I'm far from being an expert, but I did en internship in a machine shop and did a lot of surface grinding. Something feels really dangerous to me in your program : you're cutting in both direction. The thing is that when you do "climb" cutting (analogi whis milling here), if the part sleeps, the wheel will bite into it even more, making it worst. You will end up a part thrown through you're shop at bullet speed, and the wheel will probably explode. For this reason you only want to do some "conventional" cutting, and you must never stay in the plane of the wheel, because failure could lead to very bad injuries in case of a wheel explosion, which happens a lot more than you think 😅 Hope this will be helpful, take care with this kind of machine, they can be really dangerous :)

Hi Guys, Thanks for the shout out. I've been following your build from the beginning and am quite impressed with what you've achieved. I never expected that kind of tolerance or finish. The finish on it is due most likely to spindle noise, also dressing the wheel properly will make a huge difference. You need a faster traverse, and no stopping or hesitation. Keep the traverse speed as constant as possible. The single point diamond should be mounted 10 or 15 degree angle pointed away from the center of the wheel instead of straight up. A six point cluster diamond (like shown in some of my videos) may give you better results, this one you mount straight up. The wheel I would recommend would be the Radiac RAA46 H800 VOS, it's a porous wheel that is very free cutting. It generates very little heat so it works good without coolant. I have used one that I'd be happy to mail to you for use free of charge, if you'd like. Soft steel is harder to grind and get a good finish than harder steel. I would recommend trying to grind O1 or A2 that's 50-58 rockwell. I know some of your commenters give you some flack, they might be correct on some criticism, but what you achieved so far is very impressive to me. Regardless of how well the grinder turns out, the learning experience is worth it's weight in gold. Thanks for the great series. Steve

Spindle shaft and bearing dimension are probably not stiff enough and the wheel looks like it’s unbalanced. The sound produced when you started the spindle indicates a "floating" or wobbling wheel that’s why the surface finish is wavy. Look at the black marks on the wheel, it’s suppose to be all a long the perimeter of the wheel not just few spots. Hope this will helps.

I used to surface grind quite a bit when I was an apprentice and once I warmed up the spindle bearings I would dress the wheel and it would not turn off until my grinding was complete. it seemed that once you turned off the spindle it would start to chatter and you would have to redress the wheel to eliminate it. The Grinders in the shop stay on all day. I hope that helps

@jody6121

2 жыл бұрын

Thanks for teaching me something.

Cool. Looking forward to seeing this in production. Thanks for the video

I’ve enjoyed watching this project a lot, guys! Nice to see it making “chips” Have tried going way slower on your Y feed? It looked pretty high as others have said and that will tax everything a lot more. Also, as others have said, only grind in one direction- have the software wind the table back before advancing for the next pass. Take the smallest Y steps your setup can manage, to see what the best possible finish would be for the machine. Surface grinding is not fast. 😁

@Blondihacks

4 жыл бұрын

Chris You’re talking about the X axis. I said the Y is feeding too fast.

@stephencurtis2282

5 ай бұрын

Agree Blondihacks. I have slowly advanced over the Y passes and kept the X (left -right) passes as high-speed. Also, wheel dress is vital as is the minimization of vibration from any source.(belt, motor, wheel)

Good creative editing on this episode guys. All your post work shows you’re making a show not a vlog. Keep going!

I use 46 grit and have a mirror finish on parts. The reasons that I can see are 1) balance and vibration (I minimised these with an O-ring belt drive, balancing the wheel and getting rid of the V-belt discontinuity with the smooth 10mm O-Ring drive while using minimum belt tension). 2) Stiffness of the system overall - new bearings and solid material in the machine itself. 3) Wheel dress. I spent a lot of time working out how to dress the wheel so that it was smooth on the face and exit (where the final finish comes from) and nicely parallel to the ways. The edge of the wheel does the cutting. The rest of the wheel does the smoothing (pretty much regardless of the grit), thus enabled by the diamond dresser cutting off the sharp edges on the grit granules - if you're careful. Also, I used small increments (about 1mm per increment step) in ONE DIRECTION for each pass over the part. I never went back and forth in the passes - only cut one way. This was very satisfactory to observe as the zigzag pattern disappeared and the 'record grooves' pattern also became flat with no perceptible roughness - even with 46 grit J hardness wheels!!

