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1"vs 2" belt grinder (25 vs 50 mm)


Kobus

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First post. 

I am a noob and thanks for all the info here.

I am in the process of ordering a bely grinder. 

I notice that most people on that side of the world use 2". 

Locally (South Africa) a lot of people prefer 1". 

I have really googled for opinions on this matter but without luck. 

What are your thoughts on this?

As you can imagine, at this tense stage your opinions will be highly valued. 

Thanks

Kobus

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Wider belt = more sanding potential per belt.  It also gives more area to support the blade while sanding.  The biggest factor for you may in fact be availability.  2" belts are incredibly easy to get in the US.  If you can't get those but can easily get 1" belts, go that route!  Remember, don't just look at "can I get it?", availability, but also price per square inch of belt.  

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I can only think of cons for the 1" grinders we see here in the USA.  They use short belts which means they generate more heat; they never have a powerful enough motor (usually 1/4 hp or less) to move steel; no availability of contact wheels; flimsy platens; much less selection of belt grit and grit material type; run too slow to eat steel; and if you do have a solid platen and a good belt it can be harder to blend a 1" belt mark across a blade than it is a wider belt.

I have no idea of the situation in South Africa, but in the USA the 2"x72" is the most popular for the following reasons:  they are much more solidly built; you can use whatever size motor you want (3 to 5 hp is not uncommon); these motors are often variable speed from nearly stopped to over 7500 surface feet per minute (which means they can be used on a wide variety of materials to do everything from extremely rapid stock removal of hardened steel to final polishing of delicate ivory); the range of grit sizes and types is unparalleled (everything from gravel-sized zirconia chunks to submicron-sized films, not to mention cork, felt, leather, and Scotchbrite material); and you can usually get contact wheels in a wide range of diameters from less than 1/2" up to 14" with ease, larger sizes on occasion.

Here the 1" machines are cheap equipment for the small-scale hobbyist in wood and nonferrous materials, with some belts available for knife sharpening. The 2x72 (and 2x132, 4x132, etc.) Machines are industrial tooling meant to do the job on any material you throw at them provided you have the proper belts and speed controls.

Now then, price!  A cheap Chinese 1x30 here can be as low as $60.  A top-end 2x72 with a generous supply of accessories and variable speed can easily go over the $5000 mark.  And that does not include belts, which can range from $3 - $15+ apiece.

This is why so many new folks start out with an angle grinder and files.  You can do everything with files and sandpaper you can do with a big fancy grinder (and some things you can't!).  It just takes longer.  It's also cleaner, safer, and generally better for your health.  

That's my perspective based on what's available here. Here on this forum we have a surprising number of folks from South Africa, you guys should seek each other out and exchange info on what's available.

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Check out the video on the Grinders page of my web-site, then check out the DVD Build Moe's Grinder on the DVD page and consider building your own.

Let me know if I can help you.

 

Wayne Coe
Artist Blacksmith
729 Peters Ford Road
Sunbright, Tennessee
706-273-8017
waynecoe@highland.net
www.WayneCoeArtistBlacksmith.com

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Hi Everybody

First post as well, this thread made me sign up.

Kobus, I've been saving for a long time to buy a proper grinder and I have failed, I will have to use my bonus this year (if we get a bonus) to buy a grinder.

That said, it's a problem to use so much of my income for a hobby that is not self-supporting.

1" vs 2" is a big question for me as well.

Here's what I know:

I have a small grinder with 2" belts, short belts and a weak motor, but I have found it easier to feel the bevel on the broader belt.  This is on a platen....flat grind.

The maker where I did a course has a proper grinder he sourced from SA, it uses a 1" belt and a large contact wheel.  Now I have to qualify, that day was my first time ever behind a grinder, and the last time I used a proper machine.

I have a certain manufacturer (South African) in mind, and they assure me the 1" belts are better for "control".  Not sure if this is just a regional thing, but 2 other exceptional manufacturers seem to be of the same opinion......

My personal preference would be 2", but I'm way too green to argue with persons who build belt grinders and many times over my experience.

Alan - I'm sure the quality of the grinders is not in question here, rather the practical use of 1" vs 2"

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Thanks, Gerhard, that clears things up for me a bit.  In my experience with split belts (you can split a 2" belt for narrow work if needed),  given the same horsepower and belt speed, is that a 1" belt cuts faster.  This is due to the smaller surface area in play.  It is also my experience that it's easier to get a more even finish with a wider belt, because of the greater surface area.  

Then again, I only use the narrow belts without a wheel or platen, since I only use them to get into tight curves and so use J-weight extra-flexible belts for that.  It probably just comes down to what you're used to, provided you have the same speed and power.

What sort of belt selection do you guys have to choose from?

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19 hours ago, Kobus said:

Hi Gerhard, what supplier will you be going for? I am thinking of Herbst.

Hi Kobus

Herbst was my first love as well, but I'll probably get a grinder from NW Knives & supplies, they're a little cheaper I believe and the logistics is better for me, I have a cousin in Potch that visits regularly and can bring it down.......I hope, transport costs would stop my purchase dead.

I did see another manufacturer on a FB page, Rauch Engineering (or something like that)..........looks like the go-to guy for super-large contact wheels.

In the video he puts a glass of water on the work table right at the contact wheel with the grinder running, looks extremely smooth!

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Hi Alan

Your logic on the narrow belt makes sense.

I've probably picked up some bad habits working with my little grinders, but I use the platen and slack belt most often.......freehand, love convex grinds....or almost FFG into convex.

The company I'll most likely buy from sells mostly Klingspor belts......I'm still 99% clueless on the subject.... 

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Sorry for the high-jack, I'm hoping Kobus has the same question.

Everybody I've asked recommends and insists on VSD.

As I understand that allows you to bring down the speed while keeping torque, my question is, is there a guide that tells you under what conditions or using which materials, what speeds to use?

The manufacturers present courses, but attending one of those is out of the question for me.

 

Thanks

Gerhard

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I don't know of a guide and I only have three fixed speeds, but generally on steel you start at the highest speed you have, then use lower speeds for finish grinding and post-heat treat grinding.  The really low speeds are good for handle work and non-metals that burn easily.

The belt manufacturers will have suggested speeds.  The ceramic belts, for instance, do best at super-high speed and pressure.  They will actually glaze and stop cutting if you run them too slow or without enough pressure on the steel.  Aluminum oxide is the opposite.

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6 hours ago, Alan Longmire said:

I don't know of a guide and I only have three fixed speeds, but generally on steel you start at the highest speed you have, then use lower speeds for finish grinding and post-heat treat grinding.  The really low speeds are good for handle work and non-metals that burn easily.

The belt manufacturers will have suggested speeds.  The ceramic belts, for instance, do best at super-high speed and pressure.  They will actually glaze and stop cutting if you run them too slow or without enough pressure on the steel.  Aluminum oxide is the opposite.

That last paragraph is a world of information for the new belt grinder owner. It really is "mission critical information" that isn't more commonly known.

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There are also some videos about knife grinding on YouTube. Walter Sorrels is fairly well known and has some useful vids such as

 

 

 

Hope these help.

"The way we win matters" (Ender Wiggins) Orson Scott Card

 

Nos qui libertate donati nescimus quid constat

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Plesier man. Voorspoed.

"The way we win matters" (Ender Wiggins) Orson Scott Card

 

Nos qui libertate donati nescimus quid constat

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