Making Worm Gears. Harder Than You Might Think
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- Опубліковано 4 чер 2024
- G'day everyone,
I have made countless spur gears on the channel, mostly because they are relatively easy to make with a dividing head and the correct gear cutters. However they are not very space efficient when it comes to making large gear reductions i.e. 40:1 or greater. This is where me might turn to a worm gear. For a worm gear, the gear reduction equals the number of teeth on the worm wheel. A 60 tooth worm wheel will yield a 60:1 reduction and a 60 times greater mechanical advantage.
However making them is not as straightforward as you would think. Worm wheels are not simply spur gears that have been tilted back in the dividing head to create a slant. They are a helical gear and they need to be hobbled.
There are videos on UA-cam where people use taps to make "worm wheels" which look like worm wheels, but are not the correct profile and I doubt would work correctly under any proper load.
Without a proper hobbling machine, I will need to free hob the gears using the lathe.
#diy #machining #wormgear
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Timestamps
0:00 - Intro & Gear Theory
4:27 - Making The Worm Screw
9:39 - Making A Gear Cutter Arbor
12:23 - Making A "Not A Worm Gear"
17:24 - Making A Gear Hob
21:19 - Free Hobbing Helical Worm Gears - Наука та технологія
TOT and inheritance yesterday, Artisan today. This is gearing up to be a great weekend.
Don't forget edge precision.
Blondihacks as well
It's a good weekend
My watch later list is filling up
Snowball Engineering on Sunday morning too
I see you're a man of culture as well...
What I like most about this channel is that degree of difficulty or complexity are not deterrents. Spur gears, gear hobs, worm gears, taps, jumbo fly cutters that make other machinists run away are taken up as a challenge.
Very nice work. The quick and dirty method is to use a tap and just calculate the appropriate gear from that.
Or make a cutter from a 5% larger diameter worm, as I do.
Or just use a cnc lathe. I mean, its cool from a romantic nostalgic point, but with the cheapness of cnc setups now, even your smallest shops have access to cnc lathes.
I'm here to watch Artisan Makes weekly workout of cutting a big chunk of metal with a hacksaw 😅
Yeah, after all these video's, and all the machines and accessorries he has bought for it I'm really shocked he still hasn't bought a metal bandsaw. Or hell, he could have even made one himself, they're only moderately difficult to make, and especially for the bigger models it's a lot cheaper to make them yourself as well.
I’m wondering why on earth Vevor haven’t sent him one to review & keep? 🤷♂️
Yeah, i´m wondering every time why he doesn´t take the 100,- € into hand to buy, for example, a "Parkside" metal bandsaw. And if it is on sale it is just about 69,- €.
Or a cheap one out of Amazonia. The sweat and tears with the hacksaw would kill me. And that cheap one is good enough. Especially when Arti will have customized it.
What he would do - that´s for sure. Maybe we should fundraise one for him?
I'm like 98% certain that this channel is just "I Did A Thing"when he feels like being serious.
Also I just realized one of the main reasons I love your videos. Not only are they very well-filmed and edited, educational, and entertaining, but you don't do all the bullshit "UA-camr" stuff with all the "smash the subscribe button" stuff that everybody hates.
Or have a dog with big balls running through some poorly cut grass.
AGREED.
Things are getting real fancy in the shop!
You did a good job there. One thing you didn't mention, the hob you made has subtly different dimensions to the worm as it has to cut the gaps between the teeth and the gaps are thinner at the root than the width of the top of the tooth. Otherwise, well done! You've just gone through the same learning curve I went through when the worm drive in my bandsaw packed up. Couldn't find an off the shelf spare, so it was DIY time, making a new worm and worm wheel using the free hobbing method like you did.
I did this a while ago, only I used a triple start worm.
It took several attempts at each stage to figure it out, and my set up ended up being much nicer than what you have done.
The most important thing to keep in mind when free hobbing is that until the gear is cut to full depth, it does not turn at the correct ratio, and the whole thing ends up out of sync.
The "secret sauce" so to speak, is in how the hob is cut, and preparing the gear.
The hob must cut slightly deeper than the worm diameter, but its root must be exactly the same as the worm. This means you actually have to grind a different tool for the hob and the worm. The back of the teeth must be fully backed of or it will bind the gear while hobbing. You left a pretty large space behind the cutting edge and the relief, much too much. Lastly, the hob really needs to be turned between centers.
