In this video I hob a 15 degree helical gear using The Home Hobby Hobber. Find part V here: • Home Hobby Hobber Part V Find part VII here: • Home Hobby Hobber Part...
Great series of developments. I built an stepper indexer for the "hard way" using a rotary table, but hobbing is the real way to do it. Subscribed, look forward to future stimuli.
I really enjoyed these videos. I always thought that it should be possible to do this with a vertical milling machine and the Arduino is a clever way to use cheap technology for precision work.
Love the hobber project. I've considered building something like this for years. I have a home brew CNC mill with Mach3 but I don't think Mach3 has provisions to synchronize the 4th axis with the spindle. I do have experience programming the Arduino and running stepper motors with same. The main issue I've had is where and how to attach an encoder. Where did you install your encoder?
Hi Greg Crigger, I need a little more information. Do you plan to ONLY do gear hobbing? Are you familiar with writing Arduino sketches and using Arduino Libraries? Will the lathe turn the hob or will it turn the gear blank? What will you use for the second "powered" axis? Can you write an app for a smartphone-based user interface or will you use an LCD and push-button switches? The size/complexity of your project will be determined by the answers. Cheers, F.C.
As one of many who are watching this space with baited breath, how are things progressing? Any chance of some advanced info regarding the encoder design? I need to make an encoder for my "touchdro" to use to get its tachometer info, and it makes sense to try to fit one that will perform multiple functions. Would you say your encoder design is past its beta stage yet :o) Just the number of pulses per rev will probably do for now, and I can get something suitable etched for my two shafts! ( I have a dual function vertcal/horizontal mill, so two motors need rpm info on my Elliott Junior Omnimil during normal operations. Are we aiming for a hob rotating circa 500 rpm and the blank endeavouring to match that at a suitable speed using an encoder/gearing ratio combo operating at 3200 steps per rev as the ideal?
Hi Roger, Sorry about the delay. I've been tied up working out a special cycle for cutting bevel gears and leaning a LOT. Regarding the encoder, I used very good, very versatile commercial rotary encoder, the ATM102 or ATM103 (differing only in the connector orientation). It has the somewhat unique feature of dip switch selectable resolution ranging from 48 to 2,048 ppr in single channel mode and 192 to 8,192 ppr in quadrature mode. I eventually settled for 3,200 ppr in quadrature mode which runs reliably at 400-500 rpm when cutting gears with 30 teeth and up. From 12 teeth to 20 teeth I set the resolution at 1600 ppr. to maintain reasonable torque from the work spindle motor and reasonable speed at the hob. For gears with 20-30 teeth I slow the hob down a bit.
I did notice the typo, thought it churlish to mention it. I am trying to find a similar encoder in the U.K. As the crap exchange rate plus import duties has taken the gloss of buying cheaper priced stuff from the USA . How are you fitting it to the quill as both ends of the shaft are used, unless you make something that fits it to the draw bar? I am ancient as well, and today, after taking some trial cuts with my new/old mill, I learned that I should have bought a decent milling machine 40 years ago.
Take a look at ruclips.net/video/fMY8zUs3bZI/видео.html, 0:20. It shows that the encoder is mounted remotely on the spindle motor mounting frame. The encoder is driven by a timing belt (the black one labeled "Gates") and turns 2x the spindle speed. This 2:1 gearing is for no other reason than I needed a large diameter pulley in order to clear the plate that engages the spindle drive splines.
F. Cleff: How are you establishing the rpm relationship between your 4th axis and your spindles speed? I know you say that you use a spreadsheet and refer to the machinists handbook. But I am still having some difficulty in getting this to work. We are doing it on a CNC at the school equipped with a 4th axis.
Hi Tim, This is done on a manual milling machine with simple/cheap Arduino controller for the work spindle (4th axis). The spreadsheet is only needed to size of the gear blank etc. Thanks for your interest. F.C.
I've watched all your videos,. really great,. you are the only one doing it this way. other people are doing it the traditional way with an indexing head and single cutter, or using a lathe and a tap. I just need the relationship between spindle and working axis, you don't share that except in the first video you set it to a 1:1 but say it's useless.
