grinder vs sander

[Donald A]

I am working on a railroad rail to make a small anvil for copper jewelry. Which is more efficient: a 4-inch side grinder or a 7-inch disc grinder using 36 grid? The 7-inch seems to have more sparks

 

[Black Oak Bladeworks]

I would guess the seven inch if you are willing to swap the disks out frequently. Try both for a set amount of time and compare how much they each do. I betting it will take a while either way. Good luck!

 

[eveled]

I think the grinder is the better choice. You may burn out the sander.

 

[Wowbagger]

If you have both try both.
I'm not quite picturing in my mind the machines that you have.
To get it really flat (or should I say smooth and with out waves if that is your goal) and polished you may end up doing hand work once it gets part way there.

As far as efficiency what ever has the most surface feet per minute is the one. Taking into account how much it slows down approximately when you apply the work to the machine. Takes a bit of math.

 

[Wowbagger]

I googled side grinder and photos of the trusty angle grinder came up.
I googled disc grinder and a larger angle grinder came up.
If both are angle grinders then the one with the larger disc because it will have the most horse power to keep the disc up to speed under the significant load the large surface of the rail represents and the largest disc so that would equal more surface feet per minute.

 

[jpm2]

As far as I know, they're both side grinders, size being the difference. Both take abrasive discs or rubber discs with sand paper. There may be other type abrasive attachments but those are the ones I'm familiar with. One takes 4", the other 7". The 7" is a much larger tool, like 3-4x bigger.
I used to use them all the time in a past life. Back then they were all Milwaukee brand, these days there's more brands than you can count.

Not sure what this has to do with knives, but there you go.

 

[Wowbagger]

When I polished mine I think I used this big Bosch hand held belt sander. The blue and gray one at the top of the photo. with the black bag on it.
It has been a hunert years since then so not sure. Geeets 'er done quick though.
When grinding metal with this wood working tool be sure to remember to always remove the saw dust catcher bag.
Don't ask how I know that.

 

[sickpuppy1]

A rail for a train is some hard ass steel. I've heard band saw actually think of how many millions of tons a steel run over that for years.
I've always wondered about a knife from that.......

 

[3fifty7]

A rail for a train is some hard ass steel. I've heard band saw actually think of how many millions of tons a steel run over that for years.
I've always wondered about a knife from that.......

A hammer head would be better.

 

[sickpuppy1]

Lmao. And easier to cart around!

 

[Obsessed with Edges]

Also need to be sure the discs/belts are actually made/spec'd for steel-grinding capability. Sellers of belts, for example, distinguish between 'sanding belts' for wood & other soft materials, versus 'grinding belts' made with abrasives & binders designed for hard metals. The difference being, the abrasives intended for wood will be less expensive, less sharp or even round/blocky in shape and not as tough. Abrasives made for steel should be tougher & sharper, if not also harder. Big variations in aluminum oxide abrasives, for example, some of which will be intended for wood & softer materials, versus the higher-end stuff made for grinding hard metals.

So, if the tools don't have the right belts or discs, it may not matter which machine (grinder or sander) is used.