Modifying my bench grinder

My 8"/200mm grinder has been shaking itself to bits ever since I added a wire wheel to it, due to some really bad clamping and also a balance problem. In this video, I finally do something about it (Thanks Yuchol for the inspiration).
See Yuchol's ginder video here: • CHEAP BENCH GRINDER - ...
/ craigsworkshop
craigsworkshop.net

[@stevecallachor]

Runout creates a dynamic imbalance which cannot be totally removed by static balancing. Adding more mass to the rotating members (provided it doesn't induce worse static imbalance) will help as the resonant frequency depends on the value of the centrifugal (unbalanced) force and the inertial mass of the rotating element, a flea. Crawling around on an elephant doesn't throw the elephant off course , but fifty unruly school boys in a double decker bus can cause problems going around corners. It's a bit of sorcery working it all out but the rules are simple make things round and true and most of your problems are solved Estephan

[@CraigsWorkshop]

Thanks Estephan, the elephant and school bus analogy makes perfect sense. Great information. So to take what you've stated here and build on it: If I turned something denser than aluminium (e.g. steel, iron, brass, bronze, lead ...) hubs, and made them larger in OD, and thicker, by recessing the inboard shoulder, and also the outboard nut, and if I made them perfectly true and round, it would dwarf much more of the runout caused by the imperfect wirewheel? That makes very good sense to me, and I may well try it. I hope I've properly understood what you've said. Cheers, Craig

[@stevecallachor]

Baaaaabyyy, you got it!!?.......Roy Orbison.

[@CraigsWorkshop]

@@stevecallachor OK thanks :-D Cheers, Craig

[@Rustinox]

Improving the quality of machines yourself is very satisfying.

[@CraigsWorkshop]

Coming up soon: improving the quality of my coat storage :)

[@christophercullen1236]

Thanks Craig a nice practical video for smal.l workshop's and blokes in the shed! Your old apprentice at 72 still learning! Working on a old Holden at the moment it is amazing what tips and procedures from all you tubers I can use on my projects. Lathe work, milling machine , buffing stainless steel a ECT.

[@CraigsWorkshop]

Hi Christopher. I've only been using the lathe and mill for 2-3 years myself, so I consider myself an amateur still - but if you can get anything useful from the video, then it has served its purpose! Good luck with the Holden, if you ever feel like filming your restoring work, I'd be interested to have a look. Cheers, Craig

[@MattysWorkshop]

Gday Craig, great job, I’m starting to think between Max Grant and Yuchol we will always have a project to do, when you do the bearings the grinder will be brand new again, thank for another great video mate, Matty

[@CraigsWorkshop]

Thanks for the encouragement Matty! A brand new grinder would be nice - I'll have to order those bearings :)

[@woodscreekworkshop9939]

It is a lot smoother!

[@CraigsWorkshop]

Agreed. Not perfect, but much more usable! Now to sort out the bearings. I swear they were fine before I started fixing the runout... ! :-)

[@theodorewilson399]

Great job, brother! I wish u lived next door to help me balance my grinder. : )

[@Machine_NZ]

Hi Craig, over the years I've bought both cheap and expensive wire wheels to see if one is better than the other. I haven't found one yet that didn't require balancing. Luckily (so far) I have got away with cutting some of the strands to get them balanced. Good video. Regards Kevin

[@CraigsWorkshop]

Hi Kevin - I hope you're keeping well. Yes - I had the idea of cutting some strands too, but when I saw just how out of whack it was, I decided adding weight to the light side might be a better idea. Now most of the problem is solved, I may fine tune it by cutting some strands.

[@rickpalechuk4411]

Hi Craig, nice vid, thanks for sharing. You could make the outer component out of steel instead of aluminum this would give some rotational mass to which you could then drill shallow divots at the heavy areas to balance. Cheers

[@CraigsWorkshop]

That's a really great idea, thanks Rick. I could make them larger diameter too, and all I'd need to make sure of, is that I keep it indexed to the wheel properly. Thanks again. Craig

[@IAMSatisfied]

Right on point, Rick. Doing what you suggested and drilling out two holes of the same diameter (one hole in the rim on each half) you could have the discs themselves perfectly balanced with the holes 180º opposed, and gradually rotate the discs so the holes grow closer together on the heavy side of the wire wheel until balanced. Does that make sense? That way, one set of discs would be relatively universal and not drilled out for a specific wheel's imbalance.

