnet, trunk and boot, etc. In the US, the catalogs list them all as endmills, just with different flute counts. What other different names do you have for machine tools where you're from? Cheers and thanks for watching!

  • @spiderbrandt4066

    @spiderbrandt4066

    3 жыл бұрын

    @@StuartdeHaro I'm in Qld Australia , we have the same names as you just the slotdrill is different , One of my favorite is a Flycutter , it can have 2 to 8 cutting tips in it , grate for large surfaces , I didn't expect to get a reply , you have made my day , thanks Stuart .

  • @DV-ol7vt
    @DV-ol7vt2 жыл бұрын

    Great video! I was trying to learn about this and their is very little lnfo available. You did a excellent job.

  • @lucywang67
    @lucywang675 жыл бұрын

    What the hardness of the product, I think your video is very professional

  • @khalidkhairy7305
    @khalidkhairy73054 жыл бұрын

    Very nice

  • @friedmule5403
    @friedmule54035 жыл бұрын

    Really great video, thanks a lot for sharing!! May I please ask you a question on choosing the right type? I want to plunge cut into glassfiber circuit board to repair dents, burn marks and so on. I am just using a mini drill press. Am I right in understanding that a center-cutting square carbide end mill will be a okay choice? How many flutes?

  • @StuartdeHaro

    @StuartdeHaro

    5 жыл бұрын

    I'm not an expert on circuit boards by any means, but I know that fiberglass is quite abrasive, so you'll want to go with carbide rather than high speed steel. I would use a 2-flute cutter if you're going to plunge. You may want to consider using a router bit instead of an endmill because it won't want to grab as it breaks through the other side.

  • @friedmule5403

    @friedmule5403

    5 жыл бұрын

    @@StuartdeHaro Thanks a lot for your reply!! About the router bit, I am only trying to "dig a hole" so I can fill it up again with epoxy and I have not found any router bits in 1-3 mm so I think that a endmill will be the tool that is most useful.

  • @donepearce

    @donepearce

    5 жыл бұрын

    @@StuartdeHaro Making holes in glass fibre pcb material is pretty much only done with carbide drills. It's only edge profiling that uses a cutter.

  • @jenspetersen5865
    @jenspetersen58655 жыл бұрын

    Great video - thanks for putting it out there! It seems like roughing end mills and high flute counts are for very hard materials. As a novice I am wondering why you couldn't rough Aluminium with a roughing mill and finish it with say a 7 or 9 flute to get finish and tolerances. We have products where we have cuts that are 5-6 times diameter, so we would really like to have small forces and many flutes on the finishing passes. Am I just totally off on a tangent?

  • @StuartdeHaro

    @StuartdeHaro

    5 жыл бұрын

    Not necessarily with regards to hard materials. Roughing endmills produce smaller chips that are easier to evacuate. Any material could benefit from their use. They'd be used to hog off as much of the material as possible with no regard to finish or tolerance and very little regard for the tool life. This lessens the load on your nice (possibly expensive) finishing endmill. The problems you might encounter with Aluminum are the same for any endmill. Aluminum tends to be a bit gummy and loves to stick to cutting tools and itself, so it is easy to load up the flutes on your cutters which leads to failure. Keep the chips evacuated any way you can and you should be okay. Thanks for watching!

  • @jenspetersen5865

    @jenspetersen5865

    5 жыл бұрын

    @@StuartdeHaro Thanks for putting this out there and for answering!

  • @spiderbrandt4066

    @spiderbrandt4066

    3 жыл бұрын

    To keep the chips evacuated you can use Cutting compound or WD40 or Kerosene , the Kero is from when I was an apprentice in the late 60s , I'ill shut up now .

  • @manikandankrishnamurthy9459
    @manikandankrishnamurthy94595 жыл бұрын

    Good 👍

  • @antoniskaloterakis7996
    @antoniskaloterakis79963 жыл бұрын

    Hello , great video , may i ask would a corner radius endmill produce a finer cut just as a lathe tool with a big radius does ? And whats a sticker sock ? Like removing a sticker of your hands rapidly ?

  • @StuartdeHaro

    @StuartdeHaro

    3 жыл бұрын

    Corner radius end mills are more for longer tool life because the corner doesn't break down as quickly. It also eliminates a sharp corner on the inside of the part which could be a stress riser (a spot where a crack might start). That is especially important on heat treated parts. BTW, I said "sticker shock" meaning the high price causes an elevated heart rate and loss of bowel control.

  • @rufustoad1
    @rufustoad111 ай бұрын

    Hi this was a great video for a beginner. Can you face mill with that 4 flute 1/2"?

  • @toddtavares7386
    @toddtavares73865 жыл бұрын

    Stuart, where is a good place to get quality end mills?

