Rotary Platens

Crag the Brewer

Crag the Brewer

I make Nice, boring knives
Knifemaker / Craftsman / Service Provider
Joined
Oct 18, 2018
Messages
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I've had mine for a few days, I can see it's usefulness. How many of us have them, and Use them?

What should I try, anything you learned after having one?

I felt I got a good deal, and "didn't want to wait", didn't want to design one.....

Well it took around 4 weeks to get.
Now, I kinda wish I just made it, as I'm thinking I want to modify it already. I have a Ameribrade.

I don't like the guarding, and I wish I had more room coming from the left.

I might need to make it mount differently?

My grinder tracks beautifully normal, and in reverse slack belt grinding....but so far it doesn't like to track reverse with this thing on. Forward, no problem.

Are you grinding forward or reverse?
Edge up or down?

It blends real well, but I was expecting it to feel slightly firmer. I bet I'll only run it on the closest setting.


Looking forward to hearing some info/stories.
Thanks.
 
I have the same one and have only ran it with the platen. The finish that comes off of it is something else. No real tips here, mine is new to me too.

Here's a flat grind to convex tip I did with it. The knife is not finished in the pic. I am partially blind and thought I was using a 600 grit belt but realized later it was a 100u so this is a low grit grind and looks that good.

486627138_1071777688317714_1494500605212624700_n.jpg
 
It looks like the spacing between rollers on the Ameribrade are substantially greater than on my very early KMG Onion-style rotary. That is going to make it have more slack and perform altogether different. Interesting take. I definitely like the flat platen.
What is this "running in reverse"? NOT old KMG. LOL :)
 
fitzo said:
It looks like the spacing between rollers on the Ameribrade are substantially greater than on my very early KMG Onion-style rotary. That is going to make it have more slack and perform altogether different. Interesting take. I definitely like the flat platen.
What is this "running in reverse"? NOT old KMG. LOL :)
Click to expand...

So, you run yours with the belt Towards you?

Edge up, or edge down?
 
Daniel Fairly Knives said:
I have the same one and have only ran it with the platen. The finish that comes off of it is something else. No real tips here, mine is new to me too.

Here's a flat grind to convex tip I did with it. The knife is not finished in the pic. I am partially blind and thought I was using a 600 grit belt but realized later it was a 100u so this is a low grit grind and looks that good.

View attachment 2847666
Click to expand...
I haven't tried using the flat platen yet.
I might try it? In my head, If I like the platen, maybe I'd get another tungsten one, like on my normal set up. Or Teflon. I've got a chunk of it laying around
 
I grind edge up with the belt running towards me. I started out hollow grinding. One didn't have a choice back then with belt direction.. I don't remember a grinder circa 1983 or even 2000 that would reverse effectively. When one runs my KMG "Classic" in reverse the tension arm tanks and the belt flies off. I tried. :oops:
 
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fitzo said:
I grind edge up with the belt running towards me. One didn't have a choice back then. I don't remember a grinder circa 1983 or even 2000 that would reverse effectively. When one runs my KMG "Classic" in reverse the tension arm tanks and the belt flies off. I tried. :oops:
Click to expand...

I have a Pheer, and would run in reverse often.
Until now.

Do you run with a platen or no?
Even have the edge catch and kick back at you on the rotary?

Not sure if that happens
 
I have the Ameribrade as well and love it. I do all my grinding 120 grit and above on it.

I run it with the motor in forward and grind edge up just like I would on a flat platen.

The rotary platen gives the cleanest belt finish out there and also has the added benefit of softening the initial contact the blade makes with the grinder, reducing the risk of gouging the blade with the sides of the belt.

The one thing I don't like which you have discovered already is that there's no space on the lefthand side so you can't use a file guide. Bummer.

If you go ceramic 220 grit--> 65A Trizact, you can get a gorgeous ultra clean belt finish very easily. I still have some mill marks I had to go back and grind out, but these bowies were finished on the rotary platen with a 65A Trizact and are very clean if I may so so myself. I would have a really hard time doing this clean of a finish on a flat platen.

MM0aMSF.jpeg
 
Huntsman Knife Co. LLC. said:
I have the Ameribrade as well and love it. I do all my grinding 120 grit and above on it.

I run it with the motor in forward and grind edge up just like I would on a flat platen.

