delta jointer
The SHELIX cutterhead installed in the DJ-20 jointer.

Background

1 September 2017

The SHELIX cutterhead is IMO, an incredible technological advancement in cutterhead design. It also brings with it some unique challenges for the woodworker. One major challenge is table alignment.

Aligning the DJ-20 tables has typically been done by following Delta's detailed "Jointer Table Adjustment Procedure" PDF. If you do not have this PDF you need to download it if you are going to align your jointer tables.

Note!
If the above link ever goes dead, email me and I will be happy to send the PDF to you. You cannot proceed without this to guide you.

Outfeed table alignment can no longer be done as Delta suggested because the cutterhead drum-to-knife height is fundamentally different between Delta's cutterhead and SHELIX's radical cutterhead.

Specifically, Delta recommends that the outfeed table be "exactly 0.015 inch" above the cutterhead drum. Once this is accomplished, each knife is adjusted so that it is coplanar with the top surface of the outfeed table. SHELIX carbide knives are not adjustable, so this will not work.

In brief, I align the jointer's outfeed table to make it coplanar with the two outermost SHELIX carbide cutters when they are at top-dead-center (TOC).

Table Re-Alignment Procedure(s)

First of all, lets determine which the "outermost" carbide knives are that we are going to align the outfeed table against. The SHELIX cutterhead only has two of these unique "outermost" carbide knives. The following two images should make this clear.

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IMAGE 2
This is the operator end of the SHELIX cutterhead showing the outermost carbide knife.
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IMAGE 3
This image shows opposite end (the fence side) of the SHELIX cutterhead displaying its outermost carbide knife.

I will follow Delta's PDF instructions to align the outfeed table, but will ignore their 0.015" table-to-drum spec and substitute my own method.

First up, lets go over some graphics so we'll all be on the same page.

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Graphic 1
This graphic depicts the correct alignment relationship between the outfeed table and the SHELIX cutterhead as viewed from the operator position.
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Graphic 2
This graphic shows correct and incorrect alignment between the outfeed table and the SHELIX cutterhead knives as viewed from the cutterhead towards the outfeed table.
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Graphic 3
This is a top-down view of the entire jointer. Its main purpose is to define the nomenclature of the components I will be referring to as we align the tables.
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Graphic 4
This graphic shows each of the straightedge positions that will be required to align the outfeed table. It also shows the measure points over the cutterhead and outfeed table.
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Graphic 5
This final graphic shows the measure points we will use to align the infeed table after the outfeed table has been correctly aligned.

I'll be referring to these graphics as we proceed.

Step One

Disconnect your machine from its power source!

With your machine safely disconnected, back out the positive stop screws of both tables and loosen their table locks. Lower the infeed table so that it is at least 1/4" lower than the cutterhead. Raise the outfeed table to where you think it is coplaner with the SHELIX carbide knives. The more accurate the better.

Step Two

Lay your straightedge over the rearmost carbide knife as shown in Position A of Graphic 4. Delta recommends weighing down the far end of your straightedge so that it will lay snugly against the top of the outfeed table. How, or if, you do this will be determined by which method you choose to align your outfeed table. This is explained below. The way that I weight down my straightedge will follow below.

Next, rotate the cutterhead so the the rear carbide cutter is NOT making any contact with the straightedge as shown in the next image.

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IMAGE 4
This image shows the read carbide knife completely clear of the straightedge.
Step Three

Our goal is to measure the difference between the outfeed table surface and the outermost carbide knife when it is at TOC. There are two ways to determine this: audible-motion and digital. There may be other ways to do this, but I found these to be sufficient.

If you anchor down your straightedge sufficiently, it will not be dragged by the knife as it rotates beneath the straightedge. An unweighed straightedge will be dragged by the knife. This will make sense as we continue.

Audible-Motion Method
If the table surface is lower than the carbide knife at TOC the knife will raise and rub on the bottom edge of the straightedge when the cutterhead is rotated. If this happens you automatically know you need to raise the table slightly. I have resorted to slightly tapping the table raising lever with a board to do this. Oftentimes hand adjustments are excessive when you're after very slight table changes.

