March 21, 2010

When things go wrong

I was on a roll, milling stock for drawers, when disaster struck. No matter what I tried, I was getting awful tearout on the maple. I had never experienced anything like it; time to sit down for a bit, take one deep breath, and plot a plan of attack:

  • Is there much variation from board to board that some planed well, and now they weren’t?
  • How is the grain running?
  • Am I getting distracted, and in the process reversing the feed direction, and causing the tearout?
  • Should I try a hand plane, and see how the boards behave vs. the planer?
  • Have I looked at the planer itself? Blades, speeds, spider webs, gremlins, what else?
  • Should I …

The following photo shows what I was dealing with – tearout like I had never, ever, experienced <gulp!…>:

tearout

On edge, many of the maple boards showed this kind of change in grain direction – but the DW735 had handled it beautifully, until now! Photo showing change in grain direction on the edge:

grain-direction-change

Down the checklist I went. A Stanley # 4-1/2 hand plane handled the grain beautifully. Now what? Blades!  Look at the blades on the planer, dummy! In almost 5 years, I had never (ever!) changed the blades. On this planer, the blades are double-edged, and can be rotated. It took exactly 15 minutes to rotate the three blades (each was secured with 8 machine screws). Indexing pins on the blade turret made the job a snap, as nothing more is required to set the blades properly.

Problem solved! The first board off the planer looked like this:

after-planer-blade-change

The moral of the story: If you are going along fine, and everything hits the proverbial fan, something has changed. Time to find the root cause!

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—— Al Navas

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I almost missed it – buy a Leigh FMT by July 31, and get 27 FMT guides and bits FREE!

This happens maybe once a year – it is a truly terrific buy. I apologize for (almost) missing this special offer from Leigh altogether. If you follow my blog, you know I love my FMT. Shortly I will be posting about some recent work I have been doing with this wonderful tool, in addition to the Related Posts below.

Please visit the Leigh Industries Specials page for all the details on this deal. And thanks for supporting Leigh – they are one the sponsors of my blog.

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Related posts: Leigh FMT posts on this blog.

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Time to replace the blade on the table saw

The findings I report here are based on totally empirical, non-scientific “tests”. I am sure others would have conducted better tests to arrive at the same conclusions; I just could not afford to spend too much time troubleshooting the burning I saw on my cuts.

I have had the Woodworker II on the table saw for most of the last 4-1/2 years. Although the blade still cuts smoothly, recently it started burning the wood a little. This was especially evident when cutting 3-inch glued-up quarter-sawn white oak (QSWO) table legs:

Woodworker II blade

I cleaned the blade regularly; but this time I had a hunch it needed to go beyond another cleaning. I checked alignment on the table saw, without finding anything out of the ordinary. The blade was parallel to the miter slot; and the blade was also parallel to the fence.

To keep from wasting too much time, I decided to install a brand-new blade. As luck would have it, I had received the Cabinetmaker blade from Sommerfeld Tools 24 hours earlier. I installed it, and proceeded to make some test cuts. The first thing I noticed was noticeably less effort in pushing the 3-inch leg stock through the blade. Second, the cut was perfectly smooth, with no burning anywhere:

Cabinetmaker

To my amazement, it took much less effort to make the cut with the new blade. An Aha! moment.

I immediately realized that the Woodworker II needed its first sharpening. As a result, the Cabinetmaker will stay on the table saw, until it needs cleaning and/or sharpening. And, instead of wasting time on another cleaning, I resumed work immediately. Only about 15 minutes wasted, instead of an hour or two.

If, like me, you:

  1. Have a clean blade, plus
  2. Your blade has been in use on the saw for some time, and also
  3. Everything is properly aligned on the table saw, but
  4. Are experiencing either a little burning on your cuts, or
  5. It “feels” as if you are having to push through the cut a little harder,

Then you probably need to have your blade sharpened. My Forrest Woodworker II is (finally!) being sharpened this weekend.

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