[@rickpalechuk4411]

@@IAMSatisfied If we keep this up we'll have a new space shuttle in our backyards:) That's a great idea... dial in to balance!

[@eyuptony]

Yes seen this done or drill and tap the aluminium ones all round then add grub screws where needed for weight.

[@JourneymanRandy]

Run it until she blows. I pick up bench grinders for $20.00 on Kijiji like Craig's list. Two new grinding wheels are $20.00 each plus %13 tax that's close to $50. Take care Craig.

[@CraigsWorkshop]

Cheers Randy - What's weird is I went down there later that evening to find out the bearing sizes, but couldn't get it to make that sound again. It was just running quiet and smooth. I guess it was having a bad day! (No doubt the whining noise will come back after some use - then I'll decide what to do). I have a soft spot for this particular grinder because it takes the bigger wheels and it's a nice large motor (1hp). Most I see are 1/3-1/2hp. This is good for stripping very heavily rusted parts - leaning on the wheel does not slow it down much. :)

[@JourneymanRandy]

@@CraigsWorkshop try forcing some grease in with a needle. I do that often. Its probably dried out.

[@CraigsWorkshop]

Great idea Randy, if the noise comes up again, that'll be the first thing I try. Thanks for the idea. Cheers, Craig

[@celsiusswatt6021]

I learned how to mount the part flat in the chuck, using parallels. Thanks!

[@CraigsWorkshop]

No problem. Glad it was useful to you 👍

[@yvesdesrosiers2396]

Just a suggestion maybe use some lead weights in you flange instead of screws. Just a thought. Thanks for sharing

[@CraigsWorkshop]

Thanks Yves - good idea. I would just need to figure out how to make it nice and low-profile and safely mounted. I guess I could use lead wheel weights somehow?

[@yvesdesrosiers2396]

@@CraigsWorkshop It does not have to be on the outside of the brush. How about in the brush between the flanges you made or maybe holes drilled in the flanges and lead poured in those holes. Again more ideas.

[@CraigsWorkshop]

Good ideas. I'll keep this in mind in case I need to do anything like this in future. I'm hoping that what I've got will be sufficient for now, but one day I will upgrade to the 200mm/8" size wheel, and from other reports, it seems all these wheels are out of true and out of balance, so I might be pouring lead on the next version :-)

[@eyuptony]

You took the words out of my mouth but stick them in place or they will drop to the bottom every time the grinder stops rotating creating another out of balance issue.

[@user-ff1hn7ve9e]

@@CraigsWorkshop drill and tap some holes on the inside of the flange and pour molten lead slugs into those holes. Them machine them flush 😉

[@johnhall8455]

Drill some holes I each flange, that will help with balance adjustment

[@CraigsWorkshop]

Thanks John, yes lots of ways to do it 👍 In this case the wheel hubs were in balance and the wheel was out of balance so I wanted to balance the wheel itself. Otherwise if I take this on and off to change the wheel out for something else, I have to rebalance it every time.

[@EmmaRitson]

well done!

[@CraigsWorkshop]

Cheers Emma. It's nice not to have my teeth rattling when I'm de-rusting parts :)

[@ChirpysTinkerings]

looks good Craig, it sucks about the bearings, but if its not one thing, its another that will crap out when you are trying to use something, lol.

[@CraigsWorkshop]

Yeah - it does suck. What's odd is that later the same day I went back and tried to check out the bearing sizes, tested it running again, and couldn't get it to make a noise - so something is intermittent. Perhaps it was the wheel guard resonating or something. I will check all those bolts. If the problem comes back, I'll dive a bit deeper and perhaps replace bearings as a matter of course. Thanks for dropping by and commenting Chirpy! Cheers, Craig

[@RagsdaleCreek]

Nice fix Craig those wire wheels are sometimes the devil to get trued got to try on one of my grinder to get it better. Was fine till I put the wire wheel on it . Think I will check it and see if I can melt some lead to the lite side in between the 2 steel rings. God bless have an awesome weekend

[@CraigsWorkshop]

Thanks Anthony. Have a great weekend yourself. Melting in some lead is a very good idea. Someone else commented with the lead idea but I couldn't think how to affix it. Melting it might well work. Since I've already made some holes in my hub, I'll see if I can get some larger screws first. Cheers! Craig

[@eyuptony]

A job well worth doing. There's nothing more annoying than vibrations on machines when using them. I also have a Poland lathe chuck. Enjoyed the video Craig the grinders a lot better.