In this case, you had two indications of your alignment: motion and noise. If the table is higher than the TOC position of the knife then you get no feedback at all, so you have to raise the table and try again until you get some feedback. Optimally, a very slight rubbing noise - without any straigthedge lifting or dragging - is ideal. If this happens move on to Step Four.

Digital Method
The method requires the use of a Digital Height Gauge as shown next.

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IMAGE 5
This image shows the igage digital height gauge with measuring arm resting on the straightedge.

If you own a digital height tool, this is the perfect time to use it. To use this instrument the first thing we need to do is rotate the cutterhead so that it is not touching the straightedge as shown in Image 4 above. Next, push the reading arm down on the straightedge. Press 'Zero' to zero the instrument. Now any vertical motion of the straightedge will be detected and shown on the digital display.

For this method it is best if your straightedge is anchored down sufficiently so that it will not be dragged by the rotating knife. The following image shows how I anchor my straightedge on the table.

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IMAGE 6
This image shows how I weigh my straightedge down against the table. This eliminates any chance that the straightedge will be dragged by the cutterhead knife.

With your instrument zeroed, rotate your cutterhead so that the knife passes completely under the straightedge. Note the change in your digital readout.

If the readout does not change, the table may be too high. If you were able to detect a slight rubbing sound then the table may be in alignment with the carbide cutter. If you heard nothing, then it may be best to lower the table slightly and repeat the process.

Note!
Do NOT be tempted to just use this instrument sitting on the outfeed table to measure TOC of the carbide knife. This will measure TOC, but will tell you NOTHING about the alignment of the opposite end of the outfeed table. This is why we use a long straightedge in the first place. The straightedge rests parallel with both ends of the outfeed table at the same time, so the digital readout indicates the alignment of BOTH ends of the outfeed table which is what we want to know.

If the readout increases - the carbide knife raised the straightedge - then the table is too low. (This is preferred over the previous result because you know exactly what the cutter-to-table relationship is.) The readout value will determine your next course of action: If you get 0.001" then I'd be very happy with that and leave your table setting as it is. A reading such as this is close enough. Keep it real and move on to Step Four.

If it is much greater than that then it would be best to raise the table very slightly and repeat the rotational process.

Needless to say, this is a very precise method of aligning your outfeed table. You may opt not to be this precise and that is fine.

Plan B

You need to first download the following PDF which will show you in graphic detail how to align your tables. If you have never aligned your jointer tables you're in for a learning experience. If you have, then this is probably old hat to you. It's not a big deal, but you have to follow all the steps in the PDF or else you'll be spinning your wheels.

Note!
If the above link ever goes dead, email me and I will be happy to send the PDF to you. You cannot proceed without this to guide you.

Our Goal(s)

Before we continue, lets be clear on a few things.

One
The Shelix cutter does not have straight knives like the Delta cutterhead did. Therefore, we no longer can use these 8.125" long knife edges to align the outfeed table like we used to.

Two
The new cutterhead has individual carbide knives - 9/16"x9/16" - that rotate concentrically about its axis. That said, we have to have a new method of aligning the outfeed table. To do this, we must choose which carbide cutters we are going to use to align our outfeed table with. Logic dictates that we should use cutters as far apart from one another as possible. This guanantees that our final alignment will be as precise as humanly possible.

Therefore, our goals are these: First, we want the outfeed table surface to be in the same exact plane as the path that the SHELIX carbide knives make when they are at their top-dead-center rotational point. Secondly, we want the infeed table surface to be coplanar with the outfeed table surface after it has been perfectly aligned. More on this later.

The following two graphics should not be a shock to anyone. They merely serve to underline what our goals are.

So, to align the tables I use two items: a long (50") Precision Straightedge and a fairly long Feeler Gauge Set of good quality. The feeler gauges I used were about 5-1/2" in length.

