Yet another belt sharpener...

[Steve Friedman]

Thanks Mark. See what you started with that Alabama Damascus steel knife?

Don't you think the "platen" should be steel? I've watched videos of guys using the 2" x 72" grinders and they're not very gentle with them.

Steve

[CLETUS]

I'll say maybe.


The platen on my 3450rpm grinder is steel, I do all of my "rough" work on that.

On my 1725rpm grinder it is aluminum, while there are marks on the platen, it's not worn. Of course, it doesn't have a ton of use on it yet.

I only do my final sharpening on the slow speed grinder.

[Timberwolf]

By running a belt at "half motor speed" you already have a 2 to 1 advantage, so you "can" get by with a 1/4hp if you don't try to "hog" metal..Professional knife makers work on pretty large blades and push their machines to their limits, so they need heftier motors for the torque they can produce at high speed.

For a 2" belt running at 1000fpm, I think the smallest motor I would use would be 1/2hp...like anything else tho, it depends on how hard you want to "push it"..or how fast you want to grind the steel.

I have a 2X48" grinder "in the works" right now and have a 1/2hp electronically variable speed motor for it. And I may run that through a "step-pulley system" to make it even more "variable"..

[Timberwolf]

I was thinking that a 1/2" thick piece of granite would make a great platen..or even a glazed piece of ceramic tile...easy enough to come by and much cheaper than the ceramics the knife shops sell...could make it so it's clamped to the steel backer and easy to replace when needed. And heat wont affect it.

[Steve Friedman]

I'm home sick, so I've have nothing better to do than read about belt grinders. What about a piece of glass stuck to the platen? Only issue is whether the heat will melt the epoxy.

I also found DIY grinder kits. USA Knifemaker sells a $25 set of plans for a No Weld Grinder and they sell all the parts (except the motor) for only $1,200. Grinder in a Box (by Polar Bear Forge) is only $285, but doesn't include wheel, motor, and miscellaneous hardware. He estimates $800 - $900 for the whole thing.

I understand they're for 2 x 72 grinders, but the price for the parts seems to make the ready built ones seem much more reasonable. I know it's not the same thing, but they all make the Grizzly and Kalamazoo grinders look like bargains.

And it makes the Woodnet version more attractive than ever.

Steve

[Arlin Eastman]

How long should a Platen be?

It seems to me the longer the better?

Arlin

[Steve Friedman]

Arlin Eastman said:

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How long should a Platen be?

It seems to me the longer the better?

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I'll let others answer, but i think it depends on what you're doing with the grinder. I use the area above the platen a lot when sharpening knives, axes, and just recently when shaping the scales on a couple of knives. On the other hand, the platen was really helpful to flatten the flat parts of the scales, grind away the pins, and shape the spine of the knives. In my case, I would have loved a platen than was a little longer and more sturdy, but use the area above the platen much more often.

Steve

[Timberwolf]

Glass will work if it is tempered....I would not use ordinary window glass tho...I think I'm going the ceramic tile route..will use JB Weld to secure it to the steel platen.If it gets hot enough to affect it, I will devise a way to mechanically clamp it.

I would advise you to study the way those "square wheel" belt grinders are made..They are all very similar in construction, and some can be bolted together...not welded. And as for me, I think they are way over priced for what they are...I have a 72" Grizzly and I doubt that the $1400.00 belt grinders will do any more than my Griz. I think you have to kick the cost up to around $2500. to get a really excellent high speed grinder..and they will be about 2HP with variable speed. { electronically variable speed commands a premium} You can buy a 1/2HP variable speed motor from Penn State Industries for about $125.00..Not exactly "high power" but adequate if you don't push it...Buy the rollers and drive wheel on Ebay if you can't make your own.

One fellow has a Youtube vid showing how he built his own using wood, {including the wheels} and the thing works pretty darn good!! Not for professional use but fine for hobbyists, IMO. I'll post the link if I can find it..

edit...Found it....This guy's pretty clever..You can watch as he makes the parts for it.....

https://www.youtube.com/watch?v=I1j0hbz8SwA

[Steve Friedman]

Thanks Jack.

I haven't yet figured out what makes the 3 or 4 wheel grinders better than the two wheel Grizzly style. The $500 that the Grizzly costs wouldn't even buy the parts for the others. I'm sure they're worth the money, just maybe knot for someone (like me) who's just trying to make a few dozen knives.

The knock on the Grizzly appears to be the platen and grinder stand not being robust enough, but they sure look pretty sturdy to me. Maybe I'll have to take a drive over there one day.

Thanks again.

Steve

[Timberwolf]

The 3 and 4 wheelers are more compact and that may be the attraction...plus they are more versatile if they have the large wheel attachment. The "vertical" configuration of the Griz and kalamazoo is a little "Imposing"..for lack of a better word. But I have no problem with the strength of the platen assembly..I will say that the tool rest is a little too small but that is easily corrected..it's plenty strong enough. It only has a 1hp motor but it is "double ended" and I have a hard felt wheel on that end...The amount of power it has is fine with me..All a larger motor does is allow the user to put more force on the belt, plus it can speed up the work quite a bit. It's plenty fast enough for me. One thing for sure...the Griz is HEAVY!! The motor alone must weight fifty pounds!!!! I don't think you can go wrong with the Griz..it's probably the most bang for the buck!!