DIY Angle Grinder Tennis Ball Machine (Part 1)

Part 2: • DIY Angle Grinder Tenn...
Part 3: • DIY Angle Grinder Tenn...
All parts and tools were purchased through Amazon, eBay, or Home Depot. I liked the idea of using angle grinders as my motors for some reason and attaching the bench grinder wheels couldn't have been easier. (As a quick note, I left 34mm of space between the wheels which is exactly half the diameter of a tennis ball. It seems too narrow but it gives great results.) When all was said and done, I probably could have got a new factory made machine for about the same cost with what I ended up spending on parts and tools (including a lot of waste from trial and error), but building it was actually a lot of fun and I got to add a few new tools to my garage. What I didn't expect was the amount of time it would take to put together. It seems like a fairly simple project, but it ended up being pretty involved. This was my first welding project and I have no real electrical training so someone with more experience could probably do it a lot faster, but it took me about 4 months. I'd only recommend building one if you're doing it for the fun of it. Although if you don't care about it being able to move vertically or horizontally, you could simplify it quite a bit. Overall, I'm happy with the result and have enjoyed using it with no problems so far. I'll have to keep you updated on how it holds up long term. If you have any questions about a specific dimension, I'd be happy to answer them or provide my rough sketches of the circuits I made. I'll provide my parts and tools list in the comments.

[@manuellazarte_]

Wow! That's beautiful! I'm from Argentina and your project is going to be my guide to construct one for my team

[@GaryT85.]

That's excellent! I'd love to try something like this - currently have next to no time available though 😩

[@philipgoss9484]

looks great, will have a go.

[@Occlusodontiste]

Good job Tanner

[@tannerlarson3289]

Thanks!

[@carolyno4928]

Fantastic! Creative.

[@Shariiif1]

Nice job, man! 👌 Love the doggo, too.

[@Oliffin]

nice project

[@tannerlarson3289]

Thanks!

[@TediBearProductions]

Were you ever able to get it to tilt at a full 45-degree angle either forwards or backward with the mechanism described at 1:17? I ask because this does not appear to be able to handle such tilting without the nut bending (which would cause the rod and the motor attached to the rod to also tilt).

[@tomtwatarse5846]

Love this shit .. the sort of crackpot thing I'd end up creating ..and it would also look like a time machine from the 1800s.

[@tannerlarson3289]

Haha best comment

[@evanjordan7632]

Nice project! I am building one myself and nave a question on how you did your wiring. Did you use a cordless angle grinder or a battery powered one and how did you connect it to your speed controllers? Thanks

[@FollowFunk]

Great job, Where exactly did you send the outputs of the speed controllers to? What inputs on the grinders?

[@wfrasson00]

Tanner good morning all right? How many balls does your carousel support, can you send the details of the fitting that is made of the engine with the "bucket"? thank you.

[@BillStArnaud]

How do you do the automatic left right oscillation? Do you use limit switches?

[@ohnor]

I noticed that you mentioned you had a 5/8 in bore with bench grinders attached to them. I cannot figure out for the life of me how to get my motor shaft bigger than 6 to 8 mm, and that is with using a coupler to bring it up from 3.175 mm to 6 mm. All of the angle grinders that I look up have a much smaller bore size than 5/8 of an inch. Any ideas on what I can do? Also, how did you manage to get the bench grinders to attach to the motor shaft? Was it the Pololu mounting hubs? Great build by the way! And thank you for the help!

[@LiveAndLearnWithMe]

you are the winner of youtube DIY tennis ball machine. Couple questions. 1) what did you say the green thing that you tape to the grinding wheels? what is the space between the wheels?

[@tannerlarson3289]

Haha thanks! The green things are silicone wristbands that I stretched over the wheels. They're pretty grippy and don't shred the balls as much as the grinding wheels would. Here's the link where I bought them: www.amazon.com/gp/product/B01JQ3XQ2K/ref=oh_aui_detailpage_o07_s02?ie=UTF8&psc=1 The space between the wheels is 34mm, which is exactly half the diameter of a tennis ball.