Nice - Glad you guys are making and publishing again.

I worked on a large cylindrical grinding machine a long time ago. The wheelhead was a large fabricated steel box and we had loads of problems with vibrations and poor surface finish. The machine was improved by filling the void in the wheelhead with concrete to stop it vibrating !!!

Board it up and fill with epoxy granite, be super rigid then :)

@exhempknight

4 жыл бұрын

Agreed!

@ErikBongers

4 жыл бұрын

This comment pops up about every video of this project, but no. Next thing they will try on the chatter is probably repainting the machine in another color to see if that makes a difference. Stubborn.

@hinz1

4 жыл бұрын

Or just build a surface grinder from used granite tomb stones, since linear rails can be bolted to about anything. Non normalized, welded steel frame is about the worst material for machinery, especially for surface grinders, where precision and good dampening matters the most. So far, lots of effort for an inferior machine. Made those mistakes as well, when I was young. But learned from it, like that you can't build everything at home. And if you try, it usually will be a mess.

@nicoleyensen7062

4 жыл бұрын

@@hinz1 what do you suggest if they want to start a business? If they really will put in the extra work to refine things do you think it can be done, or is it just an exercise in futility?

@joesosnowski7568

4 жыл бұрын

@@ErikBongers 😂

Neat ,I am a Mold maker by trade(50 yrs). 1: Once you dress the wheel do not turn it off. Never touch of with a dead wheel. 2: You need a actual grinding spindle cartridge. 3: Grinding wheels have code which you need to learn. For general Tool and Die/ Mold making. , 46K( a harder type wheel) for soft. 46H for hardened tool steel(which is a softer bond). There is also different types of grits, and bonds used for different applications. And Lastly #4. Use a actual lead (ball type) screw on your Z axis. So you can get actual .0001 increment feeds with your hand wheel.

At about the 10 min mark in the video... I dont think that is chatter at all. I think that if you calculate how far the work piece moves for each revolution of the grinding wheel you will get a distance that corresponds with the distance between the "chatter" marks. This is caused by a slight unbalance in the wheel setup which causes some small vibrations as the work piece moves along. And the wheel revolutions is very low, so the work piece travels some distance for each revolution of the wheel. Therefore, increase wheel rpm and decrease work piece feed. I would say 3000 to 4000 rpm would be good speed for that size wheel.

@exhempknight

4 жыл бұрын

Good point about the RPM, though I don't think balancing really matters. A lot of small surface grinders (5x10, 6x12) don't have provisions to balance the wheels.Throw it on, dress it, true and go. Although I will admit they're using a wide wheel... I'm used to seeing 1/2" wide wheels. Might matter a bit more, as it's likely a bit heavier. I still think the surface waviness is related to the cogged drive belt. 3-4k RPM sounds about right. It's more about surface feet per minute (SFM). Most surface grinders with 3450 RPM motors, which gives around 6k SFM with a 6" or 7" wheel. You can change the behavior of the wheel by playing with the RPM, faster making it act like a harder wheel, slower, softer. You definitely don't want to exceed the rated speed of the wheel, however. Maybe 3450PRM +/- 20%.

@christopherleveck6835

4 жыл бұрын

@@exhempknight when you true and dress your wheel you are balancing it. The washer and nut combo that seems like a really cheesy way of mounting the wheel to begin with is like a self centering system. The first time you run it it tries to center it, you true it, you're halfway there. When you dress it you should be very close to a balanced wheel.

@MrHughk1

4 жыл бұрын

@@christopherleveck6835 Dressing the wheel has very very little to do with the ballance, think about it.

