Sunday, January 17th, 2010
10:10 pm - In Which I Am an Idiot... Twice...  
So, I started coming down with a cold last Saturday, which by Sunday was full blown and nasty, so further work on the bench got postponed. I managed not to miss any days at work, but I was miserable all week, even more so than when I had the flu in November. The symptoms finally started easing Friday, so yesterday I finally felt good enough to head back down into the basement. It was also mild outside, almost into the fifties, so it wasn't quite so cold down there, definitely good news.

I still needed to cut the panel profile into the ends of the rails for the cupboard door. Last time I tried the tenoning jig was giving me grief when I tried to fit it into the miter slot of the table saw. I wound up fixing that with the judicious application of a grinding wheel and a file to one edge of the jig's runner, basically shaving off a little bit of metal to make it fit properly. It worked (and given how badly everything else I touched down there this weekend turned out, apparently that was unexpectedly fortunate).

Now it was just a matter of clamping the rails in the jig and cutting the profile into the ends. Shaping end grain is tricky. The wood wants to splinter rather than coming off as nice shavings as it does when you shape with the grain. This is especially true when the cutter comes out the back end of the cut. It tends to take a good sized chunk of the back of the piece with it. To prevent this I clamped a second, sacrificial piece behind the actual piece, which provides support to keep those chunks from ripping out.*

* This is fairly simple when the back end is flat. It's a little trickier when the back side of the piece has the door panel profile already cut into it, and each rail gets one easy pass with the flat end back, and one tougher one with the profile facing back. Then you have to cut the corresponding profile into the sacrificial backer and interlock them to get the necessary support.

All seemed to be going fine at first. To cut down on potential problems, I did the cut in several shallow passes, raising the cutter a 32nd of an inch at a time to cut a 1/4" deep profile. I did the easy ends first, and it seemed to be working well. Then I did the cuts with the profile in back. I tried a test piece first, and that seemed to go well, too, but when I tried dry fitting it to one of the stiles, I noticed that they weren't coming together at a 90° angle like they were supposed to. I took a look at the end of the rail, and the cut was slanted at a shallow angle rather than parallel to the end of the wood. I took a quick look at the other end of the rails, and they were slightly slanted, too. Huh.

I figured that I probably hadn't clamped the pieces to the jig tightly enough, and that it had been pushed slightly up and back by the cutters as I pushed them through. No problem. Just run them through with more clamps. I also checked each rail with a level to make sure it was perfectly vertical before pass. Finished the cut on another test piece and took a look. Still slanted. WTF?!?

Turns out the base of my cheapo, but not inexpensive, tenoning jig is not perfectly flat, so that when I leaned into the cut as I was pushing the jig past the cutter, the rear of the jig was lifting off the table. That's where the slant came from. All I had to do to fix it was to do a second pass at the end of the process with my weight on the back of the frelling thing to even out the cut. An easy fix, but annoying as heck. Will be interviewing new candidates for the tenoning jig position in my workshop when time allows.

So, with all the profiles cut it was time to dry fit the frame together, so to double check the fit, and to recheck the size of the plywood panel that the door frame will hold. I laid the four pieces down flat on a table, pressed them together, and looked at my handiwork. And then looked again. And then again, because although I couldn't put my finger on it, something looked out of proportion. I got one of the drawer fronts I'd made a couple of weeks ago, and laid it on top of the frame. Now I'd measured the drawer fronts quite carefully, and checked them all once they were done. They each overlapped the opening each was to cover by an even quarter of an inch all the way around. The drawer front overlapped each side of the frame by a half an inch! I'd cut the rails an inch too short.

I have to admit, I got pretty creative with the profanity at that point. Then I checked the calculations in my notes. The door needs to be 16" wide. Each stile is and 1½" wide, so subtract 3", then add back a quarter of an inch for the tenon at each end of the rail that fits in the profile on the stile (which is what all the business above was about). Each rail needs to be 13½" The stop block was still in place on the radial ram saw from when I'd cut them. It was set for 12½". More profanity. Having spent several hours working on them already, I decided it was time to veg out in front of the computer.

After I calmed down some, I reasoned there was nothing for it but to cut two new rails. I'd already used up the 8' piece of maple I'd bought for the task (there were some issues with the first set of stiles I'd cut), so I got into the car and headed over to Lowe's to buy some more.
And then I called it a day as far as woodworking was concerned.

This morning I was back at it. I cut the edge profile, then cut the rails to length, making absolutely sure that the stop block was set at 13½". Set a test piece into the tenoning jig and ran it through the molding head, going through the whole rigamarole I'd developed to keep the cut nice and even, and was rewarded with a perfect cut... Of the wrong profile. I'd forgotten to switch out the cutters to the matching profile. No problem, that's what test pieces are for. I disassembled the molding head, swapped in the other set of cutters and ran another test piece through.

It came out shredded. It was the right depth, but the tenon was malformed, like it had been chunked out. Now by this time I'd run a lot of test pieces, and this one had cuts in the front, back, and sides, so I figured all the other cuts were responsible. I double checked the positioning of the head, and it was correct. The good side of the tenon was at the right depth from the side. I figured it was just bad wood. So rather than running another test piece, I ran one of my new, properly-sized rails... And got the exact same shredded profile as the test piece.

This could not possibly be a coincidence. It took me a couple of minutes to figure out what it had to be, and then only a second to confirm. I'd installed one of the cutters into the molding head backwards. There was some seriously inventive profanity at this point.

The molding head is a big heavy slab of steel that you clamp a set of three identical cutters into. The cutters have groove on the back, and there is an arrow on the head at each clamp showing the moron inserting them (that would be me) which way the groove should point. It becomes automatic, until you install one of them with the groove pointing the wrong way. Then, every time the first two cutters cut the proper profile, the third cutter bludgeons*** a mirror image of the profile over the original cut.

*** The edge of the reversed cutter is pointing the wrong way to actually cut anything. It's more like smashing the previously cut profile with a very oddly shaped hammer. That's why my test piece had been so splintery looking. It was right there in front of me. Sigh.

Yet another rail ruined. I had some more maple left from yesterday's purchase, so I cut another rail to length. I pulled out the molding head and turned the backwards cutter around the face the right way, and ran yet another test piece.**** That worked, so with great trepidation I started in on the rails again. Some time and rigamarole later, they were done, and once again I tried dry fitting stuff together. And this time the door was 16" wide.

**** No big deal at this point. I seem to have plenty of scrap maple hanging around for some reason.

And then I decided that cleaning the back room and doing some laundry would probably be more fun than I was having, so that's what I did.

 
 
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hackerguitarhackerguitar on January 19th, 2010 - 07:26 pm
Been there, done that, with the molding cutter. Utterly frustrating, and a reminder to be exceptionally careful around blades spinning at almost 4000 RPMs when you're in less than good form.

I'm in the midst of starting anew piece for friends -- they don't know yet, it's a gift ;-) - and was making rails for the piece from some nice local cherry. I noted that the initial cut for the panel slot had gone wide (a bit) and checked the saw, and found out that I hadn't tightened the fence - I was lucky the part wasn't damaged beyond repair, let alone that it didn't throw the piece back at me.

It happens to us all. We get better at it....remember, the best artisans live to be 90 and are often doing some of their best work at that age.

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