To answer one of your questions about electric motors, the segmented copper surface the brushes run on is called a commutator. Good job fixing this grinder!
Thanks for sharing 😀. I wonder if they make a brushless grinder that’s corded. I will say I am shocked there is any brush material left in the grinder consider what has been run through it lol.
@@makingmistakeswithgreg In general I find, "quiet" tools tend to be more likely to be brushless. Another thing to look for is "BLDC" (Brush-Less Direct Current). I believe Harbor Freight makes at least one corded Brushless tool, but I'm not sure if they make an angle grinder like that or not. Plus, general reminder for that a 3 phase motor with a VFD (Variable Frequency Drive) is the same as a "brushless" motor. Just we tend to talk about 3 phase in terms of mains power and brushless for anything else.
Those are called bellville washers if that helps out. I agree, if it's broke, might as well give it a shot at fixing it; even if you put it away for a cold winter project!
I've always thought the same thing. If it's broken already, you really can't make it worse if your alternative is buying a new one. Nothing to lose but a few minutes.
Thanks for the tip, I have never heard of that name for the washer before lol. If it slips again I will try to buy some new ones. The washer steel seemed to have lost some of its “spring”. When I bent them they took a bend and had minimal rebound.
@@makingmistakeswithgregNot a washer: a spring. Very low travel, very high force. They work like an umbrella. Be careful on the orientation: if you stack them the same way like this )))) the force adds, if you alternate them like this ()() the force stays the same but the available travel adds.
Also, you can measure the thickness of the Belleville washers and order them from McMaster, get some flat shims while you are there. But check the plkace I mentioned, they might have that spring stack as a "cheap" part.
As someone else stated, the spring washers are called "Belleville Washers", or "Belleville Disc Springs". Slipping a few times when overloaded causes rapid heating from friction, a few hundred degrees can cause them to lose their temper and go flat (lose their spring). McMaster-Carr is one source with a good selection of these so you could replace the flat ones and put the spring back in the clutch if you think the clutch action is worth the extra time. I'm also one who doesn't like to throw away favorite tools if I can fix them for a reasonable amount of TLC and a few $$$, as the replacements are often inferior quality. Dave. (Oops, looks like the other fans already told ya' about McMaster!, "like minds" ya' know!)
Thanks for the tip and I need to get a McMaster Carr book for sure. Considering how smoked the grease was and how hot that gearbox got last time I tried using it, I have no doubt the washers are smoked. Pressing them seemed to have minimal rebound like they were mild steel lol. It definitely pays to fix stuff, it’s hard finding tools that are decent. Considering what that grinder has been through it’s in far better shape than I expected.
McMaster-Carr sells Metric and Imperial Belleville Disc Springs and Belleville Washers. You should be able to measure your washers and find something pretty close from them.
Awesome tip, and thanks for sharing the name for the washer. A few people chimed in and said the same name so it must be true lol. I never heard it called that, I learned something new lol.
That would be incredible if u do that Greg more often than none I find myself using my cordless Milwaukee grinder I will have to say tho wen I need to really push th limits on something heavy I always rely on either my corded Milwaukee or dewalt grinders they’re fantastically strong very happy with both of them 🙏🏽🙏🏽🙏🏽🙏🏽
It was an interesting repair video. Thanks for showing your thinking process along the way. I'm like you, if I have a good power tool that fails I'll usually try to fix it unless it lets out the magic smoke -- then I guess it's smoked.
Back in 2006 I bought a 9inch and a 4 1/2inch Metabo grinders. Both were 240v mains and replaced Bosch blue case industrial spec grinders and both didn't last very long. I took them back to the supplier, got a refund and walked out with two Fein brand 4 1/2inch grinders, again 240v mains. Those Fein grinders were abused on the farm repairs I did for many years. When they gave up, due to the even bigger cost of Fein brand grinders I bought Makita 240v grinders. I now have eleven Makita grinders ranging from two 9inch, two 7inch, two 5inch and the last five are 4 1/2inch grinders with voltages of 240v and 110v. The Makita grinders are made in USA, UK and Romania and all are brilliant. I wouldn't touch Makita cordless having had bad luck with their 18v drill. It burnt out before my "cheap and nasty" Ozito (Einhell) supermarket get out of jail card drill. The latter is still drilling good to this day.
Fein makes some really nice tools, they are hard to find locally here (online only mostly). Makita has made some of the longest lasting grinders I have ever seen no doubt. Every shop has atleast a few sitting in some cabinet that have been used for a decade and still work lol.