The gear needs to have the concavity cut on the lathe to about 0.002" from final size, and a specially ground tool is needed to get the shape right. The gashing also needs to be done to about 90% of finish shape and depth. So you can not use a conventional spur gear cutter since it it too big in diameter. I turned a piece of tool steel to 90% of the diameter of the worm, and then ground the tooth profile into it about 10% undersized. Gashing was just like you showed.
I also used roller bearings on the gear to ensure it was clamped well, and yet able to freely spin.
The hobbing at this point is really just making the finish cut. The "blank" should actually be close enough to done after gashing that the worm will drive it.
Fascinating video. I learnt a lot about worm gears that I didn't know 30 minutes ago.
Soon: Planetary Gears 🪐🪐
Bah! He should be ready for a miniature automotive differential!
Planetary gears are just spur gears that are encased in a ring gear.
I bet spacex makes a lot of those.
@@nickwolfe483 Ok but how do you make the internal ring gear
@@bergamtwith a shaper, that is the most common old school way
One thing you can do to cheese worm gears is to make the large gear by holding it with bearings and then use a tap as an endmill to cut the gear shape. As the threads cut the blank it rotates and you feed in SLOWLY. Once you have good engagement its done. Then you can use the threads as the small gear.
Very practical on what a small shop can do. I always love discussions on what is enough and how much precision do we really need for the job. Looking forward to seeing what you are going to use this skill for.
The ol' worm drive, it has so much power. That was worth being late to work. "I was late because I let a worm drive." They probably won't think it's funny either.
In my limited experience with materials of all sorts, I've found cutting has to go in two speeds. Slow and meticulous, or as fast in a steady as possible. I would argue you're at the slow end, but only out of pure ignorance in making gears. Glad to see someone keeping this knowledge alive, the gear IS a massive gain in work, and a good gear set is months of labor saved.
Excellent approach!!!
Gears were the first insights into computing. Today they are united. One commands the other obeys.
Perfect! All that was missing was the calculations for all this to happen. São Paulo-Brazil!
Thank you for you cut scenes that show real-world stuff like all the adjustments to center something in a 4 jaw chuck. It helps us know that you operate in the same world we do.
Absolutely fascinating. I have no idea how you learn all this stuff but really appreciate the fact that you share it with us. 👍👍👍🇦🇺
Cool! My sewing machine uses this gear to wind bobbins; it was the first time I saw it. Awesome to see how it’s made. Thanks
This video was so damn informative. Such a great vid. Thanks for sharing this Artisan. 👏
Good exposition, enough depth and thoroughness. Impressive.
Great demo of developing the system, enjoyed very much!
Thank you for the great production of the video and the topic covered.
You were very happy to use "DIAL Marker for threads" as an example. There are mechanical turners who do not know and do not know how to use this "DIAL to make thread" system.
love it! showing the real world incremental process without the exclusive equipment! i got a lot out of this
I'm in awe of how you take what I see as highly complex components and just make them. Do you have no fear!?
Very Nice. You really know how to work through problems.
Kicking goals mate. Cheers.
Nice. Can hardly wait to see in what it is going to be used.
Amazing video. Very informative. Keep it up
Very interesting and pretty nice single point thread cutting for a bloke that doesn't like it very much. Thanks.
Thank you for sharing
Thats some impressive work for sure! Another thing that also amazes me about worm gears in general is that they last as long as they do. The thing being that in constast to other gearbox types where the gears just roll over each other, with worm gears you have a lot of sliding going on between the screw and the gear. Sure worm gears are filled with some good quality oil adapted specificially for worm gears but still I would expect a worm gearbox to have a much shorter lifespan because of the sliding motion. A real world example from me is the metal bandsaw at my workplace wich uses a worm gear drive. The drive motor on the saw and thus also the screw spins at 3000 rpm with slam on direct start sometimes starting and stopping 100s of times during a workday. We got the machine in 2004 and it still show no signs of wear on the gearbox after 20 years of operation. At least I cant hear any different noises or notice any backlash still on the machine.
OK, I'm sold. Ebay it is. 😁 Fantastic work as usual, well done.
Excellent work my friend.
Hey, nice copper "soft jaws"! I've got copper pipe split and hammered onto my vice in the exact same way. Works pretty good!