[@the90sInc]

Hi, please would you be willing to provide a rough sketch of the circuits you made, the dimensions you used to cut the metals and the materials and links you used to build it. I have a project similar to this, but i have to do mine using the projectile theory, i'd really love feedback. Best regards...

[@NeuralEngin33r]

3:30 dog be like: i got this

[@robertoperry7337]

Wow really nice, good job!! Can you say me wich kind of disc did u used? Please help me...

[@sweg8116]

How does the horizontal oscillation work?

[@Swenser]

I'm struggling with having many balls in the hopper jamming in all sorts of ways. How can I solve that problem? How do pro machines overcome that? Do they just use super strong motors that can push through any jamming? Or is it about geometry? Both?

[@garvinmccarron7080]

Hi Tanner, I am currently in the design process of building my own tennis ball launcher and am intrigued by the work you have done. I was just wondering if you preformed any calculations for the distance between the wheels, the distance the ball will travel or the necessary value of friction between the ball and the rubber bands? Any help would be appreciated.

[@Occlusodontiste]

5 cm beetween the wheels around

[@arsenasaturyan2502]

how far the ball can go at wheel's max.speed?

[@eduardoceccon8873]

Hi Tanner. First congrats for your great job. And congrats as well because you were the first one that made available all informations with no request. So, i am from Brazil and here the tenis machine are so expensive then i am building it as well, and i`d like to keep in touch for change ideias and request some informations when necessary. If possible i`d like used this space for ask Rodrigo wich kind and specifications of the motors that him has used. Thank you so much

[@tannerlarson3289]

Thanks man I'm happy to share. There's probably a million ways to improve on my design and I'm definitely curious to see how other people do it. If you have any questions feel free to ask me, and I don't mind you chatting with other viewers here either. Looking forward to seeing your machine!

[@eduardoceccon8873]

Thanks man.

[@tannerlarson3289]

General tools list (you could probably get by with less but this is what I used): - Protective goggles -Protective ear muffs - Leather gloves - Chop saw - Welder, welding helmet, welding gloves - 90 degree welding magnets - Level - Carpenters square - Tape measure - Permanent marker - Electronic caliper - Angle grinder - Drill press - Power drill and cobalt drill bits - Hole saw drill bits - Automatic center punch - Cutting fluid - Dremel with diamond cutting disc bit and metal-cutting carbide bit - Metal files - Screwdrivers, socket drivers, etc - Allen wrench set - Bench vise - Vise clamps - C clamps - Needle nose pliers, tongue-and-groove pliers - Wire cutters - Scissors - Wire crimpers - Anderson Powerpole crimpers - Wire strippers - Soldering Iron - Flux - Heat gun - Helping Hands soldering station - Zip ties, assorted sizes - Exacto knife - Electrical tape

[@blueprintbox5290]

You're a life saver ! THANK YOU from the bottom of my heart

[@dawoodfm_146]

What materials do you use The rotatory spong or else

[@Swenser]

How far apart are the wheels? Building my own and am about to sit the wheel mech in place. Haha.just seen your post. 34cm. Sweet.

[@izzatrusyaidi6950]

Hi Tanner. Great project. I'm a first year student in Mechanical Engineering. And we have to do design analysis about ball launcher. Do you have any cad file? Or any cad file that I can refer to? Thankyou for your time :)

[@tannerlarson3289]

Sorry I didn’t use cad to design the project. I just wrote it out on paper as I went along

[@typenn84]

how did you fit 5 grinder wheels onto the grinder? what some kind of extension used

[@tannerlarson3289]

Actually the grinder wheels have a 5/8" arbor so they thread directly onto the angle grinders' 5/8" threaded spindle- no extension needed! You just have to make sure you connect the batteries in the right polarity so the motor spins in the right direction. Otherwise the wheels' mass would loosen the wheels off and could cause some damage. Also when you go to stop the machine you have to turn the speed down slowly rather than shut it off from full speed (for the same reason).

[@typenn84]

I know the wheel fit on there, Im asking how you got 5 wheel onto the arbor. I can only fit one attachment on my grinders, how did you manage to get 5?

