How do I make my own gear hobs? (Gear cutting)
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- Опубліковано 15 жов 2021
- This is the method I use to make my own gear hobs for use with my gear hobbing attachment. These can then be used to make spur and helical gears, toothed pulleys, splined shafts, etc.
Music used in this video: 'Industry' by 'E-Shine' eshine.bandcamp.com/music - Наука та технологія
That was the clearest, most concise explanation of basic gear theory I have ever seen.
A book's worth of knowledge in thirteen minutes. Thank you.
Excellent! 25 years in a machine shop and I now know more about hobbling than ever.
Nicest explanation,thank you my teacher,....this trick is for my retire,if my wife will permits to take my my mill and lathe in garage
Thanks for going through the theory on gear design and gear standards, this is very helpful for understanding the engineering behind the standards.
Now I learned the basic of gear making, thanks for sharing this video…
You are a teacher more than a machinist ..thank you sir for sharing your knowledge.
Best video ever. I'm not kidding. Thank you for ALL the details!
Whelp... this is just the first of MANY times I'll be watching this.. So much valuable info here. Awesome work! Thank you!
Goes to show how important mathematics truly is. Thanks for sharing such an awesome video!
Awesome video, everthing was very well explained. Now I need to watch the other video about the build of the gear hobbing attachment.
Thanks for going through all the calculations, makes the process even more interesting when you can get a better grip on it!
Thank you and Greetings from Florida USA 🇺🇲😎
I like your funny words magic man. But seriously, as a plumber who will never have to touch a lathe or mill to make a gear in my life this was cool
Thanks Andy, Learning a ton
WHEN YOU KNOW YOU KNOW > You are an expert on this feild
Probably the best video on hobbing I've seen. Thanks!
Geezus F*CK that was more than I anticipated. Well, it appears I'll be purchasing my own hobs because for my application, I certainly don't have the necessary tools nor the precision mathematical abilities to do so. WOW my friend, you have garnered my complete respect, and also, admiration in the time you spent in creating this video. I applaud you.
...................now this is the way to help ourselves in the '' real World'' my friend.
Knowledge shared is a treasure we need to grow as a whole, Humanity must have people like you. [ good heart and mind ] ready to learn others what to do...many thanks for this little gem. Let it flow, so others can grow.
Greetings from Holland.
This was a great video! Prior to watching this and the two attachment videos I understood that hobbing existed but not what it entailed, and I've come away with a great appreciation for the mathematics, planning and applications of the process.
I'm not a machinist, so it's always fascinating to learn about the techniques that are part of the manufacturing of precision components.
man this video is an example of QUALITY content please keep making these
Grüße aus dem Oberallgäu
fantastic video I been cutting gears 30+ years in work and I learnt something from it
Thank you
keep up the geat work
You, sir are an excellent instructor. I was so focused during the math bit, I think I fainted for a second or two🤯🤣
Wonderful explanation. Lots of time and energy went into this one!
You are actually good in metrology as well!
WOW!!! New subscriber here. I understand almost none of what I just watched. But I really wish I did.
This is BEAUTIFUL! What a wealth of useful information without the nonsense. Thank you for this! Subscribed!
Very good explanation and demonstration.
Well done, Sir. Well done. A veritable masterclass.
Thanks, a lot of knowledge wrapped up in this video - very helpful!
Very nicely done, Andy, very enjoyable-thank you very much ✅👍
My brain hurts lol no seriously you a genius love you videos , don’t think i will get to that level but it all helps me understand the process before i attempt my first gear thanks
Hello, Andy. I enjoy your relaxed and careful videos. Thanks for sharing! Stay Healthy!
Just watched the imperial version :) It makes me appreciate this video even more.
Brilliant work in After Effects; you've cleared up some long-standing uncertainty for me.
Interesting and very well presented. You have and amazing amount of knowledge.
Thank you
I think you don't take into an account something. I would prefer to be wrong here, but...
Consider making a spur-gear having PA = 20°. That means that the toothed rack complementary to such gear would have trapezoidal profile of tooth with also 20° angle between trapezium s sides and axis of symmetry.
If you going to cur the gear using the rack as a cutter, no problem: you have to move cutting rack towards the gear in direction parallel to gear axis. With the hob things change: to compensate for helical "nature" of gear hob, you make an adjustment of milling machine axis and you mention that at 11:30. Now projection of the cutting edge (of its contour) of the hob to imaginary vertical plane will differ from its real contour - it will be compressed in by vertical axis by the factor of cos(helix_angle). If the scaling transformation has different scaling factors on X/Y axes, that transformation does not preserve angles. Thus you'll get slightly decreased PA on your gear.
You probably don't notice that the gears you make have decreased PA because with helix angles as low as 5° or 10° the cosine of helix angle is ~ 0.99619 or ~ 0.98481 respectively, which means one-axis scaling to a factor of 99.6%/98.4%. So depth of the groove you cut isn't affected, but the width of the groove is about 1% less than required.
Also, if you making two gears that should couple to each other, they will mate perfectly even if it's PA angle is unintentionally decreased. However, you are getting non-standard and modified profile of your gear teeth, so it won't mate perfectly with the gear manufactured somewhere else.
However, all this considerations become not actual if at the stage of thread cutting (07:17) you tilt you cutter by the angle matching the helix angle of you thread. Which isn't the case as far as I can see.
That's a very astute observation and clear description of this effect!
Yes, you are correct, the tilt of the hob does affect the pressure angle of the gear it generates. This is known as 'cosine error', though in this case the effects are so small that I've never felt it necessary to correct for them as they will likely be swamped by other errors that are beyond the accuracy I can achieve.
