SQUARE HEAD TOOLING, KNIVES, TECHNIQUES

SAVING AN OLD KNIFE COLLECTION

One of the salient features of our recent history is our use of wood in the manufacture of things we needed. The machines featured in this accounting — another word for “blog”, please — of of the time when our utilization of wood was at it’s highest levels. Refrigerators, box cars, bridges, radios, autos, shipping boxes, fanning mills, caskets.

And every plant required knives. Knives, knives, and knives.

The knives above were those of a casket plant. I am saving these from growing rust at this time. Before they pit. It is giving me a chance to study each knife. What I find most interesting here is the story these knives tell. Of the plant, the men, fashion, decline, ignorance.

These are the knives that came with the big 14″ molder and the 8″ 505. I received them from a tumbled disarray, out of a handful of boxes. I have been sorting them in an effort to get them back in some order similar to what they would have been in the plant. I never saw the plant set up as these had been removed twenty years ago. But generally knives are kept in pairs of similar shape and weight.

This is about as ugly as a knife can get before it needs to be discarded. It is only worth saving in this case because this is an inlay knife. The deep rust attacks the mild steel body faster than the alloy inlay, the brighter band, the actual cutting edge.

This will make a useful knife.

And slowly they begin to shine.

The story these knives tell goes like this. The earlier machine is equipped with carbon steel knives. And seem to be of general millwork patterns. Then in the 20s, a major investment in the partner 505 and casket tooling is made. It is a first class operation. No expense is spared in building a library of first class tungsten inlay knives. Disston and Guaranteed Cutterhead Co. of Seattle. Then later Jones and Orth under their own name, Ohio knife. I can see the sales reps coming through the plant, visiting with the superintendent, the knife maker. And he had a very good hand. A fairly coarse wheel. Open grain. Slow, cool grind.

Things go well for a while. Then hard times. Many patterns are going out of style, people can’t pay for the high end work. The skilled men are drawn off to war and war industries. Fashions change.

After the war things get back. But it’s not the same. The knives used most get shorter and shorter. The inlay becomes so short and unsupported that it blow out.

The men that knew better have left. The boss doesn’t want to get new steel. So the plant starts going down the drain. Now the guys are scared to death and start using the three foot wrench on the knife bolts. Maybe that will stop the chips from packing under the ends of the knives and breaking them off, scattering steel around the plant.

Soon the bolts that hold the knives are failing on account of stretched threads.

The plant changes hands. Some new steel comes into the knife room. Solid HSS knives. And a new grinding machine. Face grinding. Ouch.

So when inheriting a knife collection, go through it real well. It will have a story to tell. A few things to teach. Cull the collection and improve it. I am discarding these knives:

And these bolts:

Some of them may have a half ounce of life, some might be good for balancers, but mostly they should have been thrown out decades ago.

OTHER TYPES OF KNIVES

At this time, there are some details of different types of knives in the pages about the Sash Stickers and a little on spikes on the 6″ Houston Moulder page.

CARBON STEEL KNIVES

These are my carbon steel knives. In the foreground are mortise heads that use well fitted spikes. Above them are sizing knives in the rack. Hook knives hanging on the rail.

In the center are cap head knives, double edged.

Then come the hand rails and other left/right pairs.

Adjacent are the large slot knives.

From left to right, more large slot pairs. The picture miss the upper racks but you get the idea. Then in the corner are the small slot knives for the little machines. Adjacent are the spikes. The spikes are the heart of the system from which the most numerous combinations and variations can be had.

Above we see how a combination set up works. The bevel knives are not shown. On the left are the cove knives. The balance below is for a slightly different size in all three pairs. The next two blend to make balance of the crown.

At the top is the template. The tabs index on the edge of the cutter head and the knives are set to the fine pencil out line on the template. This pattern runs on the bottom head of a moulder. The template also shows the position on the top head knives. This particular crown is a 9 1/4″ pattern which was a stock item.

Here we can see the template a bit better. As part of the information is what side to run the knives and the projection of the weightier balance knife. The position of the top  straight knives is not drawn as that was a standard established by the operator.

An essential part of any old knife collection are the samples and the templates. They tell the story and get the balance the way the knife maker intended.

The HSS knives are on the other side of the room. We’ll look at them some other time.

To see set ups on the machines look at the New Column 8″ Moulder post and the sash sticker posts.

How to use a molder rule 1

Part 1

The first step using a molder or stickerman’s rule is to determine the cutting circle for the head you are setting the rule to use. This will establish the surfacing line at the “0” of the rule scale. If you know the circle to be a certain projection beyond the lips of the cutter head set the bottom of the rule to that distance from the turned edge by loosening the three screws in the body of the rule.