Delta's process was to accurately measure the distance between the straight edge and the cutterhead body - NOT the knives - with your feeler gauge. Delta recommended that this distance be "exactly 0.015". Looking at Delta's Alignment PDF, you will see that the straight edge was placed in four different orientations to correctly align the outfeed table with the cutterhead while taking these measurements. Table adjustments were made by rotating the eccentric bushings of which there are four(4) on each table. These are located at each of the table corners.

We can no longer make these measurements as Delta recommended with the SHELIX cutterhead because, (1) to my knowledge the correct distance from the outfeed table and the cutterhead body is not known, (2) even if it were it would take a very thick feeler gauge - 1/4"? - to take this measurement and (3) this is just not feasible.

Let's get started. The following graphics clearly show how to orient your straightedge and all of our measuring points.

Step One

Lower your infeed table so that it is about 1/4" below your cutterhead. Now raise or lower your outfeed table until you think it is coplanar with the rearmost carbide knife.

I will be following Delta's table alignment procedure as noted in their PDF with one exception: I will not measure between the straightedge and the cutterhead body. I will measure between two points: (1) The straightedge and both of the outermost carbide knives and (2) the outfeed table surface as shown in Graphic 4 above. The measuring points on either side of the table are shown in orange in the same graphic.

Rotate the cutter head so that the rear outermost carbide cutter is visible.

Place your straightedge in Position A as shown in Graphic 4 above. It is a good idea to anchor down the far end of your straightedge to keep it tight against the surface of the table as shown in the next image.

You may be thinking that this is excessive weight, but read on and you will understand why I do this.

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IMAGE 21
This image shows the straightedge over the rearmost carbide knife as noted in Position A of Graphic 4 above.

Now we want to rotate the cutter head so that the carbide knife rotates beneath the straightedge. One of two things is going to happen when you do this: (1) Nothing will happen, or (2) you will hear a scraping sound and the straightedge will try to move or lift up.

If (1) happens, this tells you that the carbide cutter is lower than your table. See Graphic 2C above. To correct this, lower your table very slightly and repeat the process.

If (2) happens, this tells you that the carbide knife is higher than the table. See Graphic 2B above. Raise the table very slightly and repeat the rotation process again. In this case, if your straightedge is not sufficiently weighed down, the rotating knife will drag the straightedge in the direction of rotation. You do not want this to happen because you will spend your time moving your straightedge every time this happens. Thus, the seemingly heavy weights.

Continue repeating these steps until you hear a very slight rubbing sound as the cutter rotates beneath the straightedge.

While this 'audible' method may work, it would be wise to run a 0.004" feeler gauge beneath the straightedge very close to the cutterhead when you hear this scraping. If the feeler gauge slips under the straightedge the table is still too low and must be raised. Again, repeat the process until the feeler gauge will not pass under the straightedge.

(Note. I use a 0.004" feeler gauge because it is very thin yet will not buckle like a 0.002" feeler gauge would when I push it beneath the straightedge.)

Using a Digital Height Gauge To Determine TOC

If you own a digital height tool, this is the perfect time to use it. I use the Digital Height Gauge from Lee Valley. To use this instrument the first thing we need to do is rotate the cutterhead so that it is not touching the straightedge as shown in Image 23 below. Next, push the reading arm down on the straightedge. Press 'Zero' to zero the instrument. Now any vertical motion of the straightedge will be detected and shown on the digital display.

With your instrument zeroed, rotate your cutterhead so that the knife passes completely under the straightedge. Note the change in your digital readout.

If the readout does not change, the table may be too high. If you were able to detect a slight rubbing sound then the table is in alignment with the carbide cutter. If you heard nothing, then it may be best to lower the table slightly and repeat the process.

If the readout increases then the table is too low. (This is preferred over the previous result because you know exactly what the cutter-to-table relationship is.) The readout value will determine your course of action: If you get 0.001" then I'd be very happy with that and leave your table setting as it is. If it is much greater than that then it would be best to raise the table very slightly and repeat the rotational process.

Needless to say, this is a very precise method of aligning your outfeed table. You may opt not to be this precise and that is fine.

Next, rotate the cutterhead so that the carbide knife passes completely under the straightedge.

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IMAGE 24
This image shows the 0.004" feeler gauge in use.