That's excellent - thanks! I need to cut a 90:1worm soon,, have read the same books as you I'm sure, but seeing it done is super helpful - cheers!
Thank you, love your videos!!
Awesome! You're an inspiration bud, love the channel! Every time i watch you quench something though, I cringe a little in how small a container you use for quenching. Maybe it doesn't matter, but in the knives I make, the oil heats up so fast in a small container that I don't get as good results as a huge oil bath. Have you ever tried a bigger container with more volume for quenching? Was there any notable difference? I watch every week, Roger from Calgary.
Where I used to work, the quench oil was preheated in order to reduce the chance of the part cracking.
Very useful and nicely done; thanks!
Cutting normal thread on a lathe is already somewhat of a challenge, at least as small as this one. When I learned lathe the only thread I cut with a chisel on a lathe was a trapezoid moving gear on a 4 cm diameter blank steel rod. The worm is not really a problem if your lathe lets you choose the correct values, but the gear is the major hurdle. You could cut every tooth with a mill when you set the table to the gradient/slope (idk the correct word in english for this) of the worm so it fits, but then you'd have to rotate it.
Or you could build a little helper. Precut every tooth with a normal thread cutter so you have the perfect gradient. Then mount it on an angle with a tiny spring that grips into the little valleys so you can mill another tooth at the exact position, combined with a quick span of course so the mill doesn't rip it apart.
And then at the end you cut a round depression into it with the lathe.
That requires of course that the piece is a bit wider so you can still put it into a chuck, and then cut the gear off.
another excellent video mate!
Love your project
Well done sir!!
Very interesting project. Well done.
Beautiful video
Great work! I didn't expect the gear wheel to be the complex bit, but I should have guessed. Would a thrust bearing help with holding the gear blank down on the hobbing setup? It should allow tight workholding with a lot less rotational resistance?
great job. I think I would a diamond blade along the cutting teeth as heat treating can distort the cutter
Could you use a thrust bearing when securing the gear to the fixture so that you can apply more pressure without preventing it from turning?
Well presented excellent information thanks very much
at tafe we make a 4 start worm gear in the horizontal mill, with the shaft that connects the two. a four start thread is mad complicated, especially because it he helix is so long compared to its rotation, so the cutter is working hard to machine it
There is a great DVD from the early 1990s tritled "Making gears the easy way" , that every hobby machinist should either watch or preferably own a copy of. It covers an array of gear setups with simplified math, and machining setups/techniques for both lathe and mill. Just as I'd recoment Machinery's Handbook and the DVD set "Lathe Learnin' " for the beginning metal turner, I would recommend Making geras the easy way for anyone foraying into gear cutting and hobbing.
Great video mate! I would like to ask you how often do you use that Hemmingway die, holder, you made some time ago and please give your honest opinion if you think it is worth me making one. Thanks so much mate
On musical instruments they are called Machine head tuning screw.
Great video!
One idea for the gear tensioning:
Use thrust washers below and above the gear your cutting and a simple plate spring (idk if it’s the correct term, translated from German) to tension the gear :)
Reduce the spacer height by the thickness of one thrust washer obviously tho.
Might be useful if you’re planning on cutting more worm gears in the future.
I came across a strange worm gear set up on an old OZITO electric chainsaw the worm gear set up was the motor shaft a 12mm metric thread driving a gear at 90 deg for the oil pump, it was defiantly a 12 mm metric thread as a 12mm nut was holding on a spacer on the end, the gear was made out of steel and had the helical profile, I thought it was odd until I saw this Video and how you made your own helical cutter , I guess the Chinese have mastered it.
Man watching you make the worm just reminds me about how fucking amazing human engineering is some times.
Like, just look at what a Lathe can do, it retracts the cutter and moves it backwards while spinning everything in reverse and spins normally when its realigned for screw teething.
Absolute math went into making them, along with all the addons like the reducer and just the gear ratios inside them to do different things.
good stuff.. tyvm!!