[@tannerlarson3289]

5"x2" refers to the wheels' dimensions. I used a total of 2 wheels that are each 2" wide and 5" in diameter. Only one wheel per grinder. 5 wheels would be pretty cool though haha

[@typenn84]

Tanner Larson ahh I guess those bands were throwing me off. Where did you purchase the wheel?

[@tannerlarson3289]

I found them on eBay: www.ebay.com/itm/2-PK-Silicon-Carbide-Grinding-Wheel-for-Shaping-Granite-Marble-Arbor-5-8-11-/162058661387?var=&hash=item25bb72ee0b Here's a link for Amazon: www.amazon.com/PK-Grinding-Stones-Abrasive-Travertine/dp/B079G4V8WT/ref=sr_1_1?ie=UTF8&qid=1524165304&sr=8-1&keywords=2+PK-Silicon+Carbide+Grinding+Wheel+for+Shaping+Granite%2C+Marble+-+Arbor+5%2F8%22-11

[@ivo7418]

What battery did you use to power the whole circuit?

[@tannerlarson3289]

Right now i'm using four 14.8v 4s 10ah Multistar LiPo batteries like they use in RC planes. Here's a link but if you look around you can find them cheaper. I got mine during a sale on hobbyking.com for around $45 a piece. www.ebay.com/itm/MULTISTAR-10000mAh-4S-14-8V-10C-20C-LIPO-BATTERY-XT90-DJI-TAROT-550-680-QUAD-HEX/272915928850?hash=item3f8b0e9712:g:tYwAAOSwFb5Z~qq0

[@msspmbbs]

The wheels on the angular grinders.. size

[@KeremCaglarY]

Hi Tanner, ı wondering about the distance of whells. what is the measure between the whells. 5 cm or 6 or anaother. thanks...

[@tannerlarson3289]

I left 34mm between the wheels

[@KeremCaglarY]

the ball diameter is 65mm...is 34 mm too little, isnt it? in this measure is the ball damaged? thanks...

[@tannerlarson3289]

It seems like it would be too small but it actually works very well and the tennis balls are able to compress without being damaged. I was following another project that had tested several different distances and 34mm is the number that provided the best results. I was skeptical too but I went with it and it works well.

[@KeremCaglarY]

You are right, ı set 50 mm but it was too slow, now ı will change 34mm. And the other one is what is yor whells material? I made teflon but its not good enough. I saw green materials on your whells, what is that? maybe ı can shield my whells witf that.@@tannerlarson3289

[@wfrasson00]

Tanner Larson hello Tanner how are you? I saw that you put a comment that the distance between one wheel and another was only 34mm, even though the ball is 65mm. did you test with 40mm, 50mm? what percentage won in the distance of the launch of the ball? thank you very much!

[@Grdlk-qd9ug]

Heyy.. Really nice job. Im about for my first same project. Can you provide your tools and list of parts?

[@tannerlarson3289]

Thanks! I listed all my tools and parts in some comments about 2 years ago. Let me find them and I’ll put them as replies to your comment too

[@tannerlarson3289]

General tools list (you could probably get by with less but this is what I used): - Protective goggles -Protective ear muffs - Leather gloves - Chop saw - Welder, welding helmet, welding gloves - 90 degree welding magnets - Level - Carpenters square - Tape measure - Permanent marker - Electronic caliper - Angle grinder - Drill press - Power drill and cobalt drill bits - Hole saw drill bits - Automatic center punch - Cutting fluid - Dremel with diamond cutting disc bit and metal-cutting carbide bit - Metal files - Screwdrivers, socket drivers, etc - Allen wrench set - Bench vise - Vise clamps - C clamps - Needle nose pliers, tongue-and-groove pliers - Wire cutters - Scissors - Wire crimpers - Anderson Powerpole crimpers - Wire strippers - Soldering Iron - Flux - Heat gun - Helping Hands soldering station - Zip ties, assorted sizes - Exacto knife - Electrical tape

[@tannerlarson3289]