  • @StuartdeHaro

    @StuartdeHaro

    5 жыл бұрын

    Any of the mail order industrial suppliers, like MSC, Travers, KBC, etc. will sell good quality endmills, like Niagara and OSG. I'll also throw out there that shars.com sells US-made carbide endmills that are really reasonably priced and cut great. They are some seriously good bang for your buck.

  • @MetrologyEngineer
    @MetrologyEngineer2 жыл бұрын

    Is there a specific size roughing endmill corner radius that you prefer for aluminum?

  • @StuartdeHaro

    @StuartdeHaro

    2 жыл бұрын

    Not specifically for aluminum. I generally use 3/8 or 1/2 diameter end mills for all metals because they give a nice blend of RPM/feed rate/chip removal rate. Then I'll switch to a larger cutter if I need to face or smaller cutters if I need a certain size radius, slot, or keyway.

  • @vincentrolfe1384
    @vincentrolfe13843 жыл бұрын

    I have an Austrian brand boring machine for woodworking (hardwoods) where I can use an end mill or convert the machine-factory equipped for a square chisel. I run mostly square chisel for furniture and wood products (1500 or 3000 rpm). I am making a plunge cut with a 5/8" end mill now for an escutcheon with a shallow cut. One brand of HSS from Korea does not have very sharp cutters on the flat end and the two flutes are also not very sharp. I returned the 5/8" end mill to the manufacturer US headquarter in Chicago and asked why the cutting edges were not razor sharp and the engineer person said they had a finishing process that left the cutting edges without burrs and this for metal would last longer. He suggested that I get their aluminum cutting tools which would be sharper but their finishing process would still not be razor sharp. Other sources for end mills (people with years of experience) were very questioning about this process from Korea? I went to a norther Illinois end mill source and the end mill is razor sharp with a smooth cut and radically less vibration and required less force to make the plunge in walnut wood. What is the real story about finishing processes for longer tool life in two flute flat cut end mills???

  • @StuartdeHaro

    @StuartdeHaro

    3 жыл бұрын

    I'm going to call BS on this "finishing process" and call it out for what it is; a quality control issue.

  • @vincentrolfe1384

    @vincentrolfe1384

    3 жыл бұрын

    @@StuartdeHaro Thanks for your comment. I know they said all the other end mills in their supply were the same. I ordered a front brake drum for the GM car some years ago and the machining from China was the wrong size and the drum would not even fit the axle hub. Returned the drum. Several months later I was at the same parts company and the manager told me the warehouse in Tennessee had to return all the drums due to failure of spec. I bought a lock miter tooling from Amana tool for a wood box contract. The fit was not even close. I called and talked with Amana and the man said, "the carbide must have moved" BS. He did not know that the carbide is bonded to the steel before the tooling is machined so how could an earlier step in his manufacturing influence the cut!!?? He was BS all the way. I returned the tooling and went with Bosch router bit and fit is good. The same Felder tooling is $400+ with a larger diameter cutting circle which I superior.

  • @chrisgray723
    @chrisgray7233 жыл бұрын

    Hey great video. I was curious if you are familiar with tialn coatings? What's that mean?

  • @StuartdeHaro

    @StuartdeHaro

    3 жыл бұрын

    Yes I am. That is Titanium Aluminum Nitride. It is a purplish gray coating and allows you to machine at a slightly higher SFM and has higher wear resistance when machining dry. It is my go-to coating for steels. You do NOT want to use it for cutting Aluminum though because it will stick like crazy to the cutter.

  • @chrisgray723

    @chrisgray723

    3 жыл бұрын

    @@StuartdeHaro ok, that helps. Thankyou. I've got some tooling I'd like to get rid of so that I can reinvest in equipment. tuffsmokegray@gmail.com if you know anyone who may be interested. Nice stuff just not what I need right now. Thanks again.

  • @audiokees4045
    @audiokees4045 Жыл бұрын

    I did ceqarch from some endmills for clock bushing, gor that I need endmils who have some measurements like for 2mm bush I need to mill a hole of 1.97 mm for press the bus in. Do you have some advice for that?

  • @StuartdeHaro

    @StuartdeHaro

    Жыл бұрын

    An endmill isn't the right tool for that. You want a reamer, which you should be able to get at a supplier like MSC or McMaster Carr. I have a video called Reamer Basics that will give you some info on them, but basically you drill slightly under-sized, then ream the rest of the way. For the reamer, run it at half the speed of the drill and use plenty of oil.

  • @joebilow2992
    @joebilow2992 Жыл бұрын

    Is there a reason you would use the 4 flute endmill to smooth sides of a slot made with the 2 flute instead of using a reamer? Edit,: if this is a stupid question I'm not trolling. I know nothing.

  • @StuartdeHaro

    @StuartdeHaro

    Жыл бұрын

    No worries. A reamer isn't built for taking side loads. Its only job is making a hole round and on size.

