115/125

[leadpig]

Is there much difference between 115 and 125 grinders in metal working.
I have always used 125mm grinders as the extra 10mm makes alot off difference when chasing out.
But there seems to be a lot more choice for 115mm grinder consumables and everything seems a lot cheaper as well

 

[dan.taylor.1]

You can use 115mm discs in any 125mm grinder, but only some 115mm grinders will take a 125mm disc. All my grinders are 125mm and I haven't found a problem getting any of the standard consumables I use for them. No reason you can't just get the 115mm bits if you're struggling.

 

[Rrobson]

Some of the 115mm grinders have slightly smaller gearboxes, which makes for a smaller head and allows slightly better access into small areas or corners.
I have 125mm grinders for the reason above, im not limited to 115mm discs which aren’t as common.

 

[angellonewolf]

as above i only use the 125 as for the cheapnesss of the disks and ease of getting them

 

[leadpig]

cheers all
will continue to search fo 125mm grinders lol, to be honest i did not really want 4.5" but all the twin packs (ie 9" include 4.5" not 5") so will just buy them separately and buy discs online

 

[Mark 2]

Or just buy a 125mm guard and fit.

 

[Other Daniel]

Is there much difference between 115 and 125 grinders in metal working.
I have always used 125mm grinders as the extra 10mm makes alot off difference when chasing out.
But there seems to be a lot more choice for 115mm grinder consumables and everything seems a lot cheaper as well

In reality, it's only 5mm difference.

 

[hotponyshoes]

Just be aware that some of the 5" grinders run at a slightly lower rpm than the 4.5" equivalent.

They'll still accept the 4.5" consumables but the stock removal rates will be decreased.

This is sometimes an advantage if you are using a polishing/surface prep disc.

On the same theme, you might find you end up running a disc overspeed If you change the guard and put a 5" in a 4.5" grinder although I've never had any issues doing it.

For general use I have a 5" and then also a 4" for getting into tighter spaces.

As mentioned, 4.5" consumables are the most common/varied but for standard stuff like cutting & flap discs I've never had a problem with sourcing 4" & 5" but then I buy stuff like that in bulk which means it needs to be ordered in anyway.
Likewise, there are also a few types of disc that are only available in 5" like the quick-change flap discs and the little bit of extra reach on a 5" disc can be handy when cutting bigger stuff or grinding into a corner.

If you buy enough then I'm pretty sure the relative price of 4.5" & 5" discs work out the same given that the 5" remove more material/last longer by virtue of having more material on them to start with.

For stuff like polishing discs, most often only easily available in small quantities in 4.5" but it's not often I try and source large amounts of them as there is normally a dedicated tool/process that is better for the job anyway.

There are also variable speed grinders available, a lower speed is good for working with wire brushes and polishing wheels.

Plus, consider the work you are doing.
If you have to chop up some old metal, remove the existing paint, Weld a bit in, chop another bit, Rinse, repeat, flat off all the welds ...
Then 3x £30 grinders each fitted with a different disc might make the job a lot easier/quicker than 1x £100 one.

 

[8ob]

I prefer115mm grinders for single handed use, other than that its the 125mm grinders.

Bob

 

[angellonewolf]

Then 3x £30 grinders each fitted with a different disc might make the job a lot easier/quicker than 1x £100 one.

2nd that I got 3 grinders now set up that way 1 realy good makita 240v fir cutting and 2 240v grinding and flap

And a 2 batterys ones for small jobs that only required a few cuts (invaluable when your on a roof cutting the cement on the ridge tiles not faffing with getting power up there)

 

[hotponyshoes]

I prefer115mm grinders for single handed use, other than that its the 125mm grinders.

Bob

I suppose the torque reaction from a 4.5" might be easier to manage with one hand.

But my 5" grinder has a narrow body and a paddle switch and it's actually a lot easier to use one-handed than plenty of 4.5" grinders.

Although 4.5" of the same design are available and might be even easier to use!

 

[MetalMonkey]

Some of the 115 and 125 machines are absolutely identical apart from the guard - Metabo seem to do this a lot, I've bought a couple from them which actually came with both guards included in the box.

No reason not to use 115 consumables on a 125 unless it is an access issue with the larger guard.
All the 100, 115 and 125 grinders I've encountered so far have run at the same speed (11,000 - 12,000), it isn't until 150mm and above that the rpm changes significantly.

The advantage of the 115 machines is you can get them with smaller, less powerful motors which can bring the overall weight and size down and make them easier to use and manoeuvre one-handed for those odd awkward cuts - cordless are handy for this too.
Otherwise I would go 125 all day long as the consumables are more or less the same price but last longer. You can always use a part worn 125mm disc on a 115 grinder safely, they are rated for the same rpm.

The obvious answer of course, is buy both. Probably several of each - after all, you can never have too many tools.

 

[Morrisman]

I prefer115mm grinders for single handed use, other than that its the 125mm grinders.

Bob

I still have an ancient 4" grinder somewhere, has to be 20 years old at least. I'm not even sure you can get discs for it any more.

And a variable speed 125mm, that is huge, a real two hander job, I've never used it other than test run.

 

[Morrisman]

Some of the 115 and 125 machines are absolutely identical apart from the guard - Metabo seem to do this a lot, I've bought a couple from them which actually came with both guards included in the box.

No reason not to use 115 consumables on a 125 unless it is an access issue with the larger guard.
All the 100, 115 and 125 grinders I've encountered so far have run at the same speed (11,000 - 12,000), it isn't until 150mm and above that the rpm changes significantly.

The advantage of the 115 machines is you can get them with smaller, less powerful motors which can bring the overall weight and size down and make them easier to use and manoeuvre one-handed for those odd awkward cuts - cordless are handy for this too.
Otherwise I would go 125 all day long as the consumables are more or less the same price but last longer. You can always use a part worn 125mm disc on a 115 grinder safely, they are rated for the same rpm.

The obvious answer of course, is buy both. Probably several of each - after all, you can never have too many tools.

 

[MetalMonkey]

I still have an ancient 4" grinder somewhere, has to be 20 years old at least. I'm not even sure you can get discs for it any more.

And a variable speed 125mm, that is huge, a real two hander job, I've never used it other than test run.

100mm discs are still available, as long as it is a 16mm bore, you shouldn't have a problem.

 

[hotponyshoes]

I still have an ancient 4" grinder somewhere, has to be 20 years old at least. I'm not even sure you can get discs for it any more.

And a variable speed 125mm, that is huge, a real two hander job, I've never used it other than test run.

It seems to be easier to get 4" discs now than when I first got my 4".
More selection now as well, 4" flap discs are useful sometimes!

 

[Morrisman]

100mm discs are still available, as long as it is a 16mm bore, you shouldn't have a problem.

I used to use it specifically for cleaning out welds in tight spaces, no guard, wheel radiused equally on both edges etc. I'm not even sure where it is now but I should dig it out as it was very useful.

 

[pint]

i use 125mm discs on all my grinders. some 115mm grinders need the guard opening up a touch, most just fit.

there's about 20% more disc on an 125mm so they work out cheaper in effective terms i reckon

 

[Mark 2]

Another year comes, men talk about grinders, and all is well in the world.

 

[MattF]

On the same theme, you might find you end up running a disc overspeed If you change the guard and put a 5" in a 4.5" grinder although I've never had any issues doing it.

Both my Bosch, (115 & 125), are rated at the same speed.