# What are the main milling components to make gears?



## awaqa909 (Jan 28, 2017)

I get to work with CNC machines and manual lathes, but I never get to set them up.  Much less know how to.  I was thinking I could get a small mill and small lathe from Grizzly or similar and make some rc car parts.  I was thinking it would be cool if I could make my own transmission for a rc car.  But I have no idea how to make gears or what hardware/tools are needed.

So,  what kind of hardware and tools would I need to manually make gears?  The gears will probably all be under 3" diameter.  I'm also looking for a cheap and not too hard method and can be done using a manual mill and lathe.

I have found that a dividing head is a way to make gears?  Ebay cheapies are $300 and I'm not sure if they would fit on a small manual mill that I would like to get. (one of Grizzly starting lineup) I don't have too much garage space or $$.

Thanks,
    Awaqa909


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## Terrywerm (Jan 28, 2017)

Gears can be made in the home shop using a rotary table or indexing head mounted on a milling machine table. Cutters come in a couple of different types, some of which you can make yourself. One thing to consider is that making gears is more complex than meets the eye, so you might want to educate yourself on the subject before getting too far. I would start out by obtaining the book "Gears and Gear Cutting" by Ivan Law. It is one of the Workshop Practice Series of books and can be purchased new for about $20. It covers gear nomenclature, design, cutters, etc. and also includes instruction on making your own cutters. I believe that this book is a must have if you plan to make your own gears.

You can also make your own gear hobs (another type of gear cutter) on your lathe using tool steel. Instructions for doing so are available on a 4 hour DVD by Jose Rodriguez and sold by Little Machine Shop for about $40. The DVD is titled "Making Gears the Easy Way".   It is packed with good information, but I will warn you, the videos will tend to put a person to sleep. Mr. Rodriguez knows what he is doing and presents it all in his DVD, but the presentation could be livened up a bit. It's sort of like watching paint dry for lack of a better way to put it. Sorry, no disrespect meant against anyone, but watching someone else machine a part in a video without being sped up or abbreviated in some way just puts me to sleep.


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## Charles Spencer (Jan 28, 2017)

terrywerm said:


> I would start out by obtaining the book "Gears and Gear Cutting" by Ivan Law. It is one of the Workshop Practice Series of books and can be purchased new for about $20. It covers gear nomenclature, design, cutters, etc. and also includes instruction on making your own cutters. I believe that this book is a must have if you plan to make your own gears.



I strongly agree.  Gears can be cut using involute gear cutters.  I have seen videos of people using a fly cutter ground to shape, but I have never tried it.  There are also gear hobs but I don't have any so I haven't tried it.  The picture below is from the book Terry mentioned.  I would use a tail stock as well for additional support.


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## BGHansen (Jan 28, 2017)

More than one way to skin a cat, but my "minimal" set up is an arbor with an involute gear cutter and dividing head.  The calculations for depth of cut and blank diameter are readily available, which means I don't remember the formulas off the top of my head . . .   Important features are the diametral pitch and number of teeth.  Involute gear cutters have a range for the number of teeth they cut for a proper tooth profile, something like 7 or 8 cutters in the series to go from 12 or so teeth up to a rack (infinite teeth).

You can gears by grinding a single-tooth HSS tool to match the gear tooth profile and mount it in a fly cutter.  Indexing could be done with a rotary table if you don't have a dividing head.

Photos attached are of my typical set up using a vertical mill instead of a horizontal.  L&W dividing head with a shop-made arbor between centers to hold the blanks.  Arbor with the involute cutter is a step-sized slitting saw arbor from Enco.  Involute cutter was from Victor Machinery for around $50.

Bruce


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## Bob Korves (Jan 28, 2017)

Welcome to Hobby Machinist!  If you can get away with only gears having tooth counts evenly divisible into 360, then a spin indexer can substitute for a dividing head or rotary table.  A spin indexer costs about $50 and up, new, plus any needed collets.  For gears made from aluminum, plastic, or other easy to machine material a tailstock can be optional, though it will require more thoughtful setups to attain enough rigidity for accurate work.  With some creativity an existing gear might be used for indexing.  

I do not want to discourage you, and your idea is quite doable, but please do note that making gears is not beginner work on the lathe and mill.  It is more like journeyman work, to be done after a good amount of other basic learning.  And that is a good thing, there are many rewarding lessons to be learned and satisfaction to be had along the way.  If you are afraid of math and not willing to study and understand the details of gear cutting, you will not likely have success.