@ipadize

4 жыл бұрын

@@christopherleveck6835 totally wrong about the balancing part. you have to balance it first and then dress it. Maybe even balance it after dressing again. no wheel comes out perfectly balanced. I work at a toolmaker company. Every machine will vibrate when the wheel is out of balance

@5tr41ghtGuy

4 жыл бұрын

Chatter could certainly be due to unbalance, but also due to the resonant frequency of the machine in the vertical direction. All machine tools have resonant frequencies, which is unavoidable, but they are designed to avoid exciting those frequencies during use. If PA did any stiffness or vibration analysis before fabricating this grinder, I missed it.

I'd say you've done a good job. The "chatter" is from the machine vibration/harmonics. If you cant add more weight or stiffening, try a counterbalance/tuning arm. It may be as simple as adding a long stiff threaded rod with heavy nut to adjust. Trial and error locating it

Epoxy granite might be able to provide some good vibration dampening and structural rigidity, if you want to reduce chatter even more.

Cool machine. Maybe balance the wheel and dress in one smooth motion.

I think that you are at the point with the surface grinder, that you have solved all the problems that you can with your skill sets, and now the only thing that holds you back is that you don’t know how to use a surface grinder.

Never touch the grinding wheel off the part without the spindle running. The moment you touch that wheel without it spinning you move the wheel itself by a slight bit. This throws off the dressing and true conditions of the grinding wheel, which destroys your finish. I got 11 years of straight surface grinding experience in a high precision (e.g., + or - .001" tolerances).

@JohnSmith-ps7wp

4 жыл бұрын

It also might put a micro crack in the wheel setting them up for an exploding grinding wheel.

@GeneralChangOfDanang

4 жыл бұрын

High precision and + or - .001"? Was that a typo?

@jonnypilotfish

4 жыл бұрын

@@GeneralChangOfDanang No shit, you could probably hold .001 even with the POS in the video

@xenonram

4 жыл бұрын

@@GeneralChangOfDanang It's someone spewing b.s., who didn't realize he should have said 50 millionths, if he wanted to impress us.

@TheHarryroks

4 жыл бұрын

@@xenonram Agreed lol

Done a diesel cylinder head surfacing couple of times on an industrial grinding machine - obtained the same pattern as showed in video

Make sure to balance the grinding wheel before using it or it will induce vibrations

@ShopperPlug

Жыл бұрын

How do you balance the wheel?

think the chatter is from the cibrations of the machine itself , you can hear it when the machine is spinning even when its not grinding the rpm are dropping down when youre start grinding too , basicy meaning that you cut more at a high rpm and then grind less once the rpm goes down another thing that might cause some shaking in the surface finish is if the drive motor for the stone has only a few poles and the shifting between them to rotate the engine causes the motor to not run quite as fluid as it should , maibe putting two motors on there with the poles slightly offset would helpn both the problem of the rpm drop and the slightly unround running

This could be even better with some epoxy granite fill in the frame (that wouldn't be too difficult either), a good preloaded spindle cartridge with abec 5 or 7 bearings, and some covers for those linear rails or they'll get crunchy and start sliding in a hurry. Having fun watching the process.

If I could make a suggestion, please remove all the retakes. They take up a lot of time when you add them up and the cut sound is annoying. The video would be much more polished and enjoyable without them, IMO

To improve your surface finish you might try 1. A 46 grit wheel and make sure that it is bonded appropriately for the material you are grinding. (hard wheel for soft material/ soft wheel for hard material) 2.Dress the wheel again just before your final pass. 3. Limit the depth of cut on your final pass to .0002". 4.Figure out some way to balance your grinding wheel. (I'm betting this would help a bunch!) 5. Try slowing your traverse speed and/or your stepover. and 6. Consider using coolant. Yes, its messy but it works and an old spray bottle is all the equipment you really need.