  • @johnpwmcgrath
    @johnpwmcgrath2 жыл бұрын

    The roughing endmills are also known as “Straussman” cutters, at least that’s what an old toolmaker taught me…

  • @StuartdeHaro

    @StuartdeHaro

    2 жыл бұрын

    Never heard that one. I'll have to look into it.

  • @adamfilip
    @adamfilip4 жыл бұрын

    Thoughts on Single Flute for Cutting Aluminum

  • @StuartdeHaro

    @StuartdeHaro

    4 жыл бұрын

    I've never had the pleasure. One consideration is that your feed rate has to be slower the fewer cutting edges you have.

  • @adamfilip

    @adamfilip

    4 жыл бұрын

    @@StuartdeHaro considering routers or small spindles turn at 24k rpm. having a single flute would mean a lower feed rate to achieve better chip size

  • @zhoushirley2637

    @zhoushirley2637

    3 жыл бұрын

    many use single flutes to cut aluminum now

  • @dirkvercauteren1876
    @dirkvercauteren18766 жыл бұрын

    Surface finish depends on the quality of the tool clamping system. A collet sytem has a lot of limitations. Hydro, heat or mechanical shrinking , Sino sytems, are much better in ballance, have less run out. All the cutting edges will cut and tools wil not snap.

  • @FredMiller
    @FredMiller6 жыл бұрын

    New subscriber... Very nicely done Stuart. Straight forward, well spoken and the lighting was superb. I am a KZread creator and am always looking to improve my channel. I make small scratch built stationary engines and dabble in gasification projects. Fred

  • @StuartdeHaro

    @StuartdeHaro

    6 жыл бұрын

    Thanks Fred. I checked out your channel. You do some really neat stuff! I subscribed to you as well.

  • @joell439
    @joell439 Жыл бұрын

    👍👍😎👍👍

  • @thatoldbob7956
    @thatoldbob79565 жыл бұрын

    When the center finder kicks off, didn’t you just passed the edge?? Especially you can locate an off center center in a hole? Coaxial one I use by hand in both direction then when close enough I use 600 rpm. I am no expert I am an ol man with old machinery, no DRO.

  • @Vipul.Canada
    @Vipul.Canada3 жыл бұрын

    Hi, very nice video. thanks for it. i am importing endmills from India. i can send you samples can you please evaluate the product for me?

  • @StuartdeHaro

    @StuartdeHaro

    3 жыл бұрын

    I can if you would like. My contact info is on the About tab on my channel page. Email me privately and I'll tell you where to mail them.

  • @MrTimmmers
    @MrTimmmers2 жыл бұрын

    Left hand is a slot drill.

  • @milesmoore5422
    @milesmoore54223 жыл бұрын

    I have no clue what "Chip Clearance" is ?

  • @StuartdeHaro

    @StuartdeHaro

    3 жыл бұрын

    It is the amount of space in the flutes for the chips. 2 flute cutters have more space so the chips can be evacuated easier. 4 flute cutters have less room because of the extra cutting edges so it's harder to evacuate the chips.

  • @milesmoore5422

    @milesmoore5422

    3 жыл бұрын

    @@StuartdeHaro thank you.

  • @mavigogun
    @mavigogun6 жыл бұрын

    It's a bit of a disservice to speak to flutes without distinguishing wood from metal- or addressing the spindle capacity required to drive the tool without causing heat damage. More flutes=more speed; more flutes+less speed=more heat. Oh, your machine can't drive the tool that fast? Too bad- you've just thrown money at a tool you can't use in pursuit of a cut quality practically obtainable via other strategies.

  • @StuartdeHaro

    @StuartdeHaro

    6 жыл бұрын

    By speed, do you mean feedrate? Because the number of flutes has absolutely nothing to do with RPM. I do have videos discussing both RPM and feedrate if you would like to check those out. The focus of this video was merely to show the different types of endmills available to the machinist and talk about their typical use.

  • @mavigogun

    @mavigogun

    6 жыл бұрын

    Spindle power-dependent feed rates. My reference, speaking to wood applications, suggests gross approximations, without consideration of nuanced application, of around 1,800-2,000 IPM to keep 4 flute tools happy, 900-1,200 for 3, down around 600 IPM or less for 2- and that running 4 flute tools at lower feed rates resulted in overheating due, as I recall, to chip loading/evacuation rates and cooling. Thanks for the reference to your other work- I'll check it out. I'd rather not carry around misapprehensions- so if you recognize such, please say so.

  • @jonathanbrooks1832
    @jonathanbrooks1832 Жыл бұрын

    I guess nobody else has ever heard of through coolant? Wtf.

  • @malnfc8565
    @malnfc85655 ай бұрын

    HSS endmills 🤢

  • @Sachinkumbharjsp
    @Sachinkumbharjsp3 жыл бұрын

    Very informative! Thank you!