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## Baithog (Jan 28, 2017)

It is easier to use a super spacer or dividing head, but I think you can make most tooth counts with just a rotary table. I cut the 4 gears for my threading clutch with a plain rotary table. The hardest part was getting the chuck centered on the table. Keeping track of your progress is an exercise in repeated, total attention to detail. Spending hours cutting teeth, only to find the last one is half a tooth is disheartening. You can cut the kind of gears you are interested in on a mini-mill once you fix its inevitable flaws. A better choice for a multi purpose garage size shop is the G0704/PM-25 class machine. A rotary table for a mini-mill should be no more than 4". I have put my 6" table on my mini-mill, but it isn't very useful. A G0704 will take a 6" or bigger table. You don't want to go too big because you do have to pick it up and move it. Get a quality table. You can get by without a tail stock for small gears, but get one if you can.

The gear cutters mentioned above are the way to go. An ebay set of cutters will get you started for well less than a hundred bucks. Or you can buy them as needed if money gets tight. A cutter will last a long time cutting aluminum or acetal. Save the titanium gears for later . 

Of course we are assuming that you also have a lathe, or access to one, to make the blanks with.


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## Reeltor (Jan 28, 2017)

You can also make gears with a shaper and some type of indexing tool as noted above.  What material do you think you will be making the gears from?


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## willthedancer (Jan 28, 2017)

Lindsay Publications has some great books on the subject. You can do it, but the details are challenging.


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## willthedancer (Jan 28, 2017)

https://en.wikipedia.org/wiki/Involute_gear


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## awaqa909 (Jan 28, 2017)

terrywerm said:


> Gears can be made in the home shop using a rotary table or indexing head mounted on a milling machine table. Cutters come in a couple of different types, some of which you can make yourself. One thing to consider is that making gears is more complex than meets the eye, so you might want to educate yourself on the subject before getting too far. I would start out by obtaining the book "Gears and Gear Cutting" by Ivan Law. It is one of the Workshop Practice Series of books and can be purchased new for about $20. It covers gear nomenclature, design, cutters, etc. and also includes instruction on making your own cutters. I believe that this book is a must have if you plan to make your own gears.
> 
> You can also make your own gear hobs (another type of gear cutter) on your lathe using tool steel. Instructions for doing so are available on a 4 hour DVD by Jose Rodriguez and sold by Little Machine Shop for about $40. The DVD is titled "Making Gears the Easy Way".   It is packed with good information, but I will warn you, the videos will tend to put a person to sleep. Mr. Rodriguez knows what he is doing and presents it all in his DVD, but the presentation could be livened up a bit. It's sort of like watching paint dry for lack of a better way to put it. Sorry, no disrespect meant against anyone, but watching someone else machine a part in a video without being sped up or abbreviated in some way just puts me to sleep.


Since you know about some books, do you have a book in mind that I could use to get closer to becoming a machinist?  I'm thinking a book that leaves out cnc stuff.  More of a manual mill book.
I'm looking at buying some other books off amazon, thinking I should get a book on milling.  Plus it should bring the total up, to get free shipping.

Lots of good info.  But it is looking like I need to start with some kind of book, then get something like the "Gears and Gear Cutting" book.  Probably start with a mill and turn aluminum into parts and then work my way up.


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## Bob Korves (Jan 28, 2017)

awaqa909 said:


> Since you know about some books, do you have a book in mind that I could use to get closer to becoming a machinist?  I'm thinking a book that leaves out cnc stuff.  More of a manual mill book.
> I'm looking at buying some other books off amazon, thinking I should get a book on milling.  Plus it should bring the total up, to get free shipping.
> 
> Lots of good info.  But it is looking like I need to start with some kind of book, then get something like the "Gears and Gear Cutting" book.  Probably start with a mill and turn aluminum into parts and then work my way up.


The best place to find 'information' is in Machinery's Handbook, the bible of machining.  An old used copy is just as good as the newest editions, more CNC and metric in the newer ones, more old school stuff in the older versions, but any of the various editions will be a good reference for hobby machining. The only down side is that it is the definition of boring, unless you need to look up something, and then it is priceless.  I have actually read through both editions I have as bathroom reading material.  Thousands of pages, a few paragraphs or charts at a time!

To learn about machining it is best to work with other machinists.  We have put together a group of H-M members in this area and meet once a month or so and share ideas, tools, lies, and generally have a good time.  The others become excellent resources in what is otherwise often a lonely hobby.

There are blogs on the internet that show machining in detail, and give you time to absorb the information.  They are useful, but teach little about the feel and workflow. 

Another really good source of learning machining is by watching YouTube videos.  The best of them are incredibly good, and even the less polished ones are good sources for learning how to do machining.  You are looking over the shoulder of someone who is doing exactly what you want to learn.  Ultimately, however, you have to get your hands dirty and get started.  You will make mistakes, and you will learn from them.  You will surprise yourself with the nice things you can make from scrap pieces of stock...


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## British Steel (Jan 29, 2017)

And surprised by the scrap you can make from nice pieces of stock 

Dave H. (the other one)


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## Uglydog (Jan 29, 2017)

Here is a pic of the set up for a bevel gear fab I made for a lathe apron power feed.
10" swivel dividing head (I now have a 4jaw on the DH), shop made arbor, correct DP involute cutter.
The gear pick pic is gear prior to hand filing to fit and hardening. 
Note the warn teeth gear on the shaft. The existing bevel just slipped out of mesh.
The math was difficult for me but worth the agony.