Hi Tim WOW, you watched all of them? Thank you for your interest. OK, here's how it works. A rotary encoder coupled to the quill spindle puts out 3,200 pulses per revolution. The stepper motor on the work spindle makes 3,200 steps per revolution. The basic ratio between the quill spindle and the work spindle is 1:1. To cut a gear the controller counts encoder pulses and outputs control pulses to the motor controller at a specific ratio. That ratio is 1/N were N is the number of teeth required. Think of it this way, if the controller put out a control pulse for every other encoder pulse the work spindle would turn at 1/2 the quill spindle speed. If it counted 3 encoder pulses for each output pulse the work spindle would turn 1/3 the speed of the quill spindle. So, if you want say 23 teeth, the controller counts 23 encoder pulses and then puts out a single control pulse. It's really that simple. Hope that helps some? Cheers, F.C.
Hi Tim, Yes, the relative speed of the hob and the work spindle is 1/N when using a single start hob. For multiple start hobs the ratio is dependent on the number of starts. Cheers, F.C.
Hi Tim, Just out of curiosity, what is the fastest RPM that your 4th axis can turn? I'm asking because the 4th axis CNC heads that I'm familiar with won't turn anywhere near 50 RPM because there is a substantial gear reduction (40:1, 60:1, etc. ) to increase torque and/or indexing precision. Just curious. Cheers, F.C.
So the hob will turn the work piece correct? so could you not just move your Y axis to the appropriate position, and then feed the x axis in, wouldn't the hob just drive the work piece, making the synchronized 4th axis unnecessary? for a worm gear, just work your way in from the top.
Hi David, Good observation. In fact, in his EXCELLENT DVD "Making Gears the Easy Way", (available from LittleMachineShop.com) Jose Rodriguez does very nearly that. But, as he points out, there can be some trouble getting the teeth started. So, he turns the hob spindle by hand until the hob is in mesh and the gear blank is tracking properly. Regarding worm wheel cutting (or plunge gear cutting in general) and "working your way in from the top", I had problems with that technique tracking properly. I think it's because the lead of the hob and the gear's circumferential pitch only mach at the pitch diameter of the gear. "Real" gear hobbing machines solve these problems (and many, many more) by keeping the hob and the gear blank in synchronicity . The "Home Hobby Hobber" is my humble attempt to eliminate or greatly reduce these problems and add a few features that expand the function beyond strictly gear cutting. Besides all that, I enjoy learning something new (programming, app building, PC board layout, etc.)
@@FCleff Interesting, Ive hobbed some worm gears before with taps(which is essentially a gear hob, at least as far as i can tell from the geometry), and yeah its hard to start. I wonder if you can first go in with a simple double angle cutter and cut teeth to start it using a dividing head. Im starting my own channel soon, and one of my projects is making some splined axle shafts, which is just gear cutting but with a 45 degree pressure angle.
@@davidfarmer Hi David, Interesting question on gashing or roughing out a worm wheel with a "simple double angle cutter". Well, here's my two cents worth. Number one, I think one would have to set the axis of the rotation axis of the cutter to the helix angle of the worm intended to mesh with the worm wheel. It's not a big deal but it's necessary. Number two, the simple cutter would need to be the same (smaller might work for roughing) diameter as the worm intended to mesh with with the worm wheel. Number three, the profile of the "simple cutter" ain't all that simple. I suppose that the cutter profile could be smaller in all dimensions than the finished tooth profile and then finished with a hob or tap in your case. Oh, BTW, where are you getting diametral pitch taps? ;-) It seems to me like a bunch of "extra" steps to me but whatever works, I always say. Anyway, good luck with your new channel. I'll check it out. Cheers, F.C.
@@gyrogearloose1345 Ive changed my mind, a tap does not have the same geometry as a hob. A tap has a taper to the profile at the tip, and a relief only along the taper. A hob has a consistent profile, and is relieved along the entire profile, also the peaks and valleys can have a fillet, or flat.
You are certainly combining some interesting content. I found your channel while looking for Quorn. I bought a completed Quorn but need to rectify errors and then after getting comfortable with it start upgrading. I just purchased an Arduino and cnc shield still to start on playing. Also purchased a Masso Cnc controller which hasn't been delivered yet. Check out DCT Teacher1 for details.
