High speed steel or tungsten carbide?

[87cyan]

I am about to change the cutting knife on my Wohlenberg, the high speed steel was quoted at around $300, the tungsten carbide was 3 times that at little over $900. Is the tungsten carbide that much better? We cut everything from newsprint to 300 gsm stock paper. Which would you choose and why?

 

[aqazi81]

Carbide knife is much better than the steel knife but make sure you have good carbide knife sharpening service nearby.

 

[mattbeals]

Carbide if you can swing it. But as was said, make sure who ever sharpens it has the equipment and experience to deal with carbide.

 

[87cyan]

Thanks for the responses,yeah, I figured that special equipment would be needed. Nobody in my area has that kind of technical service. Even the steel blades that are sharpened, don't hold their edge for long. Is there a kit or sharpening machine for in-house sharpening?

 

[Eighty7]

Thanks for the responses,yeah, I figured that special equipment would be needed. Nobody in my area has that kind of technical service. Even the steel blades that are sharpened, don't hold their edge for long.

Is your existing knife high speed steel? If not, just stepping up to high speed steel is a huge improvement. The reason I bring it up is I have known some customers to get a standard steel knife on price and it loses it's edge in half the time of high speed steel.

Of course, carbide holds its edge even longer than high speed steel. I usually see those blades in three knife trimmers more than cutters.

 

[Eighty7]

Is there a kit or sharpening machine for in-house sharpening?

I'm sure there are small machines out there for sharpening cutter knives as I've heard of knife sharpening services working out of their vans on location.

The only cutter knife machines I've seen in person are 20 plus feet long and look like machine shop equipment. They have to be heavy and expensive.

 

[mattbeals]

Good steel, like D2, T1 or M2, is critical. I don't know that you'll find D2 in that size. But it's very good at holding an edge. If you aren't keeping your edge long, then I have to wonder what kind of steel it is, what angle it's sharpened at, what it's rockwell is, etc. Good blade steel and heat treat is critical, the angle being less important than those two. No matter the angle, if the heat treat and steel are not right for the application you'll roll your edge very quickly.

It could be the case, likely I'd say, that the blade itself is good. But the sharpening job is sub par. It's real easy to do it wrong. Not so easy to do it right. Maybe send the blade off to another vendor and see what happens?

 

[akalaray]

If your cutting card stock a carbide is the way to go, if your cutting paper high speed steel.
IMHO

 

[87cyan]

Currently it is high speed steel. I don't know the grade of the steel, I will ask the vendor. I got the new blade in Feb of 2014 and the operators loved it, since it was the first time we went up to HSS. It is now March 2015 and I'm shopping around for another blade. I have thought about sending to the West Coast for sharpening, any suggestions from companies that can do this properly. Also, I have been told that I may be using the wrong cutting stick. Thanks for the responses.

 

[k_graham]

I see this is an old posting but thought to add a bit. We had a issue a year back where what was supposed to be a sharp blade would not even cut through the 28" stock after a few cuts, yet used to do so no problem. Anyway its not a big name cutter and blades appear to be a bit thinner than an old Challenge cutter so we also can't put the torque on the bolts over 40 lbs or we will pull the threads out and need a helicoil repair. Anyway by size the bolts would normally require about 55 lbs torque if there was enough thickness to blade to support it.

I did find a bit of a solution however, it appears on having to due a heavy cut the blade was shifting enough to cause the issue, by removing screws using blue Locktite on threads and retorquing to 40 lbs then leaving overnight so Locktight which filled thread gaps hardened, we were able to get through the job. Unfortunately local sharpeners think they can treat a blade like a Zamboni ice surfacing blade and take a couple millimeters off at a time warping blades, consequently we do send the blades 450 kilometers or 300 miles to a place that sharpens so as 1 was already dull , then it turned out the replacements were not better we needed a few days to get 2 replacements sharpened and returned. Anyway I can't say if its old bolts, more likely worn blade threads but I suggest if you are having issues of blade longevity to try the Blue removable Locktite in your blade change routine.

Ken

 

[akalaray]

Here in Los Angeles we use LA Grinding

 

[akalaray]

We have special dies we use on a PMC Die cutter - We have to send them to Chicago from LA - Can't find anyone who can sharpen them - They are HSS - Send them to B&H Machine

 

[lboyer]

Thanks to everyone for your input. I reposted a similar question today without checking this post first. I will LA Grinding a call. Thanks again.