Boring timing belt gears
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- Опубликовано: 5 окт 2024
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You know Stefan, instead of 'darn' you should throw in the much nicer 'verdammt'.. I'm sure it will sound nicer / authentic (and throw your English speaking audience off just a little bit, but give them a cool word to know and use themselves) 😄
I should throw the occasional "Greizdeifl" and "Zefix" in too :D
@@StefanGotteswinter or the other ‘ luja in between 😉
@@StefanGotteswinter "sacramentzifix"
verdammtnochmal
As an English speaking viewer, I've gotta say. Those words look like someone sneezed while typing. Kinda like this -> Grezxrneiz ..
😁😆
FYI, they're pulleys, not gears (I know I'm being pedantic, but it bugs me lol); gears run with each other, pulleys run with belts, sprockets run with chains.
We make these (and similar parts) by the thousands at work for medical equipment; the blanks are turned with the bore finished to size, then they are hobbed individually on an arbor, then the flanges get pressed and staked on, then they are reamed to correct the "crush" in the bore from assembly, then drill/tap on special arbors, then ream again to deburr.
Interesting! Then I was not to far off with my assumtion that they get hobbed and the rim pressed on afterwards.
I've done the clamshells a couple times at work, so it's nice to see you doing it. It makes me feel like I'm doing something right.
the jury on "right" is still undecided - But its a very well working solution :-)
"Right" is what gets the job done.
I use this technique almost daily for holding fragile or irregular shapes. I normally take a piece of close fitting Aluminium tube(we have a lot of it) bore it to the dimension and then slit one side on the bandsaw. Sometimes needs to be both sides. Much quicker than soft jaws. But depends on the tolerances. You'll never beat a set of precision made soft jaws for run out tbf.
I even learned it on my apprenticeship.
Stefan, thank you for uploading this content. I used and modified probably hundreds of timing belt gears and always used the premade outside diameter for holding it in a machine. I checked the runout a few hundred times too and I found them to be pretty accurate (within 0,01 mm runout; German supplier). I understand that these ones you made had to be "dead on" but I don't really understand why. A charming feature of timing belt drives is that they don't have to be that accurate to perform well in my opinion. The teeth of the belt are a little flexible to compensate for runout. This is also the reason to use a timing belt for eliminating drive faults from one system to another (accompanied with a drive reduction possibility for the system) in angular and alignment errors. You didn't design this feature I'm sure but maybe you have an opinion on the matter which differs from mine. If so I like to know for educational purposes only. All the best! Job
Ahoi!
In this case its mostly "Its in the drawing, so I will make it according to the drawing", I don't know the surrounding construction and design, but I know the guy who designed it and he is usually a very reasonable person :)
As for the clamping method: These blanks came from Maedler, I did one without the clam shell, checked it and got about 0,05mm runout on the tooth profile. That was when I switched my setup.
@@StefanGotteswinter 0,05mm runout on a timing belt gear? Huh, disaster....
Sorry, but all that effort to minimize the runout doesn't make any sense to me. What's next, fine balancing the belt? Just because you can?
@@paulpahl1607 it makes a difference in precision applications.
Manufacturers for belts will spec about 0.08mm runout for low end applications, 0.05 for precision applications and 0.02...0.03 for high precision applications.
You get funny errors on the output side of a belt drive of the runout is off.
@@paulpahl1607 It does make a big difference at high speeds or a precision situation like connecting a servo to some linear drive like a ball screw. If you have some runout the tightening and slacking of the belt leads to non-linearity between revolutions. And depending on how things are mounted can lead to fatigue stress over time in motor or shaft mounts. All in all, the better you make it the better everything will be. Not everyone is building a 3D printer with these where speeds are slow and precision is low...
@@cda32 If you use a teeth belt for a such a high precision application than It's you own fault ;).
Wow you have some really nice gear. Even when you say you "just knocked up this item" it means its 10x more precise than anything I have ever achieved. Very pleasurable to watch thank you
It's like you are a mind reader, every time I'm like "man I miss stefan" and I start rewatching content you drop a new video! Love it
Clamp shells. Again a clamping idea I would never have thought of. That's brilliant.