[@CraigsWorkshop]

Thanks Tony. I think the chuck is a bison brand, not 100% sure, just shows a bison logo and made in Poland as you've seen. The grinder "bearing" noise (or shield or whatever) has gone away completely for now. It's also a lot less hair-raising to use the thing now it's not vibrating. Fingers crossed it stays good. Cheers, Craig

[@eyuptony]

@@CraigsWorkshop That's what I've thought all along. These were out way before the Bison brand was available. That's my opinion anyway because I never saw them any earlier for sale. Also Bison was a lot less expensive before the Chinese tooling came along then they seemed to up the price ridiculously so it's nearly as expensive as the American and British brands. I think they're out of reach for the hobbyist now unless your loaded or selling your products to cover the outlay.

[@CraigsWorkshop]

Agreed - my eyes watered when I looked up the price of a new equivalent. Haven't got that kind of cash! I didn't know about the price change, or the brand changing. This is a top quality chuck though - I think it's very accurately made, and doesn't have any measurable wear in the jaws which is great. My Pratt Burnerd 3 jaw 6" is a different story, has a tiny bit of bellmouthing. I'll sort it out one day. I noticed your great video about making a router into a toolpost grinder. Very ingenious. Cheers, Craig

[@metalworksmachineshop]

Nice job on it 👍

[@CraigsWorkshop]

Cheers Doug, and thanks for stopping by.

[@ronyerke9250]

Nice job. Have you considered tweaking the balance with some washers or hex nuts under the screw heads?

[@CraigsWorkshop]

Thanks. I haven't tried that, no. Since doing this video (years later) I upgraded my wire wheel from that 150mm one to a 200mm one which suits the size of machine, and the balance of the newer wheel is pretty good out of the box.

[@craigtate5930]

You guys are makin me so jealous, I saw his video also. I have been wanting to doctor up my crummy grinder as well. In due time I suppose.

[@CraigsWorkshop]

I'm blown away by the number of projects you get into, and videos you put out. It's several per day some days. I struggle to do one per week. I'd have thought you could get a grinder tuned up before breakfast :)

[@craigtate5930]

@@CraigsWorkshop yeah but keep in mind they are all unedited, and often pretty rough. And of course i often just skim the surface on things. This is pretty much a coping mechanism for me

[@CraigsWorkshop]

​@@craigtate5930 Either way it's great to see how productive a dedicated person can be :)

[@saulquezada7898]

Great video. Thanks a lot for sharing.

[@CraigsWorkshop]

No problem. Thanks for watching and commenting 👍

[@joeduda8507]

Thanks I need to make something just like this my wheels don't have the centers just a big hole in the center this will work great

[@CraigsWorkshop]

Yes - when I saw those miniature plastic bushes/hubs, I knew they had to go. To me, the important bit was getting the bored hole that registers on the shaft as long as possible, and as good a fit as possible. So that the disc portion was running truly perpendicular to the shaft. Then clamping the wire wheel between those, the disc actually squishes the flexible sheetmetal inner hub into flatness to some degree. Sounds odd, but it works well to improve axial runout. Of course having it fit as well as possible in the large inner hole is good too - that's the part of it that I'd think was more obvious though. Hopefully on yours, your larger inner holes (in the sheetmetal) are rounder than mine were..

[@JakePlisskin12]

Yup i just need to bust out my ryobi milling machine and turn me up a couple washer bushings so i can use my harbor freight bench grinder with out chasing around my work bench the entire time.

[@CraigsWorkshop]

Cool, I didn't know Ryobi made milling machines.

[@brucematthews6417]

I've never found wire wheels to be well balanced but the one you're fighting is WAY out and simply needs to be replaced with something of a better quality. I cringe at the idea of adding screws like this into what appears to be thin metal or even plastic. If those should work their way loose over time? As for replacing the bearings I think you will find that it's fairly easy to do. The old noisy ones I did some years back tapped out of the casting easily. One of them FELL out in fact. And being loose might have been at the core of the issue. I stuck it back in with some medium Loctite to seat it but still be removable later if needed. The grinder never ran better. I also on a small spare grinder made up a flange and outer washer that let's me mount angle grinder discs. That's proven to be very handy with full thickness discs for using the side of them to get into spaces and with a cutoff disc for doing small notches or small cutoff jobs on wire and small rods. I made up a special rest and everything.

