More Thoughts on Grinding Moulder Knives

      Pros add to an earlier discussion about whether, when, and how to grind your own knives. October 2, 2005

How many tooling people work in the production field, and how many work in the tooling field? It seems a little lopsided. Maybe this needs to be addressed so everyone is on one page. When to buy a grinder or when to use carbide or high speed steel? Why can't my guys set up a moulder in 15 minutes compared to 45 minutes? I think this would be a good forum debate.

Forum Responses
(Solid Wood Machining Forum)
From Dave Rankin, forum technical advisor:
Good question. Most of the tooling sales companies have limited production experience. In fact, a large number of these "experts" have never run an industrial woodworking moulder, shaper or tenoner. On the other hand, there are still many excellent tooling people that do have experience in the production environment.

The same thing can be said of many machinery sales people. Some have an in-depth background in production while others have never turned on a machine. It is important to check into the real background of the machinery and tooling people that you trust and are willing to deal with. Over the years I have found some excellent folks to deal with, but I have also been taken by many. Many customers rely on the technicians that install their machines for tooling recommendations. Most techs are very well trained and many have production experience.

One thing to remember - there is always more than one source for your tooling needs and more than one brand on most products that will work. When you find a source that you really trust for your tooling needs and for your technical support, stay with them as your primary source. It is always wise to have a backup source for your tooling needs.

Another thing to think about is the difference between price and cost. Price, as I use it here, is the actual dollar spent on a product. Cost is the cost per foot to produce your product. For example: A bar of knife stock sells for $75 or $3 per inch. It runs 2000 lineal feet before it has to be sharpened. Your production run requires 5000 lineal feet. You will have to sharpen the tool twice during the run. If you use a higher grade of tool that cost $6 per inch and it makes the run without stopping, then you actually produced your product for less due to lower downtime on the moulder. If a moulder is not running, it is not making money. Most moulders can run 30 feet per minute plus. If the moulder is down for 10 minutes to sharpen the tool, then 300 feet of moulding were not produced. If you only make a nickel a foot, that is $15 lost. The tooling cost difference is covered right here with no consideration for the other lost time or wasted wood.

I work in both fields. My experience is in my history. I currently grind about 10 sets of knives a day, 5 days a week. I do all layout and grinding myself. I work no less than 12-14 hours a day.

The next time you hear someone tell you about a 5 minute setup time, look and see how many fingers they have left. I have said for years that people should be more concerned for the safety of their operators and the well being of the machinery over a 5 minute setup. Some operators can set up in 5 minutes and be perfectly safe, while others need a little more time. Some of the new machinery out there these days can really be set up in less than five minutes, but at what cost? I know that if I am rushed, I make mistakes. Many factors come into play, as well… Do the fences have to be moved? Do the bedplates have to be moved? Do chipbreakers have to be moved? Do pressure shoes have to be modifed? Have all the staples been removed from the ends of the boards? Do feed rollers have to be changed or moved? How many cutterheads need to be changed?

What people should focus more on: Is my operator safe? Is my machine that I spent so much money on being taken care of? Do I get the best quality product I can produce? Are my customers happy with my product? It seams to me the guys saying "five minute setup" have never asked all these questions.

When to buy a grinder? As soon as you can afford one. I can not believe all the customers that I deal with that don't own one. Some like the convenience of my service, others cannot justify the grinder purchase because they don't use the moulder enough. Many of my customers do own grinders and lack the time to do it themselves. I tend to spoil my customers, which keeps them coming back (I hope). I would say that if you run more than 2000 lineal feet a week, you need a grinder.

The last question was about carbide over high speed steel. Carbide is very expensive and it does not obtain the finish that high speed steel does, so it should only be used when needed. MDF, teak, composites, etc, to name a few. My basic rule of thumb is if your knives can not hold an edge for more than 500 feet, you should think about using carbide.

I picked up a used grinder almost a year ago. What a difference. The problem I had before wasn't obtaining the knives, as there are plenty of good services to grind knives for you in a very timely fashion. It was when I hit a staple or bullet (yes, bullet) or nail. Now I have to send away for resharpening and am down for several days. Now I can touch them up and be back at it in less than an hour. Usually way less. The other great thing is now I have the option of grinding myself, or if I am in a pinch, having my service take care of it.

By the way, any tricks you are using for finding staples, etc? Sometimes those little buzzards are impossible to see in the wax.

From Dave Rankin, forum technical advisor:
If you have the opportunity to have a way to regrind, even if you are not able to rough out the knife, it is an advantage. If you are not able to regrind, you may consider using a tool steel like the DGK. It holds up many times better than normal tool steel and even holds up against some of the staples and minor nick causing agents. If you do have to go out of house for grinding, use someone that would use the tools that they make for you.

In my last shop, I owned a Weinig grinder. However, I learned to buy my knife profiled, then just dress grind, for all the above reasons. In my new shop, I have been using inserts. Nevertheless, a contractor needed some wide custom woodwork. Therefore, I bought a corrugated head and custom ground knife for 500 lin. ft. of red oak. But the knife was not sharp at all. Could not even cut the edge of my fingernail! So I slip stone them for a long time. And the job is done. I'm looking for a new supplier.

Just two cents for anyone new on the grinder. For years, I have been the grinder guy and the moulder guy. There is nobody to blame for a bad finish in my shop but me. My tip: no matter what, you can't cheat in the tool room. If you try for time saving purposes, it's going to show up on the wood and you will be right back in there fixing the knives the right way.

If you don't quite know what I mean, you soon will. But as with moulder setups, experience is the best teacher and with that comes speed, accuracy and as stated above, safety. I agree that if you can afford a grinder, you should get one. The grinder, steel, etc. will pay for itself over time, but the initial investment might hurt a little.

I think I am fortunate to be responsible for both tooling and moulder setups. I can see what I have done in the tool room and how it effects the wood, instead of two people blaming each other because the boss doesn't like what's being produced. With that said, in bigger shops, it is most important to have the grinder op and the moulder op working and communicating closely to get the best results.

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