That is actually the perfect video for the pulleys I need to bore in the coming week.
Thank you Stefan!
I use my Harig Grind-All punch grinder more and more often for fast-indexing like this, it's so much more convenient than a dividing head for simple jobs. I have the same Tapmatic. it feels a bit "agricultural" but I've never broken even an M2 tap when using it in copper. I'd like a mini version that can do M1.2 through to M2.2. Nice floating reamer holder!
Ingenious work holding solutions! Your customers are lucky to have you. So are we!
I love the discussion of the problems and solutions. You have a very logical approach to solutions.
Nice. Much simpler than soft jaws.
For the inspection, how about inserting a spring blade between the gear and the indicator tip? It would capture the peak height across the crest's width and also apply a defined pressure against the pin to take up the slop in the hole's diameter.
Yep! That would be a good solution and average out some of the manufacturing tolerances of the gear.
I did it that way, it was incredibly tedious but does work. This would have been *way* faster.
german .. had to think at least 20 sec "warum sind die langweilig?" // "why are they boring?" until i realized "oh you have to bohr them"
When you indicate the run out, a drop of oil on the gauge pin will take up the oversize and give you a more accurate run out reading.
So relaxing and inspiring to watch the master at work. Thank you 🙏
I have to do the exact same thing now on a HTD5 pulley, cheers!
I'm not a machinist. My first thought was to use some scrap linoleum or plastic material. I know it would not give high precision but one could at least clamp the part.
Also happy to see the OD get machined so now that is concentric with the ID.
I like these videos because there is always a new trick.
Very nice work. I’ve used the same clamshell system to hold very small PEEK parts for machining to stop the clamping force from crushing the material inward.
Working on big parts today I see! 🙂
Haha, and you have taken over the small parts this time :D
Me: reads title of the video
Also me: "but there's nothing boring about this video"
One assumption here is that the pitch circle of the teeth and the OD are concentric. Another option is to use 4 short dowel pins held in the tooth profile with rubber bands. Then indicate over the pins. Always more than one way to skin a cat.
That was a good tip on leaving a few mm sticking out on the split bushing. (clamshell)
Never heard that before
Every single time I watch you work I am impressed. Amazing Sir. Thank you for sharing. Wow!!!
New Stefan and This Old Tony in 24 hours. This is a good weekend.
Thanks, Stephen! That was a great set of tips, I'm certain I'll use.
Your videos are always timely and useful. Thanks very much.
Thanks for the tips. Very nice camera work in there 👍
Quinn keeps saying chamfers are what separates us from the animals .. but you're a beast when it comes to precision...!
Enjoyed…great discussion/demonstration/build/video production….lots of lessons
Love all of the content you share with us
Wife: Why are you still awake ?
Me: Stefan just uploaded a video
20:57 I’ve long wondered how these tapmatics work and this explanation is wonderful. I’m envisioning a dog clutch coupled to a friction or viscous clutch. Setting the depth stop allows the dog clutch to disengage then freewheel and the friction or viscous is there as a safety. (My interpretation). Always learning something on your channel.
Yes! I have this same problem coming up soon! Thank you!
Hahaha, I love the way you do things, very rare that you comprise on anything. I had a similar job on a few slightly larger pulleys. Used the 4 jaw independent and some small pieces of wood. German way vs English way.
Lovely clear explanation and great tips.
It blows my mind though that anyone would ever need a timing pulley machined to that level of accuracy in the first place; 20um concentricity, seriously?
It’s all ball bearings these days..lol.
In general: I will make whats speced out on the drawing and also quote accordingly :-)
(Runout error on timing pulleys can be a problem for precision applications.)
50 micron of eccentricity on both pulleys could get you a degree worth of variation across a full rotation of the pulley depending on the diameters and in say a microscope stage with a gear reduction microstepping drive with this as a final coupling to the stage a degree of variation could be 5-10 full steps on the stepper oscillating with each rotation of the leadscrew
I wish you'd put a dial test indicator on the floating reamer holder to see if it actually moved in any way.
another youtube maching gem, all very nice tips, thanks alot!
very good job stefan..thanks for your time
Good stuff Sefan, enjoyed!