This hob was tilted to an angle of 4°, commercial hobs are generally larger diameter than my home-made ones and are tilted to less of an angle, around 1-2°. The cosine of 4 is 0.9976 giving a pitch error of 0.24%. At 1° the pitch error is only 0.015%. A tilt of 4° would change the pressure angle from 20° to 19.96°. I don't think I can grind the cutter used to cut the hob to within 0.04° even if I do it on the lathe and set the compound slide very carefully with a dial indicator. Also when I screw cut the hob I am not able to reproduce the module thread with an accuracy better than 0.2% on my lathe due to limitations of the leadscrew and change wheels.
Also as you say, if I cut mating gears with the same hob then they can actually have quite large deviations from the pressure angle I was aiming for and they will still be perfectly matched to each other.
However it is still useful to know about this effect and good that you pointed it out, as for example I can try and make the cosine error of the hob and the screwcutting pitch error cancel each other out rather than both adding up in the same direction.
Thank you for an excellent explanation!
Shows how useful math can be...
Geee whiz what did I just look at. Got to love it because I think I just nailed the national standards test for the 2nd year mathematics of senior high school again, this time in one single 13,14 min sitting.
Fantastic video and a great explanation of how to measure and figure out gear math!
Love it. Thank you so much for sharing this
Great reference video we're saving for future use thank you.
Man, that was GOOD!
Great,amazing Video!
Absolutely superb presentation. Thank you :)
Great video, probably the best reference on the subject
I think I sprained a frontal lobe.
Yea
very impressive but with all those calculations I can understand why some people prefer to save up and buy a commercially produced one.
Surely not! The maths takes a fraction of the time that the machining takes. Buying cutters is a good idea if you're "cash rich and time poor", but if you have the time to make them, don't let the maths put you off. :-)
Well said,@@cooperised The maths and theory behind it isn't actually that hard once you start looking into it, but I think a lot of people are put off by the very idea. It's also good to know this stuff if you never even make your own cutters as it's gives you a better understanding of how commercial ones work.
LOL. I am at the opposite spectrum. The math doesn't scare me but actually trying to machine it does.
That's awesome! I have an old CNC lathe that the control didn't work and used LinuxCNC on it. It's really great at threading and can cut any thread, inch, metric or anything else. I'm thinking that it would be great for making hobs with the odd spacing on hobs for DP gears. I love it that one hob can replace a whole set of gear cutters. It would even be possible to put a hobbing attachment directly on the CNC lathe and synchronize with the spindle that is already encoded.
I think this was the best hobbing video I’ve seen. Nice work!
Super interesting! Well done - excellent work
ToT needs to try these
Excellent, highly informative video!
Thanks, After watching this video I've decided to purchase all gears instead ;-) Great info here.
Super professional video!! Thank you very much dear man. Waiting for your next video
What a great tutorial, I learnt a lot, thanks
Thank you for this video. I haven't been able to find anything on UA-cam. I'm needing to make a batch of 3 DP 67 tooth gears for my work. This helped me immensely.
Wow! Those are pretty big gears!
If you need to make proper gears, buy a proper cutter. As impressive as this is, it's nowhere near good enough for a commercial product.
@@elanjacobs1 I'm not claiming my home-made hobs are as good as commercial cutters, and I'll always use a commercial one if I have the right size. But it is possible to make DIY cutters like this that produce results plenty good enough for most applications and at a fraction of the cost. I don't know what a 3DP gear hob would cost, but it's not going to be cheap!
@@AndysMachines it's a small batch of maybe 5 or 6.
I'm going to try and get a hold of some 6" diameter o1 tool steel for making the hob. Should work well enough if I take things slow.
Very very informative video. Thanks for sharing
Vote up, nice video, thanks for sharing :)
Спасибо Вам, буржуи! Теперь будем делать червячные фрезы по науке!
You are a friggin genius!!!
Wow, Excellent. Thank you.
Very interesting
Thank you
Impressive work
👍🎄
Excellent video !
Great video, really interesting!
Great video👌thank you for sharing
Gear profile good explain ⚙️⚙️⚙️
Great video
Thanks for sharing 👍
Great job
Thank you vey much excellent explanation!
Very detail, thx 4 sharing.
You so amazing about your diy tools
Nice and weary interesting video. Thank you
Great vid. Thanks!
This is a sound presentation. I have just learned the concepts of the module, addendum, dedendum, angle of pressure, the tip of width, and how to work them out.
Excelente conteúdo! Muito agradecido por compartilhar. Inclusive a parte das fórmulas.
Loved the video!
Thanks
Great video!!
love this - thank u for sharing
Stellar Work A Solid 10/10
just amazing
Brilliant!
Очень полезное видео.Всё показано детально и доходчиво.Большое спасибо.
Very easy to understand gear calculation tutorial. Nice video👍
Thanks for the investment and example
Well, know I know what those module and dp charts are for on the lathes. Neat.
Thanks for video learning
That is awesome!
Thank you very much
Good Job :)
Amazing!
Very good 👍
Supreme Mathematics!
Awesome.
👌outstanding 👌
You just *won* a subscriber 😂
sweet, thanks for showing the cutter flat calculation!!! Not sure if you've checked out my video on cnc gear cutting without a gear cutter but I was hoping to find this calculation and now I can update my simulator!
Yes, I did see your video in the past. That's actually a very accurate way to generate gears as you are taking a large number of individual cuts to generate the involute profile. I used to do something similar using a 'hob' with no helix, like a series of stacked discs with a rack-like tooth profile and cutting on the side of the blank, indexing by one tooth at a time produced fairly good profile, and then you can take additional cuts with the 'hob' at different heights.
Math requires balls
Thank you !!! 👍👍