I mentioned in the Shooting Board discussion
that my long plane wasn't quite ready for prime time, so it is time to fix it. My budget won't quite allow for one of those magnificent Lie-Nielsen shooting planes, so I have to settle for a cheap long plane from my local big box store. I don't claim to be an expert on plane truing, so I studied the various videos and blogs out there on how to do it, and dove in myself. I started off with what others recommended, and ended up discovering for myself what worked and what didn't FOR ME. Your mileage may vary.
Here is my long plane on my light box against a straightedge. You can easily see that it is bowed end-to-end. Feeler gauges determined the beginning gap was about 15 thousandths. It is going to get MUCH better before I am done. By the way, I use the same lightbox for candling edges being joined.
Before I get started, time to collect a few supplies:
1. Sandpaper - I got Pro grade wet/dry sandpaper in 100, 220, and 400 grits, about $3 per pack of 4. I ended up using 2 sheets of the 100, and 1 sheet each of the 220 and 400, and have plenty left over for other projects.
2. Sharpie - used to mark the sole of the plane to visualize the progress. You will see what I mean below.
3. Tape to secure the sandpaper. Read on. I gave up on the tape and switched to clamps. Some seem to prefer spray glue instead, but I did not try it.
4. Simple Green cleaner - many how-to videos suggest using this as an eco-friendly way of lubricating the sandpaper. I found it more trouble than it was worth.
It should go without saying that I also needed a very flat surface. The previous owners of my house were kind enough to leave me an offcut of the polished marble backsplash from the kitchen. This is the flatest thing I could come up with easily. Ask at your local counter shop if they have any leftovers.
To start with, take the Sharpie and draw a grid on the bottom of the plane. Don't worry, the grid is going to go away before we are done, but this will let us easily see how the sanding is progressing.
The blade should be locked in position as normal, but retracted just shy of the sole, because the locking mechanism warps the body every so slightly and you want to level in the same configuration as the plane will eventually be used.
Wet sanding with the Simple Green. Although others seem to like it as a lubricant, the tape doesn't like it and comes loose. I also did not care for the smell and finally gave up on it and sanded dry.
After just a couple minutes of sanding, the ends of the grid start disappearing, showing how high the ends were in comparison to the middle.
After a few more minutes, the entire grid is finally disappearing. But I later figured out that the Simple Green was also dissolving the grid.
The sandpaper needs to be cleaned as soon as metal dust starts accumulating, which is like every 30 seconds of sanding. I got tired of constantly washing and reattaching the sandpaper, so I started using clamps, using the paper dry, and this works much better. When the metal dust starts accumulating, I just brush it off and keep going. I should also mention that I reversed the direction of the plane after every cleaning, to help distribute any flatness errors. Most of the grid had disappeared, so it was time for a new grid.
Only one low area still remaining, and it keeps shrinking...
After about a week of a couple minutes every evening, the low spot is almost gone.
I am finally getting close, so one last (hopefully) grid marking.
Flat at last! No more divots or high spots.
It took about a week of a couple minutes per evening with two sheets of the 100 grit, but only a few minutes with each of the 220 and 400 grits, and the plane is getting almost-mirror-like.
A quick tune-up on the blade, and the plane is finally ready for use. There is plenty of information on the scary-sharp method on the internet so I will not elaborate here.
Are you as guilty of me as using the nearest ruler (which is rarely very straight) as a straightedge? If so, do it right! Hold the ruler perpendicular to the stone and sand it the same way you did the planes, and you will end up with a true straightedge.
So a little work has turned a cheap plane into a well-tuned very flat plane and am ready to shoot my next top set. I should point out that some people also sand the sliding side of their plane flat as well, but this is really unnecessary. Even if the side is not exactly perpendicular to the sole, it is a simple matter to move the tilt lever so that the blade is. I hope this inspires some of your to tune up your planes. It is not nearly as difficult as it sounds!