|
|
I've never owned anything other than 4.5" grinders and wonder if a 7" does better on some tasks. For instance,I will soon be torch cutting a few fish mouths in 2&3/8ths pipe and dressing them with grinder for better fit. Will a 7" outperform 4.5 dressing the torch cuts? Same question when grinding out old welds for disassembling damaged 1/4" angle iron frames?
Reply:I have a couple old Milwaukee grinders. Those big guys chew up metal fast BUT get heavy quick. They are great for truing up a cut on pipe or angle.I think for that little stuff the 4 1/2'' or 5'' would be much easier to control and handle.Check craigslist or facebook marketplace for a used one. I bought one Milwaukee for $75.00 with guard and a assortment of wheels. I was going to buy a guard for my old one but new they are around $35.00. Waited for a grinder with guard to be listed and bought it. You may consider a cup grinding wheel for the big grinder. https://www.amazon.com/DEWALT-DW4960...gateway&sr=8-5
Reply:7 and above will EAT metal, but get really heavy and unwieldly fast. If you are a strong guy you will just get tired, but there is a good chance of hurting yourself doing fish mouths with them (lots of "floating" grinder movement on a fish mouth). They shine where you can hold them down in the flat position - usually using their own weight to bear down - and really hog out the material. Their downside is size/weight, the lack of finesse, and a real possibility of not being able to use them in many positions/angles in a controllable manner. You also almost always need two hands on the grinder, everything you grind will;l have to be clamped down. Takes time with multiple repositions per grind.I find a good compromise is a 6 inch, still lightweight (can be safely used with one hand when the safety police aren't looking) but with some ability to move material. I don't weld really heavy material though, someone grinding on 2 inch plate all day will NEED the bigger grinder practically speaking. I love the dewalt rat tail 4.5" - 6" (contain 3 sized guards, nothing special) inch grinders myself. If you can get your hands on one of the big ones (as models vary widely in size, weight, and strength) you can get an idea if the weight and size involved, and should be able to make a much more informed decision.Any particular grinder you were considering?Last edited by SlowBlues; 09-01-2019 at 03:26 AM.
Reply:I use both,right tool for the job at hand.
Reply:When I bought my 7 Milwaukee, that was what people used.I never even tried a 4 1/2 until about 10 years later. Now, I rarely use the 7. It does take off steel much faster, and occasionally the larger wheel will reach into an area that the smaller wheel cant, but the difference in size and weight is enormous. If I didnt already own a 7 grinder now, I doubt that Id buy one.Miller a/c-d/c Thunderbolt XLMillermatic 180 Purox O/ASmith Littletorch O/AHobart Champion Elite
Reply:I would skip the 7" and get a 6". Not a lot heavier than a 4.5" and a lot more power. Grinding and cutting discs are reasonable as well . If I have real heavy grinding I use a 9" anyway.Miller xmt304, Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.
Reply:
Originally Posted by Bls repair
I use both,right tool for the job at hand.
Reply:6" grinder is the best of both worlds. Especially when it come to cut off wheels. They do not weight much more than a 4.5" grinder . The only real problem is that 6" grinding wheels are expensive compared to the 4.5" but last much longer. As the 6" grinder gains market the wheels will come down in price. The cut off wheels I use for it are about $.50 more than 4.5" but can do 3 times the work + can cut stuff a 4.5" could never cut through . For now I use 4.5" grinding wheels on my 6" grinder. They wear out faster because the grinder has more power but until I find 6" grinding wheel at a reasonable cost I will continue to the smaller ones with it. I own 3 6" Dewalts and I have a few older 4.5" ones I use as a backup incase a 6" dies. So far I have 4 years and counting on the 6" grinders.
Reply:I use a 4-1/2 most of the time but have a 6” and a 9” for when things get seriousMillermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:Thank you one and all for your insight. The comments about 7" requiring strong arms tell's me this is one new tool I have no use for. I'm coming up on 75 and lucky being able to piddle in my shop,no reason to push my luck.
