Using side of wheel vs periphery?

ADFToolmaker · May 11, 2017

We are tool makers, we surface and cylindrical grind tool steel all day long, White aluminium oxide, pink aluminum oxide and Sg Wheels. Almost always using the periphery of the wheel, only side wheeling when we need to kiss a shoulder, because side wheeling always seems to be a painful process.

Then we get a 440B blade to grind, and using the periphery of the wheel (PA), limited success, so we are not the grinding legends we thought we were. We did notice the previous grind was done with the side of a wheel, cup wheel presumably. I have noticed many knives in industry are ground this way, maybe we should do the same? What are requirements for work and wheel speed? Wheel type? Can someone explain to me why using the side of the wheel succeeds for knife grinding when we see it as a last resort?

Thanks

Andrew

Hazzert · May 11, 2017

What issue were you having using the periphery? My only thought is that side grinding the wheel is normally relieved or tapered so the entire side isn't making contact with the work piece. If contact is causing you an issue do you have a narrower wheel to try? or try dressing a slight step in half the wheel to lessen wheel contact.

Just my 2c but I'm no grinder hand.

POAx · May 11, 2017

There are wheels like heavy cup-wheels, made for drill grinders. If you would install a such wheel and also add an "swing arm" with a diamond so you can dress the side of the wheel in a proper way, I think you would have what you need. The swing arm has to be ridgid and its rotating axis parallel to the wheel axis. In that way you will have a flat wheel surface on the side, always ready for you.

ADFToolmaker · May 11, 2017

Hazzert said:
What issue were you having using the periphery? My only thought is that side grinding the wheel is normally relieved or tapered so the entire side isn't making contact with the work piece. If contact is causing you an issue do you have a narrower wheel to try? or try dressing a slight step in half the wheel to lessen wheel contact.
Just my 2c but I'm no grinder hand.

Thanks Hazzert, we have tried dressing the wheel so the contact surface is narrower, but that helped only marginally. The wheel just wont cut like it does with tool steel. It seems to loose it's edge straight away. We may be feeding the work too fast, we have made some new pulleys to get it slower but the problem prevails. (we are face grinding in a cylindrical) My question was more specific about why knife grinders are so often configured to sidewheel, and what other parameters they have to meet to get that to work and why, so that we can make an informed decision to try it.

ADFToolmaker · May 11, 2017

POAx said:
There are wheels like heavy cup-wheels, made for drill grinders. If you would install a such wheel and also add an "swing arm" with a diamond so you can dress the side of the wheel in a proper way, I think you would have what you need. The swing arm has to be ridgid and its rotating axis parallel to the wheel axis. In that way you will have a flat wheel surface on the side, always ready for you.

Thanks POax, we have a selection of large cup wheels already, but don't know how to select the grade/speed/feed for sidewheeling as well as we might for periphery grinding. We can dress the face as you describe with existing equipment. It seems widely known that 440B can be challenging to grind, so these parameters must be important.

TDegenhart · May 11, 2017

Two comments. One, slowing the wheel done has the effect of using a softer wheel. Secondly, side wheeling will give a flatter surface. Are the knives hunting or knives that would go on a wood planer?

Tom

ADFToolmaker · May 11, 2017

Not a conventional knife, it is
A 2ft diameter meat cutting blade.

Hazzert · May 11, 2017

Do you know the material of the knife? It might be worth calling your Norton or other grinding supplier and taking to an applications guy for a recommendation, we're kind of shooting in the dark here.

A harder wheel will probably last longer so my only other suggestion is to try going to a harder wheel and if you are getting any loading or glazing to go down in softness.

TDegenhart · May 11, 2017

You might want to try CBN with coolant. I would think that a face grind with a cup wheel and with the rotation from the outside to center would work the best.

Tom

ADFToolmaker · May 12, 2017

Hazzert said:
Do you know the material of the knife? It might be worth calling your Norton or other grinding supplier and taking to an applications guy for a recommendation, we're kind of shooting in the dark here.

A harder wheel will probably last longer so my only other suggestion is to try going to a harder wheel and if you are getting any loading or glazing to go down in softness.