[@CraigsWorkshop]

I did recently change that wheel for a better and bigger one, but the screws it had went into metal and they stayed where I put them for the best part of 3.5 years 👍 I love your idea of making a cut off wheel mount! I do have a D bit grinder here too, and a tool and cutter grinder here ready for restoration so the T&CG will probably get the bulk of my attention in future. But at least one of these will get a cut off wheel hub at some point. Good thinking

[@rallymax2]

Better than not doing it. I think I’ll do the same.

[@Steff320i]

Holy cow... I don't want to be around when of of those screws decides to come loose at 10.000 rpm

[@CraigsWorkshop]

Interestingly, they never did.

[@Andrew-so3vj]

Loving your channel, Craig. It induces all sorts of envy, mainly due to shortage of spare shed time! A question: when you balanced the wheel you used a bearing with a smaller OD than the hole in the wheel. Would that not give you a false reading of the balance??? To my mind that would put more mass on the lower half of the wheel as it turns. My apologies if I have it totally wrong!

[@CraigsWorkshop]

Thanks Andrew for the encouragement! With the balancing the mass was off centre top-to-bottom, but I was only measuring for front-to-back differences by continually rotating and testing it at different points. So if there's a heavy spot at the front or back, it does still drop to the bottom. Does that make any sense? Thanks, Craig

[@victoryfirst2878]

I like your lathe Craig. What is the brand and model of the machine ???

[@CraigsWorkshop]

Hi Victory. It is a Premo made by Brackenbury and Austin Lathes in Sydney. The same lathe was also sold under the name "Veem MkIII". I will be selling it later as I now have a smaller lathe and a larger lathe, allowing me to do a larger range of work. Those two new lathes need setting up and powering so that is first. Thanks 👍

[@victoryfirst2878]

@@CraigsWorkshop Keep me mind when you want to sell. What is the model number of the machine ?? Thanks

[@CraigsWorkshop]

@@victoryfirst2878 Hi Victory. No model number sorry. Are you local to Hobart? You are welcome to come and have a look. I will need to hang onto it for a month or two at least, just so I can get the new ones up and running.

[@fredcreer1929]

Could you simply drill a series of small holes in one side of the bushing and position it opposite the screws, to balance it. If the holes were drilled in the edge the size can be smaller, or drill into the edge and melt a little lead into the hole, or simply add washers to the screws!.

[@CraigsWorkshop]

Yes - all great ideas. Thanks Fred.

[@billbaggins]

Mine must have been made on a Tuesday, seems quite well balanced with very little vibration. Different story with the linishing belt on the other side tho 😕

[@CraigsWorkshop]

Does it run well when you take the belt off? That could tell you whether it's the driving pulley or the driven one that's the culprit. (I owe you an email!)

[@billbaggins]

Yep, runs fine without the belt. I reckon the linishing arm was made on a Friday. I'll pull it apart one day and make it more gooder. Good thing we aren't doing corporate business via email 🤣

[@CraigsWorkshop]

You can always drill some holes in the light side and stuff some screws into it. I've seen that done somewhere before :-)

[@billbaggins]

I think it's mostly belt tension and tracking. Not very well designed. Current round of shed tetris is nearly at the stage of bolting grinders down, so I'll probly look at it soon.

[@CraigsWorkshop]

Ooh - bolting grinders down is a good step. Then you need to make sharpening rests to bolt in front of them :) (On my todo list too)

[@78schoolboy]

Hey bubba that wire wheel is not rated for the rpm it spins because it's a 4" wheel on a 6" grinder which will speed up the rpm to almost double which causes little PCs of wire flying off and is dangerous as gell

[@CraigsWorkshop]

It's the other way around. Smaller wheels are rated to go faster than bigger wheels. So a smaller wheel on a bigger machine is usually fine. I am always careful to double check though and it was definitely safe in this case.

[@swanvalleymachineshop]

It's also a job i have to do ! They are just cheap crap pressed out rubbish & i you would think the grinding wheels would shatter . The old GMF Australian made grinders had proper steel machined flanges before things went cheap & nasty . Cheers .

[@CraigsWorkshop]

It's interesting - I have a much older grinder (also smaller and less powerful - I think 6" and 1/2hp) - but it's as quiet as a mouse and runs perfectly smooth. I think the older stuff is better all round. Hence why my workshop has several old machines from the 60s :-) It's also a bit of an addiction :-)

[@swanvalleymachineshop]

@@CraigsWorkshop Machines were just better built back then !