I had to make a worm gear for a mig welder wire feed motor. With a limited amount of tooling on hand, needing the welder for an urgent job and it would take a month to get a replacement gear I was tasked to come up with a solution. The worm gear was made out of aluminum and was stripped in a spot, But the work was made out of steel and not damaged. So checking around I found a tap with the same thread pitch as the worm. What I did was to find an end mill with the same diameter as the tap, cut a blank gear slightly larger than the original. Then used the end mill to profile most of the radius in the gear blank using a spin jig to rotate the blank. After making an arbor to hold the gear so that it spun free I used the tap in the mill like a gear hob. Now the tap has a 60° angle and the worm is basically an acme thread. So to finish form the worm gear teeth I used a lapping compound with the worm from the welder. I had the job done in under 12 hours and the welder was in use the next day. Sometimes you have to think outside of the box when you are in the middle of no where and you need to get a job done. This happened when I was in the military about 5 years ago. They are still using that welder with that gear I made.
Nice work!
Could you use thrust bearings instead of spring washers to take up the slack but retain the rotational motion of the gear being hobbed?
yes it would be better can also use a double nut setup to lock the nut in place so it doesnt tighten or loosen on its own , ideally youd use a thrust on both ends
Very neat , must buy some involute gear cutters some time , ive seen people rough hob gears using a Tap before, seems like some thrust washers would be just the job to let the blank spin.
First time viewer here! Love the content! Aus ToT 🤙
Newbie here, thankyou for being so informative and clear. Bit over my head but I'm learning.
What type of steel stock do you mainly use im in Aust as well tks
Most of the time I use cold rolled mild steel. Here it is sold has Bright Mild. It’s relatively cheap and works for most of what I do.
To help with finding useful pitches, I use a simple spreadsheet that calculates the effective pitch for all combinations of change gears I have. For a given pitch, I usually find a combination that gets within 0.01%.
Very nice.
Maybe you could just cut a slanted gear and lap the gear in? ie. make an aluminum screw and use that with some abrasive to lap the gear to the right profile. I think that would be a cool experiment at least and I think would be easy to do in a home shop
If you put a encoder on the one axis of your mill, and a stepper motor on the dividing head, you could do an electronic connection between the 2. Many people have done it. It's like a variant of an electronic lead screw on a lathe
That power feed had a metal worm and a plastic gear. Would it work to cut a metal worm (as done in this video) and 3d print a matching gear?
I forgot what goes into making a proper worm gear set. That is quite involved!!
You had great success! That was awesome to watch. Thanks!! 🔩⚙👍🙂
TIL about free hobbing. That's such a clever technique.
I designed and printed some for a school project. I can't remember the ratio, but HOLY COW... I can flatten a can with ~23g of plastic.
Love it.
You just seem to make it so easy.
Hi, you’re very smart, keep that green book! It is full of information! Being a fitter/turner isn’t about remembering everything it’s about being able to find the information you need at the time! Great video once again! Side note I lost my green book ten years ago when I moved from WA back to NSW 😢
“Aaaaand, stay out!”
Said by a parochial Sandgroper! 😜😂😂😉
I enjoyed that! I know you made it out aluminium but that should work in steel as well? Cutting a shallow profile and letting the helical cutter di the rest?
Hi Artisan, I'm about to buy the same Sieg 2.7L as yours. Since the First video you made about you price increased from 1500 aud to 2450 aud. Should i still consider buying It or do you think the price Is still excessive for It? I still cannot find a good One in the market with the same dimension and caracteristics. Please let me know your opinioni id like to buy a good machine for the right price. Also It It was good, what platform do you suggest to buy It from? Thank you
Incredible video. We should put your name on our Formula Student car as youve helped us more than some sponsors
Brilliant your a absolute wizard to me
Nice!
Do you not have Portable Band Saws in Australia? (Portaband)
20:10 you're really good at that 👌
You can use a similar process with a plastic gear, but not cutting, instead thermoforming it.
Instead of a cutting hob just use the worm itself, and heat the outside edge of the plastic gear blank then using force, push the worm into the gear while it is spinning then friction will keep the outside of the gear soft enough without the heat gun and you can finish thermoforming the plastic gear to exactly match the worm.
Plastic worm gears are very popular because they are quiet, and can have no backlash because in the final adjustment they are tight and use elastic deformation of the gear (instead of a metal gear and worm which need a fixed clearance because there is no elastic deformation).
I've been known to use acme threaded rod for worms, with regular gears. Figure the 29 degree flank angle on the threads works with the older 14.5 pressure angle on diametral pitch spur gears. Yep, I'm lazy. Not for transmitting large powers, but great for establishing odd angles.
Making gears out of worms *is* rather difficult. Worms, of course, are squishy, wiggly, and don't want to hold a particular shape (other than, of course, worm shaped). Once made, they also don't wear very well.