Obviously big iron castings are unrealistic for a home built machine like this, but have you considered achieving the same thing with concrete? There is a channel out there called "Confounded Machine" that home built a big lathe out of the stuff. This was previously done during the world wars to work around metal shortages and rapidly bring up machining capacity. I wonder if you could adapt that technique to the grinder. If you were to embed that whole frame in a concrete casting, the frame itself could serve as rebar. It's be cheap and would increase both mass and vibration damping.

The mag chuck should be moving left and right at different speeds to maintain the same cutting speed.

@Nubby007

4 жыл бұрын

It should also help to reduce the chatter

@NaturallySelected

4 жыл бұрын

Agreed. Or failing that lifting off and going back to the start without cutting Edit: think I'd prefer it to lift off anyway actually to maintain the same cutting direction

@tallbrian100

4 жыл бұрын

What? the surface speed of the wheel is 8 x 3.14 X 1750rpm = 43,960 ft/min The table speed is what 20 ft a min. Anyways you can't do anything to match the speed other than grind only one direction.

@FreeOfFantasy

4 жыл бұрын

@@NaturallySelected That depends on how accurate the z axis is. I'm not sure they can return reliable enough for lift offs.

@Nubby007

4 жыл бұрын

@@tallbrian100 The grinders I use at work do. They go slower 'against' the wheel to compensate the fact that the wheel is turning 'with the work' in the other direction. It's really obvious if you work with grinders regularly, but a bit of a strange concept to grasp if you don't have experience in machining

Please figure out what's up with your spindle, it sounds horrible. What kind of bearings are you using? Have you checked the balancing at all? Balancing is really, really important on a grinder, you want it to run as smooth as possible. Also not very pleased with all the open guide rails and ball screws, the grinding dust will chew that up in no time.

What if you just leave it alone until you have a project that it's incapable of completing sufficiently? Would a different solution just be to lap parts after grinding them in the event that you need a specific surface finish?

The quality you're getting is pretty decent for the machine you have. I really think you're reaching the limit of what you can do without a much stronger spindle.

@PhysicsAnonymous

4 жыл бұрын

Yeah, totally agree. I think the spindle is definitely the weakest link right now. But it's doing what we need it to do. We really designed it to make things flat, not make pretty looking parts.

@FreeOfFantasy

4 жыл бұрын

@@PhysicsAnonymous Bigger and heavier is always better with something like this. I'm already amazed what you reached with a relatively flimsy construction like this. I'm more used to thous cast iron 1t minimum machines. For what it is and what machinery you had while making and assembling it it's a really really good result.

@littleworkshopofhorrors2395

4 жыл бұрын

Physics Anonymous it seems to work but the spindle does sound flimsy, and there are few substitudes for cast iron mass .

That thing does one hell of a job grinding!!!!!

Kudos to you guys Your grinding WHEEL is tool thick. Use half of the thickness and the surface will ok. The structure of the machine can not absorb enough vibration generated by the machine. Keep fits

Outstanding Skip

Love the show, you guys do amazing things with gut and gumption. As others have noted, once you dress the wheel, you cannot turn it off or you might as well have not dressed it, that would be of some help with your surface finish. I would increase the left/right (usually X) speed to get a better finish, although with the rigidity issues you are having that might not be possible. Looking forward to the conversion of your mill, I was really close to doing what you are doing when I basically had a Tormach fall in my lap. It isn't perfect, but for the price it is capable and useful. I would be happy to share my experience if you would like me to. One other thing, the sound level of the music is super loud compared with your talking, when watching this video at lunch I had to jump on my volume control a bunch of times so as to not disturb my work neighbors. Not sure if this is a problem for anyone else but it was a little annoying. Thanks for what you do!

@stephencurtis2282

5 ай бұрын

I dress the wheel and it works fine a day or a week later - still gives a mirror finish. I'm not sure what that refers to @JimmyGFromDayton

Your machine is just not rigid enough. Been telling you that from the start

Try a double pass before moving the Y-axis: Grind in Standard Direction (wheel spinning opposite the feed direction), Grind in the Climb Direction (wheel spinning with the wheel direction) then move the Y-Axis, that will emulate how older surface grinders handle their auto-stepping. As many others mentioned, your Spindle Bearings sound horrible. I love the build, and am very surprised at your good results. Get some active dust collection going both in the spindle guard and on the table ends.

