Problems with flat blades on 4 1/2" angle grinder. Any suggestions?

[timmit]

Hello,

I was wondering if anyone has any suggestions on how to properly use flat grinder blades on a 4 1/2" grinder?

I have both a Dewalt and a Harbor Freight 4 1/2" angle grinder and both have the same design problem.

I am trying to use a flat diamond blades as well as the thin brown (aluminum oxide?) metal cutoff blades made for 4 1/2 inch grinders. Neither tool seems to be designed to use these thin flat blades. The thicker blades that I've used in the past aren't flat and have sort of a cup design which lifts the actual grinding part away from the shield of the grinder. The thin, flat blades however, are too thin to be held tightly between the nuts and, more importantly, cut into the safety shield of the grinder. Does anyone know of a way to get around this? Is there some sort of a spacer that is made with a flange to properly hold the blade? Washers behind the blade don't seem to be the best of ideas. I was thinking of grinding down the collar of the shield so that it sits further away from the blade but I really don't want to do that except as a last resort.

I'll be honest....I was in a bind and needed to do some fast cuts and I just put two of the super thin brown blades together and let them cut a groove in the shield. I obviously don't want to keep doing this and the diamond blade would cut even deeper into the shield regardless.

It's strange that I see these blades everywhere but don't see any adapters or spacers sold. Am I using something that isn't designed for what I'm using it for?

The grinder wheel shaft diameter is 7/8"

Thank you in advance for any help or suggestions.
I really appreciate it.
Tim

 

[JradM]

Can you post a picture? Can you perhaps just flip the nut the other way around?

 

[dutchgray]

You usually flip the clamping nut over for thin nuts, each side has a different offset.
If your blades are cutting into the guard, either the guard is in the wrong place or bent or the disc is too large diameter.

You can get those thin cutting discs with a dished centre as well, but not a diamond disc as far as I know.

 

[vwpieces]

I prefer the thin cut off wheels. Not diamond but still same issue. But all my grinders can be made towork with thin wheels. Just need to re-orient the nut and sometimes flip the inner one too.

 

[readhead]

Turn over the top nut so the flat side is against the disc. Last resort, read the directions.

 

[Zewnten]

Usually there is a washer like piece above it, same thickness as the bottom piece and a threaded nut under to pinch the disk

 

[tyyost]

Like everyone said the nuts are often double sided, I only have one that isn’t and I have quite a few, center ridge in for grinding wheels, center ridge out for cutoff and other thin wheels.

 

[timmit]

Thank you all for your replies....I only have one angle grinder with me right now (The one that I said was harbor freight) and it does have different depths for the top nut to allow for thicker and thinner blades (Which I didn't realize) but the bottom nut isn't really reversible. You can reverse it, but it has a slot cut into it to mesh with the shaft. If you do turn it over it does raise the blade height, but then there is no shoulder to hold the blade. If the blade was a lot thicker the reversed top nut would hold and center the blade, but as it is it just spins without the nuts clamping down because there is too thick of a shoulder. The grinder isn't actually H.F. brand after all...It's actually branded as Iron Hammer. I've actually used this a fair amount and it seems to work o.k. except it has a horrible design flaw - the on/off switch is a slide switch in the very back of the grinder. This is the unit that I let the blades cut a groove into the shield.

I was thinking about the dewalt and I'm pretty sure that it has a hex nut molded into the top clamping nut, so no reversing that. I'm not sure about the bottom nut. I plan to check it out tomorrow. One thing that I forgot to mention that I can hardly believe myself is that I bought the Dewalt over thirty years ago. I can remember buying it like it was yesterday, and I still feel like I'm 20, so it really didn't occur to me just how old it was. It might be possible that there really weren't thin blades around then (I don't remember seeing them) and that the grinder isn't designed for them. This Chinese version is probably in the same boat.

Well, thank you all for the advice. I really appreciate the help.
I'll update this when I get my other grinder tomorrow.
Tim

 

[Zewnten]

So the upper one has the shoulder ring down and the slot up, the nut with the four holes can be put ring up for thick blades or flipped for the thin blades you're using. If that doesn't grab it tight enough I've not seen that.

 

[Lwel9226]

For your DeWalt..... Get a newer top nut that is reversible.....
I have 3 or 4 of the older DeWalt/Black&Decker grinders that came with the hex nut like yours....Replaced them with the newer type nuts that are reversible..... all work good for thick or thin wheels....

LynnW

 

[Sumboodie]

Cutting discs/wheels have been around 30+ years.

Grinders normally use wheels, sometimes called discs, not blades.
There are blades available for wood working, but not a common item.

 

[Tools4Me]

The bottom nut/washer isn't flippable, but the top one is. The top nut/washer is usually only flipped (so the washer inner raised ring faces the wheel) if the wheel you are using is very thick where the hole through the wheel is. If it is thin (like with a cut-off wheel), you use the washer with the raised inner ring side facing out so you can properly pinch the thin wheel. None of that changes the position of the wheel related to the guard.

I'm guessing your steel guard has a slight funnel-like taper from the guard clamp to the outside guard edge? Most guards have a little, but some have too much which pushes the guard into the wheel when using wheels that are perfectly flat. Try taking the guard off and setting it on a hard work surface with the guard clamp facing up. Take a small piece of 2x4 and set it flat on the top of the guard clamp. Hit the 2x4 with a 2-4 pound hammer to try and make everything a little more flat. How hard you need to swing the hammer will depend on how thick the steel is on the guard, so start with light hits. It will take a little finesse to make the guard slowly flatten evenly without it ending up with a tilt once reinstalled. You'll know what I mean once you try it. Work carefully and do a bit of testing after each shape change, because if you get the shield too flat the outside curved in lip of the shield will often begin hitting angle grinder wheels that have offset mounting holes or offset threaded mounting holes. Try to find a happy medium where all styles of wheels work with your shield. It usually only requires about 1/8" to 1/4" of guard flattening to make everything clear properly. I don't have your specific angle grinder, but that technique has worked for me when the original guards had the same issue on my 4-1/2" and 7-9" angle grinders. Good luck.

 

[Ign]

I just went through a similar issue but with an adapter for 3" wheels for die grinders. Solution was to chuck up the base and face down the shoulder slightly

 

[welder4956]

This is what I used on my Dewalt cordless grinder:

DW4706

 

[B_Bimmer]

Guards always end up falling off my grinders... sad story.

 

[Grimm_the_Grey]

You usually flip the clamping nut over for thin nuts, each side has a different offset.
If your blades are cutting into the guard, either the guard is in the wrong place or bent or the disc is too large diameter.

You can get those thin cutting discs with a dished centre as well, but not a diamond disc as far as I know.

Lenox makes one. The 4-1/2 inch is part no. 2044467

 

[timmit]

Just wanted to thank everyone for all of the excellent advice. I got busy and never got around to posting this as soon as I should have. Sorry. I'm trying to do better.

I never throw anything away and I actually found a broken grinder in my junk tool box that had a much deeper and flatter shield on it which fit perfectly on my chinese grinder. The Dewalt actually is made differently and I'm going to look into the spacer mentioned by welder 4956. The shaft is completely different than modern grinders and I'm not sure if it will work, but I'm certainly going to look into it.

I was planning on using the angle-grinder to cut off bolts on an old school bus that has seats that I'm removing. It turns out that the bolt heads that I was wanting to cut must be case-hardened. Cutting them off is too much work. I've resorted to having my son inside the bus with a ratchet and me underneath holding the nut and we're slowly breaking the bolts off. Too rusty and long to ratchet off. Seems that the primitive way wins out most times.

Thank you all. I really appreciate the advice!

Regards, Tim