Main Parts: - Main Motors: 18v DC Ryobi brushed angle grinders (6500 rpm) - Wheels: 5"x2" Green Silicon carbide bench grinder wheels (balanced for use up to 9000rpm) - Batteries: 4 x Multistar 4s 14.8v 10ah LiPos - Vertical adjust motor: Uxcell 12v DC 550rpm gear motor - Horizontal adjust motor: Uxcell 12v DC 2rpm gear motor - Relays for random oscillation circuit: NTE Electronics R25-11D10-12 Series R25 PC Board Mount Epoxy Sealed Relay, DPDT, 10 Amp, 12VDC - Timer for random oscillation circuit: Mini Timer Time Delay Relay .2 Sec to 1000 Hours. 12V 5A. Power on or Off Delay, Cycling and More - Ball hopper bucket: Behrens 1214GS 14-quart galvanized steel pail - Feed mechanism motor: Uxcell JSX950-370 DC 12v 9 rpm motor - Feed mechanism disc: Made from plywood, styrofoam, screws and Gorilla tape - 12V DC speed controllers for main motors: KNACRO PWM speed controller 60A - 12V DC speed controller for feed mechanism: uniquegoods 12v digital display LED DC motor speed controller PWM - Bearings: 3 x UCF202-10 pillow block flange bearing 5/8" bore - Ball chute: 4 in. dryer duct from Home Depot attached to threaded PVC pipe couplers - Rocker switches: E Support Car 12v 20A rocker switches - DPST button: Uxcell a15071300ux0649 Mounted Thread Flat Head Latching Push Button Switch, DC 12V, 22 mm, White LED Light - Battery charger: Imax B6AC+ RC Lipo/NiCd/NiMH Battery Dual Power Balance Charger Discharger Y1H8 - Battery low voltage alarms: Li-Po LiPo Low Voltage Cell Checker (2S~8S) Alarm Twin Alarms U178

[@tannerlarson3289]

Other miscllaneous parts: - Pelican 1200 case for safely carrying/storing batteries - Pololu 1083 UNIVERSAL ALUMINUM MOUNTING HUB FOR 6mm SHAFT PAIR, 4-40 HOLES - 5/8" Bore Stainless Steel Shaft Collars Set Screw Style (4 PCS) - 5/8" Threaded rod for horizontal axis shaft - uxcell 6mm to 6.35mm Shaft Coupling 25mm Length 18mm Diameter Stepper Motor Coupler Aluminum Alloy Joint Connector for 3D Printer CNC Machine DIY Encoder (for vertical adjust mechanism) - 2 of uxcell 37mm DC Geared Motor Mounting Bracket Holder + 6mm Hex Coupling - TheAwristocrat Multi-Pack Wristbands Bracelets Silicone Rubber, , Adult, 202 mm, Green, 1 Dozen - AmplifiedParts F1615 Rubber Amp/Cab Feet, Large Tapered with Washers, 4 Count - 6mm x 5/8" Flexible Jaw Spider Shaft Coupling CNC Router Stepper Motor 15.875 mm (much cheaper on eBay) - Everbilt 3/4" S-Hooks - 1/4" x 12" threaded rod for vertical adjust mechanism - XT-90 High amp connectors - 30A Anderson PowerPole connectors - GardnerBender tab ring terminals - 14 AWG wire - Rubber grommets, assorted sizes - Heat shrink, assorted sizes - Solder - Square steel tubing, steel flat bar, round steel rods, sheet metal, miscellaneous screws, nuts, couplers, etc. all purchased at Home Depot - Wilson 75 Tennis Ball Pick Up Hopper - INNX Stretchable Back Seat Dog Barrier with Storage Net, Front Seat Pet Barrier for Sedan,Suv, Mini-Van,pick up truck (11" x 12.6")

[@neelmanne6585]

Where did you find those angle grinders

[@tannerlarson3289]

I bought them at Home Depot

[@ashleylarson8645]

Would you be able to give me tips and possibly a list of tools for a “DIY husband”? Mine seems to be broken 😕

[@tannerlarson3289]

😂 broken but still good!