First off, great job guys. IMO, you've done the impossible! I've run a few surface grinders, and I think you guys can get a better finish with what you've made there. I think your step-over was too high for the rigidity of the machine and the HP of the spindle. You might try reducing the step-over for a finishing pass. Also I think if you did a finish pass of like 0.5-1 tenth on the opposite direction while slowing down the feeds it'll clean a lot of that up. On my big 8x24 Thompson grinder I typically take 1-2 tenths for a finish pass, and to get the best finishes I would let it spark out or continue traversing the work piece until I stop seeing sparks/hearing cutting.

Nice video as always! :) You should get some fluid cooling on the grinding wheel, this should also reduce the shatter ;)

Very nice surface for this design. Are there construction plans or videos for this grinder?

The Lovejoy couplers are called spider couplers. The plastic or rubber star in the center is called the spider. For accuracy, you should be using solid couplers and aligning the shafts properly. Any type of flex coupler will have too much backlash to be accurate.

hey guys awesome video! one tip make some tool for grinding that grinder wheel with a diamond to make it horizontal :) donz make the z axis moveable with little motor ! i work for a german company and we have herkules&hommel they have locked z axis with a realy big dc motor. find z0 with the grinder on and DONT find the z point only going up and down but going forward and backward and make little z steps! use coolant fluid ! the structure on top of the surface comes from the not aligned grinder wheel

do you know about sparking out with a continual y feed? so like the wheel is diagonal zig zaging across the part a bunch? also the amount the y feeds per pass in x should be less then the amount it was advancing when you where roughing. Thats the only way ive ever gotten really good finishes on a manual surface grinder. Also sry if i missed it but have you balanced the spindle?(like the shaft that the wheel is on, i would think balance of the spindle and the wheel would be alot more important since the machine has less mass to resist the vibrations) it sounds like something is really out of balance to me.

not sure what scale your spindle control is but i program grinders and would estimate you need about 1200 rpm for that size wheel. i program in Surface per minute, about 3000 for a 10 inch wheel. stiffer spindle would surely help also. nice build though. thanx for sharing.

Strip down, rebuilt and repaint of my chipmaster lathe, about 70 hours.

You have some really powerful feedback in the comments, I’d love to have a detailed follow up... Maybe consult with one one of these machine design professionals and get some real education flowing. Awesome stuff Also. The blooper cuts are cool, but very distracting... maybe limit ourselves too 2 or 3 per video

For finishing on surface grinder the death of cut is about 0.01 mm or 0.0004 inch ... 1 thou Is 0.025 mm . And the wheel balancing Is of quite a bit ,

@valentijnraw

2 жыл бұрын

i would finish with a feed of 0.001 mm

Man, I love your safety shoes !! 🤣🤣

Before you switch it in i would cover the slidingways,what you think how long they will last without cover?

A few words to those who rush into criticizing this project: the general mantra when it comes to scraping is that the straight edge should be made out of cast iron, stress relieved and let to rest for over a year. I made a 43 inches straight edge out mild carbon steel, no stress relieved, I power scraped it. I got a solid 4 tens over the entire 43 inches and then I did my Bridgeport bed with it and I got a decent 6 tens off over 25 inches. The straight edge is one and a half years old now and it has retained its precision. And I am certainly not the only one, check this out as well : kzread.info/dash/bejne/i5WiztuamLqqf9o.html

In the case that no one has mentioned it, WD 40 tends to improve finish greatly as well as placing the dressing stone on the leading edge of the wheel rather than the center.

maybe having handles on each axis that have switches that when you start pulling it turns off the motors and allows your to move the axis manually might be an easy solution

How heavy is it? I was thinking of putting a RF-45 milling machine on top of their larger U.S. General chest (The 22x44 ones that can hold 1500 lbs, that way all of my tooling is with the machine and it is all portable) and was wondering how yours is holding up.