It’s a normal multiple spring clutch. Lathes and other machinery use similar designs, though more sophisticated. They’re used for the carriage feed clutch.
Love those old German tools. Build quality was top notch back then. We just recently repaired an Bosch angle grinder and a hammer drill from the early 90s. Explosion drawings and parts are available even today. Same with Metabo. Have a great day! Jan
I have some older Bosh rotary hammers and they have been used for a stupid amount of jobs. The fact you can get parts for them is awesome. 100% worth fixing them.
I have many grinders that die on the bearing before the pinion , if you can get the bearing it is an easy fix. Makita seems to work for me, but it is good to know that Metabo china production remains quality.
The particular grinder in the video I believe came from Germany (it’s older). I know they bought out hitachi and rebranded them metabo HPT, and I have had bad luck with the pre metabo ownership tools. I have also heard the newer metabos are made in china, but I have not looked into it. The bearings should be able to be sourced, obviously for a pretty penny if from the company direct. I am sure the same size can be found elsewhere for less. 100% worth a bearing replacement to save the grinder, it’s crazy how much tools cost now lol.
A few minutes of work and you got a working grinder again. This disposable age we live in, most people would have bought a new one. That’s to bad, I’ve brought some tools home for pennies or free, repaired them and cleaned them up to use them myself or resell them. Good topic Greg, I hope more people take some time and effort to fix their tools instead of buying a new one. Thanks.
I've rebuilt my Milwaukee 4 1/2 inchers at least twice.New brushes and bearings,back to work! I would put the model number up but the tags are worn off.They're about 20 years old,back when they were made here in the states!
That’s an old but good grinder lol. I just tore apart a Bosch grinder (video out this week) and I assure you that won’t last long enough for the tags to be worn off 😅.
Actually you can go on their website, scroll to the bottom and there's a link to their parts site. And they have actual parts, not just assemblies of half the tool Edit: you might be right about them not selling them directly though, I can't find anything that looks like a "add to cart" button
I saw a parts company that sold parts for them, but I couldn’t find a breakdown of the whole head assembly. They wanted 98$ for it, which is half the price of the tool I think lol.
@@makingmistakeswithgreg Ah you see you have to get the part number from metabo then Google that and it should come up Or at least it did for the random model I picked, it may not for yours
Looks a good design to me, fact it has epoxy on there is a step above majority of Chinese grinders. I never really buy new, and attempt repair on broken, I can fix most of what breaks, but it does help knowing about electronics sometimes, if you can solder, weld metals and weld plastic, you can fix a lot of things. Might be a silly question, but after you pressed the washers/shims, would it have been a good idea to heat up the metal to relax it?
It’s hard to say what would have happened if I heated the washers. I really should throw some new ones in but I think it will work for a while 😀. I just edited a video tearing open a Bosch and a Dewalt grinder, surprisingly enough they have different builds than the metabo. The video will be out this week. 😀
I have heard the common Dewalt corded 4.5 grinder is a beast. I have only had makita, Bosch, metabo and Milwaukee grinders. I might have to do a comparison on the grinders out there on build quality.
Great thought, there might have been. I am going to open up the other metabo I have and see if it has one. That one doesn’t slip one bit. It’s a slightly more powerful one. I would imagine the clutch is identical in design though.
Metabo... top noch grinders. Have one for 25 years now, done all sh*t of the job, including concrete. OK it was one of the most expencive models in its size at the time of the purchase (125mm disc, around 500 DEM, roghly 250 USD back in 1999, or about 470USD today acording to inflation calc), but worth every cent. (1400W on 5"/125mm, MMC or constant velocity no metter of the load, soft start/quick soft stop, protection from start after power loss, "marathon" bearings whatewer it mean :) but supposedly should last longer...) As other mentioned... bellwile washers, actualy not washers but springs, with declared specific force.. Not expencive, but sometimes hard to find (at least in my country, you falks have mcmaster, we don't :( ) Metal on metal cluch is not so unusual, for this kind of application, when somtehing have to slip just in rare ocations, and for the short time. Actualy.. it's much less prone to material deviation when you calculate torque that is required to slip. Usual clutch materials like one on the brake pads, are very incosistent. Of course, it's not usable for something that need to slip regulary (like your car clutch), cos of excessive wear when it slips.
Thanks for sharing your thoughts. What you said makes sense, a brake pad or clutch material has variable friction based on a bunch of factors. Metal on metal would have to be more predictable, and for the little bit of use it actually sees it wouldn’t likely wear much.