Reply:Just the lift generated by that 7 inch wheel is something to definiely be aware of!IMPEACH BIDEN!NRA LIFE MEMBERUNITWELD 175 AMP 3 IN1 DCMIDSTATES 300 AMP AC MACHINEGOD HELP AMERICA!Freedom is never more than one generation away from extinction.We didnt pass it to our children in the bloodstream".RONALD REAGAN
Reply:If you want a big grinder go for the 9 inch.... I have got a few different 6's,7's for jobs thinking they would be better for the job at hand....WRONG!!! they don't reach in more than a quarter inch more than the 4.5/5's.... they have more power but not a lot
and they are heavier so you may as well get a 9 and be done a lot faster
Any more for those troublesome jobs that need more 'reach' I just throw a 6/7 wheel on my 5 inchers and go for it
Reply:The new generation DeWalt 6" grinders are really manageable. Light weight, with adequate power.https://www.dewalt.com/products/powe...ock-on/d28144nLast edited by farmersammm; 09-02-2019 at 12:56 AM.
Reply:Get a 6" grinder. I personaly love dewalt stuff because they have a narrow profile but you can't go wrong with Makita either!
Live life to the fullest; Accept nothing else.
Reply:Yeah, Makita makes some good stuff too. My old chopsaw is still going strong. I hope it stays running, I'm not sure the new models are as good, although I really don't know.
Reply:This is my fave 6 inch, https://www.homedepot.com/p/DEWALT-1...3116/301354058. A bit pricey for a grinder, As light as a 4.5, light enough to operate with one hand (with trigger lock - safety alert), more power less RPMs, and the rat tail makes it very manageable. Rat tails give you great control due to the increased handle leverage.
Reply:I keep wanting to look at the grinder sizes from more of a 'surface feet per minute' perspective, plus the torque to maintain that sfpm of course. I'm lazy or I would do the math, but it seems like a question could be is a 7 inch running at 7,000 or 8,000 rpm really that much better than a 4.5 inch turning at 10,000 to 12,000 rpm?? Seems like if the sfpm at the leading edge of both sizes are similar, then the removal rate would be similar. Again, it would have to be assumed that both motors had/have sufficient torque to maintain something close to the stated rpm when you start leaning on it. Maybe the radius of the wheel makes more of a difference than I suspect it does."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:
Originally Posted by farmersammm
The new generation DeWalt 6" grinders are really manageable. Light weight, with adequate power.https://www.dewalt.com/products/powe...ock-on/d28144n
Reply:I did a stupid video years ago when I first picked up the 6" DeWalt.Pair it up with the Sait coarse grit wheel, and it's a real metal hog. And......that's a half worn out wheel with a smaller diameter, and less surface speed
I like the Sait wheels for metal removal, like beveling and such. Then, for grinding a weld, I like the Flexovit wheels. For razor wheels, probably Flexovit is about the best.
Reply:DEWALT & PORTER CABLE have been acquired by BLACK & DECKER. I USE A LENNOX CUTTING WHEEL, much like a concrete cutting wheel but for my use they are excellent.they're about 14 bucks at Lowes.Last edited by CAVEMANN; 09-02-2019 at 10:45 PM.IMPEACH BIDEN!NRA LIFE MEMBERUNITWELD 175 AMP 3 IN1 DCMIDSTATES 300 AMP AC MACHINEGOD HELP AMERICA!Freedom is never more than one generation away from extinction.We didnt pass it to our children in the bloodstream".RONALD REAGAN
Reply:Depends. 4.5s are great for tight areas, overhead or when used for intricate shaping. But the 7-9 really shines for material removal in the horizontal position. It is actually EASIER to handle as you are allowing the weight of the grinder to do the cutting and only using your arms to guide it. And takes a FRACTION of the time compared to a smaller grinder with comparable disc or wheel. For straight grinding I will grab the 7-9 more than half the time over a 4.5.