Workpeice material is 440B. When you say harder wheel do you mean the grit or the bond? We are pretty familiar with the theory of soft vs hard bond and have experimented with several WA wheels of different bond hardness but we are not getting the same performance feedback we normally get with the toolsteels we normally grind. Our kinik supplier recommended a PA wheel which was slightly better, but not really good enough. His next suggestion is a SG wheel, which he can't supply for up to four months. (We are in New Zealand). Since he thought the PA would work and it didn't, and wasn't able to recommend a work speed either, I'm not going to keep throwing money his way until we trip over a solution. I am quite prepared to spend the money on an SG or CBN but need to have some certainty it will work. My op was to establish if peripheral or side grinding is the best approach and why. Imagine spending say $3000.00 on a cbn plain wheel only to be told afterwards a cup wheel would have worked better.

ADFToolmaker · May 12, 2017

TDegenhart said:
You might want to try CBN with coolant. I would think that a face grind with a cup wheel and with the rotation from the outside to center would work the best.

Tom

Interesting suggestion Tom. I can imagine that working, but need to find some certainty before spending the cbn money (it is a 400mm wheel) Whats the reason outside in rotation works best? Do you have some suggestions for work speed?

CarbideBob · May 12, 2017

Everything is different between a cup or face wheel and a OD wheel.
Think about the grain contact time and stroke with the part and the chip that is formed.
Grinding is milling on a tiny scale. One here is face milling the other periphery milling.
Bob

ADFToolmaker · May 12, 2017

Thanks Bob, I follow your description of the differences. I can imagine as with milling, depending on various factors one method will be superior to another. My question is, what are the factors I need to consider to decide in my case?

cash · May 12, 2017

These kind of blades are ground on pretty specific machines. Many of these machines are built specific for the blade or have massive amount of adjustments in them.

These guys make the machines and regrind knives, but very secret.

Cozzini Food Equipment Solutions, Integration & Technologies

On a straight knife a reform or goekel grinder is very popular, they use a cylinder wheel.

Type 5 - Reform - Knife Grinders - Grinding & Sharpening - Machinery

SeaMoss · May 12, 2017

ADFToolmaker said:
Interesting suggestion Tom. I can imagine that working, but need to find some certainty before spending the cbn money (it is a 400mm wheel)

Have you tried the Cubitron II wheels ? I understand Norton makes something similar .... We have a customer who did some testing and it really did make a huge difference.

TDegenhart · May 12, 2017

I sharpen straight knives made from stellite. I built a grinder somewhat like a Blanchard with a vertical spindle and a cup wheel. This works great, has high stock removal and minimum heat problems. By grinding away from the edge to the heavy part of the blade, the heat from grinding is directed way from the thin edge.

Tom

ADFToolmaker · May 12, 2017

TDegenhart said:
I sharpen straight knives made from stellite. I built a grinder somewhat like a Blanchard with a vertical spindle and a cup wheel. This works great, has high stock removal and minimum heat problems. By grinding away from the edge to the heavy part of the blade, the heat from grinding is directed way from the thin edge.

Tom

That's great info Tom, that's the kind of anecdote I was hoping to get. May I ask 1. What grade of wheel you use?
2. What speed your work passes under the wheel?

Andrew

ADFToolmaker · May 12, 2017

cash said:
These kind of blades are ground on pretty specific machines. Many of these machines are built specific for the blade or have massive amount of adjustments in them.

These guys make the machines and regrind knives, but very secret.

Cozzini Food Equipment Solutions, Integration & Technologies

On a straight knife a reform or goekel grinder is very popular, they use a cylinder wheel.

Type 5 - Reform - Knife Grinders - Grinding & Sharpening - Machinery

That's a bit of what I was afraid of cash. With unlimited time and money I could learn what cozzini knows, but I do have limits on those things. I am hoping to collect together the valuable info from the members here to shorten the learning process.

ADFToolmaker · May 12, 2017

duplicate post removed

ADFToolmaker · May 12, 2017

SeaMoss said:
Have you tried the Cubitron II wheels ? I understand Norton makes something similar .... We have a customer who did some testing and it really did make a huge difference.

I googled cubitron. Appears to be only available for hand held equipment? Still, if someone said clamp a 9" angle grinder to my workhead I might just try it...

Using side of wheel vs periphery?

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