ATB, Robin
Thanks Robin! Hope you are well.
I’m sorry for asking, I have used timing pulleys for years, but I’m not a mechanic, just a bit puzzled why you buy “blanks”, I have never seen it before. However if you need to bore the pulleys, the clam solution looked smart.
The combination of bore diameter and teeth count was not availible as a stock item, thats why we got undrilled ones.
Later today the plan to exactly do this. Let's first watch and learn
Me too, I'm making a toolpost spindle and have all the parts pretty much made, been leaving the pulleys until the end because they'd be trivial. I'm glad I did leave them now, my original workholding plan would have been pretty flawed having seen this video👍👍
Beautiful still shots at 2:35 :)
Very nice work Stefan👍
Thanks Steve!
Superb. Thanks again Stefan.
Learned a lot from this one, finally with some relevance to normal people ;-). Thenk you Stefan.!
As always, a cut above!
Do you still have your small CNC machine? Why not give it a fresh piece of rod stock, tell it to get busy, and yourself go out to dinner?
I'm enjoying your sabbatical at least as much as you are!
Very interesting, thank you I learnt something today
Good job stefan
Wow....very nice work.......excellent video......Thanks for sharing
very cool setup using the punch grinder v-block. I was wondering how you were going to realign the part to tap -- that was a cool setup in the drill press. learned a couple of things. thanks!
I was puzzled as to why the punch grinder setup was not used in the drill press for both drilling and tapping, but I guess maybe the Tapmatic collar would have fouled the clamping arrangement.
For the trouble of the hobbing and the insert and the flange and your work, surely it'd be cheaper to make them from scratch. Drill holes for the teeth, drill and ream bore, turn OD features.
Nope, making them from scratch would have cost the customer wayyyyyyyyyy more.
The correct way to turn the boer true to the pitch diameter is to use pins in the grooves and indicate over the pins . This is the mer accurate way to do it
Doesnt change the measurement since the full toth profile including the crown of the teeth is hobbed with the same tool.
@@StefanGotteswinter if that is the then your are totally correct ti agree. I have machined many sprockets and spur gears where the od and pitch dia did not run true to each other . That is why I said to cut over pins. No offence
Lovely work as always.
Oh No! A new posting from Stefan! Now I need to postpone whatever I was going to do and watch it.
Hmm what a strange coincidence that i exactly needed that. Is this for a HDT or GT or AT type Belt?
I did both T and HDT profile gears in this project.
One might reasonably ask why they chose this particular order of operations for manufacturing the blank given the tolerance requirements...
Grunk: (noun) A way to exert an exact amount of force on a 6 jaw chuck of a lathe. Also oompf, joink.
I like your clam shell technique. Would it make sense to make sure your six jaw is preset to zero run out first with a solid similar dia and length piece BEFORE you introduce the clam shell with part inside to machine?
That will get you already extremely close, but I prefer to do a runout check on the real setup/part in cases like this.
@@StefanGotteswinter Of course!
can't help but wonder why one would need that precision for a timing pulley.....🤔
Because the print says it :-)
Odd coincidence, I was researching M2.5 taps for aluminum last night.
Ever used a roll form tap in that size?
No, I have never used a form tap so far - But I want to try them with the tapmatic.
Me, guessing how to workhold this: “Hmm, i wonder if you could make a pair of matching rack jaws, and then indicate in the bore on the mill?
Stefan: “I made a pair of clamshells.”
Me: “Oh.” (My mill is much more capable than my lathe, so I always mentally jump to mill based solutions first)
At 7:30 you can hear his lathe making ALIEN VOICES.
Stefan is using Area 51 technology I am sure of it. 🤔
Figures I have to get up for work in a few hours and Stefan uploads a new video. Decisions decisions... Ah screw it, 4 hours of sleep it is bc I'm watching it now! 😂
get some sleep! :)
Video will still be there tomorrow.
Thank you. I hope that your full-time business is going well. Do you need to look for customers or do they find you?
