You're very good at teaching. I don't know how many times I've tried to understand diametral pitch, but I finally got it. Thank you! And same with pressure angle. Thank you again!
This is an older video but it is the best one I have seen on setting up a dividing head on UA-cam. Thanks so much for making it and you teaching style is superb.
I just got the last component that I need to make the gears that I want for a project and the gears that I want to make to help some fellows out with transposing metric gears on their old American made 10 inch lace I wanted to help them out cuz people charge so much I'm going to do it for free I know people think that stupid but I will learn something and be giving back to the community at the same time it's just what I want to do. I'm sure there's plenty of people out there willing to buy gears that will never even hear about me so I won't be stepping in too many people's toes After watching how meticulous you are with the mathematics I decided I'm going to go buy a whole bunch of nylon from alro steel or maybe delran I don't know in practice on that so I don't wear out any gear cutters on steel. I have a very small dividing head it's the medium size Chinese one which is still very small if I would have saved up all this time I could have bought a very nice old Browning sharp or some other old nice american-made dividing head by now but live and learn I will save my money toward that end going forward. Machining is so expensive I just bought an arbor press That's too small and I held on to it for too long to even return it live and learn live and learn empty your pocketbook living learn
What a coincidence. I just set up my rotary table to cut a couple of gears tomorrow. So I used your video to check what I was doing. Only difference is my rotary table is 90/1 ratio and the DP I am cutting is 16. I have a wonderful cheat though. My rotary table came with a manual that shows the settings for most numbers of gear teeth and I can just follow the chart. Thanks for the video.
Es lo mejor que he visto hasta ahora sobre el tema; muy bien explicado, muy didáctico y de inestimable ayuda para quienes enseñamos diseño de engranajes a alumnos secundarios. Muchas gracias!!!!
@@LESPRODUCTIONSMAL Thanks a lot, Marc. I am pleased to contact you. I am Mechanical Engineer and teach these issues in Technical Secondary Schools, adding to it my personal experience in companies. Best Regards from Rosario, Argentina!
Hi Marc; on the dividing plate, we should think number of spaces not number of holes, sometimes holes gets confusing. I think you taught me that on another lesson or was it Mr. Pete?
I was just curious as to how it was done. for a long time I thought the the tool was going to cut from a front profile (don't ask why, or how that would even work) But I totally understand now. Very cool
Thanks Marc excellent video, one thing ive never seen is how to use a gear mic would this be the same use as the wires in gear making or am I way of track?. thanks Jeff
Hi Marc, another very useful video, thanks! I'm hoping you or a viewer can help with a related question. I have an older used lathe that came with a badly trashed quick-change gearbox. I'm interested in rebuilding it, and I'm sure I'll have to cut the gears myself. I'm having trouble figuring out the P formulas for the gear clusters. There are several clusters and shafts, but I'll describe one group to illustrate my difficulty. There is a group of three gears 38T, 40T, and 36T on a splined intermediate shaft, and this group can be shifted so any of the three gears can mesh with a 30T on the input shaft. Naturally the two shafts are parallel at a fixed distance, so it seems like the cluster of three must have the same Diametral Pitch (P) if they are going to mesh with the 30T driver. But if they all have the same P, then they will have different Outside Diameters (Do). Different by about 0.2" in fact. This would prevent them from shifting. And in fact some of the gear clusters are in good shape, and the gears in each cluster have the same Do. So on the other hand, if the gears in this cluster have the same Do, then all three will have a different P. For this group, that's Diametral Pitches of 20, 21, and 19. As far as I can find, only the DP20 cutter is available. Am I correct in assuming that I'd use a DP20 cutter for all of these gears, and just make the 40T and 36T "close enough?" Or am I missing something? Are there some secret tricks to make this work out?
Hi! The diametral pitch (tooth size) must be the same for gears that will mesh together. If two gears have the same diametral pitch but not the same number of teeth, they cannot be the same size (outside diameter). A few pictures could help me wrap my head around your problem. If possible from different angles including the shafts and gearbox. Thanks for watching and for taking the time to write, Marc.
HEYYYYYYYY! I keep one of these 3 million dollars toys under my bed... let me deploy it! Thanks a lot for all the educative shtuff... fun to watch! Huhh! ...you forgot to wipe off any minute shavings that might have landed on your littul guide on the dividing head... your division could be off by a catastrophic error and there goes your transmission!