I personally hate those 11 amp metabo grinders, we get them where I work and every one I have used has had nasty vibration after only about 2 weeks of moderate use and they get very hot. I even had one that got so hot that It burned my hand through my gloves.
Surprised at that, the one in the video is many years old and has been beat pretty good. It is still smooth, smoother than most I have. I have heard that metabo switched to china manufacturing and maybe the more recent ones are sub par? That one was made in Germany.
@@makingmistakeswithgreg Probably the same model. Maybe my issues with them is because of the other guys I work with now that I am thinking about it. There are signs that they are a lot harder on them than me, we use fiber discs with rubber backing pads which beat up a lot. I forgot to consider that as a possibility.
Most don’t, but metabo in specific has it in many models. For the most part you would never know it’s there. I only noticed it when it was at full power and a cutoff disc caught into something hard. Grinding stuff it would never slip.
@@makingmistakeswithgreg I looked online and my DeWalt 60V grinder does have an electric brake and clutch system. Guess any could have a mechanical slip system like your Metabo. I'm sure it's safer that way, it's just something I never considered. At least I learned something today. Thank you!
Dont think the battery ones do, simply because they are not that dangerous if they stick, but seen some big angle grinders with 2kW motor-two handed monsters, imagine if one of those got stuck, it could certainly knock you off your feet.
To answer one of your questions about electric motors, the segmented copper surface the brushes run on is called a commutator. Good job fixing this grinder!
Thanks for sharing 😀. I wonder if they make a brushless grinder that’s corded. I will say I am shocked there is any brush material left in the grinder consider what has been run through it lol.
@@makingmistakeswithgreg In general I find, "quiet" tools tend to be more likely to be brushless. Another thing to look for is "BLDC" (Brush-Less Direct Current).
I believe Harbor Freight makes at least one corded Brushless tool, but I'm not sure if they make an angle grinder like that or not.
Plus, general reminder for that a 3 phase motor with a VFD (Variable Frequency Drive) is the same as a "brushless" motor. Just we tend to talk about 3 phase in terms of mains power and brushless for anything else.
Love the Boltr type video. Love you videos brother.
Thanks for the kind words 😀. I am going to take apart some more stuff on camera because it’s enjoyable and I have learned a ton from the comments.
Those are called bellville washers if that helps out. I agree, if it's broke, might as well give it a shot at fixing it; even if you put it away for a cold winter project!
I've always thought the same thing. If it's broken already, you really can't make it worse if your alternative is buying a new one. Nothing to lose but a few minutes.
Thanks for the tip, I have never heard of that name for the washer before lol. If it slips again I will try to buy some new ones. The washer steel seemed to have lost some of its “spring”. When I bent them they took a bend and had minimal rebound.
@@makingmistakeswithgregNot a washer: a spring. Very low travel, very high force. They work like an umbrella.
Be careful on the orientation: if you stack them the same way like this )))) the force adds, if you alternate them like this ()() the force stays the same but the available travel adds.
Also, you can measure the thickness of the Belleville washers and order them from McMaster, get some flat shims while you are there. But check the plkace I mentioned, they might have that spring stack as a "cheap" part.
As someone else stated, the spring washers are called "Belleville Washers", or "Belleville Disc Springs".
Slipping a few times when overloaded causes rapid heating from friction, a few hundred degrees can cause them to lose their temper and go flat (lose their spring).
McMaster-Carr is one source with a good selection of these so you could replace the flat ones and put the spring back in the clutch if you think the clutch action is worth the extra time.
I'm also one who doesn't like to throw away favorite tools if I can fix them for a reasonable amount of TLC and a few $$$, as the replacements are often inferior quality.
Dave.
(Oops, looks like the other fans already told ya' about McMaster!, "like minds" ya' know!)
Thanks for the tip and I need to get a McMaster Carr book for sure. Considering how smoked the grease was and how hot that gearbox got last time I tried using it, I have no doubt the washers are smoked. Pressing them seemed to have minimal rebound like they were mild steel lol. It definitely pays to fix stuff, it’s hard finding tools that are decent. Considering what that grinder has been through it’s in far better shape than I expected.
McMaster-Carr sells Metric and Imperial Belleville Disc Springs and Belleville Washers. You should be able to measure your washers and find something pretty close from them.
Awesome tip, and thanks for sharing the name for the washer. A few people chimed in and said the same name so it must be true lol. I never heard it called that, I learned something new lol.