Daryl
MN
MN


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## Charles Spencer (Jan 29, 2017)

A good general book on machining is the US Army TC 9-524 FUNDAMENTALS OF MACHINE TOOLS.  You can find a pdf copy here:

https://maritime.org/doc/pdf/machinist.pdf

And the best part is that since it's a US government publication, you have already paid for it and it is legal for you to reproduce.

And I second getting a copy of Machinery's Handbook.  The standard for reference.  Indispensable.


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## Terrywerm (Jan 29, 2017)

awaqa909 said:


> Since you know about some books, do you have a book in mind that I could use to get closer to becoming a machinist? I'm thinking a book that leaves out cnc stuff. More of a manual mill book.
> I'm looking at buying some other books off amazon, thinking I should get a book on milling. Plus it should bring the total up, to get free shipping.
> 
> Lots of good info. But it is looking like I need to start with some kind of book, then get something like the "Gears and Gear Cutting" book. Probably start with a mill and turn aluminum into parts and then work my way up.



All of the aforementioned books and videos are very good. YouTube is a great resource but you have to be careful about what you watch and believe. There is nearly as much trash out there as there is good stuff. Machinery's Handbook gives you TONS of data and information, but gives little in the way of basic instruction or knowledge.

If you are looking for some good instructional books that teach from the ground up, I highly recommend Machine Shop Practice by Karl Hans Moltrecht,  Volumes 1 and 2. Published by Industrial Press. It is available from MSC or from Amazon as well as Barnes and Noble and others. These books go into the details of how cutting tools work, layout, methods of measurement, etc, so that you understand the how and why of various machine tool practices. I have both volumes, and do not often refer to them anymore, but they were an excellent place to start and learn the basics. Google Books has a *preview of volume 1 available here*.

Any of the 49 books from the *Workshop Practice Series from Tee Publishing* in the UK are good. I have a number of them and thus far none of them have been a disappointment, so I suspect that the remainder are just as good. They are available from a number of sources, such as Amazon or direct from the publisher. Some of these books are for absolute beginners, whereas others are for more advanced projects.

You may also want to have a look at this thread: *http://www.hobby-machinist.com/threads/beginners-book.48539/*  It has a very good discussion about books and videos for beginners.


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## willthedancer (Jan 29, 2017)

awaqa909 said:


> Since you know about some books, do you have a book in mind that I could use to get closer to becoming a machinist?  I'm thinking a book that leaves out cnc stuff.  More of a manual mill book.
> I'm looking at buying some other books off amazon, thinking I should get a book on milling.  Plus it should bring the total up, to get free shipping.
> 
> Lots of good info.  But it is looking like I need to start with some kind of book, then get something like the "Gears and Gear Cutting" book.  Probably start with a mill and turn aluminum into parts and then work my way up.



Any texts by Colvin and Stanley are great!
Machine Shop Practice by Moltrecht


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## DaveInMi (Jan 30, 2017)

The Gingery series is written for the beginner without anything but hand tools.  I don't remember which book covers making change gears for the lathe but it would be after making the mill because it uses the mill to make the gears.  That was all I had when I made my first successful gear.  He doesn't tell you everything but enough to make a gear.


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## Reeltor (Jan 30, 2017)

Here is my setup to cut gears.  The cost is retaliative to the savings over purchasing ready-made or custom gears from someone like Boston Gears or Rush Gears (BTW, Rush Gears has a great on-line program for designing your gear)  I need to make a 4-DP (diametrical pitch) gear 4" in diameter with a 2" width plus a hub.  On line cost for the gear is around $176 but the gear is only 1-1/8" wide.  I don't know what a custom one would cost.  I also need a 3-4' long rack to match.  On line cost is over $470.  Raw material for gear was a drop from metals supermarket.  The chunk of steel was just under $50 with enough material to make 3 gears.  The material for the rack was $30, drop from a structural steel supplier.  I found that if I wasn't extremely careful the sector arms would move a hole which would ruin the gear.  I took some soapstone and marked the correct hole.
	

		
			
		

		
	






When cutting the gear on a horizontal machine with the blank on an arbor, you want a footstock to hold the off end.


	

		
			
		

		
	
 Cutter on mill arbor



Cutters come in a set of 8, very old used set off of ebay.  These are 4dp, you will need to know the pitch that you need for your gears.  Some are 16dp, others could be metric.  If you know how many teeth you will need to cut, as mentioned above, you can buy single cutters.
For the job I want to do, I am at a break even between cost of materials and tooling vs buying ready made; and I have the tooling for future use.

Good luck, have fun and practice on some inexpensive material; it's easy to screw a gear up.  Ask me how I know


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