Single Knife and Counterweight Setup on a Moulder

Using just one knife rarely gives the best results. November 19, 2006

Does anyone use only one knife and counterweights on their Williams and Hussey moulder? I've used only one knife and counterweights on my Belsaw for years.

Forum Responses
(Architectural Woodworking Forum)
From contributor G:
Never heard of anyone doing this on a W&H. Why would you want to?

From the original questioner:
I grind my own knives with a Viel machine, so two knives is twice as much work. The fine details have to be done by hand with a Dremel tool so the two knives are not exactly the same, so you end up cutting with one knife anyway.

From contributor G:
Does your Belsaw have a square arbor like the W&H, or a round planer head? Never seen a Belsaw.

From the original questioner:
It is round. When you have custom knives made for it, they supply counterweights. You could put three knives in it, but it would be nearly impossible to align them. Even with one knife, the mill marks are less than store bought moldings. Belsaw is an old fashioned machine, but a real workhorse. I've used it for thirty years. The only things I have had to do to maintain it is rebuild the motor at ten and twenty years, and I had to buy a new one after thirty. It looks very much like the Woodmaster machine.

From contributor B:
This is not a good idea. The Belsaw has a large diameter head, which places your knife and counter balances further away from one another. This allows some leeway in the forces applied by not only the weight, but also projection of the knives.

The W/H head, as you know, is only about 1 1/4" square. This means that balance issues are much more critical. The projection of one knife is not going to be counteracted by a piece of squat steel mounted on the opposite side. You cannot even take two knives and offset them sideways on a W/H (I have tried this). Even though they weigh the same, they are not directly opposite one another, and the result is huge vibration.

Also, with the smaller cutting arc of the W/H, you will not get the same quality of cut with one knife that you will get with the large diameter head on the Belsaw. Quite frankly, having owned a couple Belsaws over the years (as well as a bunch of W/Hs), I can also tell you from first hand experience that you are shortchanging yourself by going the one knife route. I'd strongly suggest making the investment in one 3-knife set at some point to see the difference in ease, speed and quality of cut. If you are only going to run 20 ft or so with a custom knife, then yes, 1 knife is the way to go. For runs of hundreds of feet, though, you will be surprised at the difference the 3-knife setup will make. It is worth the extra investment.

From contributor G:
Do you get a lot of chatter marks on your moulding? You are right about one knife doing the final finish. Whether you have one or three knives, one knife does the final finish pass. The other knives, if ground within the proper tolerance, only assist. I have seen dual knives that were out so far that one knife was not even touching wood. Those get sent back. I wonder why you would ask about the W&H since you have been using this Belsaw for so long, unless you were having a problem with quality?

From contributor C:
Contributor B is right on the money. The difference in head body diameters between the Belsaw and the W & H does play a part in knife (and/or counterbalance) projection and its overall relation to tool balance. In a smaller diameter head, the centrifugal force plays a larger role. Save your machine bearings and use the extra knives! The end result finish will be improved, even though only one knife does the actual end cut. Balance is an inexpensive form of insurance and must not be overlooked. Even a slight misbalance of any part of the tool causes vibration and the resulting finish problems; but even worse, premature bearing failure and other machine damage. Balance not only the knives, but check balance on gib wedges and gib screws as well. We (Wood Tech Tooling) recommend the use of a precision balance scale, as a difference in balance of only 1 gram at 6,000 RPM's results in a rotational force of a whopping 22 pounds! Keep your tools balanced, and clean: yes, even built-up sawdust will adversely affect balance!

From the original questioner:
You asked why I bought a W&H after using a Belsaw for so long. The Belsaw is a workhorse, but it is very difficult to set up for cutting moldings, and even more difficult tot get the three planer knives back in at the same height. The tendency for the gibs to lift the knife up is very annoying. I do old house architectural woodworking, so I wanted the W&H to do curved moldings and panels. It is also nice to have two machines so that when one is set up for moldings, the other can still be used as a planer. Thanks for all of your great advice.

From contributor J:
I have a W & H, about 6 months old. Great machine. Have run close to 20000 lf of trim with it. Have changed the pressure rollers out twice now. Is this a common occurrence? How many feet do you get before having to change out the rollers? I've been running 5" poplar and 5" white oak for casing.

From contributor G:
Seems like the rollers don't hold up on these machines very well. A lot of it depends on the type of moulding you are running. I think one of the biggest problems is that a lot of guys don't have uniform blanks. The blanks need to be within a few thousands of each other in width or one will feed smoothly through the machine and the next one will drag or hang up and cut grooves in the rollers. We saw our blanks and then turn them on
their edges in clusters of 4 or 5 and run them through the widebelt sander. The blanks are all the same width, and they feed perfectly. Stress in wood can cause the blanks to bow sideways and drag or bind. This will also eat away at the rollers.

From contributor C:
Here's some info on replacement feed rollers for the Williams & Hussey molder. The feed rollers come in two hardnesses. The Green 70 duro lasts longer while the Yellow 50 duro provides better grip. Use only enough feed pressure to feed the material, through. Excessive pressure will prematurely wear out your rollers. Contributor G's thoughts are dead on the money on this machine concerning blank size consistency.