That would be incredible if u do that Greg more often than none I find myself using my cordless Milwaukee grinder I will have to say tho wen I need to really push th limits on something heavy I always rely on either my corded Milwaukee or dewalt grinders they’re fantastically strong very happy with both of them 🙏🏽🙏🏽🙏🏽🙏🏽
It was an interesting repair video. Thanks for showing your thinking process along the way. I'm like you, if I have a good power tool that fails I'll usually try to fix it unless it lets out the magic smoke -- then I guess it's smoked.
That magic smoke is a bad sign lol. When it starts arcing inside you know you’re in for some trouble 😅
Back in 2006 I bought a 9inch and a 4 1/2inch Metabo grinders. Both were 240v mains and replaced Bosch blue case industrial spec grinders and both didn't last very long. I took them back to the supplier, got a refund and walked out with two Fein brand 4 1/2inch grinders, again 240v mains. Those Fein grinders were abused on the farm repairs I did for many years.
When they gave up, due to the even bigger cost of Fein brand grinders I bought Makita 240v grinders. I now have eleven Makita grinders ranging from two 9inch, two 7inch, two 5inch and the last five are 4 1/2inch grinders with voltages of 240v and 110v. The Makita grinders are made in USA, UK and Romania and all are brilliant. I wouldn't touch Makita cordless having had bad luck with their 18v drill. It burnt out before my "cheap and nasty" Ozito (Einhell) supermarket get out of jail card drill. The latter is still drilling good to this day.
Fein makes some really nice tools, they are hard to find locally here (online only mostly). Makita has made some of the longest lasting grinders I have ever seen no doubt. Every shop has atleast a few sitting in some cabinet that have been used for a decade and still work lol.
Nice fix! Looks like you could also just eliminate the clutch by welding everything together in some way.
I thought about that and determined it would be a pain to weld it. If it ever slips I will definitely “solve it” lol. So far it’s holding up well 😀
It’s a normal multiple spring clutch. Lathes and other machinery use similar designs, though more sophisticated. They’re used for the carriage feed clutch.
Never heard of the carriage feed clutch?
Love those old German tools. Build quality was top notch back then. We just recently repaired an Bosch angle grinder and a hammer drill from the early 90s. Explosion drawings and parts are available even today. Same with Metabo.
Have a great day! Jan
I have some older Bosh rotary hammers and they have been used for a stupid amount of jobs. The fact you can get parts for them is awesome. 100% worth fixing them.
Nice breakdown and rebuild.
LET'S SEE THE STACH!
Greg, it's a Metabo, ya gotta fix it..........cheers, Paul
For sure, it’s one of those things that is worth keeping around. It’s outlasted every other grinder I have had lol.
I have many grinders that die on the bearing before the pinion , if you can get the bearing it is an easy fix. Makita seems to work for me, but it is good to know that Metabo china production remains quality.
The particular grinder in the video I believe came from Germany (it’s older). I know they bought out hitachi and rebranded them metabo HPT, and I have had bad luck with the pre metabo ownership tools. I have also heard the newer metabos are made in china, but I have not looked into it. The bearings should be able to be sourced, obviously for a pretty penny if from the company direct. I am sure the same size can be found elsewhere for less. 100% worth a bearing replacement to save the grinder, it’s crazy how much tools cost now lol.
A few minutes of work and you got a working grinder again. This disposable age we live in, most people would have bought a new one. That’s to bad, I’ve brought some tools home for pennies or free, repaired them and cleaned them up to use them myself or resell them. Good topic Greg, I hope more people take some time and effort to fix their tools instead of buying a new one. Thanks.
The best tools are ones you fixed for cheap and got for almost nothing lol.
I've rebuilt my Milwaukee 4 1/2 inchers at least twice.New brushes and bearings,back to work! I would put the model number up but the tags are worn off.They're about 20 years old,back when they were made here in the states!
That’s an old but good grinder lol. I just tore apart a Bosch grinder (video out this week) and I assure you that won’t last long enough for the tags to be worn off 😅.
Actually you can go on their website, scroll to the bottom and there's a link to their parts site. And they have actual parts, not just assemblies of half the tool
Edit: you might be right about them not selling them directly though, I can't find anything that looks like a "add to cart" button
I saw a parts company that sold parts for them, but I couldn’t find a breakdown of the whole head assembly. They wanted 98$ for it, which is half the price of the tool I think lol.
@@makingmistakeswithgreg Ah you see you have to get the part number from metabo then Google that and it should come up
Or at least it did for the random model I picked, it may not for yours
Looks a good design to me, fact it has epoxy on there is a step above majority of Chinese grinders. I never really buy new, and attempt repair on broken, I can fix most of what breaks, but it does help knowing about electronics sometimes, if you can solder, weld metals and weld plastic, you can fix a lot of things.