😜
LOL, they are a shear mess...
Or you could make another 'worm' from tool steel and turn it into a gear 'hob'.
Plenty of videos on UA-cam.
Yeah, that’s a much bigger and involved project there
top job
what type of steel did you make that hob out of?
Gear hob - material
Hello AM!
Nice Video, thanks!
What type of steel did you use for the gear hob?
I used an offcut of 4140. It’s not really the correct material for a hob but got decently hard enough to work. I would have used silver steel or anything similar if I had a piece in the correct diameter
Did you try to cut the wormgear with a threading tap?
16:40
I would think if instead of using the long axis, one can just use the in/out axis to cut the worm gear profile… It will cut an inward concave groove in sort of the same way a proper worm gear is. The only real problem is the radius of the cutter, which can be solved by using a custom rotating cutter with an adjustable depth, similar principle to a fly cutter but specific for the application. A makeshift one made from a broken boring bar with a carbide tip ground to profile might be the ticket, though not adjustable unless mounted on a boring head.
Though, 22:30 is also one smart way to do it
good video
what was the book with the green cover you used for information called?
It’s called ‘fitting and machining technical book’
@@artisanmakes thank you
I have a silly question regarding making the helical shape on gear (not a machinist here, just a curious viewer):
What if one were to take a round (tube shaped) file and fit it into tool holder of the lathe and slowly grind the profile onto the gear turning on lathe's chuck?
The helical shape is to do with the tooth profile itself. The tooth curves backwards, instead of being straight. The concavity you are referring to is the throat of the gear.
I have the smaller CALOR GAS bottles here in Dublin, IRE.
I have about 10 of them and I'm weary about taking the head valve off. How do u know if there is no more GAS left in the bottles. The ones I have have been sat in a shed for 20 or more years. Some of them have someth in them bcos I feel it moving inside the bottle.
Any advice would be greatly appreciated. I want to build a stove for my workshop. It's bloody freezing in the winter and I'd love to be able to heat it up then.
Great video but the tool u made is beyond me pal.. LOL
What would be the best wrench to take the valve off with?
I enjoyed the video. It's a bit hazy in the picture though mate. Maybe the lighting is off a wee bit bt I still enjoyed ur video anyways..
Cool Work!! Can you make bevel gears too!
Straight cut or with the actual radiused profile, it's still a worm wheel. That radius is used most times (but not always) when the drive loads get higher or better tooth longevity would be helpful. So in reality, it all depends on what the worm and worm wheel were designed to do and for how long.
And fwiw, all threads and gears can't ever be made to be "perfect" if your metrology to measure them is accurate enough. What that's normally referred to is there lead and lag pitch errors. Moore Tools in the U.S. spent massive amounts of money in effort to produce as close to perfect lead screws and nuts for their jig borers and grinders before very high accuracy dro's and then cnc were invented by grinding and then precision lapping. There final errors in thread pitch weren't out by much, low millionths of an inch in fact. But they were still there no matter how much time, effort and money they invested. Luckily and for us when used in something like a rotary table or dividing head, any pitch errors are divisible by the gear ratio between the worm and worm wheel. So the accuracy can be much better than the worm and wheel itself.
Wouldn't a couple of thrust washers either side of the gear be better than washers?
Q. On the 'not a worm gear' if you built adjustability in housing as it wore down you get better bearing? Not ideal but I'm asking in theory
I've wondered about similar things. I.e. two parts that don't fit well? Put some abrasive paste in it and run it a bit until the two parts are bedded in.
Not sure how well that would work though. Maybe more of a case-by-case thing that can be done.
@@rcjbvermilion Thats an interesting idea indeed. Its really cool when the comments section works the way it should.
Either make a hob or for a small worm gear, simply make a tap at the pitch and pressure angle you need and use it as a hob.
Well done you, I thought I had already subscribed when I had omitted to do so - rectified.
Your very talented and have a head for the math i am unable to understand due to my disability but this was fun to watch its a cool gear :)
Idea: Make a lathe chuck backplate with teeth cut into its perimeter so you can turn it with a worm like a rotary table, eliminating the need for an indexing head while also adding the ability to mill in polar coordinates using a mini spindle on the cross slide.
12:00 Feels like cutting and bending a tab on your copper softener jaws to retain them during loading/unloading material would be a nice, but simple upgrade.