Hi I’m trying to cut a spur gear mod4 18 teeth I’ve cut gears before no problem but after two gear cutters later I seem to keep get the same problem again and again the bottom part of the cutter is ok but the top gets its shoulder knocked off check everything out square and all Usual thing just can’t put my finger on it any advice would be great full
Thank you so much for all your time. My 30th edition of Machinery's Handbook says to find the Diametral Pitch of a gear by, dividing the number of Teeth by the Diameter of the gear (P=N/D). Now, every other video I watch says to find the Pitch by "adding 2" to the number of teeth then dividing by the gears diameter (P=N+2/D). This has me confused. I'd like to try my hand at making tumbler/ reversing gears for my little Atlas 618 lathe. 20N x .915Do and 24N x 1.075Do (These are worn and broken gears). Can anyone share some insight on this?
Late answer here, and I'm no expert. But anyway, as I understand it, P=N/D is Diametral Pitch, where N is number of teeth and D is Pitch Diameter. Pitch Diameter is NOT the Outside Diameter, it's a smaller circle that indicates approximately where the gear teeth contact the teeth of the meshing gear. The formula you gave is correct, but is usually shown as D=N/P (same thing). The second formula is wrong. You need to change D to Do, Outside Diameter. That's the full diameter of the gear across the crests of the teeth. Looking at the corrected formulas, you'll see that Do must be larger than D, which makes sense. See the first formula on Marc's whiteboard. Do=(N+2)/P.
The easiest way is to compare the teeth to gear cutters or another known gear, you could also measure the gears teeth width (at the pitch circle level) and total heath (this includes the clearance in the bottom this second method will give you the DP. For the pressure angle you will need an optical comparater. I hope this helps? Marc
Hi Marty! Climb milling gives a better finish and imparts less force on the part so it is a more accurate way of cutting. However it is a dangerous way for cutting so make sure you have a backlash eliminator of some sort. Some were in my videos I explain about climb millings advantages and disadvantages but I am having trouble finding witch video it is? Anyone out there remember the video? If not I will have to produce a little quickie video on the subject. Thanks for watching and be safe!!! Marc
THATLAZYMACHINIST so if I've no backlash adjustment on my mill table feed, there's no problem with conventional milling as long as the finishing cut leaves a good finish ?
Hi Kris! It all depends on how confident you are. If you are unsure of your indexing, the first cut could just be a skim (a couple of thousandths) in order to make sure that a full turn of the part will actually bring you back to your start point. If you are confident about the indexing, I would take a first cut that would be 0.010" to 0.015" from full depth of cut calculated. This will leave you enough material to measure over wires, determine the exact amount needed for the last cut and take your finishing cut. Two passes should do it if you are well prepared. I hope that this answers your question, and thanks for watching and for taking the time to write, Marc. P.S. I may add this question to my next Q&A video (coming out today or tomorrow)
THATLAZYMACHINIST wow that was a quick detailed answer!!! Thanks for the answer, you got great in depth explanations on your videos! I will keep watching your videos, hope you make more!
Now this is a late response (sorry)!!! In the Machineries Handbook there is one chart for even number of teeth and one for odd number of teeth. For even numbers you put your wires opposite one another and for odd numbers you put them as close to opposite as you can. I hope this helps and sorry for the late response
This is one of the best explanations of gear cutting that I have seen on UA-cam.
You're very good at teaching. I don't know how many times I've tried to understand diametral pitch, but I finally got it. Thank you!
And same with pressure angle. Thank you again!
This is an older video but it is the best one I have seen on setting up a dividing head on UA-cam. Thanks so much for making it and you teaching style is superb.
Thank you for your video. This is probably the most comprehensive video on spur gear cutting on the internet.
I just got the last component that I need to make the gears that I want for a project and the gears that I want to make to help some fellows out with transposing metric gears on their old American made 10 inch lace I wanted to help them out cuz people charge so much I'm going to do it for free I know people think that stupid but I will learn something and be giving back to the community at the same time it's just what I want to do. I'm sure there's plenty of people out there willing to buy gears that will never even hear about me so I won't be stepping in too many people's toes
After watching how meticulous you are with the mathematics I decided I'm going to go buy a whole bunch of nylon from alro steel or maybe delran I don't know in practice on that so I don't wear out any gear cutters on steel.