Might be a silly question, but after you pressed the washers/shims, would it have been a good idea to heat up the metal to relax it?
It’s hard to say what would have happened if I heated the washers. I really should throw some new ones in but I think it will work for a while 😀. I just edited a video tearing open a Bosch and a Dewalt grinder, surprisingly enough they have different builds than the metabo. The video will be out this week. 😀
ask a auto mechanic if they have a garbage push rod laying around and save it for the domed washer repair
If you happen to know any good welders Greg, just weld the assembly together. 😅
Haha I will have to find a guy to do that for me 😅😅
Thank u Greg I wonder if my Milwaukee An DEWALT have th same quality of parts in them 😂😂😂😂😂😂😂😂🤦🏻♂️🤦🏻♂️🤦🏻♂️
I have heard the common Dewalt corded 4.5 grinder is a beast. I have only had makita, Bosch, metabo and Milwaukee grinders. I might have to do a comparison on the grinders out there on build quality.
I would strongly advise against using brake cleaner. That stuff can damage a lot of plastics. The electronics cleaners have milder solvents.
Great tip. I generally use electric cleaner but you’re 100% right that certain plastics would be eaten by the cleaner, or made brittle.
Is there a place were they may have had a fiber washer AKA clutch pad and the concrete dust was not concrete but the clutch pad that wore down.
Great thought, there might have been. I am going to open up the other metabo I have and see if it has one. That one doesn’t slip one bit. It’s a slightly more powerful one. I would imagine the clutch is identical in design though.
Metabo... top noch grinders.
Have one for 25 years now, done all sh*t of the job, including concrete.
OK it was one of the most expencive models in its size at the time of the purchase (125mm disc, around 500 DEM, roghly 250 USD back in 1999, or about 470USD today acording to inflation calc), but worth every cent. (1400W on 5"/125mm, MMC or constant velocity no metter of the load, soft start/quick soft stop, protection from start after power loss, "marathon" bearings whatewer it mean :) but supposedly should last longer...)
As other mentioned... bellwile washers, actualy not washers but springs, with declared specific force..
Not expencive, but sometimes hard to find (at least in my country, you falks have mcmaster, we don't :( )
Metal on metal cluch is not so unusual, for this kind of application, when somtehing have to slip just in rare ocations, and for the short time.
Actualy.. it's much less prone to material deviation when you calculate torque that is required to slip. Usual clutch materials like one on the brake pads, are very incosistent.
Of course, it's not usable for something that need to slip regulary (like your car clutch), cos of excessive wear when it slips.
Thanks for sharing your thoughts. What you said makes sense, a brake pad or clutch material has variable friction based on a bunch of factors. Metal on metal would have to be more predictable, and for the little bit of use it actually sees it wouldn’t likely wear much.
I personally hate those 11 amp metabo grinders, we get them where I work and every one I have used has had nasty vibration after only about 2 weeks of moderate use and they get very hot. I even had one that got so hot that It burned my hand through my gloves.
Surprised at that, the one in the video is many years old and has been beat pretty good. It is still smooth, smoother than most I have. I have heard that metabo switched to china manufacturing and maybe the more recent ones are sub par? That one was made in Germany.
@@makingmistakeswithgreg They still are made in Germany, I think the HPTs are made in China if I remember correctly. Is yours the WP 11-125 Quick?
@@survivor1014 I don’t have it infront of me but I do believe that’s the part number. It is stamped made in Germany.
@@makingmistakeswithgreg Probably the same model. Maybe my issues with them is because of the other guys I work with now that I am thinking about it. There are signs that they are a lot harder on them than me, we use fiber discs with rubber backing pads which beat up a lot. I forgot to consider that as a possibility.
I'm not aware of any of my grinders having a clutch.
Most don’t, but metabo in specific has it in many models. For the most part you would never know it’s there. I only noticed it when it was at full power and a cutoff disc caught into something hard. Grinding stuff it would never slip.
@@makingmistakeswithgreg I looked online and my DeWalt 60V grinder does have an electric brake and clutch system. Guess any could have a mechanical slip system like your Metabo. I'm sure it's safer that way, it's just something I never considered. At least I learned something today. Thank you!
Dont think the battery ones do, simply because they are not that dangerous if they stick, but seen some big angle grinders with 2kW motor-two handed monsters, imagine if one of those got stuck, it could certainly knock you off your feet.
@@engjds 2kW? That must be like using a floor buffer as a grinder. No thanks.