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IMAGE 24
A semi-quilted maple board just passed over the new Shelix cutterhead. I'm happy!

Non-Digital Method

I am assuming here that your infeed and outfeed tables are perfectly aligned as they should be. If not, no matter how carefully you install your knives your results will never match those of a jointer whose tables are on spec.

What I have found is that if all of the set-screws and the cutter head gutter(s) are perfectly clean and free of all debris, the adjustments will go much smoother. Dirty gutters tend to hang the knives which is not what you want. I first blow out all the debris with my air compressor and then clean the gutters with an alcohol soaked cotton-tipped swab. I back off the set screws so the knives are slightly below the outfeed table. I then use a plastic-tipped hammer to gently tap the knives so they are seated against the set screws and then snug the hold-down bolts very slightly. I then use the set screws to raise the knives (measured at the ends only) until both ends read "0.000". This reading guarantees that the knife is now in the same exact plane that the outfeed table is.

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Phasellus imperdiet, risus ut cursus ultrices, augue sem tempus nisl, sit amet euismod leo quam in ipsum. Nam sed est sit amet dui tincidunt suscipit. Integer suscipit, turpis vel dictum cursus, sapien purus porttitor diam, ac facilisis sem augue et risus. Sed in ligula. In semper augue sed nisl. Nunc eget ligula ut magna tempor fringilla. Etiam mi nibh, laoreet ut, rutrum ut, accumsan sed, arcu. Sed eu mauris eget orci dignissim lobortis. Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Nam quam. Nunc venenatis urna eget mi. Praesent placerat. Suspendisse potenti. Sed odio leo, tempus ut, sollicitudin id, vehicula quis, erat. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Phasellus blandit lectus ut risus. Suspendisse massa. Curabitur vulputate, est eu consequat condimentum, risus ligula egestas lacus, in dignissim nisi metus a metus.

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Photo 2. Sharp chisels.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin arcu mi, elementum at, rutrum suscipit, molestie sit amet, sapien. Nullam convallis. Suspendisse sit amet odio. Aliquam vitae ligula non magna sagittis malesuada. Vivamus congue bibendum lorem. Nullam nunc. Maecenas lectus. Donec id dui at purus dapibus rhoncus. Quisque in mi id massa interdum mattis. Suspendisse vel purus eget dui convallis posuere. Sed iaculis egestas neque. Sed turpis purus, congue ut, auctor non, convallis eget, ligula. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Donec vitae tellus. Proin arcu. Morbi tempor. Vivamus congue suscipit arcu.

Phasellus rutrum quam ut nisi. Aliquam ornare. Ut scelerisque feugiat magna. Nullam ipsum mauris, posuere ullamcorper, laoreet et, facilisis in, arcu. Nullam pellentesque commodo orci. Aliquam erat volutpat. Nam tempus turpis mollis tellus. Suspendisse et leo at ante rhoncus condimentum. Vestibulum et elit. Phasellus sed diam. Proin vel justo a lorem semper venenatis. Cras sapien diam, consectetuer sed, consectetuer quis, mollis ut, turpis.

Phasellus imperdiet, risus ut cursus ultrices, augue sem tempus nisl, sit amet euismod leo quam in ipsum. Nam sed est sit amet dui tincidunt suscipit. Integer suscipit, turpis vel dictum cursus, sapien purus porttitor diam, ac facilisis sem augue et risus. Sed in ligula. In semper augue sed nisl. Nunc eget ligula ut magna tempor fringilla. Etiam mi nibh, laoreet ut, rutrum ut, accumsan sed, arcu. Sed eu mauris eget orci dignissim lobortis. Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Nam quam. Nunc venenatis urna eget mi. Praesent placerat. Suspendisse potenti. Sed odio leo, tempus ut, sollicitudin id, vehicula quis, erat. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Phasellus blandit lectus ut risus. Suspendisse massa. Curabitur vulputate, est eu consequat condimentum, risus ligula egestas lacus, in dignissim nisi metus a metus.

END!!!

Final Thoughts

Don't forget about the worn out bearing.