I have a very small dividing head it's the medium size Chinese one which is still very small if I would have saved up all this time I could have bought a very nice old Browning sharp or some other old nice american-made dividing head by now but live and learn I will save my money toward that end going forward. Machining is so expensive I just bought an arbor press That's too small and I held on to it for too long to even return it live and learn live and learn empty your pocketbook living learn
What a coincidence. I just set up my rotary table to cut a couple of gears tomorrow. So I used your video to check what I was doing. Only difference is my rotary table is 90/1 ratio and the DP I am cutting is 16. I have a wonderful cheat though. My rotary table came with a manual that shows the settings for most numbers of gear teeth and I can just follow the chart. Thanks for the video.
Brilliantly explained - easy to follow the mathematical calculations. Great instructional video - Thanks. John 🇬🇧
Truly lessons for the beginner like me another lesson learnt excellent video thank you Marc
Es lo mejor que he visto hasta ahora sobre el tema; muy bien explicado, muy didáctico y de inestimable ayuda para quienes enseñamos diseño de engranajes a alumnos secundarios. Muchas gracias!!!!
@@LESPRODUCTIONSMAL Thanks a lot, Marc. I am pleased to contact you. I am Mechanical Engineer and teach these issues in Technical Secondary Schools, adding to it my personal experience in companies. Best Regards from Rosario, Argentina!
Excellent video as ever. Thanks for the lesson
added to my watch later vids' Ive to cut some spur gears in the near future - thanks Marc.
Hi Marc; on the dividing plate, we should think number of spaces not number of holes, sometimes holes gets confusing. I think you taught me that on another lesson or was it Mr. Pete?
Mr. P did do a particularly good vid on dividing plates. That was a few years ago.
Thank you so much….This video was awesome
I was just curious as to how it was done. for a long time I thought the the tool was going to cut from a front profile (don't ask why, or how that would even work) But I totally understand now. Very cool
Excellent video.
Thanks Marc excellent video, one thing ive never seen is how to use a gear mic would this be the same use as the wires in gear making or am I way of track?. thanks Jeff
Hi Marc, another very useful video, thanks!
I'm hoping you or a viewer can help with a related question. I have an older used lathe that came with a badly trashed quick-change gearbox. I'm interested in rebuilding it, and I'm sure I'll have to cut the gears myself. I'm having trouble figuring out the P formulas for the gear clusters.
There are several clusters and shafts, but I'll describe one group to illustrate my difficulty. There is a group of three gears 38T, 40T, and 36T on a splined intermediate shaft, and this group can be shifted so any of the three gears can mesh with a 30T on the input shaft. Naturally the two shafts are parallel at a fixed distance, so it seems like the cluster of three must have the same Diametral Pitch (P) if they are going to mesh with the 30T driver. But if they all have the same P, then they will have different Outside Diameters (Do). Different by about 0.2" in fact. This would prevent them from shifting. And in fact some of the gear clusters are in good shape, and the gears in each cluster have the same Do.
So on the other hand, if the gears in this cluster have the same Do, then all three will have a different P. For this group, that's Diametral Pitches of 20, 21, and 19. As far as I can find, only the DP20 cutter is available. Am I correct in assuming that I'd use a DP20 cutter for all of these gears, and just make the 40T and 36T "close enough?" Or am I missing something? Are there some secret tricks to make this work out?
Hi! The diametral pitch (tooth size) must be the same for gears that will mesh together. If two gears have the same diametral pitch but not the same number of teeth, they cannot be the same size (outside diameter). A few pictures could help me wrap my head around your problem. If possible from different angles including the shafts and gearbox.
Thanks for watching and for taking the time to write, Marc.
@@THATLAZYMACHINIST Thanks for your help. I have some photos - I sent an email via your website.
It's a real Catch-22...
HEYYYYYYYY! I keep one of these 3 million dollars toys under my bed... let me deploy it!
Thanks a lot for all the educative shtuff... fun to watch!