Hi Mike, Good luck correcting the QUORN errors. If you haven't done so already, I would suggest that you get a copy of Professor Chaddoc's machining, assembly, adjustment and operation book. Thanks for the heads-up on DCT TEACHER1 too. Cheers, F. C.
Hi Erick,Glad to see you have such confidence in me and this technique. This is a hobby for me but, playing amateur market researcher (along with amateur machinist and amateur programmer) for a moment, what is a complete, Bridgeport-compatible working " Home Hobby Hobber" worth to you? This would include: Controller (compiled code installed), 4th Axis assembly (ER32 collet spindle, tail stock not included), Y-axis motor/pulleys/belts/mounding structure, Rotary encoder/pulleys/belt/mounting structure, wiring cables, power supply, Compiled smart phone app. It would NOT include any source code, electrical schematics, user manual, warranty, liability on my part (signed hold harmless statement prior to delivery), customer service, field service, spare parts.F.C.
F. Cleff All I want is something easy to select spacing(gears most likely) without me going back&F with gears calculations. Whatever amount of teeth i need to cut just select and go as well be able to run helical gears and feed on the helix angles by a simple number of teeth to be cut and 4th axis cordinate with table servo/stepper motor. Not looking for electrical schematics, center etc(I do have all that)
Hi Erick, I hear ya and understand completely. Please understand that what you want is exactly why I designed and built The Home Hobby Hobber. That said, how much is it worth to you? Cheers, F.C.
Great series of developments.
I built an stepper indexer for the "hard way" using a rotary table, but hobbing is the real way to do it.
Subscribed, look forward to future stimuli.
Hi Ray,
Thanks for your interest and kind words.
Cheers,
F.C.
I really enjoyed these videos. I always thought that it should be possible to do this with a vertical milling machine and the Arduino is a clever way to use cheap technology for precision work.
Thank you, George. I appreciate the interest and encouragement.
Love the hobber project. I've considered building something like this for years. I have a home brew CNC mill with Mach3 but I don't think Mach3 has provisions to synchronize the 4th axis with the spindle. I do have experience programming the Arduino and running stepper motors with same. The main issue I've had is where and how to attach an encoder. Where did you install your encoder?
Hi Chuck,
Go to 00:19 of this video ruclips.net/video/fMY8zUs3bZI/видео.html. The encoder is mounted with a simple "L" bracket.
Cheers,
F.C.
I have been working on trying to do something similar with a lathe, my problem is the sketch for the Arduino, any help?
Hi Greg Crigger,
I need a little more information. Do you plan to ONLY do gear hobbing? Are you familiar with writing Arduino sketches and using Arduino Libraries? Will the lathe turn the hob or will it turn the gear blank? What will you use for the second "powered" axis? Can you write an app for a smartphone-based user interface or will you use an LCD and push-button switches? The size/complexity of your project will be determined by the answers.
Cheers,
F.C.
As one of many who are watching this space with baited breath, how are things progressing? Any chance of some advanced info regarding the encoder design? I need to make an encoder for my "touchdro" to use to get its tachometer info, and it makes sense to try to fit one that will perform multiple functions. Would you say your encoder design is past its beta stage yet :o) Just the number of pulses per rev will probably do for now, and I can get something suitable etched for my two shafts! ( I have a dual function vertcal/horizontal mill, so two motors need rpm info on my Elliott Junior Omnimil during normal operations.
Are we aiming for a hob rotating circa 500 rpm and the blank endeavouring to match that at a suitable speed using an encoder/gearing ratio combo operating at 3200 steps per rev as the ideal?
Hi Roger,
Sorry about the delay. I've been tied up working out a special cycle for cutting bevel gears and leaning a LOT. Regarding the encoder, I used very good, very versatile commercial rotary encoder, the ATM102 or ATM103 (differing only in the connector orientation). It has the somewhat unique feature of dip switch selectable resolution ranging from 48 to 2,048 ppr in single channel mode and 192 to 8,192 ppr in quadrature mode. I eventually settled for 3,200 ppr in quadrature mode which runs reliably at 400-500 rpm when cutting gears with 30 teeth and up. From 12 teeth to 20 teeth I set the resolution at 1600 ppr. to maintain reasonable torque from the work spindle motor and reasonable speed at the hob. For gears with 20-30 teeth I slow the hob down a bit.