Cutting circles can vary. A machine may have data that says one thing while the actual machine is different. Some heads have been re-conditioned. The lips are dressed down and the knife surfaces are trued.

When the rules were developed, they were primarily developed for those using square head babbitt bearing machines and favoring combination or multiple knife set ups. The ability to adjust to a machine condition was key to getting accurate use of the rule. For instance, if the pour in the bearings was not perfect or if it has worn more one side than the other, an adjustment to the knives to make a flat board may be required. It is a feature of the rule that this adjustment to the cutting circle can be made.

Molders also have elevated and lead set feed rolls which can affect the behavior of the material as it passes under the top head. The weighted chip breaker will also factor in the true surfacing line location. A good way to find the surfacing line is to place a planed board in the machine and crank the bed up towards the head. Place card stock equal in thickness to the amount of material you want to remove at the top head under the feed rolls and over the board. Bring the bed up to a firm and square engagement with the rolls. Advance the rolls slightly by hand to see the imprint of the rolls in the card stock. It should be even across the width of the material. Some molders have devices to keep rolls in parallel but many older machines have back hinged rolls shafts. Once this looks good, see what the distance from the head to the board looks like. If it is more than a quarter inch, the machine may not have the correct heads. If you can bring the bed higher and retain the nice even engagement with the rolls, do so until the head is about an 1/8 inch from the wood.

Now take the shorter of the knife bolts – the ones you will want to use for surfacing – and put them in a slot in the head. Rotate the head so that they are upside down. If they strike the wood, you will need to lower the bed, or, grind the bolts down. Just not too short to fully engage the nut when knives are secured.

If the bolts are clear then finger tight install a head width surfacing knife, rotate the head backwards and seat the knife to the surface of the material. The chip breaker, the feed roll weights must be down and bearing on the material when this is done.

Now you have the cutting circle. If you have a patent rule, place it behind the knife and set the bottom of the scale to the edge of the knife. It may not be straight. Which is fine. It is reflecting the condition of the machine and this is where the knives need to be to produce a parallel board. Any pattern that has a flat in it will have that part of the pattern set to this line. The depths of all parts of a pattern are measured in reference to this line.

The surfacing line is also the point below which no bolt must strike. Now if a bolt is long but in the wake of a deeper part of the pattern there is no issue. The surfacing line should also be at the place where the least material is required to remove to develop a clean finish but still with adequate engagement to freely feed the material. Some trial and error may be required but for the most part what I have described should find the best circle to use.

How to use a molder rule 2

Part 2

Once the surfacing line is set it is time to set the end stop on the rule. The stop on the right is the one to use at the top head. The rule is made so that the stop on the left, needed for the bottom head, can be positioned out of the way. It is vulnerable to being knocked out of adjustment when left out.

Where the stop is set depends on two things. How far inside the inside guide one runs the top head and how much material one is taking off at the inside cutter head. If one is not using the inside head, then set the stop so that when hanging over the end of the head the beginning of the inch scale from right to left lines up with the inside guide or frame of the machine. Make sure the ends of the head are not dinged up. Removable heads sometimes get dropped and banged up and the corners get dinged. The rule need to locate the same at all four sides.

When surfacing is happening at the inside head the amount of material removed must be added to the stop distance. This will make it so that a point on your pattern will be located as you expect after the inside head has made its cut.

How to use a molder rule Part 3

Once the rule is adjusted select the knives. You can check the profile of the knives for projection on the rule. For a first time set up with no prior reference template or set up stick, I simply set the knives to the points I want to make on the pattern. I work right to left. In this case here the location and depth of the fillet or quirk is the starting point. Then next point I want is the top of the the bead which I want to run slightly below surfacing because I want no scant finish.

The next fillet width is determined by the location of the cove. The rotation and placement for a full quarter is easy to locate using the rule.

Angles are easy on the rule. Just use the grid. In the case shown here the compliment is a hair shallow because I want the rake to sit nice to the wall and ceiling. Use ratio rather than degrees.

Applying masking tape to the rule is useful. One can trace a profile to the rule and set to that rather than known points. I use tape to record a placement. In this case, I an using it to make sure my balancing knives are outside the cut of my desired detail or in the same sweep if the knives are a matched pair like the bevels here.

So it’s pretty simple to use a molder rule. And fun too.

READING MATERIAL

MODERN SHAPER PRACTICE by W H Rohr

This is a great book. A companion to Machine Molder Practice also by Rohr.

It is a large file and will take time to load.

 

And while yer waitin for that to load, you can watch this movie about sorting knives:

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