An explanation and demonstration of climb milling and conventional milling. Positive and negative points of each technique will be covered as well as examples of what can go wrong.
Hands-down one of the most informative pieces on climb- vs conventional milling. I accidentally clicked on this right before I was supposed to leave for a meeting, but was so impressed with it's depth of information, that being late was completely worth it. What a really, *really* great video and demonstration. To the point, clear, with immediate feedback, and you covered all the directions, angles and styles. I wish all such videos I've found online were this informative, and in such an impressively short time too. (I've learned less in hour-long videos.) Thanks for helping make me a better machinist.
I’ve been a Toolmaker for 22 years and today my son sent me a picture of his mill setup at his high school. I asked if they’re teaching them the basics like climb and conventional and he said no. I’m not a good person to explain with words so figured I’d do a quick search and your video came up. I’ll definitely watch it again with him as your explanation is far better than mine and the visual examples are excellent. Nice machine shop too. I’ve always wanted to have one but it’s hard to justify the cost when my employer allows us to use the shop for our own stuff on our own time. Thx again
Great piece Tom. This is the best explanation of why conventional vs climb milling finishes differ I have ever seen. Thanks for taking the time to educate us! Fred
+Toms Techniques! yes sir much better explanation and a helluva lot less expensive than using the bosses hi speed video / computer file set-up over at the tech lab. thanks tom. (i personally used a similar video set-up @ ITW / paslode fastener engineering dept. to observe how prototype 'roundrive' nails went thru a 'windowed' nose piece of a pneumatic nailer tool > kinda like trying to find a needle in a haystack searching the 'bazillions' of frames per second...)
This is THE best explanation of Climb vs conventional milling I have ever seen, and I have seen a few. I always new it was all about chip thickness but I never really visualised it as well as this.
Good explanation, I learned the same 40 years ago. Anyhow, in the modern machines with very little backlash climb cutting is always used, as it saves tool life and produces better surfaces.
This is great for a manual machine. You are spot on with all the issues and benefits. Additionally, on a CNC with ball screws and very little backlash, climb milling is best all around due to the better chip clearance and better surface finishes. As an added bonus, tool life also goes up with climb milling with light, fast passes (High Speed Machining or High Efficiency Machining) on a CNC.
Learned a lot, and your demonstrations (rather than just verbal explanations) make both the procedure and the results - desirable and undesirable - very clear. Super helpful. Thanks again.
Thank you for your video, just 18 minutes and now I "get" it. I went to school for a year, bought the textbooks, listened to the lecturer...but it never really sank in. Watching you explain things in action though, now it makes sense! Again thank you, you earned a new subscriber.
That is the best description i have heard explaining conventional vs climb milling. I had never thought of the chip formation. Great video. Thank you for taking the time to make, edit and post this.
Thanks, Tom, have zero training on a milling machine I basically have taught my self, though not always with good results as you just demonstrated. I could see the surface finish differences and the mill talking back to me but never knew why. You have made it all make sense!
this is a much more interesting point than what my teacher told me in school, all he said was climb milling wears out your cutting edge faster, conventional makes it last longer, so always conventional mill, but now I see I should do conventional for rough milling, and climb for the last fine cut, cheers!
Sounds like your teacher needs to go back to school. In theory, climb milling should wear less than conventional due to more rubbing when entering the cut.
As someone that is still new to machining with a mill I learned a lot from this video. I had a part climb out of my vice as you describe around the 13 minute mark and did not know what I did wrong but your explanation and example really put everything into perspective. Thanks.
Nice job Tom. I think of it as scooping, conventional..... and clawing, climb milling. What I didn't know was the physics of how and why one worked better than the other depending on the finish you were working toward. That lesson was presented really well. Thanks Tom.
Wow that was a great explanation. Thank you. Before this video I understood why climb milling grabbed the part but not why the surface finish was better. Thank you for clearing that up.
Thanks for the clear explanation as I am new to the game getting started in all of this at a late age in my life and can use the wisdom of those that have been in the game for a long time like you.
Thanx Teach! Like I'm back in school, but the fun stuff, like auto or wood... or metal/machining (the one my school lacked). I like your way of describing, really drew me and made the lesson fun. I really hope they bring back more tradesman schools here in Cali. Thanks again, now I have to watch the rest of your videos.
That's good to hear. It's been a long time since I taught in a classroom. Once manufacturing starts coming back to the country, so will the "fun stuff" in education. Tom
Great Video! This is a lesson I learned the hard way, back when I was just out of high school at my first machinist job. I actually broke the Y-Axis shear pin and slammed the whole table to the end of the Way. I knew not to hog climb cut but as kids do, I just wasn't paying attention that moment... I've been a Toolmaker for 20 years, It NEVER happened again!