Oops. That's AMT102 or AMT103. Also, I'm LEARNING a lot about bevel gears, not leaning a lot. I'm old but not that old, yet. ;-)
I did notice the typo, thought it churlish to mention it. I am trying to find a similar encoder in the U.K. As the crap exchange rate plus import duties has taken the gloss of buying cheaper priced stuff from the USA . How are you fitting it to the quill as both ends of the shaft are used, unless you make something that fits it to the draw bar?
I am ancient as well, and today, after taking some trial cuts with my new/old mill, I learned that I should have bought a decent milling machine 40 years ago.
Take a look at ruclips.net/video/fMY8zUs3bZI/видео.html, 0:20. It shows that the encoder is mounted remotely on the spindle motor mounting frame. The encoder is driven by a timing belt (the black one labeled "Gates") and turns 2x the spindle speed. This 2:1 gearing is for no other reason than I needed a large diameter pulley in order to clear the plate that engages the spindle drive splines.
F. Cleff: How are you establishing the rpm relationship between your 4th axis and your spindles speed? I know you say that you use a spreadsheet and refer to the machinists handbook. But I am still having some difficulty in getting this to work. We are doing it on a CNC at the school equipped with a 4th axis.
Hi Tim,
This is done on a manual milling machine with simple/cheap Arduino controller for the work spindle (4th axis). The spreadsheet is only needed to size of the gear blank etc.
Thanks for your interest.
F.C.
I've watched all your videos,. really great,. you are the only one doing it this way. other people are doing it the traditional way with an indexing head and single cutter, or using a lathe and a tap. I just need the relationship between spindle and working axis, you don't share that except in the first video you set it to a 1:1 but say it's useless.
Hi Tim
WOW, you watched all of them? Thank you for your interest. OK, here's how it works. A rotary encoder coupled to the quill spindle puts out 3,200 pulses per revolution. The stepper motor on the work spindle makes 3,200 steps per revolution. The basic ratio between the quill spindle and the work spindle is 1:1. To cut a gear the controller counts encoder pulses and outputs control pulses to the motor controller at a specific ratio. That ratio is 1/N were N is the number of teeth required. Think of it this way, if the controller put out a control pulse for every other encoder pulse the work spindle would turn at 1/2 the quill spindle speed. If it counted 3 encoder pulses for each output pulse the work spindle would turn 1/3 the speed of the quill spindle. So, if you want say 23 teeth, the controller counts 23 encoder pulses and then puts out a single control pulse. It's really that simple. Hope that helps some?
Cheers,
F.C.
Hi Tim,
Yes, the relative speed of the hob and the work spindle is 1/N when using a single start hob. For multiple start hobs the ratio is dependent on the number of starts.
Cheers,
F.C.
Hi Tim,
Just out of curiosity, what is the fastest RPM that your 4th axis can turn? I'm asking because the 4th axis CNC heads that I'm familiar with won't turn anywhere near 50 RPM because there is a substantial gear reduction (40:1, 60:1, etc. ) to increase torque and/or indexing precision. Just curious.
Cheers,
F.C.
So the hob will turn the work piece correct? so could you not just move your Y axis to the appropriate position, and then feed the x axis in, wouldn't the hob just drive the work piece, making the synchronized 4th axis unnecessary? for a worm gear, just work your way in from the top.
Hi David,
Good observation. In fact, in his EXCELLENT DVD "Making Gears the Easy Way", (available from LittleMachineShop.com) Jose Rodriguez does very nearly that. But, as he points out, there can be some trouble getting the teeth started. So, he turns the hob spindle by hand until the hob is in mesh and the gear blank is tracking properly. Regarding worm wheel cutting (or plunge gear cutting in general) and "working your way in from the top", I had problems with that technique tracking properly. I think it's because the lead of the hob and the gear's circumferential pitch only mach at the pitch diameter of the gear. "Real" gear hobbing machines solve these problems (and many, many more) by keeping the hob and the gear blank in synchronicity . The "Home Hobby Hobber" is my humble attempt to eliminate or greatly reduce these problems and add a few features that expand the function beyond strictly gear cutting. Besides all that, I enjoy learning something new (programming, app building, PC board layout, etc.)