Definitely add a 2x72 belt sander grinding head for an amazing cross purpose machine!

to avoid the stone loading up with material, I wonder if you could use a belt tensioner to hold a smaller wheel to dress, or clean the finer grit stone while it's in use.

Make the wheel travel twice over the surface before moving it in the y axis, and when the whole surface is done go in the reverse direktion until you reach the starting point and you Will gett a mirror finish 👍

If you watch really closely when the wheel gets to grinding it looks like it slows down a bit. Is is possible that is the chatter your getting? If it is could you reduce that by adding a flywheel or a motor with more torque?

When I learned to surface grind I was always told to never let the wheel stop spinning after you dress it, just in case anything settles.

@leaftye

4 жыл бұрын

I haven't heard that except when there's coolant.

The beep is funny once, after that it's just trying too hard.

@gorak9000

3 жыл бұрын

Yeah, ditto for the same music track that starts at the beginning over and over again every minute. Yes, it's a cool track, but I JUST heard that part and you're playing it for me again?

I'm curious: How did you identify that the casters were the primary contributors to the machine lack of rigidity ?

If the wheel is not balanced, dressing does not give almost anything.

@gusmcgussy3299

4 жыл бұрын

It most certainly does....it opens the cavities and creates sharp edges to grind with

@10satan

4 жыл бұрын

@@gusmcgussy3299 yes, but the shape of the wheel still is not perfectly round. Found that on a big surface grinder i was working on.

when you start the grinder you can hear that there are vibrations. this can be because you have unbalanced wheel, shaft or motor. This can cause shatter. Moreover you cant try to lower feed rate and check if it goes away, but first of all balance wheel. Try to make wheel holder with balancers

You have to surface the grinding wheel by running it over a diamond tip so it's perfectly round

@CatNolara

4 жыл бұрын

not only that, it has also to be balanced. Even if it is perfectly round, if it is off balance it starts to wobble when going faster.

@sidgar1

4 жыл бұрын

They did @ 8:15

@JSMachineWorks

4 жыл бұрын

@@sidgar1 oh 🙆‍♂️

Is it possible to add some type of fluid balancer to the end of the spindle? That way it be continually balanced as the wheel wears. Also is there a way to measure deflection in you spindle while it is running?

@1pcfred

4 жыл бұрын

A worn grinding wheel won't cut. So you're constantly dressing it to sharpen it. Which means you're worried about something that isn't going to happen before you have more serious problems.

I know you have probably heard this already but you need structural deadening. That's why machines are built from cast iron and ductile iron. You could improve by adding some concrete to the bottom of the tool box. You could also buy a cast iron ball and hang it. One Important step y'all are missing is the wheels aren't balanced.... I was running a surface grinder making mirrors for the DoD and I replaced my wheel ( didn't balance) and ruined $6700 worth of materials. That's not including buying a NEW wheel....

I'm most probably wrong but the chatter marks on the steel might correspond with everytime the x stepper motor moved as it seemed finer when the speed was decreased. Maybe smoothing out the step pulses going to the stepper? Great videos btw the lathe got me hooked😂

@CatNolara

4 жыл бұрын

Nah, definitely coming from the wheel

@1pcfred

4 жыл бұрын

@@CatNolara yeah the spindle they have is completely inadequate.

Put some of that etching liquid they use for welding, might help to see the grain or chatter?

@XPbIM3

4 жыл бұрын

That also would require a microscope, a steel grain is visible at x100 magnification after etching. Welding grain is much more bigger bacuse of thermal overheating.

@ifell3

4 жыл бұрын

@@XPbIM3 cool, I did think after posting maybe it shows differently because if the two different metals, but you delivered a sound bit of knowledge there. Thank you

Balance wheel better and avoid cutting against the wheel? The wheel should cut only none direction and skim to go back with no stop over.