Nice job explaining the difference in milling directions. If you don't mind, I would like to offer a couple other points. Another reason that the conventional cut makes a crappy finish is that it drags chips that adhere to the cutter back into the fresh cut surface. These chips get wedged and smeared under high pressure embedding them in the otherwise smooth surface. If you use a lubricated air blast you will get a much better finish conventional milling. Plunge milling on an edge can have the same consequences as climb milling. Always pre-load the leadscrew counteracting the cutting force as well as using the lock screw on the table slide. One other point is that you should always check the tram (squareness) of the head and square of the vise after a climb milling crash. 9 times out of 10 something will have moved. By the way, mills have adjustments on the backlash of the leadscrew nuts. You should be able to get the backlash down to less than .005" pretty easily if the screw itself is not badly worn in the middle of it's travel. This small backlash will make quite a difference in not grabbing a part when climbing.
+David S. Thanks David. All good points. The amount of backlash is only a problem if it's ignored. Proper tool overlap, feed direction and use of table locks will keep it from becoming a problem. Tom
Good vid there Tom... as an aside, anyone getting into woodworking and more specifically, using a router... the same theory applies.... except you should NEVER climb cut using a handheld router or even a table-mounted router. ALWAYS use conventional cutting when routing... 😎
I retired with 34 years machine shop experience, with at least half of the years being a Milling machine specialist- meaning my entire work day was using Milling machines. A couple of additions I'll make is that the conventional Milling pull on the cutter can actually undercut the metal being machined. If the operator checks a part thickness and notes there's for instance, .200 of material left to remove and in turn positions the table to remove .200, the resulting cut cut may actually take off more than .200. This is because the conventional cut will "pull" the cutter into the material being machined. This result is compounded when using a long narrow cutter that bends easily. The operator may have a layout line on the top of the part but after the conventional cut completes, the bottom of the machined part thickness may be undercut while the top layout line is still visible . This is because the cutter bends in at the bottom during conventional cuts. The opposite occurs with climb cutting - the bottom of the cutter is deflected off of the part - resulting in a tapered thickness with the bottom being thicker. If one made a climb cut pass to the layout line on top, the bottom of the part may be thicker. If the operator floats the cutter back across the part in a conventional direction, the bottom of the part may be undercut. This will all vary with the length and diameter of the cutter along with how much material is being removed in one cut. Aircraft machine shop.
Good points. End mill deflection is why I always square up parts by end milling rather than side milling. I retired recently as well after 45 years of making chips, and guess what? I'm still making chips. At least I'm doing for myself now instead of someone else.
Great video! I would always use a two fluted end mill when machining aluminum! Chips wouldn't load up and better finish! Coolant and or continuous air blast always helped!
Hello TOM All the best for Your 2016. As always, we have improved on the sum of our Machining skills with this great explanation and presentation. Did not realise the difference when U did that "squaring the Block" Video. It clearly shoes the difference on the Burrs here. Fantastic stuff. Keep 'em rolling aRM
+aR M Thanks. The burr thing I do without thinking because I've been doing it for so long. It wasn't until someone called me out for not deburring the part that I realized that it wasn't obvious what I was doing on the video. Tom
+Bleu Wolf Yup. I wanted to show how much backlash was in the table before taking the cut, but I couldn't move the table by hand. The cutter had no trouble moving it. Tom
Thank you for the reply Tom. I am making my own locks(for small boxes),and the stainless steel parts i'm machining are the moving parts of the mechanism. I was under the impression that 304 Grade was easiest to machine.
+Alan Jackson 304 is good for welding and fabrication (sheet metal work), but it doesn't machine well at all. If you have a lot of machining to do and haven't started yet, I would definitely recommend using 303 instead. Tom
Very good description, but the camera threw me as it looks like the tool is moving and not the part. So I have to confess and say either you are drawing it wrong or I still have not got it ( the money is on me being wrong ). I will have to do some more searching on this subject, I always thought that if the work moves in the same direction as the spin of the tool ( with regards to the cutting edge ) then you are Climb Milling, but you look to be drawing it the other way, so I am really confused now, but I have to say I watch your videos a lot, you have always given me good advice, I like it keep it up, thank you very much.
If the feed rate and spindle speed remains unchanged, They also produce different SFPM speeds because one direction the travel is adding to the attack speed, the other way it is subtracting from the attack speed.. Great Video !!Thanks !!
Perfect explanation, thanks Tom.. I have a light smaller machine and everything I was reading was to use climb (even the default setting in fusion 360 for gcode) now knowing this I will try conventional for my rough cuts and climb for finishing.. Thanks
Good demo! Think of this same principle next time you see a large milling machine on a road construction job doing profiling and milling. In 1975 when these machines started hitting the market they were lighter and set up for the cutter wheel to rotate down with the machine moving forward just like climb milling and it would grab and propel the machine forward and make a mess out of the profile. We mechanics out in the field got together with the manufacturers and soon changed the rotation of the drum and configuration of the cutter teeth to make it an up cut (conventional milling) and to this day is still used to make it a more stabilized cut. Same principals-Different trades with many similarities. Thanks for the flash back. Ed K. Cleve. Oh. AKA-DoneWrenching.