@@FCleff Interesting, Ive hobbed some worm gears before with taps(which is essentially a gear hob, at least as far as i can tell from the geometry), and yeah its hard to start. I wonder if you can first go in with a simple double angle cutter and cut teeth to start it using a dividing head.
Im starting my own channel soon, and one of my projects is making some splined axle shafts, which is just gear cutting but with a 45 degree pressure angle.
@@davidfarmer Hi David,
Interesting question on gashing or roughing out a worm wheel with a "simple double angle cutter". Well, here's my two cents worth. Number one, I think one would have to set the axis of the rotation axis of the cutter to the helix angle of the worm intended to mesh with the worm wheel. It's not a big deal but it's necessary. Number two, the simple cutter would need to be the same (smaller might work for roughing) diameter as the worm intended to mesh with with the worm wheel. Number three, the profile of the "simple cutter" ain't all that simple. I suppose that the cutter profile could be smaller in all dimensions than the finished tooth profile and then finished with a hob or tap in your case. Oh, BTW, where are you getting diametral pitch taps? ;-) It seems to me like a bunch of "extra" steps to me but whatever works, I always say. Anyway, good luck with your new channel. I'll check it out.
Cheers,
F.C.
@@davidfarmer Yes, I've come across use of a dividing head and "gashing" the beginnings of teeth on the mill. See RUclips, good luck!
@@gyrogearloose1345 Ive changed my mind, a tap does not have the same geometry as a hob. A tap has a taper to the profile at the tip, and a relief only along the taper. A hob has a consistent profile, and is relieved along the entire profile, also the peaks and valleys can have a fillet, or flat.
You are certainly combining some interesting content. I found your channel while looking for Quorn. I bought a completed Quorn but need to rectify errors and then after getting comfortable with it start upgrading. I just purchased an Arduino and cnc shield still to start on playing. Also purchased a Masso Cnc controller which hasn't been delivered yet. Check out DCT Teacher1 for details.
Hi Mike,
Good luck correcting the QUORN errors. If you haven't done so already, I would suggest that you get a copy of Professor Chaddoc's machining, assembly, adjustment and operation book. Thanks for the heads-up on DCT TEACHER1 too.
Cheers,
F. C.
I'm ready to buy if you sell me one ready to work...
Hi Erick,Glad to see you have such confidence in me and this technique. This is a hobby for me but, playing amateur market researcher (along with amateur machinist and amateur programmer) for a moment, what is a complete, Bridgeport-compatible working " Home Hobby Hobber" worth to you? This would include: Controller (compiled code installed), 4th Axis assembly (ER32 collet spindle, tail stock not included), Y-axis motor/pulleys/belts/mounding structure, Rotary encoder/pulleys/belt/mounting structure, wiring cables, power supply, Compiled smart phone app. It would NOT include any source code, electrical schematics, user manual, warranty, liability on my part (signed hold harmless statement prior to delivery), customer service, field service, spare parts.F.C.
F. Cleff All I want is something easy to select spacing(gears most likely) without me going back&F with gears calculations. Whatever amount of teeth i need to cut just select and go as well be able to run helical gears and feed on the helix angles by a simple number of teeth to be cut and 4th axis cordinate with table servo/stepper motor. Not looking for electrical schematics, center etc(I do have all that)
Hi Erick,
I hear ya and understand completely. Please understand that what you want is exactly why I designed and built The Home Hobby Hobber. That said, how much is it worth to you?
Cheers,
F.C.
F. Cleff It will def make my gears cutting easy, so you tell me or how you I contact you?
F. Cleff Also I am thinking to use 1200 onz. stepper motor cus I will be cutting more on steel up to 8"-10" and max of 5"-6" on face.