Huhh! ...you forgot to wipe off any minute shavings that might have landed on your littul guide on the dividing head... your division could be off by a catastrophic error and there goes your transmission!
Great Vid. Thanks Marc!
Sir, Please one lesson for Helical gear and Lead . Thank you.
Thank you excellent explanation on the math
Hi I’m trying to cut a spur gear mod4 18 teeth I’ve cut gears before no problem but after two gear cutters later I seem to keep get the same problem again and again the bottom part of the cutter is ok but the top gets its shoulder knocked off check everything out square and all Usual thing just can’t put my finger on it any advice would be great full
Thank you so much for all your time.
My 30th edition of Machinery's Handbook says to find the Diametral Pitch of a gear by, dividing the number of Teeth by the Diameter of the gear (P=N/D).
Now, every other video I watch says to find the Pitch by "adding 2" to the number of teeth then dividing by the gears diameter (P=N+2/D).
This has me confused.
I'd like to try my hand at making tumbler/ reversing gears for my little Atlas 618 lathe.
20N x .915Do and 24N x 1.075Do (These are worn and broken gears).
Can anyone share some insight on this?
Late answer here, and I'm no expert. But anyway, as I understand it, P=N/D is Diametral Pitch, where N is number of teeth and D is Pitch Diameter. Pitch Diameter is NOT the Outside Diameter, it's a smaller circle that indicates approximately where the gear teeth contact the teeth of the meshing gear. The formula you gave is correct, but is usually shown as D=N/P (same thing).
The second formula is wrong. You need to change D to Do, Outside Diameter. That's the full diameter of the gear across the crests of the teeth. Looking at the corrected formulas, you'll see that Do must be larger than D, which makes sense. See the first formula on Marc's whiteboard. Do=(N+2)/P.
Amazing video ❤️
Excellent, thank you.
good job 👍
hi
can talk metric system, is it the same or different.
thanks
do you need to lock the sector arm ,after adjustment ?, I didn't se you do it
Yes! It is important that their adjustment stays the same as they are rotated around the hand wheels shaft.
Good work, sir. Nice reuse of stock footage
how do you find the dp and the preasure angle mark.
The easiest way is to compare the teeth to gear cutters or another known gear, you could also measure the gears teeth width (at the pitch circle level) and total heath (this includes the clearance in the bottom this second method will give you the DP. For the pressure angle you will need an optical comparater. I hope this helps? Marc
Marc, why climb cut the gear?
Thx.
Marty
Hi Marty! Climb milling gives a better finish and imparts less force on the part so it is a more accurate way of cutting. However it is a dangerous way for cutting so make sure you have a backlash eliminator of some sort. Some were in my videos I explain about climb millings advantages and disadvantages but I am having trouble finding witch video it is? Anyone out there remember the video? If not I will have to produce a little quickie video on the subject. Thanks for watching and be safe!!! Marc
THATLAZYMACHINIST so if I've no backlash adjustment on my mill table feed, there's no problem with conventional milling as long as the finishing cut leaves a good finish ?
Conventional milling will work just fine! Marc
What do u put in for your 1st cut?
Hi Kris! It all depends on how confident you are. If you are unsure of your indexing, the first cut could just be a skim (a couple of thousandths) in order to make sure that a full turn of the part will actually bring you back to your start point. If you are confident about the indexing, I would take a first cut that would be 0.010" to 0.015" from full depth of cut calculated. This will leave you enough material to measure over wires, determine the exact amount needed for the last cut and take your finishing cut. Two passes should do it if you are well prepared. I hope that this answers your question, and thanks for watching and for taking the time to write, Marc.
P.S. I may add this question to my next Q&A video (coming out today or tomorrow)
THATLAZYMACHINIST wow that was a quick detailed answer!!! Thanks for the answer, you got great in depth explanations on your videos! I will keep watching your videos, hope you make more!
Please make video machine maintanace
I'm still waiting for the part where you're lazy.
Excellent explanation except you didn't mention how to measure over the wires with an odd number of teeth.
Now this is a late response (sorry)!!! In the Machineries Handbook there is one chart for even number of teeth and one for odd number of teeth. For even numbers you put your wires opposite one another and for odd numbers you put them as close to opposite as you can. I hope this helps and sorry for the late response
Right at 16:14 is a picture answering your question