Using a smaller than normal wheel for profiling?

[Brian.Evans]

USAKM is out of stock on their 8", 70 duro wheel. I have a WHOLE bunch of knives to profile. I really don't want to use the platen as I'd like to not groove it up. I really can't afford the premium a 10" wheel commands. Could I use a 5" or 6" wheel for profiling, or is that getting too small? Or, asked another way, how small is too small? Could I use a 2" contact wheel? Where's the line?

Stock thickness is 1/8", if that makes any difference.

 

[Greenberg Woods]

I dont do most of my profiling on the grinder, I have a nice metal cutting bandsaw I use to get the basic shape, but i find that the wheels can be pretty small. I would say you will want To check and make sure your table is exactly at a level to bisect the wheel, otherwise you will have some nasty edges.

 

[Britt_Askew]

I use a 5" for profiling , works for me

 

[Lo/Rez]

Would having a second platen for profiling be cheaper?

 

[Brian.Evans]

I want a wheel for longer belt life and more efficient material removal.

 

[tim37a]

The bigger the wheel the better, but 5 or 6" should be fine.

Tim

 

[elementfe]

Brian, wheels definitely take more material off faster, but try using used coarse belts that you were going to throw away anyway for profiling on the platen.
For most of what we do, sharp belts work way better, but I had a very interesting conversation with Mr. Poplin (Pop's supply) about ceramic belts- he said they are actually designed for industrial processes that involve way more speed and pressure than we ever use. This is obvious when you look at a belt that has stopped cutting very well- there's a ton of abrasive untouched, but for hand held grinding, it's usually not a great idea to lean into it enough to make use of it. FOR ME, profiling is where I use all that otherwise wasted abrasive.
YMMV- this works for me, but isn't a technique you'll find a lot of folks using.

 

[Jack O'Neill]

The bigger the wheel the better, but 5 or 6" should be fine.

Tim

WHY ? I cannot see any difference at all for rough basic profiling with a 6" wheel as to a 8 or 10 " . I've used an 8" , now a 10"and I am going to start using my 6" . The only reason I am going to start using the 6" is to save my good 10"for the bevel grinding . I have found ( for me anyhow ) is I wear down the edge of a wheel I use to profile with , which hurts when doing bevels .

 

[Tin.Man]

Just call sunray poly, specify you want an aluminum hub, 2" wide, 8 or 10" diameter, 70 duro poly in whatever color tickles your fancy. Also ask for bearings, 1/2" id of the bearings and away you go.

I have used a 5" for profiling, you have to account for the sharper concave then say a 10", now using it horizontally makes no difference. What I mean is say your work rest is dead center of wheel, as you get closer to your scribed lines because its ) into / you could touch the line above and go right through on the bottom hope that makes sense. It happens with any wheel just made worse the smaller the wheel.

http://www.sunray-inc.com/online-store/idler-wheels-with-bearings/

 

[Travis Fry]

Brian, wheels definitely take more material off faster, but try using used coarse belts that you were going to throw away anyway for profiling on the platen.
For most of what we do, sharp belts work way better, but I had a very interesting conversation with Mr. Poplin (Pop's supply) about ceramic belts- he said they are actually designed for industrial processes that involve way more speed and pressure than we ever use. This is obvious when you look at a belt that has stopped cutting very well- there's a ton of abrasive untouched, but for hand held grinding, it's usually not a great idea to lean into it enough to make use of it. FOR ME, profiling is where I use all that otherwise wasted abrasive.
YMMV- this works for me, but isn't a technique you'll find a lot of folks using.

^This. I really don't understand the obsession with profiling with a wheel. I've only done that on rare occasions at someone else's shop, instead using a bandsaw and then a flat platen for everything. Why the knock against using a platen? I mean, I get that a wheel takes off material faster, but if you don't have one, who cares? You're overthinking it. Use what you have. Just grind the d@m& thing to the line.

 

[Cox Workshop]

Hey Tin.Man I checked out the wheels on sunray-inc but they look like they are only rated up to 800 rpm. Even their drive wheels without bearings were only rated to 800rpm. Am I looking at the wrong thing?

 

[Jack O'Neill]

Hey Tin.Man I checked out the wheels on sunray-inc but they look like they are only rated up to 800 rpm. Even their drive wheels without bearings were only rated to 800rpm. Am I looking at the wrong thing?

They also melt if they get too hot . I have read that they are good for basic grinding but may get to hot for a lot of hard hogging .

 

[Salem Straub]

I really don't understand the obsession with profiling with a wheel. I've only done that on rare occasions at someone else's shop, instead using a bandsaw and then a flat platen for everything. Why the knock against using a platen? I mean, I get that a wheel takes off material faster, but if you don't have one, who cares? You're overthinking it. Use what you have. Just grind the d@m& thing to the line.

A lot of heavy profiling on a platen will wear your platen out unevenly- and it's harder on the grinder, and on your belts, and heats things up faster. It works great if that's all you have, but if you have a wheel you could be using instead, particularly a serrated one, it's a more pleasant experience and saves having to resurface or replace your platen early. You can use those half worn out belts just as well, profiling with a wheel...

 

[Tin.Man]

Oneil- Have you ever seen or melted one? That myth gets perpetuated all the time and it drives me crazy!

I used an 8 inch poly wheel at 70 duro aluminum hub from sunray to profile 12 3/16" blanks in a row. Motor was 3600 rpms, 6" drive wheel, I did all 12 with a 36 grit belt and after taking the 36 off to switch to 60 it wasnt even warm to the touch. Ive also profiled a 1/4" thick tomahawk using the same wheel, again not even warm. Not sure what kind of grinding some are doing, but you would have to grind non stop, without quenching once which if you did that I imagine you would burn the hell out of your finger tips long before you could possibly melt the wheel.


Ext- I called sunray and asked about that, he said it was a typo and they are fine up to something like 7000-8000 rpms without a problem. But Im not affiliated with sun ray, just someone who has actually used their wheels and loved them.