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Belt sander vs bench grinder

SimonM

SimonM

Active Member
I’m looking to upgrade from the grinder in the vise.

I can see the advantages of a disc/belt grinder combo, is there anything that they don’t do as well as a bench grinder?

Main use will be sharpening hss lathe tooling and tungsten buy it would be nice to be able use the sander for finishing.
 
I have both, I use the belt sander more than the bench grinder.
I need to build a new platen for the belt machine.
 
I use the bench grinder when I need to create a 'sharper' corner. The way my belt grinder works I can't clean into a corner because the belt will drift away because of the pressure from the side.
I will do 98% of HSS grinding on the belt because it's far quicker. I use 80 gr ceramic belts which make quick work when shaping HSS.
 
I also have both and use the disc/belt unit more as well. Mine is a Delta 1”x42” belt and 8” disc so not the biggest out there but it’s done a lot of work for me over the years.

I did try sharpening HSS on mine when I first got into lathe turning but I wasn’t thrilled with the slightly rounded edge produced by the belt so went back to my grinder for that. I am accustomed and prefer the slightly hollow grind produced by the wheel although others may strongly disagree. It’s my preference though. With either machine, a solid and reliable tool rest or table is imperative for satisfactory use in my opinion.

-frank
 
+1 to the need for a good rest. The size of the table is a big reason why I use the belt grinder.
My bench grinder has the usual tiny rest which is next to useless.
@francist has built an excellent grinder rest :)
 
I've got the works: 20" Kalamazoo disc sander, devoted 2.5" Ellis belt sander and an 8" grinder. I mostly use the grinder now for tungsten. But the other side of it is invaluable with a 8" wire wheel; it's one of the most used tools in the shop. Having said this, I'm more of a fabricator than a machinist and don't grind my own tools. My materials tend to be bigger stuff such as 2" tubing and a lot of angle iron.

My one piece of advice would be to ask yourself what size of materials you work on. If you intend to use either the grinder or sander on large stock, the smaller bench top machine won't square up 3" tubing that's 1/4" wall thick. It all comes down to needs. If you are just wondering WRT tool making, I'll defer to the machinist types here on which approach is better.
 
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+1 for wire wheel on the bench grinder. It does a really good job at cleaning parts up and removing rust. I like the belt sander more when building stuff for deburring
 
I mostly use wire wheel on my little 6" bench grinder. Then the little soft grinder wheels on two bench grinders. Then the big guys at 3hp and 12" or even 14" grind wheels I can easily remove stock. My belt sander 6x48 never got the round part used - maybe a delete. The belt gets rare use mostly for cleaning larger drill bits. If I need to remove lots of steel nothing beats a grinder - so much so that its more about cooling the metal then actually grinding.

To be honest I though the belt would get more use - it just is no match for a large grinder. I guess 6x48 is more powerful for metal then your average princess auto 8" grinder but is no match at all against Baldor 3ph 3hp grinder.

I also find that basic sharpening is far easier on a small grinder - you have more control. All tungsten is done on small grinder 6" or 8" with soft wheel.

I can see some use for a "metal workers" belt sander for cutting different shapes into a pipe but I guess there is a reason "regular" belt sanders are mostly wood working machines - I never saw them in a metal shop.

Oh belt sanders with finder belt are also great for sharpening knives - I see them all the time used for that. Finish on a larger drill but, chisel etc. is far more uniform with a belt then a grinder. With grinder its usually gets to be choppy, with belt its nice and smooth and with fine belt even shiny.
 
Once again, the answer to which tool is best is ALL of them.

While I like many things the belt sander can do, what I need most is a way to effectively sharpen lathe tooling and the bench grinder seems better suited.

A 6” bench grinder with a 2x48” belt sander on the other side might be a good compromise too.
 
SimonM said:
Once again, the answer to which tool is best is ALL of them.

While I like many things the belt sander can do, what I need most is a way to effectively sharpen lathe tooling and the bench grinder seems better suited.

A 6” bench grinder with a 2x48” belt sander on the other side might be a good compromise too.
Click to expand...
That is exactly the arrangement that I have.
They are literally back to back on a pedestal.
 