Last edited by Lis2323; 09-02-2019 at 11:00 PM.:
Reply:If craigslist or facebook marketplace is avaiable check them for a used one. I have seen the big Milwaukee ones for as cheap as $50.00. Usually around $100.00 with a assortment of wheels.Verify the the RPM , usually 6,000. Handy to have for sure.
Reply:This is very good 7", light and powerful, but not cheap. https://www.metabo.com/com/en/tools/...e-grinder.htmlSent from my iPhone using TapatalkMiller Dynasty 280 DX TIGRunnerFronius Transsteel 2200
Reply:I didn't replace my larger grinder many years ago when it broke, probably 30. Someone gave me a 6 DeWalt the other day with a few cut off, its ok, I wanted to get a 1/4 wheel for it but havnt got to the welding store as the boxes don't seem to carry them. Its been near 10 years since I run more than a wheel off steady at one time. My go to grinder anymore is the BD from Walmart at about 30$, they really last and have sufficient power especially for out of position work. Other companies may have similar econo models but this is handy.www.urkafarms.com
Reply:
Originally Posted by BD1
If craigslist or facebook marketplace is avaiable check them for a used one. I have seen the big Milwaukee ones for as cheap as $50.00. Usually around $100.00 with a assortment of wheels.Verify the the RPM , usually 6,000. Handy to have for sure.[QUOTE=Lis2323;8715402]Not to say this will always be the case but I only got a year out of my Craigslist 7-9 Milwaukee.
Ended buying a new Makita 7-9. That's the newer plastic junk. Mine are old-time all steel body with plastic handle. I had a couple 4 1/2" Milwaukees, junk too! Those were a waste of $$. I still favor my METABO'S. The higher amp DeWalts are OK. I do have one Mikita that has died.
Sent from my iPhone using Tapatalk
Reply:Some live longer than others, but they all eventually die, if used a lot, angle grinders are consumables. Sent from my iPhone using TapatalkMiller Dynasty 280 DX TIGRunnerFronius Transsteel 2200
Reply:
Originally Posted by precivilization
Some live longer than others, but they all eventually die, if used a lot, angle grinders are consumables. Sent from my iPhone using Tapatalk
Reply:There were a couple welding shop owners pm me and say,,, don't tell anyone but I use those too.www.urkafarms.com
Reply:I only buy Makitta or Dewalt. I use a 5 90% of the time. 7 or 9 the other 10%.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:7 is ok. Use turbo backers and fiber disks and not rocks or maybe use flaps.Not too bad.I like a 5" with the same. Rat tail styles.
Reply:The big grinders are great when cleaning up or polishing stock like 2" square tube as long as you can lay it flat, makes quick work of it. I'll have to think about adding a 6" to my collection, I love the Dewalt paddle switch model but $340 wow! Might have to wait till ChristmasMiller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:
Originally Posted by Bonzoo
7 is ok. Use turbo backers and fiber disks and not rocks or maybe use flaps.Not too bad.I like a 5" with the same. Rat tail styles.
Reply:But only if they're green... Right?