Very cool Tom! I am healing a dislocated wrist and guess I will get back to the shop. I can't stay away :) I Don't want to over step but, like a drawing, multiple views can sometimes describe a full idea. Your explanation of climb/conventional, push/pull and such is awesome. Simple and to the point! This comment is more for finishing. As for all cutting efficiency I also think of materials as having a skin and the sharpness of the cutting edge is directly related to the starting cutting pressure of conventional. Where the "bite" distance to get under that "0" thickness increases with conventional compared to climb. To exaggerate a tool with a little "shine" on the edge or if we look real small and consider it to be a slight micro radii can cause that pressure until the cutter lip is at least that deep into the material. Unfortunately with end mills this is constant. Plus the chip evacuation of the trailing side of side climb cutting helps better than "chopping through the chips that were already cut once. Thank for a great basic, easy to understand visual on this. It makes me want to get yet another camera. Climb when ever possible within reasonable time and cost is what I aim for. Thanks again
I can't find what I was talking about. Thanks Tom I will keep watching and if I figure out what I was talking about ill let you know. Keep up the great work.
I can not admit that you gave me a uniform surface, at least from what image allows me to see, through the reflection of light! I think it would be good to clean the metal nuggets with a brush ....
Just read about this in our machinist trade theory book. "Read" not hands on... we read about this and tested on it. Not qual'ed to run a milling machine yet. THIS IS THE TYPE OF VIDEO WE APPRENTICES NEED TO WATCH!
Thank you Tom for making the difference between both types of milling so clear. Is there any specific reason that you didn't use the term, 'hook milling' in association with your thorough coverage of the processes? Is it fairly common to also call climb milling, hook milling, or has the expression become archaic in the machine shop? Great video Tom, thanks again!
You narrate good when I do videos I am a stumbling narrator. Anyway a couple of things to point out to people new to machining when coming up to a workpeice like he was showing that be aware that theoretically any time the cutter enters the part you have a zone in which you are climb cutting which can cause trouble because you may crank to the left and go to town hogging off conventional from left to right--but there is a problem that when you enter the part it can and will slam the table in the Y possibly crashing a bit. I myself sometimes use the lock thing but not aways I just am aware of it and cautious first starting out if you have a long length of cut and a huge cutter. Using a small cutter almost all of the climb/convential grabbing goes away especially at the higher rpm. Also on the TOP finish people should be aware that a square end mill like that you should use a diamond lap and stone a micro radius or micro chamfer on there before using it the first time. A dead square sharp cutter the tiny corner breaks off anyway microscopically in the first seconds. Another reason the small radius or chamfer is a must is that with dead square cutters you will get "breakout pits" in the workpeice because the very final cut there can be a tiny island standing that then breaks off and does not cut. Also the EDGE will do that sometimes very bad with some materials. With a radius insert or cutter or also a chamfer all that goes away because the final tit is a cone which gets smaller and smaller and is gone. eze lap makes excellent diamond laps for that purpose that last forever. When stoning on the radius you will get better finishes cutter lasts longer etc. To grind it on it does take an optivisor and skillful tilting of the lap so as to put the micro radius on WITH SOME CLEARANCE--You thus will be stoneing a microscopic cone. Untill you gain the skills best to do a micro chamfer of about .005 or so.
Quick comment on the whiteboard demo of chip shape and finish near the end of your video. This was explained to me via whittling wood with a knife. Imagine trying to whittle a chip that starts thin and get's thicker! Most whittling is 'climb whittling', and you may find that your 'vise' hand gets tired more quickly than your 'tool' hand. The analogy is a bit weak, but it made sense to me when I was ten, ha! :)
I haven't done much whittling, but it sounds like you may have it backwards. When climb milling, the chip starts out thick and finishes up thin. I suspect whittling is the other way around. Tom
nice. I just bought a Mill bracket for my lathe, the bracket has a vice that keeps the work piece in place. and a 5.5 mill cutter. to mill a groove in a steel cylinder. I got the "climb milling" effect pretty fast and it broke the cutter snap off. I wear safety glasses when doing this . Conventional milling is what I need to do. The rotation needs to be so the flutes throw the chips out toward the high uncut profile. Chips can not be trown out the already cut profile side, making it a climb mill .
+Bill De La Vega Thanks Bill. I wasn't sure how that was going to look, but I thought I'd give it a try. It was a lot easier than hanging the camera off a tripod over the mill. Less scary too. Tom
+the russian machinists For the record, this is the only end mill I own that won't completely fit in the collet. I would hate to cut it off and then have the need for one with a long reach. Maybe it's time to bite the bullet and just buy a holder.
Tom you are the man but i will call you out on using a pined stationary jaw. Your stationary jaw is is held w/ a square peg which is subject to moving due to vibration. Solid back vices are always better (especially for demonstration)