Bench grinder is best for sharpening drill bits. especially if you need to thin the web. Also best for hollow grinding hand scrapers or deburring tools.
 
What is the ideal speed?

I was looking at 8” grinders and there is low speed 1750rpm and high speed 3450rpm, which would be preferable?

@YYCHobbyMachinist fantastic thread, thanks for sharing, you surely saved me a head scratching.
 
I believe the slow speed grinders are sold for tool sharpening for wood turning tools at least. I would think that would follow for metal lathe tooling as well.
 
SimonM said:
What is the ideal speed?

I was looking at 8” grinders and there is low speed 1750rpm and high speed 3450rpm, which would be preferable?
...
Click to expand...
As they say, "it all depends":

http://www.abrasiveengineering.com/speeds.htm

The surface feet per minute from the grinding wheel depends on both the RPM's and the wheel diameter. At a given RPM, an 8" wheel has 33% higher SFPM than a 6" wheel. Bigger wheels are also heavier and require a beefier motor and bearings and are thus generally more expensive. Wheels all have a maximum safe RPM. You really don't want to find out what happens when a wheel explodes. Remember where your face normally is with relation to the wheel. BTW, if you think a wheel has _ever_ been damp and exposed to freezing temperatures, throw it out.

As @Hruul says, woodworkers often look for 1.725 RPM grinders. This is because they are more likely to be grinding high carbon (v. HSS) tools. With a 3,450 RPM grinder, it is pretty easy to overheat a high carbon tool and ruin the temper leaving the metal softened. With HSS, you'll burn your fingers long before affecting the tool hardness.

Then there is the whole subject of what wheel to mount. Most of us just use a general purpose wheel that really isn't very good at anything. There are thousands (literally) of specific purpose wheels that will efficiently do the thing they're designed to do--be that fast stock removal, fine finish, or something else. A wheel that's great for HSS will probably suck grinding common low carbon steel...and so on.

Craig
(Back in my days in public accounting, one of my clients manufactured grinding wheels. Taking inventory was a nightmare.)
 
About the first piece of machinery I ever bought was a 1×42 belt grinder with a 8" disc on it. I bought it my first year out of high school (1988) for knife making primarily but have used it alot over the years. Incendently I just took it apart yesterday as the bearings have been noisy for a while now and have recently got real bad....4 out the 5 bearings and the v belt are in rough shape. That's the only maintenance I've had to do in the 33 years. Not bad.

Possibly the second piece of equipment (not including hand drill or tools) I ever bought was a 8" bench grinder. I just repaired that item also. I use them both, but if I was only concerned with metal grinding I would go for a bench grinder first. If wood was my primary medium and just needed to do a bit of metal grinding, then a belt sander would be my choice.
 
I have a bunch of sanders and grinders.

Pro Grinder:
you can mount rubberized wheels, wire wheels, various types and grits of hard wheels, and diamond wheels...
Small footprint, can be had very cheap.

Grinders Con:
You cant get a straight surface (please don't as a rule use the side of any flat hard wheel - use a cup wheel)
You can't get inside a curve or corner easily or safely. (sorry @David_R8 safer on a belt sander)

Pro Belt sander:
you get flat smooth metal removal.
removes metal 2-3X faster than a typical 1/2 HP grinder - even on a 3HP sander and a 3HP hard grinder, the sander removes metal faster, flatter, cooler.
you can sharpen HSS bits on a sander without the radius you get on a grinder, which makes the geometry a little more accurate and easier for a beginner

Belt Sanders Con:
much more expensive than a grinder
the low power belt sanders suck big.
when reducing a sharp edge you can tear your belt (I've done it more than once)

I use both in my shop a lot. My 6X48 belt sander is my go-to for 80% of my grinder/sander work.
 
Had to pick up material got work today in Delta and couldn’t resist making a stop at KBC.

They had a King 8” grinder for sale, probably not the best but it will do for now. Everything on the used market was either way overpriced or absolute junk and still overpriced.

As recommended by @francist and @David_R8, I will be building a tool rest before putting it in service. Stamped 16ga chinesium isn’t going to cut it.

I would like to get a belt sander still but I think it might be a build project. They had a Kalamazoo 3x42 on display for 899$ And it was unimpressive, didn’t look sturdy at all.
 

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