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Revamping my Delta Contractor Saw #6: The First Cut Reveals a Problem

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Blog entry by Mark Colan posted 08-28-2010 03:53 PM 2820 reads 2 times favorited 6 comments Add to Favorites Watch
« Part 5: Assembly Complete! Part 6 of Revamping my Delta Contractor Saw series Part 7: Re-installing the Delta Uniguard »

Completing the Alignment Procedure

I talked about completing the alignment procedure for the right side of the blade last time. Now it’s time for the left side.

Moving the positioner base unit towards that side showed an immediate problem: it gradually got harder to do it. I figured out that the rails must not be parallel, and confirmed it with my tape measure. Note to Incra: add to the instructions that you push the rail all the way into the bracket as you tighten the bolt. Reseting all four rail bolts, pushing firmly on each as I tightened, solved the problem.

Also, since the brackets that slide on the rails were exposed, I decided to make a minor improvement:

Added UHMW tape to a sliding part of the Incra Fence

To allow them to slide a little better, I applied some UHMW tape I had to the sides (it shows as translucent in the picture). I had to trim the tape to avoid blocking the holes. There is already a plastic pad for the main point of contact, the weight-bearing part, but on the sides, it is aluminum to aluminum, and it has to bes a reasonably snug fit if you don’t want the mount to wobble. And you don’t.

I noticed a problem when zeroing the fence to the blade. You’re supposed to use the micro-adjuster to make a fine adjustment, but it seemed to lag – like I had to turn it many times to get it to start to move, and then turn it many times before it would move in the opposite direction. Hmmm. Sounds like a problem? I wish I had done a test cut at this point, but I saved it for later.

Replacing the Extension Table

As I mentioned earlier, I had to remove my extension table to tighten screws on the underside of the base mount. I took some time to attach it again. It is much closer to being level with the metal top than the first time I installed it, years ago, because I used a clamping rig to put it and keep it at the correct height while tightening the bolts.

Extension table clamped in place

Finally, The First Cut! But…

Because of the problem with zeroing the blade, I thought I would try cutting a scrap to exactly 1 inch by the fence guide, then measure it with calipers. They suggest this as an alternate way of zeroing the fence. If it is off, you simply dial in the amount it is off, and reset the scale to make THAT zero.

Yow! Even after a careful blade-zeroing, my calipers said the cut was 1 3/64”! I could do MUCH better than that with my Delta Unifence and eyeballing it! What gives?

This is where I was certain there was a problem, because the microadjust did not change the fence position for a more accurate cut.

Diagnosing the problem

I put the SuperBar gauge into the miter slot, and brought the fence close enough to contact the gauge’s rod.

Testing the Micro-adjust

Then I rotated the microadjust to watch the scale change. IT DIDN’T MOVE, not at all. Yikes. I kept turning the microadjust. Eventually, it started moving, and moved about 1 mil (thousandths of an inch) for each click, like it’s supposed to. Tried the opposite direction. No movement until after about 50 clicks, then consistent movement.

Then it hit me… 50 mils… well, 3/64” was the error in the test scrap, and 3/64” is 47 mils. Perhaps this is not a coincidence.

Next, I locked down the fence, grasped it, and tried to move it. Nope, it’s solidly locked. I partly unlocked to microadjust mode and did it again. It moves. Measuring, I find it can be moved 50-55 mils back and forth. But why? The fence system is impressive, even intimidating, at first glance. But I’m an engineer, so let’s keep going.

I removed the fence carriage from the LS positioner, allowing me to examine the latter closely. The problem is with the microadjusting mechanism, and the red lever must be set to middle position to be in microadjusting mode, so…

The Culprit

I put my finger inside, and touched the silver part (red arrow points to it). It moved! This seems to be the clamp that controls microadjusting.

I removed the screws that hold the windows in place for better access. It was clear that this part wobbles because the two screws that hold it in place have not been tightened. The red arrow above points to the back of one of the screw holes. I the loose screws also explain why sometimes it was hard to insert the carriage into the positioner: this threaded clamp may have been in the way sometimes, and not others, depending on how it wobbles.

Conclusions and Next Steps

I would call this a manufacturing flaw. Obviously these fences are built by hand, and someone just did not tighten it. But it also got by whatever quality control they have.

The screws to tighten it are inaccessible without disassembling the critical LS Positioner. There are four screws holding a bracket that holds the microadjust clamp into place, but they are tightened VERY firmly, and since there are four, I assume that this part is adjusted critically, probably using a jig that I don’t have.

So I’m not going to mess with it. If this was an old tool from a company that is out of business, I’d fix it myself as best as I could. But given that I paid a lot of money for a brand-new tool, I’ll ask them to send me a replacement, or to walk me through the fix if that can be done by me.

This is extremely disappointing. I was really looking forward to using it this weekend. I even had a bad dream about it not working last night, and spent some insomniac time wondering what was wrong. Well, at least now I know what’s wrong. And I’ll spend the weekend doing other tasks that I have been putting off in my excitement to get this fence going.

-- Mark, hack amateur woodworker, Medford (greater Boston) MA



6 comments so far

View Toolz's profile

Toolz

1004 posts in 3207 days


#1 posted 08-28-2010 04:13 PM

For the amount of $$$ you had to pay for one of these I certainly hope the INCRA support folks either replace or walk you through corrective procedures.

-- Larry "Work like a Captain but Play like a Pirate!"

View RonPeters's profile

RonPeters

713 posts in 2345 days


#2 posted 08-28-2010 11:14 PM

No kidding!

Very accurate explanation of the install! Great pictures too. Thanks.

”...spent some insomniac time wondering….” Is THAT what they call it?! ;-)

Learn something new every day!

-- “Once more unto the breach, dear friends...” Henry V - Act III, Scene I

View Mark Colan's profile

Mark Colan

209 posts in 2310 days


#3 posted 08-29-2010 12:20 AM

@Toolz: I am totally confident they will.

@RonPeters: I don’t know what THEY call it. Saying I was losing sleep over it would be overstated. More like during the time I couldn’t sleep anyway, at dawn, it was on my mind enough that I went down to read the manual to look for clues. Glad you have enjoyed this series! There’s more coming, of course.

-- Mark, hack amateur woodworker, Medford (greater Boston) MA

View PurpLev's profile

PurpLev

8523 posts in 3113 days


#4 posted 08-29-2010 03:59 AM

hmm.. sorry to hear you are having this issue. Incra support and Incra in genaral are top notch and friendly people, I am 100% positive you’ll get the best service and support one can get. Even the best of us have a bad day.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View MattMcC's profile

MattMcC

27 posts in 2475 days


#5 posted 09-04-2010 03:02 PM

Thanks for this Blog. I just ordered the Incra TS-LS with the wonderfence as a I have a router table as a left side extension on my saw. It appears I will need to take both that extension and the cast iron extension on the right side of teh saw off when I mount this thing. Bummer. I hope I don’t encounter the same QC problem you had. I have also been dreaming about using this fence system, particularly for the router applications. I hope I can get by the learning curve quickly.

View Mark Colan's profile

Mark Colan

209 posts in 2310 days


#6 posted 09-04-2010 11:17 PM

@Matt: I had to remove my right-side extension table because it went 32 inches, and thus made the underside of the positioner base inaccessible. If your cast-iron fence is less than say 24 inches, try leaving it on while you install; you will find out soon whether you need to remove it. And the left-router table should be ok as is. Please let me know how it goes.

-- Mark, hack amateur woodworker, Medford (greater Boston) MA

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