Reply:I like my Porter Cable rat tails, got 4 or 5 of them and one Hilti that I got somehow.IMPEACH BIDEN!NRA LIFE MEMBERUNITWELD 175 AMP 3 IN1 DCMIDSTATES 300 AMP AC MACHINEGOD HELP AMERICA!Freedom is never more than one generation away from extinction.We didnt pass it to our children in the bloodstream".RONALD REAGAN
Reply:I prefer the DeWalt 4.5-6 rat-tail grinder. I use 5 grinding wheels and 6 cut-off wheels, mostly. I do use 7 grinding wheels if I need to remove a lot of material, and the 4.5-6 spins them easily. I still use my 7/9 DeWalt with the cast aluminum body when grinding pipe bevels. The extra weight makes that chore a breezeIn the field: '06 Ram 3500/Miller PP350 '14 F-350/Lincoln Classic 300DIn the shop: MM252, Hypertherm PM-85, White face MM200
Reply:Just try 9"My self I like the 4 1/2" for all my work.I have own and use both 7 and 9 they can be no fun and two employees had there zipper remove from there pants.The 4 1/2 is mush safer and up a latter you use with one hand.DaveHF 170 welderHF 4x6 band sawSouth Bend 9NMillB&D mag drillVictor torch
Reply:
Originally Posted by smithdoor
Just try 9"My self I like the 4 1/2" for all my work.I have own and use both 7 and 9 they can be no fun and two employees had there zipper remove from there pants.The 4 1/2 is mush safer and up a latter you use with one hand.Dave
Reply:
Originally Posted by SlowBlues
This is my fave 6 inch, https://www.homedepot.com/p/DEWALT-1...3116/301354058. A bit pricey for a grinder, As light as a 4.5, light enough to operate with one hand (with trigger lock - safety alert), more power less RPMs, and the rat tail makes it very manageable. Rat tails give you great control due to the increased handle leverage.
Reply:dewalt 6"
Reply:Milwaukee 4 1/2". Worn out several angle grinders; I think in general you have to be careful and not press on them too hard, they just can't take it @ 13,000RPM. Relax and let the grinder do the work.-RuarkLincoln 3200HDHobart Stickmate LX235TWECO Fabricator 211i
Reply:
Originally Posted by Ruark
Milwaukee 4 1/2". Worn out several angle grinders; I think in general you have to be careful and not press on them too hard, they just can't take it @ 13,000RPM. Relax and let the grinder do the work.
Reply:
Reply:Those barrel grips are great, but really do a number on my hands carpal tunnel wise for extended use. Their small size and available higher amperage is an asset but can get you into some really scary kickback situations (new versions with electronic clutches may have solved that problem, no idea though). As with any power tool, It's gonna get dangerous, but be smart about it and think about everything you're about to do before you do it, don't go into autopilot and just do it.
Reply:
Originally Posted by Ruark
Milwaukee 4 1/2". Worn out several angle grinders; I think in general you have to be careful and not press on them too hard, they just can't take it @ 13,000RPM. Relax and let the grinder do the work.
Reply:In the shops I worked in the 5-6” angle grinders were the favorite for heavy duty stuff. The big grinders are heavy but the big thing is if you get something caught in them like a narrow corner . If it grabs, you need so strong hands to hang on. They don’t finesse things very well.its hard to just “take a skin cut” smoothly. On the flat, yeah they are hard to beat.As it was said to us, “ if it’s so rough you need a big grinder, maybe you need to make a better first cut”. Then just polish it with the 41/2.
Reply:The 7 and 9 inch grinders certainly are the way to go if you are after fast removal but something that people don't mention is the risk of carpal tunnel damage from trying to hold these big and heavy units. I used the big ones for many years and escaped serious damage although my neurologist found the beginnings of damage in my right hand. If you use these heavy grinders use a guard, have no loose clothing and use your hip or gut to help pressing the grinder into the work. If you use just your arms eventually you will give yourself carpal tunnel syndrome. You are not only fighting the weight but also the gyroscopic action when you shift the grinder. You will notice it tries to tilt when you quickly move it when at full speed.
Reply:I find I get more 'carpal tunel' if you want to call it that from grinding for hours on end with a tiny 5 inch grinder than actually using one of the big boys for half an hour or two to get the same job done.
Reply:
Originally Posted by ronsii
I find I get more 'carpal tunel' if you want to call it that from grinding for hours on end with a tiny 5 inch grinder than actually using one of the big boys for half an hour or two to get the same job done.
Reply:You do much overhead or vertical grinding with that 9 inch grinder? Every tool has it's place for sure, as mentioned before in the flat position hogging it out a big'n is the way to go. For the stuff 99% of the people that need to ask (op) are doing that's too much tool for a multitude of reasons. |
|
发表于 2021-9-1 23:14:03