Great video. The old guy who taught me basic machining skills claimed that if you got two pieces of tool steel perfectly parallel and flat, they would 'cold-fuse' if you put them together. Is this true? Is that something you guys are capable of now that you've got your own surface grinder dialed in? Thanks again for your videos, I really enjoy them.

@1pcfred

4 жыл бұрын

I think the pieces sticking together has something to do with the Van der Waals force? Something about atoms close together attracting each other. Wringing gage blocks makes them stick together.

Was literally just watching your last vid. 😂

I would guess, that grinding contrarotary to rotation direction could give you better final-touch cut. Why wouldn't you use some linear brake at frozen Z-axis? It could theoretically remove any clearance in this particular dimension. The same could be done with X axis - at surface grinding machine only working direction is Y-axis, so there is no need for preserving movement in any other XZ direction.

OMG why did you use so much infill for the speed controller housing? 5% would have been mote than enough

the cut sounded like the wheel was not balanced. dressing and trueing are two different things. remember your setup needs to be wider on the magnet than high for safety.

How do you guys feel about the way fusion 360 has they're layout now? Personal i miss the old one before the update.

Just a thought, but maybe a locking system to lock the motor/head assembly to the frame after you position it on the Z axis help with rigidity ? Otherwise I would suspect the spindle bearings as the issue. I enjoy your channel very much. I'm just a low budget in my apartment version of you guys's set up...B^ )

Hey very good vídeo, are you going to do a homemade milling machine??

Have you considered filling the structure with epoxy to convert the body to a single solid piece?

Local tool store had a used brown sharpe surface grinder with hydraulic power system, for sale, $600. If only I had the room in my garage! :(

Do you balance the wheel? Wheel imbalance will cause chatter even on a professional machine.

I didn't see you dress the wheel when you installed it. Very nice build.

I'd go with spindle bearings over rigidity for the chatter possibly. Fun seeing this from birth

Balance the stone, you can hear the vibration when only the motor is running.

A Lot of things come to mind, but how do you know your depth of cut? It seems it is by eye.

I'm new to your channel. I'd like to say something, I believe x axis feed is quite fast and if there is a coolant used, it would have been better.. Anyhow I'm no expert and I admire your work

Aaah yes! I see your know your repetitive music well. Gooood one!

E-Stop should not be used as a start-stop switch since this causes a safety hazard. In general any safety device should not be used to start a machine. Use a separate start button to prevent unexpected movement when the e-stop is released.

I can almost guarantee that's not chatter. I'll bet it has something to do with the cogged timing belt you're using to drive the spindle. When you're down in the tenths, everything matters. Even the type of motor. Single-phase AC motors have an ever-so-slight cogging effect, just because of how they operate, and that can easily show up in the finish on a surface grinder. This is why pretty much every surface grinder is 3-phase. You guys are using a brushless motor, which is a 3-phase, so you've eliminated the motor effect, but you've put it right back in with that cogged belt. I'll bet the waviness in the surface finish correlates to the actual tooth spacing on the belt.

@PhysicsAnonymous

4 жыл бұрын

That is an awesome theory, and not one we considered. Maybe the next update we will replace the timing belt with a v belt. There is also a good chance it's coming from the spindle bearings. Despite our best efforts, there is still a tiny amount of play in them

@exhempknight

4 жыл бұрын

@@PhysicsAnonymous Axial or lateral play? Is there still play in the after you let the spindle run a while? Let it run 4-5 minutes, then check... See if letting it come up to temp makes a difference. Awesome work with this, by the way. Seriously impressive that a home-built surface grinder can hold a couple of tenths tolerance.

@PhysicsAnonymous

4 жыл бұрын

Axial play, probably about about a thou when cold, and maybe 3 or 4 tenths when warmed up. After installing proper AC bearings in the cnc (upcoming video) I have a bit more of a feel for what it should be like, and the ones we used on the surface grinder are definitely out of spec. which is probably why got them so cheap.

try a shock absorber on the Z to dampen that harmonic mass

once you dress the wheel you shouldn't stop it until you are done with the grinding that is probably one of the reasons that you have so much chatter. each time you turn the wheel on the wheel will shift on the arbor slightly causing your wheel to no longer be running completely concentric to the arbor which can cause chatter like you showed.