[@koshitek]

Nice job. Why not just use two china motors like you did with the tilt and swivels.

[@wfrasson00]

Hi You can share your size of your project? Do you have cad file? Thanks

[@wfrasson00]

You project is amazing! If is possible, you can share with me? [e-mail]

[@tannerlarson3289]

Thanks! Sorry I didn’t use any cad in designing the project. But if you have any questions I’ll answer them as best I can

[@vanlanchannel1983]

what motors do you use?

[@tannerlarson3289]

They’re Ryobi 18 volt angle grinders

[@modsavant]

Was this a high-dea? holy Christ... but damn that's impressive.

[@tannerlarson3289]

Haha high on life

[@tannerlarson3289]

Other miscllaneous parts: - Pelican 1200 case for safely carrying/storing batteries - Pololu 1083 UNIVERSAL ALUMINUM MOUNTING HUB FOR 6mm SHAFT PAIR, 4-40 HOLES - 5/8" Bore Stainless Steel Shaft Collars Set Screw Style (4 PCS) - 5/8" Threaded rod for horizontal axis shaft - uxcell 6mm to 6.35mm Shaft Coupling 25mm Length 18mm Diameter Stepper Motor Coupler Aluminum Alloy Joint Connector for 3D Printer CNC Machine DIY Encoder (for vertical adjust mechanism) - 2 of uxcell 37mm DC Geared Motor Mounting Bracket Holder + 6mm Hex Coupling - TheAwristocrat Multi-Pack Wristbands Bracelets Silicone Rubber, , Adult, 202 mm, Green, 1 Dozen - AmplifiedParts F1615 Rubber Amp/Cab Feet, Large Tapered with Washers, 4 Count - 6mm x 5/8" Flexible Jaw Spider Shaft Coupling CNC Router Stepper Motor 15.875 mm (much cheaper on eBay) - Everbilt 3/4" S-Hooks - 1/4" x 12" threaded rod for vertical adjust mechanism - XT-90 High amp connectors - 30A Anderson PowerPole connectors - GardnerBender tab ring terminals - 14 AWG wire - Rubber grommets, assorted sizes - Heat shrink, assorted sizes - Solder - Square steel tubing, steel flat bar, round steel rods, sheet metal, miscellaneous screws, nuts, couplers, etc. all purchased at Home Depot - Wilson 75 Tennis Ball Pick Up Hopper - INNX Stretchable Back Seat Dog Barrier with Storage Net, Front Seat Pet Barrier for Sedan,Suv, Mini-Van,pick up truck (11" x 12.6")

[@neelmanne6585]

could you post a link?

[@tannerlarson3289]

www.homedepot.com/p/RYOBI-18-Volt-ONE-Cordless-4-1-2-in-Angle-Grinder-Tool-Only-P421/100519983

[@ryanwilkes7800]

sickest thing ever zomg

[@Swenser]

Very sad. I can come and play tennis with you.

[@tannerlarson3289]

Main Parts: - Main Motors: 18v DC Ryobi brushed angle grinders (6500 rpm) - Wheels: 5"x2" Green Silicon carbide bench grinder wheels (balanced for use up to 9000rpm) - Batteries: 4 x Multistar 4s 14.8v 10ah LiPos - Vertical adjust motor: Uxcell 12v DC 550rpm gear motor - Horizontal adjust motor: Uxcell 12v DC 2rpm gear motor - Relays for random oscillation circuit: NTE Electronics R25-11D10-12 Series R25 PC Board Mount Epoxy Sealed Relay, DPDT, 10 Amp, 12VDC - Timer for random oscillation circuit: Mini Timer Time Delay Relay .2 Sec to 1000 Hours. 12V 5A. Power on or Off Delay, Cycling and More - Ball hopper bucket: Behrens 1214GS 14-quart galvanized steel pail - Feed mechanism motor: Uxcell JSX950-370 DC 12v 9 rpm motor - Feed mechanism disc: Made from plywood, styrofoam, screws and Gorilla tape - 12V DC speed controllers for main motors: KNACRO PWM speed controller 60A - 12V DC speed controller for feed mechanism: uniquegoods 12v digital display LED DC motor speed controller PWM - Bearings: 3 x UCF202-10 pillow block flange bearing 5/8" bore - Ball chute: 4 in. dryer duct from Home Depot attached to threaded PVC pipe couplers - Rocker switches: E Support Car 12v 20A rocker switches - DPST button: Uxcell a15071300ux0649 Mounted Thread Flat Head Latching Push Button Switch, DC 12V, 22 mm, White LED Light - Battery charger: Imax B6AC+ RC Lipo/NiCd/NiMH Battery Dual Power Balance Charger Discharger Y1H8 - Battery low voltage alarms: Li-Po LiPo Low Voltage Cell Checker (2S~8S) Alarm Twin Alarms U178