The rotary platen gives the cleanest belt finish out there and also has the added benefit of softening the initial contact the blade makes with the grinder, reducing the risk of gouging the blade with the sides of the belt.

The one thing I don't like which you have discovered already is that there's no space on the lefthand side so you can't use a file guide. Bummer.

If you go ceramic 220 grit--> 65A Trizact, you can get a gorgeous ultra clean belt finish very easily. I still have some mill marks I had to go back and grind out, but these bowies were finished on the rotary platen with a 65A Trizact and are very clean if I may so so myself. I would have a really hard time doing this clean of a finish on a flat platen.

MM0aMSF.jpeg
Click to expand...

Ok, I feel better about buying it now....haha.

Do you use the hard platen behind the belts?

What about the side guarding? I'm thinking of taking it off and on the left mounting, grinding closer to the wheels for more clearance.

Edit..
Your lines look Crisp!
 
Crag the Brewer said:
I have a Pheer, and would run in reverse often.
Until now.

Do you run with a platen or no?
Even have the edge catch and kick back at you on the rotary?

Not sure if that happens
Click to expand...

I had one incident with the rotary. Edge caught, cut, blade flew, abrasive belt flew, rubber belt cut a bit, necessitating a replacement belt. One learns to be careful in a knife shop or accumulates scars, no? I've got a whole lot of scars. LOL

One of my KMGs has a platen on it most of the time. The other has a 14" wheel on that steel bar and a big pillow block for the shaft. that thing is so darned heavy and I have become so feeble it is really a chore to change, so it mostly stays there. Everything else switches in and out of the "platen" machine.
 
Crag the Brewer said:
Ok, I feel better about buying it now....haha.

Do you use the hard platen behind the belts?

What about the side guarding? I'm thinking of taking it off and on the left mounting, grinding closer to the wheels for more clearance.

Edit..
Your lines look Crisp!
Click to expand...

Thanks!

I always use the hard platen. I even sharpen on it. I would 100% recommend investing in the platen chiller or running wet if possible. The platen gets hot fast.

I've now ground over 100 knives on my rotary platen and its held up great. I figured the belt would start degrading by now from all the friction but its still going strong.

I havent done anything with the side guarding. I'm just not using a file guide once I switch to the rotary platen.
 
When I had the KMG version (sold it 10 years ago to Matt Parkinson after he won Fif!), I usually used the closest space setting. The belt wanted to cup a bit, so the flat platen may be a nice option for flat grinding and cleaning up the grinds! For convex grinding, I usually went pretty tight, but it's nice to have different amounts of slack/tension. I want to get another rotary platen so I can stop messing with felt and get more reproducable results and even plunges. Hard felt and leather can mess up nice plunges quickly when the backing wears a bit!
 
anyone using one of those Moen Evo units? They expensive! But wow it sure looks like a well designed machine
 
Lorien said:
anyone using one of those Moen Evo units? They expensive! But wow it sure looks like a well designed machine
Click to expand...
I have the blue Moen platen. It's nice, but it wasn't a total game changer for me. Most people that really love the Moen use it with the grinding jig, and I don't grind with a jig. I also have the older KMG rotary platen and rarely use it. It kind of scares me to be honest.
 
J. Hoffman said:
I have the blue Moen platen. It's nice, but it wasn't a total game changer for me. Most people that really love the Moen use it with the grinding jig, and I don't grind with a jig. I also have the older KMG rotary platen and rarely use it. It kind of scares me to be honest.
Click to expand...
what's the scary part?
 
Getting a finger pulled in between the belt and the ribbed wheels
 
I've had a KMG rotary platen for 21 years. I flat grind 75% on a 45 degree angled platen then finish the grind on the 5 1/2" to 6" section of the rotary platen at 45 degrees. I run my grinders rotating away from me.
J. Hoffman said:
Getting a finger pulled in between the belt and the ribbed wheels
Click to expand...
That happened to me one time. You really need to concentrate while using it.
 
Gossman Knives said:
I've had a KMG rotary platen for 21 years. I flat grind 75% on a 45 degree angled platen then finish the grind on the 5 1/2" to 6" section of the rotary platen at 45 degrees. I run my grinders rotating away from me.

That happened to me one time. You really need to concentrate while using it.
Click to expand...

But the belt running Towards you?
 
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