Well how flat is your harbor freight granite block - Ya, I have the same block! ;) Still, love the content and it's a great project!

I was always told never to feed something into a spinning wheel, always out of one. That way if you've made a mistake with your Z height it won't bind the machine up or explode the wheel, it'll just kick the piece back out. So, while I totally understand that you're playing a game of thousandths of an inch here, it squicks the hell out of me to see the piece moving both directions under the grinder like that.

@Getbent97

4 жыл бұрын

Don't know what to tell you but basically every if not all surface grinders work in both directions. Nature of the beast.

@1pcfred

4 жыл бұрын

@@Getbent97 Well, you always begin the cut with the work piece on the right side of the wheel. Your back pass you're just doing a spring cut. So you cut conventional.

Wheel doesn’t sound balanced! 😂

Still waiting for the lathe

CLOSED TOE SHOES IN THE SHOP!!!!!!!!1!1!!!one

@1pcfred

4 жыл бұрын

My shop my rules!

Is the wheel balanced? Maybe that's the reason for the chatter

I love it! You can see the chatter in the thumbnail on the video where you declare that we were wrong to say that it wasn't going to work as well as you thought. Not "won't work", just "not going to get real surface grinder quality from a machine built as though you wanted it to resonate like a bell." Couldn't have picked a better thumbnail to illustrate what we predicted long ago. It's a cool project I just can't figure out why you would make it out of hollow tubing without at least filling the tubing with lead. Never mind making it out of solid members.

@PhysicsAnonymous

4 жыл бұрын

Our main goal was just to have a machine that makes flat parts. I don't care too much about surface finish. The main reason is just cost and time. At some point it makes more sense to just buy a used one, but that doesn't make for a very interesting video. Solid tube costs 4 or 5 times the price, and casting led into hollow tubes can be a pretty big pain. But all things considered we exceeded our goal by a good margin, it just didn't live up to other people's expectations, which is fine by me.

@hippieengineeringworks2310

4 жыл бұрын

I bet they can get much less chatter with better feeds and speeds. But say maybe 0.0002" flatness and surface finish enough to get the air bearing effect on a surface plate is good enough for anything you want in a home shop, and that machine has the perfect form factor for one too. No, they won't regrind their lathe bed with that (and they didn't mean to anyway), but neither will they with some clapped out monstrosity from 50 years ago which is they only reasonable alternative to this build.

nothing like working in the shop in sandels hahaha

I think the chatter is either weak motor mounting to the frame or too much play in the motor bearings.

Dress the wheel again and u have to feed the diamond smoother a little coolant will help

The problem is that the machine is not build from cast iron. Metal frame are not ridged enough. Big brand put spring loaded bearings on the spindle as well. It is not easy as abc to build a good surfice grinder at home. I have a 70 years old surfice grinder and it still producing accurate and mirror finish.

What's the reason it chatters? I mean I am a total noob but I would guess something like too much play, or not enough speed or something about getting to the natural frequency. Would like to know the answer though. Great work guys appreciate your effort!

@PhysicsAnonymous

4 жыл бұрын

Total noob to total noob, but there are a lot of ways to combat chatter (every machine will have chatter, even the big ones, if not used right) in our case it's probably a combination of spindle play, feeds and speed, and total rigidity of the frame. Though i think the frame is contributing a lot less then people think. After this video was made we played with the feeds and speeds even more and got better results. If the over all machine was stiffer and heavier, we could run a lot faster and be less likely to get chatter, but for our needs, this machine does just fine.

@JBFromOZ

4 жыл бұрын

The chatter will partly be because of an unbalanced spindle... example of unbalanced spindle in my video here Buffalo Machinery Microcut 612B surface grinder first run kzread.info/dash/bejne/q3911dpwfJWtnMo.html

im a professional grinder and i would optimalize this setup in about an hour