Clamshells.Thank you.
Interesting as always. Thanks.
I had do do only one ... i removed the thin outer Ring, drilled and reamed the hole and re-added the Ring afterwards.
Sounds like a good solution for one or two :)
Your boring videos are never boring.
OK, but why the high precision for a gear running a very compliant belt?
Because the print says so.
(Imagine a Belt driving a high precision device and having oscillations from an runout error. That will lead to a non linear output rotation.)
Great tips. Can you show a Picture or give Brand/ Model number of the T-Slot Clamp used on drill press to hold down vise? Thx
Its a Kopal Clamp: www.kopal.eu/en/produits.asp?IDFam=37
Wie war der Runout von dem aufgepressten Bund? war der wirklich so schlecht? 2 gedrehte Teile die aufeinandergepresst sind sollte ja immer noch einigermassen rund zueinander laufen?
Das waren gerne mal 0,05mm zwischen Verzahnung und dem Bund :-\
@@StefanGotteswinter Thanks Peter, thanks Stefan. I was curious about this too. [Q: how bad was runout between teeth and pressed on collar originally? A: 50um ie more than the required 20um.]
I would call the Clam Shells a Sabot, but that's just semantics nothing important just an observation. Just about anyone will understand clam shell, sabot, not so much, so perhaps I'm barking up the wrong Quill.
Ha! Yeah, sabot would be a very precise term :)
If you cold blue the sabot, you get the ultimate metal: Black Sabot!!!
@@bobweiram6321 Good one!
@@StefanGotteswinter Then the technique is "sabotage".
Stefan a little off topic here. If You had to make Your lathe spindle shaft... what material would You use and would it be something that need heat treatment and post machining to get it all true.
the end rim comes off for a lot of this type, not sure if you tried that.
Not on these, full press fit.
Hi! I assume you used your Emco Super 11 lathe for the procedure? 😁
Yep!
As expected, nice work!
I bet you could drill and tap a hole or two in the bottom of the V-block and then drill and counter-bore a hole or two in the parallel clamp to hold it to the V-block while changing parts.
yeah - But the V-Block is trough-hardened :D
Could be drilled with carbide or EDM-drilled, but thats such a rare application, where I dont want to modify the V-Block to such an extend.
@Stefan Gotteswinter Yes, I know. Certainly not the easiest mod. Actually, it would be a good thing for the factory to do before heat treat. Good challenge, though... Carbide thread mill, perhaps? It's possibly a good video.
I love youtube. It's like watching magic
Great method. Thanks 👍
When you zero in the adjustable chuck do you have to re-zero your drill bit holder to pick up the new centerline?
No, the center of rotation always stays the same, its just the chuck with the part thats shifting around.
(In reality you have to compensate always a bit with the drill chuck since the drill chuck does not clamp consistent either. But thats a problem with either tailstocks and with drill chucks in the toolpost.)
Never seen an aluminum clam, I say rename the fixture to clamp shell. Excellent video the precision in the machining is equally matched with the precision videography.
It looked like both ends had holes for centers but I guess they were not as I don't see why they would be needed for making the blank.
yeah they are centered on both ends, but I could not figure out a good way to use that for precision drilling/boring/reaming in this case
@@StefanGotteswinter Ok. Could one have turned down the pressed on ring between centers and then hold on to that part in a collet? Might be more work I guess. Nice to learn from your videos. I would have struggled to come up with the clamp shell idea :)
Hey Stefan what are the absolute craziest tolerances you ever had to work with?
generally the worst is like +-2µm
What cutting fluid are you using and where can I get a bottle with a metal tip like yours? Love your videos. Been watching since you started.
I think he uses a lot of ethanol. McMaster in the states has a similar set of tips listed as "Stainless Steel Dispensing Needles with Luer Lock Connection" and you can probably find a bottle with a matching top connector. Hopefully that points you in the right direction
What bobbob said :-)
Luer lock dispenser needles and bottles, i use 3 cooleants in the shop:
- Isopropanol alcohol for aluminium/some plastics
- Jokisch Alpha 93 cutting oil for slow, heavy cutting operations
- Water soluable cooleant for high surface speed operations and flood cooling on the mill
@@StefanGotteswinter damn I though you use Indian Pale Ale,,, that's what I use anyway, but no surprise German beer is made of Isopropanol
And, to expand your potential options: “Luer Lock” is the same connection used nearly universally for syringes/needles in the medical field.