[@coolestdadever]

Tanner, this is really cool. I'm building one myself but for some reason my ball feeder is getting stuck. Do you have any issues when the bucket is full? Or the bottom plate keeps turning no matter what?

[@tannerlarson3289]

Rodrigo, thanks man! Yeah I'm kind of working through that issue myself. Sometimes when the bucket is full the balls will push on each other in such a way that they get suspended above the bottom feeding plate. The plate is turning fine but no balls are dropping in. I suspect it is partly due to the funnel shape of the bucket. If I hit the bucket a couple times the balls shift and fall into place and it works normally again for a while. I tried to fix this by adding a big vertical bolt into the feeder plate to kind of stir the balls as it goes around, but what ended up happening is that the bolt would eventually pin a tennis ball or two up against the side of the bucket and the mechanism would get jammed and stop turning. Then I'd have to dig through the bucket to unjam the balls, which was more of a hassle than the original problem. I think what I'm going to try next is some kind of solenoid bolt on a timer, where every 10 seconds or so it gives the bucket a jolt to keep the balls from getting suspended above the plate. If I get it working I'll let you know. Do you have any videos of your build? I'd love to see it!

[@coolestdadever]

Hi Tanner, I don't have any videos yet and I'm far behind you :) I'm prototyping with wood right now and using "scooter wheels" to throw the balls. For the feeder, I found out the motor I was using didn't have enough torque, now I'm good and the thing is turning right. To avoid having 2 balls dropping at the same time, what I did was instead of having the "L" plate you have, I've put a metal wire "transversal" to the bucket... as such, no balls drop on top of the one the feeder has already collected. I've also added some cardboard inside of the bucket so it looks more like a tunnel. So far, so good. Question, where / how did you build the metal structure of yours? Did you weld all this together?

[@eduardoceccon8873]

Hi Rodrigo could send me your email for change some ideias with you? Thanks

[@eduardoceccon8873]

Or if you prefer you can send a email - [e-mail]

[@VietPham-ps9dr]

hello tanner

[@tannerlarson3289]

Hello!

[@smarttrain7651]

Hello, we are a group of 16 year olds from Spain and we have a project underway. Our project is to make a paddle ball machine. We've seen your result and we've been amazed. We just wanted to know if you could help us on some issues because we're a little blocked. The only thing our ball thrower wouldn't have to be so professional. Something more accessible to us and feasible. We would appreciate a lot a little help explaining the process because we really need it. Could we talk about it? Thank you very much.

[@tannerlarson3289]

That sounds like an awesome project. I’d be happy to help with whatever I can!

[@smarttrain7651]

Thank you very much! Can we contact you by mail and we explain you what is the project about? We have some doubts about the mechanism of the ball thrower.

[@tannerlarson3289]

Sure! Send an email to [e-mail] and I’ll respond with my real email address.

[@smarttrain7651]

Okay @@tannerlarson3289

[@jeffbrand3775]

Hey @@tannerlarson3289 I sent an email to the address above. It didn't appear to get kicked back, so I wonder if you receieved it?

[@joseppi4cinqua]

Weighs only 400 lbs.

[@steinanderson9849]

I won't judge the welding, but there's no welds on that frame, only bird poop!