Don Crockett's Hollow Grinding Platen

[Terry Primos]

In an earlier thread, CKD member, Don Crockett made mention of a curved platen he made for doing hollow grinds. There was some interest and Don promised to take some photos. He's having a bit of trouble with his image hosting site and sent these to me. I think this is a really neat idea and wanted to show you guys.

Don Crockett's Hollow Grinding Platen
Side view


With belt mounted

Photos and platen design by Don Crockett

In the original thread, Don stated the following:
... [ I ] drew an 11 inch radius on a sheet of paper, cut it out and traced it onto the edge of a slab of quarter inch thick mild steel. I then sawed and ground the curve out so that when mounted on the grinder, the platten made the belt bow outward, between the two wheels, and ground the blade edge-up, moving back and forth at a 90 degree angle to the belt, just like the platten was a big grinding wheel. I hope that makes some sense!

Don added the following in the email to me:
... here are two I snapped. One shows the shape of the platen well, the other shows how the belt rides. I just held the belt in place, I didn't adjust tracking so the belt hangs over the edge a bit. In use the platen is just wide enough so I can grind either plunge without tracking the belt to one side or another. This really helps me avoid the dreaded two-inch mark.

Prett cool eh? The arc of a BIG wheel without the expense of the wheel.

[Rob Frink]

Neat stuff! Thanks for posting it Terry.

-Rob

[floridafred]

Hey Rob:
That looks like a neat attachment for the KMG. I'll be the first to order one.

[Andrew McLurkin]

I hear them talked about but I've never seen one. Thanks for posting the pictures. Looks like you would get a long radius; edge to spine.

[hammerdownnow]

Don, Thanks for posting those. a picture does tell a thousand words. Thanks also for dropping off those belts and letting me handle those blades. The handle feels great in your hand. the hollow grind makes you want to touch it . It is very subtle but obviously there. As you probably noticed, I could hardly put down your WAR ZONE. I gotta get me one of those before you get back logged. Here is a pic

[hammerdownnow]

Don, The only time imagestation gives me trouble is when I make a mistake. If I forget to save my pic in a gif format, or I try to copy my pic from the upload preview page instead of from my storage bin. Oh, by the way, Your little EAGLET seems like it would be a handy little EDC, especially for someone who opened boxes or the like. another pic

[combs6136]

i read the item on the curved platen today and got the idea to go to the local scrap yard and get a piece of ss 10 in . pipe...I cut it to 2 x 7 in and attached it to the one on my Wilton Square Wheel......Anyone is welcome to the rest of the pipe...A one foot piece 10 in. in diameter cost me $2.00.......Thanks for getting me going on this...I have wanted a larger wheel for a long time, but i couldn't afford it.........Now i am ready to hollow grind some blades..........carl

[SharpByCoop]

Pretty neat idea. The first pic looks more like it's a +20" radius rather than an 11" one. What a wheel!!!

Coop

[Geno]

I could see where that would almost be as good as using a wheel that size. Except for the pinch factor of the belt riding between the platen and work, it shouls be the same.
You could also have different diameters made up instead of different wheels the same size.

[SharpByCoop]

Originally posted by Coop747
Pretty neat idea. The first pic looks more like it's a +20" radius rather than an 11" one. What a wheel!!!

DUUUHHH!!! I wuz looking and commenting on wheel SIZE and not radius. It was clearly stated as 11" RADIUS.

Coop

[Bob Warner]

I did this early on before I had a wheel of any size. I had only one problem and that was the friction of the belt riding over the metal. The belt tried to wear out from the back side.

I used less than clean metal for mine. Good clean new (smooth) steel would problably work great, especially with some silicone lubricant to lessen the friction.


Thanks for sharing.

[MongoForge]

I think Wayne Goddard has
something similliar in the
$50 knife shop...
Looks like something i need

[Crockett]

Terry,

Thanks for posting these pics.

H.D.N.,

the trouble I was having with Imagestation was operator error/computer illiteracy, not a problem on their part. I enjoyed visiting your place and I'm impressed by your collection. As far as getting a War Zone before I'm back logged...too late! We gotta collaborate on some knives since we live so close together. You might want to make your own War Zone. I can hook you up with materials, patterns, etc. Just be prepared, it takes a long time!
Don

[millironknives]

I love the ideas be posted for the hollow grind platten. Another idead is using a block of hard wood for the curve. I can't remember the name of the wood that is naturally greasy and lubricates itself. Matbe someone else knows out there? but it is an idea that might be easyeir than using steel and simple to make another if it would wear out.! One could even cover it with a teflon face!!

[Frank Niro]

The wood is probably Lignum Vitae. It was used for guilds on saws in saw mills at one time ang even shaft beering guilds in ships a while back of course. Frank