So, you could get pretty much any diameter “stainless steel dispensing needle” at your local drugstore.
The more tricky part would be finding a Luer-lock compatible cap for a squeeze bottle.
Is there a reason why you can't indicate the tooth section while clamping the end? Also, is such a small runout going to make much of a difference when driving a timing belt?
I didnt trust the pressed on end at all for runout and wobble - That would have made me question every part constantly :D
You know a this guy is a machinist because he erars an "O"ring on his wrist!
wouldn't few pieces of needle bearing rollers in the grooves and grabbed in a collet be good enough for this?
would probably work well, but I had to do 22 in total, thats a lot of picking up dropped needle rollers :D
@@StefanGotteswinter rubber bands to hold them in place while sliding into the collet :D
Wie funktioniert das einstellen vom Zentrafutter mit den seitlichen Einstellschrauben? Musst du da erst Schrauben lösen und danach wieder festziehen? Oder bleibt das Futter auf dem Flansch aufgeschraubt und die Schrauben dehnen sich um den Verstellbereich? musst du jeweils die 3 Schrauben wieder gegeneinander verspannen oder kann man diese nach dem Justieren wieder etwas zurückdrehen?
Früher hab ich die Futterschrauben etwas gelöst zum verstellen, aber mittlerweile mach ich das nicht mehr - Zwischen Futter und Flansch hab ich MoS2 Montagepaste und die M10x1 Feingewindemadenschrauben schaffen es spielend das Futter bei voll angezogenen Schrauben zu verschieben - Nach dem verrutschen nehm ich die Madenschrauben auch wieder etwas zurück, das Futter bleibt einwandfrei stehen.
Hi Stefan, würdest du in einem deiner nächsten Videos kurz auf deinen Stabschleifer eingehen? Grüße aus Laaber😅
Oder du verlinkst mir hier ein Video indem du darauf eingehst:)
Das ist ein NSK EVO - Ein richtiges Video hab ich dazu nicht, man sieht ihn halt abundzu :D
Ich kann auf dem deutschen Kanal evtl ein kurzes Video dazu machen.
How confident are you that the OD of the pulley teeth is concentric with the pitch diameter?
In this case very confident - Since the gears where hobbed with a full profile hob, that cuts everything on the profile, including the OD (You can see the machining marks on the OD from the hob)
@@StefanGotteswinter YOU can see the machining marks, I wasn't sure whether I could on video😀
? Why is the tolerance of the centre so tight for a timing belt pully? It's not like the belt itself is so precise, nor can the belt work under very high speeds (if it was for vibrations)
I spy an Adam made thin Vee block...
quick and easy
Nice one! I don’t quite get why the engineer in charge wants 20um concentricity on a belt gear but still a nice method to know.Maybe someone can enlighten me? :)
These Belong in a high precision rotary axis - Any larger concentricity would lead to dividing error on the output spindle.
Stefan are you listening to your own voice in the background for an expert's opinion?😅👍🏻
:D
Im qurious about the application. Tight tolerances on the concentricity, but then, I assume, drive a rubber belt with it..?
"rubber belt" is a bit simplified - Modern timing belts are precision components and the gears have a decent requirement for precision too, to keep speed and timing constant. (In this case some sort of precision rotary axis is driven)
Hi Stefan, just wondering how you deal with the burr in the bore from the tap, do you team again?
Cordless drill and reamer 😎
I wonder what machine or mechanism needs 0.02mm runout precision on a timing belt gear...
Something that needs very precise timing and constant speed - Any runout in the gear will give problems in that regard.
(These go in some sort of rotary axis)
Also: its speced in the drawing, so i will make it like that ;)
@@StefanGotteswinter Good old MIL-TPF-41 :)
@@StefanGotteswinter fair enough 😊